Article

The “Vertical Response Time”: Barriers to Ambulance Response in an Urban Area

October 2007
Academic Emergency Medicine 14(9):772-8

DOI:10.1197/j.aem.2007.04.016

Source
PubMed

Authors:

Robert K Silverman

SUNY Upstate Medical University

Sandro Galea

Boston University

John Freese

Frisbie Memorial Hospital

Show all 11 authorsHide

Ambulance response time is typically reported as the time interval from call dispatch to arrival on-scene. However, the often unmeasured "vertical response time" from arrival on-scene to arrival at the patient's side may be substantial, particularly in urban areas with high-rise buildings or other barriers to access. To measure the time interval from arrival on-scene to the patient in a large metropolitan area and to identify barriers to emergency medical services arrival. This was a prospective observational study of response times for high-priority call types in the New York City 9-1-1 emergency medical services system. Research assistants riding with paramedics enrolled a convenience sample of calls between 2001 and 2003. A total of 449 paramedic calls were included, with a median time from call dispatch to arrival on-scene of 5.2 minutes. The median on-scene to patient arrival interval was 2.1 minutes, leading to an actual response interval (dispatch to patient) of 7.6 minutes. The median on-scene to patient interval was 2.8 minutes for residential buildings, 2.7 minutes for office complexes, 1.3 minutes for private homes (less than four stories), and 0.5 minutes for outdoor calls. Overall, for all calls, the on-scene to patient interval accounted for 28% of the actual response interval. When an on-scene escort provided assistance in locating and reaching the patient, the on-scene to patient interval decreased from 2.3 to 1.9 minutes. The total dispatch to patient arrival interval was less than 4 minutes in 8.7%, less than 6 minutes in 28.5%, and less than 8 minutes in 55.7% of calls. The time from arrival on-scene to the patient's side is an important component of overall response time in large urban areas, particularly in multistory buildings.

Cardiac Arrest Occurring in High-Rise Buildings: A Scoping Review

Article

Full-text available

Jan 2021

Out-of-hospital cardiac arrests (OHCAs) occurring in high-rise buildings are a challenge to Emergency Medical Services (EMS). Contemporary EMS guidelines lack specific recommendations for systems and practitioners regarding the approach to these patients. This scoping review aimed to map the body of literature pertaining to OHCAs in high-rise settings in order to clarify concepts and understanding and to identify knowledge gaps. Databases were searched from inception through to 6 May 2021 including OVID Medline, PubMed, Embase, CINAHL, and Scopus. Twenty-three articles were reviewed, comprising 8 manikin trials, 14 observational studies, and 1 mathematical modelling study. High-rise settings commonly have lower availability of bystanders and automatic external defibrillators (AEDs), while height constraints often lead to delays in EMS interventions and suboptimal cardiopulmonary resuscitation (CPR), scene access, and extrication. Four studies found return of spontaneous circulation (ROSC) rates to be significantly poorer, while seven studies found rates of survival-to-hospital discharge (n = 3) and neurologically favourable survival (n = 4) to be significantly lower in multistorey settings. Mechanical chest compression devices, transfer sheets, and strategic defibrillator placement were suggested as approaches to high-rise OHCA management. A shift to maximising on-scene treatment time, along with bundling novel prehospital interventions, could ameliorate some of these difficulties and improve clinical outcomes for patients.

High-rise residential resuscitation: Scaling the challenge

Article

Jan 2016

The Influence of Cardiac Arrest Floor-Level Location within a Building on Survival Outcomes

Article

Full-text available

Aug 2023

This nationwide, population-based observational study investigated the association between the floor level of out-of-hospital cardiac arrest (OHCA) incidence and survival outcomes in South Korea, notable for its significant high-rise apartment living. Data were collected retrospectively from OHCA patients through the South Korean Out-of-Hospital Cardiac Arrest Surveillance database. The study incorporated cases that included the OHCA’s building floor information. The primary outcome assessed was survival to discharge, analyzed using multivariate logistic regression, and the secondary outcome was favorable neurological outcome. Among 36,977 patients, a total of 29,729 patients were included, and 1680 patients were survivors. A weak yet significant correlation between floor level and hospital arrival time was observed. Interestingly, elevated survival rates were noted among patients from higher floors despite extended emergency medical service response times. Multivariate analysis identified age, witnessed OHCA, shockable rhythm, and prehospital return of spontaneous circulation (ROSC) as primary determinants of survival to discharge. The floor level’s impact on survival was less substantial than anticipated, suggesting residential emergency response enhancements should prioritize witness interventions, shockable rhythm management, and prehospital ROSC rates. The study underscores the importance of bespoke emergency response strategies in high-rise buildings, particularly in urban areas, and the potential of digital technologies to optimize response times and survival outcomes.

Estimation of Health and Economic Benefits of a Small Automatic External Defibrillator for Rapid Treatment of Sudden Cardiac Arrest (SMART): A Cost-Effectiveness Analysis

Article

Full-text available

Feb 2022

Background Sudden cardiac arrest (SCA) occurs in 0.4% of the general population and up to 6% or more of at-risk groups each year. Early CPR and defibrillation improves SCA outcomes but access to automatic external defibrillators (AEDs) remains limited. Methods Markov models were used to evaluate the cost-effectiveness of a portable SMART (SMall AED for Rapid Treatment of SCA) approach to early SCA management over a life-time horizon in at-risk and not at-risk populations. Simulated patients ( n = 600,000) who had not received an implantable cardioverter defibrillator (ICD) were randomized to a SMART device with CPR prompts or non-SMART approaches. Annual SCA risk was varied from 0.2 to 3.5%. Analysis was performed in a US economy from both societal (SP) and healthcare (HP) perspectives to evaluate the number of SCA fatalities prevented by SMART, and SMART cost-effectiveness at a threshold of

100,000/Quality Adjusted Life Year (QALY). Results A SMART approach was cost-effective when annual SCA risk exceeded 1.51% (SP) and 1.62% (HP). The incremental cost-effectiveness ratios (ICER) were

95,251/QALY (SP) and

100,797/QALY (HP) at a 1.60% SCA annual risk. At a 3.5% annual SCA risk, SMART was highly cost-effective from both SP and HP [ICER:

53,925/QALY (SP), $59,672/QALY (HP)]. In microsimulation, SMART prevented 1,762 fatalities across risk strata (1.59% fatality relative risk reduction across groups). From a population perspective, SMART could prevent at least 109,839 SCA deaths in persons 45 years and older in the United States. Conclusions and Relevance A SMART approach to SCA prophylaxis prevents fatalities and is cost-effective in patients at elevated SCA risk. The availability of a smart-phone enabled pocket-sized AED with CPR prompts has the potential to greatly improve population health and economic outcomes.

Preserving Geo-Indistinguishability of the Emergency Scene to Predict Ambulance Response Time

Article

Full-text available

Aug 2021

Emergency medical services (EMS) provide crucial emergency assistance and ambulatory services. One key measurement of EMS’s quality of service is their ambulances’ response time (ART), which generally refers to the period between EMS notification and the moment an ambulance arrives on the scene. Due to many victims requiring care within adequate time (e.g., cardiac arrest), improving ARTs is vital. This paper proposes to predict ARTs using machine-learning (ML) techniques, which could be used as a decision-support system by EMS to allow a dynamic selection of ambulance dispatch centers. However, one well-known predictor of ART is the location of the emergency (e.g., if it is urban or rural areas), which is sensitive data because it can reveal who received care and for which reason. Thus, we considered the ‘input perturbation’ setting in the privacy-preserving ML literature, which allows EMS to sanitize each location data independently and, hence, ML models are trained only with sanitized data. In this paper, geo-indistinguishability was applied to sanitize each emergency location data, which is a state-of-the-art formal notion based on differential privacy. To validate our proposals, we used retrospective data of an EMS in France, namely Departmental Fire and Rescue Service of Doubs, and publicly available data (e.g., weather and traffic data). As shown in the results, the sanitization of location data and the perturbation of its associated features (e.g., city, distance) had no considerable impact on predicting ARTs. With these findings, EMSs may prefer using and/or sharing sanitized datasets to avoid possible data leakages, membership inference attacks, or data reconstructions, for example.

Factors affecting the activation and reaction times of the emergency medical care

Article

Full-text available

Jan 2018

Snežana Bogunović

Introduction: The chain of events that leads to the intervention of the Emergency Medical Aid team at the site of the incident has four links: (1) reporting the incident, (2) registering the call for intervention, (3) dispatching the vehicle and (4) emergency medical team intervention. Objective: to identify some of the elements that can affect activation and reaction time. Methods: The research has been designed as a prospective study with the sample of immediate priority calls for medical intervention in Belgrade between January 1st 2011 and December 31st 2011. For each call, the activation and reaction times were measured. Results: The mean activation time for 2011 is 1,54±2,25 minutes (median 0,83, IKO (0,33; 1,83) min.). The mean reaction time for 2011 is 9,07±6,05 minutes (median 7,85, IKO (4,88; 11,87) min.). Discussion: The mean activation time for interventions in a public place is 0.73 minutes shorter than for interventions in the patient's place of residence. Interventions in suburbia are expected to have a longer reaction time than those downtown. Conclusion: The activation time analysis shows that the activation time is significantly shorter when the intervention is in a public place. It takes longer for teams to arrive to the patient's place of residence or to a suburban setting.

Exploratory analysis of real personal emergency response call conversations: considerations for personal emergency response spoken dialogue systems

Article

Full-text available

Nov 2016
J NEUROENG REHABIL

Background: The purpose of this study was to derive data from real, recorded, personal emergency response call conversations to help improve the artificial intelligence and decision making capability of a spoken dialogue system in a smart personal emergency response system. The main study objectives were to: develop a model of personal emergency response; determine categories for the model's features; identify and calculate measures from call conversations (verbal ability, conversational structure, timing); and examine conversational patterns and relationships between measures and model features applicable for improving the system's ability to automatically identify call model categories and predict a target response. Methods: This study was exploratory and used mixed methods. Personal emergency response calls were pre-classified according to call model categories identified qualitatively from response call transcripts. The relationships between six verbal ability measures, three conversational structure measures, two timing measures and three independent factors: caller type, risk level, and speaker type, were examined statistically. Results: Emergency medical response services were the preferred response for the majority of medium and high risk calls for both caller types. Older adult callers mainly requested non-emergency medical service responders during medium risk situations. By measuring the number of spoken words-per-minute and turn-length-in-words for the first spoken utterance of a call, older adult and care provider callers could be identified with moderate accuracy. Average call taker response time was calculated using the number-of-speaker-turns and time-in-seconds measures. Care providers and older adults used different conversational strategies when responding to call takers. The words 'ambulance' and 'paramedic' may hold different latent connotations for different callers. Conclusions: The data derived from the real personal emergency response recordings may help a spoken dialogue system classify incoming calls by caller type with moderate probability shortly after the initial caller utterance. Knowing the caller type, the target response for the call may be predicted with some degree of probability and the output dialogue could be tailored to this caller type. The average call taker response time measured from real calls may be used to limit the conversation length in a spoken dialogue system before defaulting to a live call taker.

Khảo sát tuân thủ điều trị trên bệnh nhân đái tháo đường típ 2 điều trị ngoại trú tại bệnh viện Thống Nhất

Article

Nov 2024

Đặt vấn đề: Cấp cứu ngoài bệnh viện là một hoạt động từ khi nhận được thông tin cấp cứu cho đến khi vận chuyển người bệnh tới bệnh viện. Mạng lưới cấp cứu ngoài bệnh viện tại Thành phố Hồ Chí Minh gồm một Trung tâm Cấp cứu 115 và 34 trạm vệ tinh. Chưa có nhiều nghiên cứu các đặc điểm về cuộc gọi yêu cầu cấp cứu và trường hợp thực hiện cấp cứu ngoài bệnh viện tại Thành phố Hồ Chí Minh (TPHCM). Mục tiêu: Xác định đặc điểm các trường hợp cấp cứu ngoại viện của người dân tại TP.HCM từ năm 2014 đến năm 2020 và dự đoán nhu cầu cấp cứu của người dân TP.HCM từ năm 2021 đến năm 2025. Đối tượng và phương pháp nghiên cứu: Nghiên cứu hồi cứu và phân tích chuỗi thời gian, thu thập số liệu từ tháng 01/2014 đến tháng 12/2020. Toàn bộ các trường hợp yêu cầu cấp cứu của người dân trong giai đoạn này thu thập từ số “Tiếp nhận và điều phối cấp cứu cấp cứu” của Tổng đài 115 được đưa vào phân tích. Nghiên cứu thu thập các biến số về lý do gọi cấp cứu (gồm 33 lý do) và các biến số về thời gian kích hoạt cấp cứu, thời gian tiếp cận hiện trường. Dự báo nhu cầu cấp cứu của người dân theo ngày từ năm 2021-2025 được thực hiện bằng mô hình ARIMA và so sánh với mô hình Exponential Smoothing thông qua quan sát và các chỉ số thống kê (AICc, MAPE, MRSE). Kết quả: Có 128.208 trường hợp thực hiện cấp cứu, trong đó bệnh nhân nam giới chiếm 52,8%, có đến 69,1% là người trên 50 tuổi, chủ yếu (70%) vào khung giờ từ 8-23 giờ, các quận trung tâm Thành phố có cuộc gọi cấp cứu lớn hơn các quận, huyện ngoại thành. Có 5 lý do yêu cầu cấp cứu phổ biến nhất phân loại theo hệ thống điều phối ưu tiên là: tai nạn giao thông (20,3%), rối loạn tri giác (13,4%), khó thở (13%), té ngã (7,8%), và cuộc gọi triệu chứng (7,8%). Ngưng tim và đột quỵ lần lượt là 0,85% và 4%. Khoảng thời gian kích hoạt cấp cứu và thời gian tiếp cận hiện trường (TB±ĐLC) lần lượt là 2,7±1,7 phút và 15,9±6,9 phút. Sử dụng mô hình SARIMA để dự đoán trung bình trường hợp cấp cứu theo ngày (KTC 95%) của các năm 2021 là 93 (76-112); 2022 là 103 (73-133); 2023 là 113 (71-154); 2024 là 122(70-171); 2025 là 132 (69-195) trường hợp/ngày. Kết luận: Trường hợp cấp cứu được thực hiện chủ yếu người trên 50 tuổi, và khung giờ 8-23 giờ, năm lý do cấp cứu ngoại viện nhiều nhất là tai nạn giao thông, rối loạn tri giác, khó thở, té ngã, và cuộc gọi triệu chứng. Số trường hợp yêu cầu cấp cứu được dự báo là tăng theo từng năm. Từ khoá: cấp cứu ngoài bệnh viện; cấp cứu trước viện; đặc điểm; dự báo nhu cầu cấp cứu; SARIMA

Effect of location on out-of-hospital cardiac arrests involving older adults in Hong Kong: secondary analysis of a territory-wide cohort

Article

Mar 2023

Ronald TM Wong

Introduction: Most out-of-hospital cardiac arrests in Hong Kong involve older adults. The likelihood of survival varies among locations. This study investigated patient and bystander characteristics, as well as the timing of interventions, that affect the prevalences of shockable rhythm and survival outcomes among cardiac arrests involving older adults in homes, on streets, and in other public places. Methods: This secondary analysis of a territory-wide historical cohort used data collected by the Fire Services Department of Hong Kong from 1 August 2012 to 31 July 2013. Results: Bystander cardiopulmonary resuscitation was primarily performed by relatives in homes but not in non-residential locations. The intervals in terms of receipt of emergency medical services (EMS) call, initiation of bystander cardiopulmonary resuscitation, and receipt of defibrillation were longer for cardiac arrests that occurred in homes. The median interval for EMS to reach patients was 3 minutes longer in homes than on streets (P<0.001). Forty-seven percent of patients who developed cardiac arrest on streets had a shockable rhythm within the first 5 minutes after receipt of EMS call. Defibrillation within 15 minutes after receipt of EMS call was an independent predictor of 30-day survival (odds ratio=4.07; P=0.02). Fifty percent of patients who received defibrillation within 5 minutes in non-residential locations survived. Conclusion: There were significant location-related differences in patient and bystander characteristics, interventions, and outcomes among cardiac arrests involving older adults. A large proportion of patients had a shockable rhythm in the early period after cardiac arrest. Good survival outcomes in out-of-hospital cardiac arrests involving older adults can be achieved through early bystander defibrillation and intervention.

Production of categorical data verifying differential privacy : conception and applications to machine learning

Thesis

Full-text available

Jan 2022

Héber H. Arcolezi

Private and public organizations regularly collect and analyze digitalized data about their associates, volunteers, clients, etc. However, because most personal data are sensitive, there is a key challenge in designing privacy-preserving systems to comply with data privacy laws, e.g., the General Data Protection Regulation. Differential privacy (DP) is a formal definition that allows quantifying the privacy-utility trade-off. With the local DP (LDP) model, users can sanitize their data locally before transmitting it to the server.The objective of this thesis is thus two-fold: O1) To improve the utility and privacy of LDP protocols for frequency estimation, which is fundamental to statistical learning. And O2) To propose privacy-preserving systems for data mining tasks with DP guarantees.For O1, we first tackled the problem from two multiple perspectives, i.e., multiple attributes and multiple collections throughout time (longitudinal studies), while focusing on utility. Secondly, we focused our attention on the multiple attributes aspect only, in which we proposed a solution focusing on privacy while preserving utility. In both cases, we demonstrate through analytical and experimental validations the advantages of our proposed solutions over state-of-the-art protocols.For O2, we proposed systems based on machine learning (ML) to solve real-world problems while ensuring DP guarantees. Indeed, we mainly used the input data perturbation setting from the privacy-preserving data mining literature. This is the situation in which the whole dataset is perturbed independently and, thus, we implemented LDP algorithms from the perspective of the centralized data owner. In all cases, we concluded that differentially private ML models achieve nearly the same performance as non-private ones.

Assessment of Ambulance Response Time: A Study of Tabriz Emergency Medical Center, Tabriz City, Iran

Article

Full-text available

Apr 2022

Background: The emergency medical services system has a vital role in the timely treatment of victims and the reduction of injury and mortality rates. Ambulance response time is an essential variable in evaluating the quality of its services. The aim of this study was to determine the ambulance response time and to compare it according to background variables. Materials & Methods: This descriptive study was conducted on ambulance emergency missions in Tabriz Emergency Medical Center. The data file related to the eligible missions in the server of the center was read and listened and ambulance response time and background variables were extracted and analyzed using descriptive statistics. Results: The average ambulance response time was 11.58 (5.69) minutes and was long. The results showed there is a statistically significant relationship between ambulance response time and ambulance technical readiness, traffic conditions, accident time, and the educational level of ambulance personnel. Conclusion: Compared to the standard value, the average ambulance response time in Tabriz Emergency Medical Center was longer. By recognizing the effective variables and taking the required actions, one can improve the ambulance response time and facilitate the medical services providing process in emergency conditions.

Use of discrete event simulation and genetic algorithms to estimate the necessary resources to respond in a timely manner in the Medical Emergency System in Bogotá

Article

Full-text available

Apr 2022

Introduction: Bogotá has a Medical Emergency System of public and private ambulances that respond to health incidents. However, its sufficiency in quantity, type and location of the resources demanded is not known. Objective: Based on the data from the Medical Emergency System of Bogotá, Colombia, we first sought to characterize the prehospital re- sponse in cardiac arrest and determine with the model which is the least number of resources necessary to respond within eight minutes, taking into account their location, number, and type. Methods: A database of incidents reported in administrative records of the district health authority of Bogotá (2014 to 2017) was obtained. Based on this information, a hybrid model based on discrete event simulation and genetic algorithms was designed to establish the amount, type and geographic location of resources according to the frequencies and typology of the events. Results: From the database, Bogotá presented 938 671 ambulances dispatches in the period. 47.4% high priority, 18.9% medium and 33.74% low. 92% of these corresponded to 15 of 43 medical emergency codes. The response times recorded were longer than expected, especially in out-of-hospital cardiac arrest (median 19 minutes). In the proposed model, the best scenario required at least 281 ambulances, medicalized and basic in a 3:1 ratio, respectively, to respond in adequate time. Conclusions: Results suggest the need for an increase in the resources that respond to these incidents to bring these response times to the needs of our population.

Production of Categorical Data Verifying Differential Privacy: Conception and Applications to Machine Learning

Preprint

Full-text available

Apr 2022

Héber H. Arcolezi

_1

) To improve the utility and privacy in multiple frequency estimates under LDP guarantees, which is fundamental to statistical learning. And O

_2

) To assess the privacy-utility trade-off of machine learning (ML) models trained over differentially private data. For O

_1

, we first tackled the problem from two "multiple" perspectives, i.e., multiple attributes and multiple collections throughout time, while focusing on utility. Secondly, we focused our attention on the multiple attributes aspect only, in which we proposed a solution focusing on privacy while preserving utility. In both cases, we demonstrate through analytical and experimental validations the advantages of our proposed solutions over state-of-the-art LDP protocols. For O

_2

, we empirically evaluated ML-based solutions designed to solve real-world problems while ensuring DP guarantees. Indeed, we mainly used the input data perturbation setting from the privacy-preserving ML literature. This is the situation in which the whole dataset is sanitized independently and, thus, we implemented LDP algorithms from the perspective of the centralized data owner. In all cases, we concluded that differentially private ML models achieve nearly the same utility metrics as non-private ones.

Rationale, development and implementation of the ReACanROC registry for out-of-hospital cardiac arrests in France and Canada

Article

Jun 2021

France and Canada prehospital systems and care delivery in out-of-hospital cardiac arrests (OHCAs) show substantial differences. This article aims to describe the rationale, design, implementation and expected research implications of the international, population-based, France-Canada registry for OHCAs, namely ReACanROC, which is built from the merging of two nation-wide, population-based, Utstein-style prospectively implemented registries for OHCAs attended to by emergency medical services. Under the supervision of an international steering committee and research network, the ReACanROC dataset will be used to run in-depth analyses on the differences in organisational, practical and geographic predictors of survival after OHCA between France and Canada. ReACanROC is the first Europe-North America registry ever created to meet this goal. To date, it covers close to 80 million people over the two countries, and includes approximately 200 000 cases over a 10-year period.

Self-reported incidence of verbal and physical violence against emergency medical services personnel in Singapore

Article

Sep 2020

Background: Western studies have highlighted alarmingly high rates of work-related violence experienced by emergency medical services (EMS) staff. As there is a paucity of Asian studies, we aimed to investigate the incidence of physical and verbal violence against the EMS crew in the Singapore Civil Defence Force (SCDF). Methods: This was a cross-sectional study, utilising an online survey made available to all active paramedics in the SCDF. Paramedics with at least one year of work experience were eligible to participate. All responses were kept anonymous. Results: The response rate was 50.9% (n = 246), out of 483 paramedics in service at the time of the study. The respondents consisted of 144 males (58.5%) and 102 females (41.5%). They were between 18 and 55years old; 160 (65.0%) of them had worked in EMS for less than 6 years. The paramedics experienced high levels of verbal and physical violence, but there was reticence in reporting these incidents. The main risk factor for violence appeared to be alcohol intoxication. Conclusions: Paramedics may benefit from security escort for clients with history of alcohol intoxication or violence and more teaching on self-defense and soft restraints. Current training and protocols should be revised to meet these needs.

EMS Access Constraints And Response Time Delays For Deprived Critically Ill Patients Near Paris, France: Study examines emergency response times for critically ill patients who live in an area of low socioeconomic status near Paris, France.

Article

Jul 2020

Increased emergency medical services (EMS) response times and areas of low socioeconomic status are both associated with poorer outcomes for several time-sensitive medical conditions attended to by medical personnel before a patient is hospitalized. We evaluated the association between EMS response times, area deprivation level, and on-scene access constraints encountered by EMS in a large urban area in France. We conducted a multicenter prospective cohort study of EMS dispatches occurring in the forty-seven cities in a region southeast of Paris. We fit multilevel mixed-effects linear regression models for multivariate assessment of the predictors of EMS response times and then used multivariate logistic regression on outcomes among a subgroup of patients presenting with out-of-hospital cardiac arrest. We found evidence that access constraints were more frequently encountered by EMS in the most deprived areas compared to less deprived ones, and were associated with increased EMS response times until patient contact and with poorer outcomes from cardiac arrest. Strategies to anticipate and overcome access constraints should be implemented to improve outcomes for emergent conditions attended to by prehospital medical teams.

Worsened survival in the head-up tilt position cardiopulmonary resuscitation in a porcine cardiac arrest model

Article

Full-text available

Sep 2019

Objective: Head elevation at an angle of 30° during cardiopulmonary resuscitation (CPR) was hemodynamically beneficial compared to supine position in a previous porcine cardiac arrest experimental study. However, survival benefit of head-up elevation during CPR has not been clarified. This study aimed to assess the effect of head-up tilt position during CPR on 24-hour survival in a porcine cardiac arrest experimental model. Methods: This was a randomized experimental trial using female farm pigs (n=18, 42±3 kg) sedated, intubated, and paralyzed on a tilting surgical table. After surgical preparation, 15 minutes of untreated ventricular fibrillation was induced. Then, 6 minutes of basic life support was performed in a position randomly assigned to either head-up tilt at 30° or supine with a mechanical CPR device, LUCAS-2, and an impedance threshold device, followed by 20 minutes of advanced cardiac life support in the same position. Primary outcome was 24-hour survival, analyzed by Fisher exact test. Results: In the 8 pigs from the head-up tilt position group, one showed return of spontaneous circulation (ROSC); all eight pigs expired within 24 hours. In the eight pigs from the supine position group, six had the ROSC; six pigs survived for 24 hours and two expired. The head-up position group showed lower 24-hour survival rate and lower ROSC rate than supine position group (P<0.01). Conclusion: The use of head-up tilt position with 30 degrees during CPR showed lower 24-hour survival than the supine position.

A US National Study of the Association Between Income and Ambulance Response Time in Cardiac Arrest

Article

Full-text available

Nov 2018

Importance Emergency medical services (EMS) provide critical prehospital care, and disparities in response times to time-sensitive conditions, such as cardiac arrest, may contribute to disparities in patient outcomes. Objectives To investigate whether ambulance 9-1-1 times were longer in low-income vs high-income areas and to compare response times with national benchmarks of 4, 8, or 15 minutes across income quartiles. Design, Setting, and Participants A retrospective cross-sectional study was performed of the 2014 National Emergency Medical Services Information System data in June 2017 using negative binomial and logistic regressions to examine the association between zip code–level income and EMS response times. The study used ambulance 9-1-1 response data for out-of-hospital cardiac arrest from 46 of 50 state repositories (92.0%) in the United States. The sample included 63 600 cardiac arrest encounters of patients who did not die on scene and were transported to the hospital. Main Outcomes and Measures Four time measures were examined, including response time, on-scene time, transport time, and total EMS time. The study compared response times with EMS response time benchmarks for responding to cardiac arrest calls within 4, 8, and 15 minutes. Results The study sample included 63 600 cardiac arrest encounters of patients (mean [SD] age, 60.6 [19.0] years; 57.9% male), with 37 550 patients (59.0%) from high-income areas and 8192 patients (12.9%) from low-income areas. High-income areas had greater proportions of white patients (70.1% vs 62.2%), male patients (58.8% vs 54.1%), privately insured patients (29.4% vs 15.9%), and uninsured patients (15.3% vs 7.9%), while low-income areas had a greater proportion of Medicaid-insured patients (38.3% vs 15.8%). The mean (SD) total EMS time was 37.5 (13.6) minutes in the highest zip code income quartile and 43.0 (18.8) minutes in the lowest. After controlling for urban zip code, weekday, and time of day in regression analyses, total EMS time remained 10% longer (95% CI, 9%-11%; P < .001), translating to 3.8 minutes longer in the poorest zip codes. The EMS response time to patients in high-income zip codes was more likely to meet 8-minute and 15-minute cutoffs compared with low-income zip codes. Conclusions and Relevance Patients with cardiac arrest from the poorest neighborhoods had longer EMS times compared with those from the wealthiest, and response times were less likely to meet national benchmarks in low-income areas, which may lead to increased disparities in prehospital delivery of care over time.

Optimal Scene Time to Achieve Favorable Outcomes in Out-of-hospital Cardiac Arrest: How Long Is Too Long?

Article

Full-text available

Oct 2018

Relationship Between Emergency Medical Services Response Time and Bystander Intervention in Patients With Out‐of‐Hospital Cardiac Arrest

Article

Full-text available

May 2018

Background: The response time of emergency medical services (EMS) is an important determinant of survival after out-of-hospital cardiac arrest. We sought to identify upper limits of EMS response times and bystander interventions associated with neurologically intact survival. Methods and results: We analyzed the records of 553 426 patients with out-of-hospital cardiac arrest in a Japanese registry between 2010 and 2014. The primary study end point was 1-month neurologically intact survival (Cerebral Performance Category scale 1 or 2). Increased EMS response time was associated with significantly decreased adjusted odds of 1-month neurologically intact survival (adjusted odds ratio [aOR] for each 1-minute increase, 0.89; 95% confidence interval [CI], 0.89-0.90), although this relationship was modified by bystander interventions. The bystander interventions and the ranges of EMS response times that were associated with increased adjusted 1-month neurologically intact survival were as follows: bystander defibrillation, from ≤2 minutes (aOR, 3.10 [95% CI, 1.25-7.31]) to 13 minutes (aOR, 5.55 [95% CI, 2.66-11.2]); bystander conventional cardiopulmonary resuscitation, from 3 minutes (aOR 1.48 [95% CI, 1.02-2.12]) to 11 minutes (aOR 2.41 [95% CI, 1.61-3.56]); and bystander chest-compression-only cardiopulmonary resuscitation, from ≤2 minutes (aOR 1.57 [95% CI, 1.01-2.25]) to 11 minutes (aOR 1.92 [95% CI, 1.45-2.56]). However, the increase in neurologically intact survival of those receiving bystander interventions became statistically insignificant compared with no bystander interventions when the EMS response time was outside these ranges. Conclusions: The upper limits of the EMS response times associated with improved 1-month neurologically intact survival were 13 minutes when bystanders provided defibrillation (typically with cardiopulmonary resuscitation) and 11 minutes when bystanders provided cardiopulmonary resuscitation without defibrillation.

The effect of resuscitation position on cerebral and coronary perfusion pressure during mechanical cardiopulmonary resuscitation in porcine cardiac arrest model

Article

Feb 2017
RESUSCITATION

Objective: It is unknown whether patient position is associated with the optimal cerebral (CePP) and coronary (CoPP) perfusion pressure. Methods: This study utilized a randomized experimental design and anesthetized, intubated and paralyzed female pigs (n=12) (mean 42, SD 3kg). After 6min of untreated ventricular fibrillation, mechanical CPR with was performed for 3min in 0° supine position. The CPR was then performed for 5min in a position randomly assigned to either 1) head-up tilt (HUT) by three angles (30°, 45°, or 60°) or 2) head-down tilt (HDT) by three angles (30°, 45°, or 60°) and at 3) supine position between HUT and HDT positions. 4 Pigs were assigned to each angle of HUT or HDT position and 12 pigs were assigned to supine position. CePPs and CoPPs were measured and compared using MIXED procedure with pig as a random effect among angles and compared between angles with Tukey post-hoc analysis. Results: With 60°, 45°, 30° head-down, 0° (supine), and 30°, 45°, 60° head-up positioning, mean(SD) CePPs increased consistently as follows: 2.4(0.4), 9.3(1.6), 16.5(1.6), 27.0(1.5), 35.1(0.4), 39.4(0.6), and 39.9(0.3) mmHg, respectively. CoPPs were followings according to same angle: 12.9(2.5), 13.3(2.5), 12.8(0.4), 18.1(0.7), 30.3(0.4), 24.1(0.6), and 26.5(0.9) mmHg, respectively. The CePPs were peak at HUT(45°) and HUT(60°), but CoPP was peak in HUT(30°) and higher than HUT(45°) and HUT(60°). Conclusion: Cerebral perfusion pressure during mechanical CPR were similar and highest in the HUT(45° and 60°) positions whereas the peak coronary perfusion pressure was observed with HUT(30°).

Response times of the emergency medical services Kočevje to patients with emergency conditions

Article

Full-text available

Sep 2011

Introduction: The response time in pre-hospital treatment of emergency patients is defined as the period between the time of the emergency call and the arrival of emergency medical services on scene of the incident which has a significant impact on the positive outcome of intervention. The established international standards mandate a 7 minute response time on emergency calls in urban areas and up to 14 minute response time in more remote or distanced regions in at least 90% of cases. Aim: The aim of the study was to analyze the emergency response times and assess them in relation to the recommended international standards. Methods: A quantitative research method was used to collect the data on random samples of all emergency interventions within a period of three months in 2009. The dispatch database, kept in the archives of the Emergency medical services Kočevje (EMSK) notes 80 emergency interventions within the period stated. The study analyses the distance from the EMSK (15 to 60 km) and the nearest hospital 60 to 120 km), the types of emergency and the emergency treatment outcomes. The anonymity of the patients was secured. The statistical analysis of the data was performed with the SPSS program. A descriptive statistics was used for the measured variables - the one-sample t-test was used to identify statistically significant difference in response times in relation to the international standards and the independent samples t-test was employed to determine the relation between the mean response times and the patients' survival. Results: Included in the study were 67.7% of internal emergencies and 32.9% of traumas. In 75.9 % of cases, the patients were transported to definitive care, 16.5% of patients were appropriately treated on scene, in 6.3% the outcome was fatal and 1.3% of calls were false reports of emergencies. Results of the study show that in the majority of cases the mean response time to the distance of more than 15 km was 16.5 to 27.3 minutes with statistical dispersion 20.60. The one-sample t-test shows statistically significant differences in response times of EMSK in relation to the international standards (p=0.004). In emergencies with fatal outcomes the response time of EMSK was 12.0 13.5 minutes. Discussion and conclusions: Results of the study show that the mean response times to the scene of incident in the distance of more than 15.km from EMSK and 75 km from the nearest hospital exceeds the international standards by nearly 50%. Consequently, the emergency patients who should be treated within the first 14minutes have little or no chance of survival. One of the solutions in cases of cardiac arrest would be the use of automated defibrillators by laymen. The results obtained present a good basis for further study in the filed.

Out-of-hospital cardiac arrest in high-rise buildings: delays to patient care and effect on survival

Article

Full-text available

Jan 2016

Background: increasing number of people living in high-rise buildings presents unique challenges to care and may cause delays for 911-initiated first responders (including paramedics and fire department personnel) responding to calls for out-of-hospital cardiac arrest. We examined the relation between floor of patient contact and survival after cardiac arrest in residential buildings. Methods: We conducted a retrospective observational study using data from the Toronto Regional RescuNet Epistry database for the period January 2007 to December 2012. We included all adult patients (≥ 18 yr) with out-of-hospital cardiac arrest of no obvious cause who were treated in private residences. We excluded cardiac arrests witnessed by 911-initiated first responders and those with an obvious cause. We used multivariable logistic regression to determine the effect on survival of the floor of patient contact, with adjustment for standard Utstein variables. Results: During the study period, 7842 cases of out-of-hospital cardiac arrest met the inclusion criteria, of which 5998 (76.5%) occurred below the third floor and 1844 (23.5%) occurred on the third floor or higher. Survival was greater on the lower floors (4.2% v. 2.6%, p = 0.002). Lower adjusted survival to hospital discharge was independently associated with higher floor of patient contact, older age, male sex and longer 911 response time. In an analysis by floor, survival was 0.9% above floor 16 (i.e., below the 1% threshold for futility), and there were no survivors above the 25th floor. Interpretation: In high-rise buildings, the survival rate after out-of-hospital cardiac arrest was lower for patients residing on higher floors. Interventions aimed at shortening response times to treatment of cardiac arrest in high-rise buildings may increase survival.

Factors affecting the ambulance response times of trauma incidents in Singapore

Article

Sep 2015

Simplified Method for Evaluating the Impact of a Transportation Network on Posthurricane Access to Healthcare Facilities

Article

Full-text available

Jul 2014

To estimate the impact of Hurricane Ike of 2008 on local communities, service areas of hospitals and corresponding service populations were calculated at both the county and facility levels within the Houston metropolitan statistical area. A hospital access indicator was defined to measure the level of access to medical services when compared to the prestorm level. The result indicated that the hospital access indicator reached its lowest value on the next day after the hurricane landfall due to lane closures and hospital shutdowns before showing a steady comeback. However, the recovery was briefly interrupted around September 18, 2008, as a result of road closures to remove debris on State Highway 146. Access to hospitals nearly returned to the prestorm level by the end of October 2008. Simulations were then performed to identify priorities for repairing damaged roads in order to minimize storm's adverse impact. This paper offered a simplified method to measure, monitor, and analyze the effect of transportation network on access to healthcare facilities in the aftermath of a hurricane. Since only a small number of publicly available variables were required, the method could be applied to other catastrophic events in support of disaster response and recovery decisions.

Association between EMS response times, low socioeconomic status, and poorer outcomes in out-of-hospital cardiac arrest: the MEDIC multicenter retrospective cohort study for disparities in access to prehospital critical care in the Paris metropolitan area

Article

Aug 2024
EUR J EMERG MED

Background and importance Prolonged emergency medical services’ response times (EMS-RT) are associated with poorer outcomes in out-of-hospital cardiac arrest (OHCA). The patient access time interval (PATI), from vehicle stop until contact with patient, may be increased in areas with low socioeconomic status (SES). Objectives The objective of this study is to identify predictors of prolonged EMS-RT intervals, and to evaluate associations with clinical outcomes in OHCAs occurring in the largest metropolitan area in France. Design Using the Utstein-style, prospectively implemented, population-based SDEC registry for OHCAs, we conducted a multicenter, region-wide, retrospective cohort study of EMS dispatches for OHCA cases occurring in the 152 cities of the Greater Paris area, France, between January 1, 2017 and December 31, 2018. Settings and participants Adult, nontraumatic, EMS-assessed, non-EMS witnessed OHCAs. Exposure Geographic location and scene-level SES. Outcome measures and analysis The primary outcome was the EMS-RT interval, from activation until arrival at patient’s side. As secondary outcomes, we evaluated patient access outcomes of: (1) dispatch-to-patient contact interval (‘EMS-RT’); and (2) vehicle scene arrival-to-patient contact interval (PATI); and patient clinical outcomes of: (1) death; and (2) unfavorable neurological status, both at 30 days. Area-level SES was assessed at census tract level using the European Deprivation Index (EDI; continuous, and divided into quintiles, Q5 = most deprived). We fitted multilevel mixed-effects regression models to identify predictors of patient access outcomes, and their association with clinical outcomes. Main results We included 4082 cases; the median EMS-RT was 10.85 min (interquartile range [8.87–13.15]), and 138 (3.4%) survived to hospital discharge. Independent predictors of increased EMS-RT and PATI were age >65, female sex, residential location, occurrence at elevated floors, arrest unwitnessed by a bystander, and low EDI (all P < 0.018). After multivariable analysis, an overall EMS-RT interval >8 min was associated with higher mortality and poorer neurological status at hospital discharge (both P < 0.001). Conclusion In OHCA cases occurring in the Greater Paris metropolitan area, after adjustment for scene characteristics, EMS delays until patient contact were longer in neighborhoods of low SES, and were associated with poorer clinical outcomes.

Predicting EMS Response Time using Geographic Zones’ Socio-Economic Indicators

Conference Paper

Full-text available

Oct 2023

Comparison of prehospital resuscitation quality during scene evacuation and early ambulance transport in out-of-hospital cardiac arrest between residential location and non-residential location

Article

Dec 2022
RESUSCITATION

Background: High-quality prehospital cardiopulmonary resuscitation (CPR) is important for out-of-hospital cardiac arrest (OHCA). We aimed to evaluate prehospital CPR quality during scene evacuation and early ambulance transport in patients with OHCA according to the type of cardiac arrest location. Methods: This retrospective observational cohort study enrolled patients with non-traumatic adult OHCA in Seoul between July 2020 and March 2022. Prehospital CPR quality data extracted from defibrillators were merged with the national OHCA database. The location of cardiac arrest was categorized into two groups (residential and non-residential). CPR quality indices including no-flow (any pause > 1.5 sec) fraction were compared according to the type of arrest location at each minute of EMS scene evacuation and early ambulance transport (5 min prior to 5 min after ambulance departure). Results: A total of 1,222 OHCAs were enrolled in the final analysis after serial exclusion. A total of 966 OHCAs (79.1%) occurred in the residential areas. The CPR quality deteriorated during the scene evacuation in both location type. The mean no-flow fractions were significantly higher in residential places than in non-residential places. The mean proportion of adequate compression depth and rate was lower in cardiac arrests in residential places. The discrepancy in EMS CPR quality during scene evacuation was more prominent when mechanical CPR devices were not used. Conclusion: Deterioration of CPR quality was observed just before and during early ambulance transport, especially when the cardiac arrest location was a residential area or when only manual CPR was provided.

Part II - Optimizing Healthcare Systems

Article

Apr 2022

Healthcare has recently seen numerous exciting applications of artificial intelligence, industrial engineering, and operations research. This book, designed to be accessible to a diverse audience, provides an overview of interdisciplinary research partnerships that leverage AI, IE, and OR to tackle societal and operational problems in healthcare. The topics are drawn from a wide variety of disciplines, ranging from optimizing the location of AEDs for cardiac arrests to data mining for facilitating patient flow through a hospital. These applications highlight how engineering has contributed to medical knowledge, health system operations, and behavioral health. Chapter authors include medical doctors, policy-makers, social scientists, and engineers. Each chapter begins with a summary of the health care problem and engineering method. In these examples, researchers in public health, medicine, and social science as well as engineers will find a path to start interdisciplinary collaborations in health applications of AI/IE/OR.

Optimizing Defibrillator Deployment

Chapter

Apr 2022

The feasibility of medical unmanned aerial systems in suburban areas

Article

Aug 2021
AM J EMERG MED

John Ryan

Out-of-Hospital Cardiac Arrests (OHCA) are one of the biggest challenges facing medical systems world-wide. Each year, more than 420,000 Americans experience cardiac arrests with a survival rate of approximately 10%. 1 A large challenge to treating OHCA continues to be rapid access to AEDs which can increase survival rates up to 40%. 1 While pivotal to an OHCA patient's survival, AEDs are not always readily available. Advances in unmanned aerial systems (UAS) - commonly referred to as drones – can provide a solution since UAS have the ability to rapidly carry an AED payload to an emergency site. This study examined the potential use of UAS delivered AEDs in suburban areas by using the Charlottesville-Albemarle area as an example. This study was carried out by using Geographical Information Systems mapping. Specifications of the Eagle drone model by Flirtey were used to develop a beneficial drone placement plan. Models were created with drones at first responder stations. Coverage area of the drones at first responder stations was compared to coverage area of drone units placed at “ideal” locations in the Charlottesville-Albemarle County area. Population statistics were gathered from the GIS program Social Explorer, using data from the U.S. Census Bureau. The “ideal” location placement plan was then evaluated for an estimate of total population covered by the system. Finally, ideal drone placements were evaluated and compared to response time and distances versus a local EMS ground unit. With the derived ideal placements, 70.08% of the area would have drone coverage that could deliver an AED in less than five minutes and 97.97% of the area would have coverage in less than 10 min. At minimum, 94.72% of the population would be covered by the ideal placements of drones within the area. Drone response time was significantly faster than ground EMS response by a factor of 5× (P value < .05). Drones were able to get to the incident scene of a theoretical OHCA faster without and with vertical response challenges. Our results show that UAS delivery of AEDs is not only possible in the Charlottesville-Albemarle County area, but an effective way to decrease response time to improve chances of survival for a person experiencing an OHCA in similar suburban areas.

After the Lights and Sirens: Patient access delay in cardiac arrest

Article

Aug 2020
RESUSCITATION

The association of scene-access delay and survival with favourable neurological status in patients with out-of-hospital cardiac arrest

Article

Jun 2020
RESUSCITATION

Background Rapid emergency medical service (EMS) response after out-of-hospital cardiac arrest (OHCA) is a major determinant of survival, however this is typically measured until EMS vehicle arrival. We sought to investigate whether the interval from EMS vehicle arrival to patient attendance (curb-to-care interval [CTC]) was associated with patient outcomes. Methods We performed a secondary analysis of the “CCC Trial” dataset, which includes EMS-treated adult non-traumatic OHCA. We fit an adjusted logistic regression model to estimate the association between CTC interval (divided into quartiles) and the primary outcome (survival with favourable neurologic status at hospital discharge; mRS ≤ 3). We described the CTC interval distribution among enrolling clusters. Results We included 24,685 patients: median age was 68 (IQR 56–81), 23% had initial shockable rhythms, and 7.6% survived with favourable neurological status. Compared to the first quartile (≤62 seconds), longer CTC quartiles (63 to 115, 116 to 180, and ≥181 seconds) demonstrated the following associations with survival with favourable neurological status: adjusted odds ratios 0.95, 95% CI 0.83 to 1.09; 0.77, 95% CI 0.66 to 0.89; 0.66, 95% CI 0.56 to 0.77, respectively. Of the 49 study clusters, median CTC intervals ranged from 86 (IQR 58–130) to 179 seconds (IQR 112–256). Conclusion A lower CTC interval was associated with improved patient outcomes. These results demonstrate a wide range of access metrics within North America, and provide a rationale to create protocols to mitigate access obstacles. A two-minute CTC threshold may represent an appropriate target for quality improvement.

ReACanROC: Towards the creation of a France–Canada research network for out-of-hospital cardiac arrest

Article

Jul 2020

Aims There are large differences between emergency medical systems, which may account for variability in outcomes. We seek to compare prehospital organizations, response modes, patient characteristics and outcomes after out-of-hospital cardiac arrest, between France and Canada, and discuss the need for the first European–North American prehospital research network on out-of-hospital cardiac arrest. Methods Preliminary comparative description of data drawn from two nation-wide, population-based, Utstein-style prospectively implemented registries for out-of-hospital cardiac arrest in France and Canada (France: RéAC, Canada: CanROC), covering approximately 80 million people, and soon to be participating in an international research network in 2020. Results Since creation, 103,722 cases were included in France and approximately 99,317 in Canada. Data used in this work were drawn from 2011 to 2016, and comprised around 33,688 adult, non-traumatic, treated cases in Canada, and 55,358 in France, leading to estimated incidence rates of 75.3/100,000 inhabitants in France and 83/100,000 in Canada. In both countries, out-of-hospital cardiac arrest predominantly occurred in male patients, in their late sixties, at home, of presumed cardiac aetiology. Bystander cardiopulmonary resuscitation was provided in half of the cases. First assessed cardiac rhythm was shockable in 16% (France) vs. 22% (Canada). Professional resuscitation was attempted in 82% (France) and 60% (Canada). Prehospital organizations and response modes differed in the constitution of responding teams (France: physician-led advanced life support, Canada: trained paramedics), in response time intervals (call to first professional responders’ arrival at scene 6.5 min (interquartile range IQR [5.2–8.3]) (Canada) vs. 10 min [7–15] (France)), in on-scene interventions, type of referral at hospital (France: systematic bypass of emergency department, tertiary hospital first, Canada: occasional bypass, mainly closest hospital first), and in outcomes (overall survival at hospital discharge in France: 5% vs. Canada: 11%). Conclusion Despite similarities in some out-of-hospital cardiac arrest Utstein variables, several differences exist between French and Canadian prehospital systems, and ultimately, between outcomes. The creation of the ReACanROC research network will facilitate the conduction of further analyses to better understand predictors of this variability.

ReACanROC: Towards the Creation of a France-Canada Research Network for Out-of-Hospital Cardiac Arrest

Article

May 2020
RESUSCITATION

Abstract Aims There are large differences between emergency medical systems, which may account for variability in outcomes. We seek to compare prehospital organizations, response modes, patient characteristics and outcomes after out-of-hospital cardiac arrest, between France and Canada, and discuss the need for the first European-North American prehospital research network on out-of-hospital cardiac arrest. Methods Preliminary comparative description of data drawn from two nation-wide, population-based, Utstein-style prospectively implemented registries for out-of-hospital cardiac arrest in France and Canada (France: RéAC, Canada: CanROC), covering approximately 80 million people, and soon to be participating in an international research network in 2020. Results Since creation, 103,722 cases were included in France and approximately 99,317 in Canada. Data used in this work were drawn from 2011 to 2016, and comprised around 33,688 adult, non-traumatic, treated cases in Canada, and 55,358 in France, leading to estimated incidence rates of 75,3/100,000 inhabitants in France and 83/100,000 in Canada. In both countries, out-of-hospital cardiac arrest predominantly occurred in male patients, in their late sixties, at home, of presumed cardiac aetiology. Bystander cardiopulmonary resuscitation was provided in half of the cases. First assessed cardiac rhythm was shockable in 16% (France) vs. 22% (Canada). Professional resuscitation was attempted in 82% (France) and 60% (Canada). Prehospital organizations and response modes differed in the constitution of responding teams (France: physician-led advanced life support, Canada: trained paramedics), in response time intervals (call to first professional responders’ arrival at scene 6.5 min (interquartile range IQR [5.2-8.3]) (Canada) vs. 10 min [7–15] (France)), in on-scene interventions, type of referral at hospital (France: systematic bypass of emergency department, tertiary hospital first, Canada: occasional bypass, mainly closest hospital first), and in outcomes (overall survival at hospital discharge in France: 5%, vs. Canada: 11%). Conclusion Despite similarities in some out-of-hospital cardiac arrest Utstein variables, several differences exist between French and Canadian prehospital systems, and ultimately, between outcomes. The creation of the ReACanROC research network will facilitate the conduction of further analyses to better understand predictors of this variability.

Comparison of Chest Compression Quality Between Transfer Sheet and Stretcher Use for Transporting Out-Of-Hospital Cardiac Arrest Patients in a High-Rise Building - A Randomized and Open-label Cross-over Design

Article

Apr 2020

Objectives: Stretchers are commonly used for transporting cardiac arrest patients, but their use may be limited in confined spaces, like elevators. Use of transfer sheet as an alternative has not been explored. We aimed to compare manual chest compression quality between these two methods. Methods: In this prospective, open-label, randomized cross-over manikin study, the subjects included emergency medical technicians who were assigned to 12 three-person crews. Scenarios included transport of a cardiac arrest in a high-rise building and elevator using transfer sheet (TS) and stretchers adjusted to 45° (S45) and 90° (S90). Chest compression quality was measured using a recording manikin and that before (on-scene phase) and after (transport phase) the manikin moved via transfer sheet or stretcher were compared. Results: The final analysis included 72 simulation runs. Chest compression quality did not differ among the groups in the on-scene phase. In the transport phase, the transfer sheet group provided greater mean compression depth (54.4 ± 4.2 vs 39.6 ± 7.2 mm, p < 0.01 and 54.4 ± 4.2 vs 40.6 ± 8.3 mm, p < 0.01, respectively) than stretchers of S45 and S90, and higher percentage of deep-enough compression (TS: 51.0 [23.8-74.8]% vs S45: 19.5 [5.8-29.5]%, p < 0.01) than the S45 group. Transfer sheet use showed a trend of lower percentages of full recoil (TS: 40.0 [12.8-64.5]% vs S45: 70.5 [47.0-79.8]% vs S90: 52.5 [25.3-76.0]%, p = 0.09). Chest compression fraction, compressions with correct hand position, and mean compression rates did not differ between groups in the transport phase. The TS group showed shorter time intervals of simulation start-to-first-compression (TS: 13.9 [12.4-15.1] sec vs S90: 15.9 [13.3-16.4] sec, p = 0.04) and total run time (TS: 145.7 [135.1-151.4] sec vs S90: 160.0 [151.9-175.4] sec, p < 0.01) than the S90 group. Conclusion: In this simulation, using transfer sheet outperform using stretcher for transporting cardiac arrest patients from high-rise buildings. Rescuers need to be aware of full chest recoil.

Factors Influencing the Emergency Medical Service Response Time for Cardiovascular Disease in Guangzhou, China

Article

Jun 2019

While emergency medical service (EMS) response time (ERT) is a major factor associated with the survival of patients with cardiovascular disease (CVD), relatively few studies have explored the factors associated with ERT. This study aimed to assess the current status of ERT and to identify the factors affecting ERT in patients with CVD in China. Between January 1, 2011 and December 31, 2015, EMS responses to CVD incidents in Guangzhou, China, were examined. The primary outcome was ERT, defined as the time from receipt of an emergency call to the arrival of paramedics on the scene. Factors associated with ERT were evaluated by multivariable logistic regression. A total of 44 383 CVD incidents were analysed. The median ERT was 12.58 min (interquartile range=9.98–15.67). Among the risk factors, distance (OR=13.73, 95% CI=11.76–16.04), level of hospital (OR=1.57, 95% CI=1.40–1.75), and site of the incident (OR=1.53, 95% CI=1.38–1.69) were the top three significant factors affecting the ERT. Our results suggest that greater attention should be given to factors affecting the ERT. It is essential to make continuous efforts to promote the development of effective interventions to reduce the response time.

Effects of dispatcher-assisted bystander cardiopulmonary resuscitation on neurological recovery in paediatric patients with out-of-hospital cardiac arrest based on the pre-hospital emergency medical service response time interval

Article

Jun 2018
RESUSCITATION

Objectives: We investigated the effect of bystander cardiopulmonary resuscitation (BCPR) with dispatcher assistance (DA) on neurological outcomes based on the response time interval (RTI) of the pre-hospital emergency medical service (EMS) among paediatric patients with out-of-hospital cardiac arrest (OHCA). Methods: This retrospective registry study was conducted on paediatric patients (< 19 years old) with OHCA who were assessed by EMS providers between 2012 and 2016. The primary outcome was good neurological recovery based on BCPR with or without DA and the EMS RTI. Differential effects of BCPR with DA based on the EMS RTI were analysed by multivariable logistic regression analysis with interaction terms. Results: Adjusted odds ratios (AORs) and corresponding 95% confidence intervals (95% CIs) for good neurological recovery were 2.22 (1.27-3.88) for BCPR with DA and 1.51 (0.77-2.97) for BCPR without DA compared to no BCPR. The faster EMS RTI group (< 5 minutes) had better neurological recovery than the later EMS RTI group (≥ 5 minutes) (AOR: 1.87 [1.04-3.29]). The AORs for good neurological recovery following BCPR with DA based on the EMS RTI were 2.52 (0.91-6.97) in the faster EMS RTI group and 2.17 (1.13-4.19) in the later EMS RTI group compared to the no BCPR group. Conclusion: BCPR with DA and a faster EMS RTI were significantly associated with good neurological recovery in paediatric patients with OHCA. When the EMS RTI was delayed, the association of BCPR with DA with good neurological recovery was preserved in paediatric patients with OHCA.

The Regional Characteristics of 119 Ambulance Dispatch, the Distance and Response Time to the Scene

Article

Jan 2016

Purpose This study is to investigate regional characteristics of 119 ambulance dispatch and the relationship between the distance and response time to the scene. Methods This study was retrospectively conducted 119 running sheets with 1,321 patients who had been transferred to the hospital by 119 ambulance during ambulance attendant training. The training was performed at two, five and three fire station in Seoul, Daejeon and Chungnam respectively, from June 24, 2013 to July 19, 2014. Results Almost the emergency medical services provided were no more than basic first aid in all regions. The patients transferred by 119 ambulance in Seoul were more than other region. The time of call to scene and scene to hospital were the slowest in Chungnam. The major reason of call 119 was due to disease in Seoul and Daejeon, however due to injury in Chungnam. Conclusion Our study suggests that learning from ambulance attendant training course could diverse from region to region. It is, therefore, needed that standardization of ambulance attendant training course, appropriate logistics and resource allocation for providing universal quality of emergency medical services.

Impact of Building Height and Volume on Cardiac Arrest Response Time

Article

Sep 2015

Emergency medical services (EMS) care may be delayed when out-of-hospital cardiac arrest (OHCA) occurs in tall or large buildings. We hypothesized that larger building height and volume were related to a longer curb-to-defibrillator activation interval. We retrospectively evaluated 3,065 EMS responses to OHCA in a large city between 2003–13 that occurred indoors, prior to EMS arrival, and without prior deployment of a defibrillator. The two-tiered EMS system uses automated external defibrillator-equipped basic life support firefighters followed by paramedics dispatched from a single call center. We calculated three time intervals obtained from the computerized dispatch report and time-synchronized defibrillators: initial 911 call to address curb arrival by first unit (call-to-curb), curb arrival to defibrillator power on (curb-to-defib on), and the combined call-to-defib on interval. Building height and surface area were measured with a validated program based on aerial photography. Buildings were categorized by height as short (<25 ft), medium (26–64 ft) and tall (>64 ft). Volume was categorized as small (<60,000 ft3), midsize (60,000–1,202,600 ft3) and large (>1,202,600 ft3). Intervals were compared using the two-tailed Mann-Whitney test. EMS responded to 1,673 OHCA events in short, 1,134 in medium, and 258 in tall buildings. There was a 1.14 minute increase in median curb-to-defib on interval from 1.97 in short to 3.11 minutes in tall buildings (p < 0.01). Taller buildings, however, had a shorter call-to-curb interval (4.73 for short vs 3.96 minutes for tall, p < 0.01), such that the difference in call-to-defib on interval was only 0.27 minutes: 6.87 for short and 7.14 for tall buildings. A similar relationship was observed for small-volume compared to large-volume building: longer curb-to-AED (1.90 vs. 3.01 minutes, p < 0.01), but shorter call-to-curb (4.87 vs. 4.05, p < 0.01); the difference in call-to-defib on was 0.18 minutes. Both taller and larger-volume buildings had longer curb-to-AED intervals but shorter 911 call-to-curb arrival intervals. As a consequence, building height and volume had a modest overall relationship with interval from call to defibrillator application. These results do not support the hypothesis that either taller or larger-volume buildings need cause poorer outcomes in urban environments.

A Quantile Regression Analysis of Ambulance Response Time

Article

Full-text available

Dec 2012
PREHOSP EMERG CARE

Abstract Background. Shorter ambulance response time (ART) contributes to improved clinical outcomes. Various methods have been used to analyze ART. Objectives. We aimed to compare the use of quantile regression with the standard ordinary least squares (OLS) model for identifying factors associated with ART in Singapore. A secondary aim was to determine the relative importance of patient-level (e.g., gender and ethnicity) versus system-level (e.g., call volumes within the last one hour) factors contributing to longer ART. Methods. We conducted a retrospective review of data electronically captured from ambulance dispatch records and patient case notes of emergency calls to the national ambulance service from January to May 2006 (n = 30,687). The primary outcome was ART, defined as the time taken for an ambulance to arrive at the scene upon receiving an emergency call, and modeled as a function of patient- and system-level factors. We used a quantile regression model to account for potential heterogeneous effects of explanatory variables on ART across different quantiles of the ART distribution, and compared estimates derived with the corresponding OLS estimates. Results. Quantile regression estimates suggested that the call volume in the previous one hour predicted increased ART, with the effect being more pronounced in higher ART quantiles. At the 90th and 50th percentiles of ART, each additional call in the last one hour was predicted to increase ART to the next call from the same area by 93 and 57 seconds, respectively. The corresponding OLS estimate was 58 seconds. Patient factors had little effect on ART. Conclusion. The quantile regression model is more useful than the OLS model for estimating ART, revealing that in Singapore, ART is influenced heterogeneously by the volume of emergency calls in the past one hour.

Pediatric prehospital evaluation of NYC cardiac arrest survival (PHENYCS)

Article

Aug 2012
PEDIATR EMERG CARE

The objective of this study was to describe the demographics of out-of-hospital cardiac arrests (OOHCAs) in children younger than 18 years and characteristics associated with survival among these children in New York City (NYC). A prospective observational cohort of all children younger than 18 years with OOHCA in NYC between April 1, 2002, and March 31, 2003. Data were collected from prehospital providers by trained paramedics utilizing a previously validated telephone interview process. Data included Pediatric Utstein core measures and critical prehospital time intervals. Analyses utilized descriptive statistics and bivariate association with survival. Resuscitation was attempted on 147 pediatric OOHCA patients in NYC during the study period; outcome data were collected on these patients. The median age was 2 years; most (58%) were male. The majority of arrests occurred at home (69%). Lay bystanders witnessed 33% of all OOHCA; 68% of witnesses were family members. Bystander cardiopulmonary resuscitation (CPR) was performed on 30% of children. Median emergency medical services response time was 3.6 minutes (range, 0.4-14.4 minutes). Initial rhythm was as follows: ventricular fibrillation, 2%; asystole, 50%; pulseless electrical activity, 9.5%; other rhythms, 11.6%; no rhythm recorded, 26%. Survival was 4% to hospital discharge and was present only among witnessed arrests (6/58 witnessed vs 0/70 unwitnessed, P < 0.05). Pediatric OOHCA survival rate is low. Witnessed arrest was the most important determinant of survival. Ventricular fibrillation was an uncommon rhythm measured by emergency medical services. The majority of arrests occurred at home. The rate of bystander CPR was low. Strategies to increase the rate of bystander CPR for children, especially by family members, are needed.

Pediatric prehospital evaluation of NYC respiratory arrest survival (PHENYCS)

Article

Aug 2012
PEDIATR EMERG CARE

The objective of this study was to describe the demographics, epidemiology, and characteristics associated with survival of children younger than 18 years who had an out-of-hospital respiratory arrest (OOHRA) during a 1-year period in a large urban area. A prospective observational cohort of consecutive children younger than 18 years with OOHRA cared for by the New York City 911 emergency medical services (EMS) system from April 12, 2002, to March 31, 2003. Following resuscitative efforts, data were collected from prehospital providers by trained paramedics using a previously validated telephone interview process. Data included Pediatric Utstein core measures and critical prehospital time intervals. Analyses used descriptive statistics and bivariate association with survival. Resuscitation was attempted on 109 OOHRAs during the study period. The median age was 7 years, 52% were male. Lay bystanders witnessed 56%. Most occurred at home (77%). Witnesses were family members in 59%. Bystander cardiopulmonary resuscitation (CPR) was performed in 31% of all respiratory arrests (RAs). A chronic medical condition existed in 28%. Median EMS response time was 4.4 minutes (range, 0-12 min). Overall survival was 79% to hospital discharge. Time interval to EMS arrival, witnessed arrest, bystander CPR, and ventilation method were not associated with survival. Most OOHRAs occurred at home, and bystander CPR occurred infrequently. The majority of children in OOHRA survived. Strategies to increase the rate of bystander CPR, especially by family members, are needed. Out-of-hospital RAs are a large proportion of all arrests in children. Future studies of pediatric arrest should include RA as well as cardiac arrest.

Emergency Medical Services Response Time and Mortality in an Urban Setting

Article

Full-text available

Jan 2012
PREHOSP EMERG CARE

A common tenet in emergency medical services (EMS) is that faster response equates to better patient outcome, translated by some EMS operations into a goal of a response time of 8 minutes or less for advanced life support (ALS) units responding to life-threatening events. To explore whether an 8-minute EMS response time was associated with mortality. This was a one-year retrospective cohort study of adults with a life-threatening event as assessed at the time of the 9-1-1 call (Medical Priority Dispatch System Echo- or Delta-level event). The study setting was an urban all-ALS EMS system serving a population of approximately 1 million. Response time was defined as 9-1-1 call receipt to ALS unit arrival on scene, and outcome was defined as all-cause mortality at hospital discharge. Potential covariates included patient acuity, age, gender, and combined scene and transport interval time. Stratified analysis and logistic regression were used to assess the response time-mortality association. There were 7,760 unit responses that met the inclusion criteria; 1,865 (24%) were ≥8 minutes. The average patient age was 56.7 years (standard deviation = 21.5). For patients with a response time ≥8 minutes, 7.1% died, compared with 6.4% for patients with a response time ≤7 minutes 59 seconds (risk difference 0.7%; 95% confidence interval [CI]: -0.5%, 2.0%). The adjusted odds ratio of mortality for ≥8 minutes was 1.19 (95% CI: 0.97, 1.47). An exploratory analysis suggested there may be a small beneficial effect of response ≤7 minutes 59 seconds for those who survived to become an inpatient (adjusted odds ratio = 1.30; 95% CI: 1.00, 1.69). These results call into question the clinical effectiveness of a dichotomous 8-minute ALS response time on decreasing mortality for the majority of adult patients identified as having a life-threatening event at the time of the 9-1-1 call. However, this study does not suggest that rapid EMS response is undesirable or unimportant for certain patients. This analysis highlights the need for further research on who may benefit from rapid EMS response, whether these individuals can be identified at the time of the 9-1-1 call, and what the optimum response time is.

The Frequency and Consequences of Cardiopulmonary Resuscitation Performed by Bystanders on Patients Who Are Not in Cardiac Arrest

Article

Mar 2011
PREHOSP EMERG CARE

The American Heart Association encourages trained and untrained bystanders to perform, at a minimum, chest compressions on anyone who suddenly collapses. It is possible that people who are not in cardiac arrest may receive bystander cardiopulmonary resuscitation (CPR), from which the potential for injury is unknown. To determine the number of victims who received bystander CPR but were not in cardiac arrest and to identify any injuries resulting from receiving bystander CPR. Retrospective review of patient care records from a countywide emergency medical services (EMS) database. All patients treated by EMS between March 2003 and February 2009 who received bystander CPR were queried. Victims who were determined not to be in cardiac arrest upon EMS personnel assessment were identified as likely not in cardiac arrest. Hospital medical records for transported patients were reviewed for injuries possibly related to CPR. Patient demographics were collected and descriptive statistics were used for analysis. Six hundred seventy-two incidents of bystander CPR occurred, with 77 (11.5%) cases not being identified as cardiac arrests by EMS. Twenty-three percent of the patients were less than 19 years of age. Emergency medical services arrived in less than 6 minutes for 68% of patients. Seventy-two patients were evaluable for injury; of those, 53% were admitted to the intensive care unit. One patient (1.4%) had an injury that was documented in the medical record as possibly CPR-related: rhabdomyolysis. Bystanders provide CPR for patients who are not in cardiac arrest at a relatively low frequency. Short-duration bystander CPR caused injury in less than 2% of victims. Our results suggest that the benefits of bystander CPR for adults who suddenly collapse outweigh the risk of injury for those not in cardiac arrest.

Association between deprivation status at community level and outcomes from out-of-hospital cardiac arrest: A nationwide observational study

Article

Mar 2011

We sought to examine the association between area deprivation and outcomes of out-of-hospital cardiac arrest in Korea. Data were obtained from the emergency medical service (EMS) system. A nationwide OHCA cohort database from January 2006 to December 2007 was constructed via hospital chart review and ambulance run sheet data. We enrolled all EMS-assessed OHCA victims and excluded cases without available hospital outcome data or residential address. The Carstairs index was used to categorize districts according to level of deprivation into five quintiles, from (Q1, the least deprived) to (Q5, the most deprived). Main outcomes were survival to hospital discharge, survival to admission, and return of spontaneous circulation (ROSC). 34,227 patients were included. Initial rhythm, witnessed status, attempted bystander cardiopulmonary resuscitation (CPR), CPR by EMS, CPR in the emergency department (ED), and elapsed time interval significantly varied according to area deprivation level (p < 0.001). OHCA outcomes were consistently worse in the most deprived areas. The adjusted OR (95% CI) for survival to hospital discharge was 0.58 (0.45-0.77) in the most deprived areas compared to the least deprived areas. Community deprivation was strongly associated with survival among out-of-hospital cardiac arrest patients in Korea.

A Model for the Association of the Call Volume and the Unavailable-for-Response Interval on the Delayed Ambulance Response for Out-of-Hospital Cardiac Arrest Using a Geographic Information System

Article

Aug 2010
PREHOSP EMERG CARE

An optimal ambulance response interval is desirable for emergency medical services (EMS) operations. Arriving on scene within a treatment time window is often delayed for many reasons, including overwhelming call volume. To determine whether an association exists between the ambulance call volume (ACV), the unavailable-for-response (UFR) interval, and the delayed ambulance response for out-of-hospital cardiac arrest (OHCA) patients. This was a retrospective observational study conducted in Seoul, Republic of Korea. The EMS ambulance logs from the metropolitan city's 22 EMS agencies, from January 1, 2006, to June 30, 2007, were obtained from the National Emergency Management Agency. These data included patient demographics and call location addresses. The addresses of the call locations and ambulance stations were geocoded and configured with a polygon expressing the optimal coverage areas in which an ambulance could travel within 4 minutes from their base station. The median ACV and mean UFR interval of each EMS agency were calculated. An actual response time interval greater than 4 minutes compared with the optimal coverage area was defined as a suboptimal response. Potential influencing factors on suboptimal response were analyzed using a multivariate logistic regression model to calculated the odds ratio (OR) and 95% confidence interval (95% CI). Geocoding was successful for 255,961 calls, and 3,644 cardiac arrests occurred within the configured optimal response coverage areas. The response rate intervals for cardiac arrest patients, however, were optimal in only 22.6% of calls. Influencing factors for suboptimal response (occurring in 77.4% of the cases) were the median ACV and the mean UFR interval of each EMS agency. When the median ACV was seven or more, the OR of suboptimal response was 1.407 (1.142-1.734). If the mean UFR interval was 55 minutes or more, the OR for suboptimal response was 1.770 (1.345-2.329). The ambulance response time intervals in this study setting were associated with EMS agencies with higher ACVs and longer UFR intervals.

Measuring the EMS patient access time interval and the impact of responding to high-rise buildings

Article

Full-text available

Jan 2005

To measure the patient access time interval and characterize its contribution to the total emergency medical services (EMS) response time interval; to compare the patient access time intervals for patients located three or more floors above ground with those less than three floors above or below ground, and specifically in the apartment subgroup; and to identify barriers that significantly impede EMS access to patients in high-rise apartments. An observational study of all patients treated by an emergency medical technician paramedics (EMT-P) crew was conducted using a trained independent observer to collect time intervals and identify potential barriers to access. Of 118 observed calls, 25 (21%) originated from patients three or more floors above ground. The overall median and 90th percentile (95% confidence interval) patient access time intervals were 1.61 (1.27, 1.91) and 3.47 (3.08, 4.05) minutes, respectively. The median interval was 2.73 (2.22, 3.03) minutes among calls from patients located three or more stories above ground compared with 1.25 (1.07, 1.55) minutes among those at lower levels. The patient access time interval represented 23.5% of the total EMS response time interval among calls originating less than three floors above or below ground and 32.2% of those located three or more stories above ground. The most frequently encountered barriers to access included security code entry requirements, lack of directional signs, and inability to fit the stretcher into the elevator. The patient access time interval is significantly long and represents a substantial component of the total EMS response time interval, especially among ambulance calls originating three or more floors above ground. A number of barriers appear to contribute to delayed paramedic access.

Improved out-of-hospital cardiac arrest survival through the inexpensive optimization of an existing defibrillation program: OPALS study phase II. Ontario Prehospital Advanced Life Support

Article

Jan 1999
NEW ENGL J MED

The Utstein style for uniform reporting of data from out-of-hospital cardiac arrest

Article

Aug 1991
ANN EMERG MED

RO CUMMINS

Outcome of Out-of-Hospital Cardiac Arrest in New York City

Article

Mar 1994

Gary Lombardi

Objective. —To determine survival from out-of-hospital cardiac arrest in New York City and to compare this with other urban, suburban, and rural areas.Design. —Observational cohort study.Setting. —New York City.Participants. —Consecutive out-of-hospital cardiac arrests occurring between October 1, 1990, and April 1, 1991.Intervention. —Trained paramedics performed immediate postarrest interviews with care providers, using a standardized questionnaire.Main Outcome Measures. —Entry criteria, elapsed time intervals, and nodal events conformed to Utstein recommendations. The single target end point was death or discharge home.Results. —Of 3243 consecutive cardiac arrests on which resuscitation was attempted, 2329 (72%) met entry criteria as primary cardiac events. Overall survival was 1.4% (99% confidence interval [CI], 0.9% to 2.3%). No patients were lost to follow-up. Survival from witnessed ventricular fibrillation was 5.3% (99% CI, 2.9% to 8.8%). Using survival from witnessed ventricular fibrillation for intersystem comparison, our survival rate was similar to that of Chicago, III (4.0%; 99% CI, 1.9% to 7.5%; P=.41), the only other large city on which data were available. However, it was significantly lower than that reported from midsized urban/suburban areas (33.0%; 99% CI, 30.4% to 35.6%; P<.0001) and suburban/rural areas (12.6%; 99% CI, 8.9% to 16.3%; P<.0001). Survival rate among arrests occurring after arrival of emergency medical services personnel (8.5%; 99% CI, 4.7% to 14.0%) was comparable with Chicago (6.6%; 99% CI, 3.3% to 11.5%; P=.41) but markedly lower than King County, Washington (36%; 99% CI, 28.6% to 43.8%; P<.0001).Conclusions. —Survival from out-of-hospital cardiac arrest in New York City was poor. This was partly attributable to lengthy elapsed time intervals at every step in the chain of survival. However, examination of survival among arrests occurring after emergency medical services arrival suggests that other features may predispose residents of large cities to higher cardiac arrest mortality than individuals living in more suburban or rural settings. Since half the US population resides in large metropolitan areas, this represents a public health problem of considerable magnitude.(JAMA. 1994;271:678-683)

Epidemiology of Avoidable Delay in the Care of Patients With Acute Myocardial Infarction in ItalyA GISSI-Generated Study

Article

Jul 1995
ARCH INTERN MED

Background: The delay between onset of symptoms and coronary care unit admission is decisive in the outcome of patients with acute myocardial infarction.Objective: To evaluate the influence of the factors that affect the delay in acute myocardial infarction treatment.Methods: Multicenter case-control study conducted by 118 coronary care units in Italy. The median and mean times in cases and controls were compared for decision time, home-to-hospital time, and in-hospital time, and the influence of several potential risk factors on the delay was evaluated by comparison of patients admitted more than 6 hours after onset with those admitted within 6 hours after onset.Results: Among 5301 patients with acute myocardial infarction, 590 who came to a coronary care unit after 12 hours were considered cases. Controls included 600 patients treated within 2 hours, 603 between 2 and 6 hours, and 466 between 6 and 12 hours. The median decision time among cases was 50-fold higher than that of controls who presented within 2 hours. Home-to-hospital time and in-hospital time appeared to play a less important role. Among the patient-related variables, advanced age, living alone, low intensity of initial symptoms, history of diabetes, strong pain at onset of the infarction, occurrence of symptoms at night, and involvement of a general practitioner seemed to affect delay significantly.Conclusion: Interventions aimed at reducing the delay in acute myocardial infarction treatment should primarily focus on the help-seeking behavior of patients.(Arch Intern Med. 1995;155:1481-1488)

Article

Sep 1991

Outcome of CPR in a large metropolitan area - Where are the survivors?

Article

May 1991
ANN EMERG MED

Survival from out-of-hospital cardiac arrest in cities with populations of more than 1 million has not been studied adequately. This study was undertaken to determine the overall survival rate for Chicago and the effect of previously reported variables on survival, and to compare the observed survival rates with those previously reported. Consecutive prehospital arrest patients were studied prospectively during 1987. The study area was the city of Chicago, which has more than 3 million inhabitants in 228 square miles. The emergency medical services system, with 55 around-the-clock ambulances and 550 paramedics, is single-tiered and responds to more than 200,000 emergencies per year. We studied 3,221 victims of out-of-hospital cardiac arrest on whom paramedics attempted resuscitation. Ninety-one percent of patients were pronounced dead in emergency departments, 7% died in hospitals, and 2% survived to hospital discharge. Survival was significantly greater with bystander-witnessed arrest, bystander-initiated CPR, paramedic-witnessed arrest, initial rhythm of ventricular fibrillation, and shorter treatment intervals. The overall survival rates were significantly lower than those reported in most previous studies, all based on smaller communities; they were consistent with the rates reported in the one comparable study of a large city. The single factor that most likely contributed to the poor overall survival was the relatively long interval between collapse and defibrillation. Logistical, demographic, and other special characteristics of large cities may have affected the rates. To improve treatment of cardiac arrest in large cities and maximize the use of community resources, we recommend further study of comparable metropolitan areas using standardized terms and methodology. Detailed analysis of each component of the emergency medical services systems will aid in making improvements to maximize survival of out-of-hospital cardiac arrest.

Cardiac arrest and resuscitation: A tale of 29 cities

Article

Mar 1990
ANN EMERG MED

Published reports of out-of-hospital cardiac arrest give widely varying results. The variation in survival rates within each type of system is due, in part, to variation in definitions. To determine other reasons for differences in survival rates, we reviewed published studies conducted from 1967 to 1988 on 39 emergency medical services programs from 29 different locations. These programs could be grouped into five types of prehospital systems based on the personnel who deliver CPR, defibrillation, medications, and endotracheal intubation; the five systems were three types of single-response systems (basic emergency medical technician [EMT], EMT-defibrillation [EMT-D], and paramedic) and two double-response systems (EMT/paramedic and EMT-D/paramedic). Reported discharge rates ranged from 2% to 25% for all cardiac rhythms and from 3% to 33% for ventricular fibrillation. The lowest survival rates occurred in single-response systems and the highest rates in double-response systems, although there was considerable variation within each type of system. Hypothetical survival curves suggest that the ability to resuscitate is a function of time, type, and sequence of therapy. Survival appears to be highest in double-response systems because CPR is started early. We speculate that early CPR permits definitive procedures, including defibrillation, medications, and intubation, to be more effective.

The location of collapse and its effect on survival from cardiac arrest

Article

Aug 1987
ANN EMERG MED

Survival from cardiac arrest is higher when the collapse occurs outside the home. Of 781 patients collapsing at home, 101 (13%) survived to hospital discharge. This compared with 66 survivors among 248 (27%) patients arresting outside the home (P less than .001). Patients collapsing outside the home were younger and more frequently were men. Cardiac arrests outside the home were more often witnessed, more likely to have bystander CPR, less often preceded by symptoms, and the collapsing rhythm was more frequently ventricular fibrillation. Mean time to CPR was shorter. Multivariate logistic regression showed that the effect of location on survival was still statistically significant, although diminished, after adjusting for the above variables (P less than .01). We speculate that comorbidity, underlying etiology, and activity level may explain the remaining difference. Because 76% of arrests occur in the home, efforts to increase the frequency of bystander-CPR through targeted and dispatcher-assisted CPR programs are warranted.

Vehicle-at-Scene-to-Patient-Access Interval Measured With Computer-Aided Dispatch

Article

Mar 1995
ANN EMERG MED

To determine whether the vehicle-at-scene-to-patient-access (VSPA) interval could be measured by means of crew reporting to a computer-aided dispatch operation. A prospective demonstration-proof-methodology pilot study using crew reporting of access time on emergency calls. An urban, public utility model (a type of EMS system), all-ALS system. Six ambulance crews (four day and two night). Times were collected by radio reporting. A survey was to be completed for each call. Two hundred ninety-two calls met study criteria; 181 had corresponding surveys. Crew reporting compliance ranged from 52.8% to 94%. Poor radio transmission was cited infrequently as a reason for noncompliance. The median VSPA interval for all calls was 1.3 minutes (interquartile range, .8 to 2.6 minutes). Twenty-five percent of calls had intervals of more than 2.5 minutes, and 10% had an interval of more than 5 minutes. Our study suggests that it is feasible for ambulance crews to report patient access times. Methods to improve the consistency and frequency of crew reporting should be considered. The VSPA access interval varies in length and is not normally distributed.

Outcome of out-of-hospital cardiac arrest in New York City. The Pre-Hospital Arrest Survival Evaluation (PHASE) Study

Article

Mar 1994

To determine survival from out-of-hospital cardiac arrest in New York City and to compare this with other urban, suburban, and rural areas. Observational cohort study. New York City. Consecutive out-of-hospital cardiac arrests occurring between October 1, 1990, and April 1, 1991. Trained paramedics performed immediate postarrest interviews with care providers, using a standardized questionnaire. Entry criteria, elapsed time intervals, and nodal events conformed to Utstein recommendations. The single target end point was death or discharge home. Of 3243 consecutive cardiac arrests on which resuscitation was attempted, 2329 (72%) met entry criteria as primary cardiac events. Overall survival was 1.4% (99% confidence interval [CI], 0.9% to 2.3%). No patients were lost to follow-up. Survival from witnessed ventricular fibrillation was 5.3% (99% CI, 2.9% to 8.8%). Using survival from witnessed ventricular fibrillation for intersystem comparison, our survival rate was similar to that of Chicago, Ill (4.0%; 99% CI, 1.9% to 7.5%; P = .41), the only other large city on which data were available. However, it was significantly lower than that reported from midsized urban/suburban areas (33.0%; 99% CI, 30.4% to 35.6%; P < .0001) and suburban/rural areas (12.6%; 99% CI, 8.9% to 16.3%; P < .0001). Survival rate among arrests occurring after arrival of emergency medical services personnel (8.5%; 99% CI, 4.7% to 14.0%) was comparable with Chicago (6.6%; 99% CI, 3.3% to 11.5%; P = .41) but markedly lower than King County, Washington (36%; 99% CI, 28.6% to 43.8%; P < .0001). Survival from out-of-hospital cardiac arrest in New York City was poor. This was partly attributable to lengthy elapsed time intervals at every step in the chain of survival. However, examination of survival among arrests occurring after emergency medical services arrival suggests that other features may predispose residents of large cities to higher cardiac arrest mortality than individuals living in more suburban or rural settings. Since half the US population resides in large metropolitan areas, this represents a public health problem of considerable magnitude.

Ambulance arrival to patient contact: The hidden component of prehospital response time intervals

Article

Aug 1993
ANN EMERG MED

To determine the time between ambulance arrival at the scene to paramedic arrival at the patient (arrival to patient contact) and the effect of barriers to paramedic movement on this time interval. A prospective, observational study. Time intervals were collected by independent third-party riders on emergency (Code 1 and Code 2) calls. Potential barriers to paramedic movement were recorded. Public utility model urban emergency medical services system. Two hundred thirty-two emergency ambulance calls were observed, and data were analyzed from 216. None. The median arrival-to-patient contact interval for all calls was 1.33 minutes (interquartile range, 0.67 to 4.13 minutes). Barriers prolonged the arrival-to-patient contact interval (P < .001, Kolmogorov-Smirnov test). The median arrival-to-patient contact interval was 2.29 minutes (1.01 to 4.82 minutes) for 122 runs with barriers and 0.82 minutes (0.37 to 1.96 minutes) for 94 runs without barriers. The arrival-to-patient contact interval adds a variable and potentially lengthy amount of time to the total prehospital response time interval, and barriers impeding paramedic movement to the patient prolong this time interval. In 25% of all observed paramedic calls, the arrival-to-patient contact interval was more than four minutes. Measurement of the time from ambulance arrival on the scene to paramedic arrival at the patient is necessary to appropriately determine the relationship among total prehospital response time, paramedic interventions, and patient outcome.

Prospective validation of a new model for evaluating emergency medical services systems by in-field observation of specific time intervals in prehospital care

Article

May 1993
ANN EMERG MED

To develop and validate a new time interval model for evaluating operational and patient care issues in emergency medical service (EMS) systems. DESIGN/SETTING/TYPE OF PARTICIPANT: Prospective analysis of 300 EMS responses among 20 advanced life support agencies throughout an entire state by direct, in-field observation. Mean times (minutes) were response, 6.8; patient access, 1.0; initial assessment, 3.3; scene treatment, 4.4; patient removal, 5.5; transport, 11.7; delivery, 3.5; and recovery, 22.9. The largest component of the on-scene interval was patient removal. Scene treatment accounted for only 31.0% of the on-scene interval, whereas accessing and removing patients took nearly half of the on-scene interval (45.8%). Operational problems (eg, communications, equipment, uncooperative patient) increased patient removal (6.4 versus 4.5; P = .004), recovery (25.4 versus 20.2; P = .03), and out-of-service (43.0 versus 30.1; P = .007) intervals. Rural agencies had longer response (9.9 versus 6.4; P = .014), transport (21.9 versus 10.3; P < .0005), and recovery (29.8 versus 22.1; P = .049) interval than nonrural. The total on-scene interval was longer if an IV line was attempted at the scene (17.2 versus 12.2; P < .0001). This reflected an increase in scene treatment (9.2 versus 2.8; P < .0001), while patient access and patient removal remained unchanged. However, the time spent attempting IV lines at the scene accounted for only a small part of scene treatment (1.3 minutes; 14.1%) and an even smaller portion of the overall on-scene interval (7.6%). Most of the increase in scene treatment was accounted for by other activities than the IV line attempts. A new model reported and studied prospectively is useful as an evaluative research tool for EMS systems and is broadly applicable to many settings in a demographically diverse state. This model can provide accurate information to system researchers, medical directors, and administrators for altering and improving EMS systems.

Estimating Effectiveness of Cardiac Arrest Interventions : A Logistic Regression Survival Model

Article

Dec 1997

The study objective was to develop a simple, generalizable predictive model for survival after out-of-hospital cardiac arrest due to ventricular fibrillation. Logistic regression analysis of two retrospective series (n=205 and n=1667, respectively) of out-of-hospital cardiac arrests was performed on data sets from a Southwestern city (population, 415,000; area, 406 km2) and a Northwestern county (population, 1,038,000; area, 1399 km2). Both are served by similar two-tiered emergency response systems. All arrests were witnessed and occurred before the arrival of emergency responders, and the initial cardiac rhythm observed was ventricular fibrillation. The main outcome measure was survival to hospital discharge. Patient age, initiation of CPR by bystanders, interval from collapse to CPR, interval from collapse to defibrillation, bystander CPR/collapse-to-CPR interval interaction, and collapse-to-CPR/collapse-to-defibrillation interval interaction were significantly associated with survival. There was not a significant difference between observed survival rates at the two sites after control for significant predictors. A simplified predictive model retaining only collapse to CPR and collapse to defibrillation intervals performed comparably to the more complicated explanatory model. The effectiveness of prehospital interventions for out-of-hospital cardiac arrest may be estimated from their influence on collapse to CPR and collapse to defibrillation intervals. A model derived from combined data from two geographically distinct populations did not identify site as a predictor of survival if clinically relevant predictor variables were controlled for. This model can be generalized to other US populations and used to project the local effectiveness of interventions to improve cardiac arrest survival.

Response times and outcomes for cardiac arrests in Las Vegas casinos

Article

Jun 1998
AM J EMERG MED

This study was conducted to measure emergency medical services (EMS) response times in sudden out-of-hospital cardiac arrests and relate those times to probability of survival in cardiac arrest victims in Las Vegas casino-hotels from January 1993 to June 1996. Times from 911 activation to casino arrival and casino arrival to arrival at patient's side (time to first defibrillatory shock), as well as survival to hospital discharge, were studied with regression analysis. Sixty patients survived (29.3%). Response times to the hotels for survivors and nonsurvivors were similar (4.8 v 5.6 min, P = .44). However, times from arrival at the casino to arrival at the patient's side (5.0 v 6.88 min, P = .01) and elapsed times from 911 activation until first shock (9.88 v 12.46 min, P = .02) were substantially longer for nonsurvivors. Model fitting disclosed that with a 911-to-shock time of 4 minutes, survival probability was 36%. Odds decreased by 5% each minute, to 19% after 23 minutes. Ventricular fibrillation was the most common initial rhythm (187 cases) and was associated with the shortest times from 911 to shock (10.7 +/- 7.8 min). There was a strong trend to increased survival with ventricular fibrillation. The 911-to-shock times in this study are considerably better than in other published reports for large metropolitan EMS systems, but the time from 911 to shock was nearly 3 minutes longer for nonsurvivors, and even those defibrillated at 4 minutes had only a 36% chance of survival. New measures, including use of the automatic external difibrillator, to reduce the "vertical" response are urgently needed.

Improved out-of-hospital cardiac arrest survival through the inexpensive optimization of an existing defibrillation program: OPALS study phase II. Ontario Prehospital Advanced Life Support

Article

Apr 1999

Survival rates for out-of-hospital cardiac arrest are low; published survival rates in Ontario are only 2.5%. This study represents phase II of the Ontario Prehospital Advanced Life Support (OPALS) study, which is designed to systematically evaluate the effectiveness and efficiency of various prehospital interventions for patients with cardiac arrest, trauma, and critical illnesses. To assess the impact on out-of-hospital cardiac arrest survival of the implementation of a rapid defibrillation program in a large multicenter emergency medical services (EMS) system with existing basic life support and defibrillation (BLS-D) level of care. Controlled clinical trial comparing survival for 36 months before (phase I) and 12 months after (phase II) system optimization. Nineteen urban and suburban Ontario communities (populations ranging from 16 000 to 750 000 [total, 2.7 million]). All patients who had out-of-hospital cardiac arrest in the study communities for whom resuscitation was attempted by emergency responders. Study communities optimized their EMS systems to achieve the target response interval from when a call was received until a vehicle stopped with a defibrillator of 8 minutes or less for 90% of cardiac arrest cases. Working both locally and provincially, communities implemented multiple measures, including defibrillation by firefighters, base paging, tiered response agreements with fire departments, continuous quality improvement for response intervals, and province-wide revision and implementation of standard dispatch policies. All response times were obtained from a central dispatch system. Survival to hospital discharge. The 4690 cardiac arrest patients studied in phase I and the 1641 in phase II were similar for all clinical and demographic characteristics, including age, sex, witnessed status, rhythm, and receipt of bystander cardiopulmonary resuscitation. The proportion of cases meeting the 8-minute response criterion improved (76.7% vs 92.5%; P<.001) as did most median response intervals. Overall survival to hospital discharge for all rhythm groups combined improved from 3.9% to 5.2 % (P = .03). The 33% relative increase in survival represents an additional 21 lives saved each year in the study communities (approximately 1 life per 120000 residents). The charges were estimated to be US

46900 per life saved for establishing the rapid defibrillation program and US

2400 per life saved annually for maintaining the program. An inexpensive, multifaceted system optimization approach to rapid defibrillation can lead to significant improvements in survival after cardiac arrest in a large BLS-D EMS system.

Delays in the EMS response to and the evacuation of patients in high-rise buildings in Singapore

Article

Jan 2000

Singapore is a highly urbanized and cosmopolitan city situated at the crossroads of Southeast Asia. High-rise buildings and "vertical living" are common, and the city serves as a major business, financial, and industrial hub in the region. More than 80% of the population live in high-rise apartments. This poses unique problems and challenges for emergency ambulance services personnel in the access to and evacuation of patients. To estimate the arrival-to-patient contact delay when accessing patients in high-rise buildings and evacuating them to the hospital, compared with accessing patients in ground-level premises. This was a prospective study carried out from February 2 to March 1, 1998, for emergency calls from two of the busiest fire stations. The first 150 consecutive cases were enrolled into each of the two groups. Cases of road traffic accidents were excluded because these did not require the crew to get into a building. The times were clocked by one of the paramedics, using a stopwatch. A high-rise building was defined as one where the crew had to ascend at least one flight of stairs. A ground-level building did not involve any stair climbing. We set forth to determine whether the interval between the following was statistically significant when comparing high-rise vs ground-level premises: 1) time when the ambulance arrives at the scene (taken as the time when the driver turns the engine off) and time of arrival at the patient's side; 2) time of leaving the dwelling with the patient and time when the ambulance starts its journey to the hospital (taken as the time when the driver starts the engine). Data analysis was done with the use of SPSS, and the one-tailed unpaired Student's t-test was used for significance testing, with the alpha error rate set at 0.05. Results. One hundred fifty runs were analyzed for each group. The mean delay from arrival to patient contact was 2.49 +/- 0.98 minutes for the high-rise group compared with 1.02 +/- 1.41 minutes for the ground-level group (difference was statistically significant with 95% CI: 1.20, 1.74 minutes; p = 0.0106). The mean delays from the time of leaving the building with the patient to the time when the ambulance turned its engine on to start its journey to the hospital were 3.24 +/- 1.58 minutes and 1.27 +/- 0.71 minutes for the two groups, respectively (difference was statistically significant with 95% CI: 1.68, 2.04 minutes; p = 0.0098). There were significant delays present when accessing patients in high-rise buildings and evacuating them to the hospital. Modification to buildings and increasing public awareness and education have been suggested to help minimize these delays.

Factors modifying the effect of bystander cardiopulmonary resuscitation on survival in out-of-hospital cardiac arrest patients in Sweden

Article

Apr 2001

To describe possible factors modifying the effect of bystander cardiopulmonary resuscitation on survival among patients suffering an out-of-hospital cardiac arrest. A national survey in Sweden among patients suffering out-of-hospital cardiac arrest and in whom resuscitative efforts were attempted. Sixty per cent of ambulance organizations were included. Prospective evaluation. Survival was defined as survival 1 month after cardiac arrest. In all, 14065 reports were included in the evaluation. Of these, resuscitation efforts were attempted in 10966 cases, of which 1089 were witnessed by ambulance crews. The report deals with the remaining 9877 patients, of whom bystander cardiopulmonary resuscitation was attempted in 36%. Survival to 1 month was 8.2% among patients who received bystander cardiopulmonary resuscitation vs 2.5% among patients who did not receive it (odds ratio 3.5, 95% confidence interval 2.9-4.3). The effect of bystander cardiopulmonary resuscitation on survival was related to: (1) the interval between collapse and the start of bystander cardiopulmonary resuscitation (effect more marked in patients who experienced a short delay); (2) the quality of bystander cardiopulmonary resuscitation (effect more marked if both chest compressions and ventilation were performed than if either of them was performed alone); (3) the category of bystander (effect more marked if bystander cardiopulmonary resuscitation was performed by a non-layperson); (4) interval between collapse and arrival of the ambulance (effect more marked if this interval was prolonged); (5) age (effect more marked in bystander cardiopulmonary resuscitation among the elderly); and (6) the location of the arrest (effect more marked if the arrest took place outside the home). The effect of bystander cardiopulmonary resuscitation on survival after an out-of-hospital cardiac arrest can be modified by various factors. Factors that were associated with the effect of bystander cardiopulmonary resuscitation were the interval between the collapse and the start of bystander cardiopulmonary resuscitation, the quality of bystander cardiopulmonary resuscitation, whether or not the bystander was a layperson, the interval between collapse and the arrival of the ambulance, age and the place of arrest.

Factors Influencing Early Admission in a French Stroke Unit

Article

Feb 2002
STROKE

Intravenous tissue plasminogen activator improves outcome after ischemic stroke when given within 3 hours of symptoms onset in carefully selected patients. However, only a small proportion of acute stroke patients are currently eligible for thrombolysis, mainly because of excessive delay to hospital presentation. We sought to determine the factors associated with early admission in a French stroke unit. We prospectively studied the admission delay of acute stroke patients in a French stroke unit during a 12-month period ending July 1999. Univariate and multivariate regression analyses were performed to evaluate the factors influencing early stroke unit admission and transport by the Emergency Medical Services (EMS) or Fire Department (FD) ambulances. One hundred sixty-six patients were primarily admitted to the stroke unit, with a median admission time of 4 hours 5 minutes. Twenty-nine percent presented within 3 hours of symptoms onset and 75% within 6 hours. Univariate analysis showed that early stroke unit arrival was significantly associated with the following factors: female sex, stroke severity assessed by the National Institutes of Health Stroke Scale score, lowered consciousness, sudden onset of stroke, not living alone, recognition of symptoms by bystanders, and transport by EMS or FD ambulances. Age, ethnicity, level of education, employment status, nocturnal onset, distance from place of stroke to the stroke unit, stroke lesion location, presence of brain hemorrhage, and awareness about the symptoms and risk factors of stroke had no measurable effect on early admission. A multivariate regression model demonstrated that the most significant factors associated with early stroke unit arrival were transport by EMS or FD ambulances and sudden onset of stroke. Female sex and not living alone were also significantly associated with early admission in the multivariate model. Multivariate analysis of the mode of transport showed that transport by EMS or FD ambulances was significantly more frequent among female patients, when stroke symptoms were recognized by bystanders, and when the general practitioner was not the first medical contact. The present study shows that hospital arrival within the first hours of stroke is feasible in a French stroke unit. As many as 75% of the patients are admitted within the first 6 hours of stroke. This is the first study demonstrating that stroke unit admission in France is fastest in patients brought to the hospital by EMS or FD ambulances. However, only 35% of stroke patients activate the emergency telephone system and are currently transported by EMS or FD ambulances. French stroke patients should be encouraged to seek immediate medical attention by using the emergency telephone system, and stroke management should be reprioritized in the French EMS as a time-dependent medical emergency, with the same level of organization and expertise currently applied to myocardial infarction.

Optimal defibrillation response intervals for maximum out-of-hospital cardiac arrest survival rates

Article

Sep 2003
ANN EMERG MED

Many centers optimize their emergency medical services (EMS) systems to achieve a target defibrillation response interval of "call received by dispatch" to "arrival at scene by responder with defibrillator" in 8 minutes or less for at least 90% of cardiac arrest cases. The objective of this study was to analyze survival as a function of time to test the evidence for this standard. This prospective cohort study included all adult, cardiac etiology, out-of-hospital cardiac arrest cases from phases I and II of the Ontario Prehospital Advanced Life Support (OPALS) study. Patients in the 21 Ontario study communities received a basic life support level of care with defibrillation by ambulance and firefighters but no advanced life support. Survival was plotted as a function of the defibrillation response interval. The equation of the curve, generated by means of logistic regression, was used to estimate survival at various defibrillation response interval cutoff points. From January 1, 1991, to December 31, 1997, there were 392 (4.2%) survivors overall among the 9,273 patients treated. The defibrillation response interval mean was 6.2 minutes, and the 90th percentile was 9.3 minutes. There was a steep decrease in the first 5 minutes of the survival curve, beyond which the slope gradually leveled off. Controlling for known covariates, the decrement in the odds of survival with increasing response interval was 0.77 per minute (95% confidence interval 0.74 to 0.83). The survival function predicts, for successive 90th percentile cutoff points, both survival rates and additional lives saved per year in the OPALS communities compared with the 8-minute standard: 9 minutes (4.6%; -18 lives), 8 minutes (5.9%; 0 lives), 7 minutes (7.5%; 23 lives), 6 minutes (9.5%; 51 lives), and 5 minutes (12.0%; 86 lives). The 8-minute target established in many communities is not supported by our data as the optimal EMS defibrillation response interval for cardiac arrest. EMS system leaders should consider the effect of decreasing the 90th percentile defibrillation response interval to less than 8 minutes.

for the Ontario Prehospital Advanced Life Support Group Optimal defibrillation response intervals for maximum out of hospital cardiac arrest survival rates

Jan 2003
242-50

Vj Demaio
Ig Stiell
Wells
Ga
Spaite

DeMaio VJ, Stiell IG, Wells GA, Spaite DW, for the Ontario Prehospital Advanced Life Support Group. Optimal defibrillation response intervals for maximum out of hospital cardiac arrest survival rates. Ann Emerg Med. 2003; 42:242–50.

Housing and Household Economics Statistics Division. NYC Housing and Vacancy Survey 2002, Series 1B-Table 18 Available at: http:// www.census.gov/hhes

May 2002

U S Bureau

U.S. Census Bureau, Housing and Household Economics Statistics Division. NYC Housing and Vacancy Survey 2002, Series 1B-Table 18. Available at: http:// www.census.gov/hhes/www/housing/nychvs/2002/ s1bt18.html. Accessed Apr 29, 2007.

Housing and Household Economic Statistics Division American Housing Survey for the United States Available at: http://www.census.gov/hhes

Mar 2003

U S Bureau

U.S. Census Bureau, Housing and Household Economic Statistics Division. American Housing Survey for the United States: 2003, Table 1B-2 2003. Available at: http://www.census.gov/hhes/www/housing/ahs/ ahs03/tab1b2.htm. Accessed Apr 29, 2007.

The “Vertical Response Time”: Barriers to Ambulance Response in an Urban Area

Abstract

No full-text available

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