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Derek J Roberts,
Craig N Jenne,
Caroline Leger,
Andreas H Kramer,
Clare N Gallagher,
Stephanie Todd,
Ian F Parney, Christopher J Doig,
V Wee Yong,
Paul Kubes,
David Zygun
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ABSTRACT: Accumulating pre-clinical data suggests that matrix metalloproteinase (MMP) expression plays a critical role in the pathophysiology of secondary brain injury. We conducted a prospective multimodal monitoring study in order to characterize the temporal MMP response after severe traumatic brain injury (TBI) in 8 critically ill humans and its relationship with outcomes. High-cutoff, cerebral microdialysis (n=8); external ventricular drainage (n=3); and arterial and jugular venous bulb catheters were used to collect microdialysate, cerebrospinal fluid, and arterial and jugular bulb blood over 6-days. Levels of MMP-8 and -9 were initially high in microdialysate and then gradually declined over time. After these MMPs decreased, a spike in the microdialysate levels of MMP-2 and -3 occurred, followed by a gradual rise in the microdialysate concentration of MMP-7. Use of generalized estimating equations suggested that MMP-8 concentration in microdialysate was associated with mortality (p=0.019) and neurological outcome at hospital discharge (p=0.013). Moreover, the mean microdialysate concentration of MMP-8 was 2.4 fold higher among those who died after severe TBI as compared to those who survived. Mean microdialysate levels of MMP-8 also rose with increasing intracranial pressure while those of MMP-7 decreased with increasing cerebral perfusion pressure. Significant changes in the mean microdialysate concentrations of MMP-1, -2, -3, and -9 and MMP-1, -2, -3, -7, and -9 also occurred with increases in microdialysate glucose and the lactate/pyruvate ratio, respectively. These results imply that monitoring of MMPs following severe TBI in humans is feasible, and that their expression may be associated with clinical outcomes, ICP, CPP, and cerebral metabolism.
Journal of neurotrauma 05/2013; · 4.25 Impact Factor
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ABSTRACT: BACKGROUND: Evaluating geographic access to health services often requires determining the patient travel time to a specified service. For urgent care, many research studies have modeled patient pre-hospital time by ground emergency medical services (EMS) using geographic information systems (GIS). The purpose of this study was to determine if the modeling assumptions proposed through prior United States (US) studies are valid in a non-US context, and to use the resulting information to provide revised recommendations for modeling travel time using GIS in the absence of actual EMS trip data. METHODS: The study sample contained all emergency adult patient trips within the Calgary area for 2006. Each record included four components of pre-hospital time (activation, response, on-scene and transport interval). The actual activation and on-scene intervals were compared with those used in published models. The transport interval was calculated within GIS using the Network Analyst extension of Esri ArcGIS 10.0 and the response interval was derived using previously established methods. These GIS derived transport and response intervals were compared with the actual times using descriptive methods. We used the information acquired through the analysis of the EMS trip data to create an updated model that could be used to estimate travel time in the absence of actual EMS trip records. RESULTS: There were 29,765 complete EMS records for scene locations inside the city and 529 outside. The actual median on-scene intervals were longer than the average previously reported by 7-8 minutes. Actual EMS pre-hospital times across our study area were significantly higher than the estimated times modeled using GIS and the original travel time assumptions. Our updated model, although still underestimating the total pre-hospital time, more accurately represents the true pre-hospital time in our study area. CONCLUSIONS: The widespread use of generalized EMS pre-hospital time assumptions based on US data may not be appropriate in a non-US context. The preference for researchers should be to use actual EMS trip records from the proposed research study area. In the absence of EMS trip data researchers should determine which modeling assumptions more accurately reflect the EMS protocols across their study area.
International Journal of Health Geographics 10/2012; 11(1):42. · 2.62 Impact Factor
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ABSTRACT: ObjectifLe score de défaillance multiviscérale (DMV) et le score de SOFA (Sequential Organ Failure Assessment) mesurent la dysfonction
organique et ont été validés sur leur association avec la mortalité. Nous avons comparé leur performance chez des patients
successivement admis à l’unité des soins intensifs (USI) pour une atteinte multiviscérale. Méthode : Les mesures quotidiennes,
prospectives et automatisés des scores de DMV et de SOFA ont été faites chez 1 436 patients admis à une USI multiviscéraux
dans la région de Calgary pendant une année. Une modélisation de régression logistique a servi à décrire l’association des
scores de SOFA et de DMV à la mortalité. La capacité discriminatoire du modèle a été évaluée par les courbes ROC (Receiver
Operator Characteristic).
RésultatsConcernant la mortalité à l’USI et à l’hôpital, les scores de SOFA et de DMV présentaient une très petite différence pratique
de capacité à distinguer les résultats comme l’a montré l’aire sous la courbe ROC. Comparée aux données des publications antérieures,
la capacité discriminatoire des deux scores était faible pour la population évaluée. Aussi, le calibrage des modèles était
pauvre pour les deux scores. Le score de la composante cardiovasculaire du SOFA a présenté une meilleure performance que celui
de la DMV quant à la détermination de la mortalité à l’USI et à l’hôpital.
ConclusionLes scores de SOFA et de DMV n’ont qu’une faible capacité à distinguer les patients qui vont survivre ou non. Cela remet en
question la pertinence d’utiliser des scores de dysfonction organique comme «substitut» à la mortalité dans les essais cliniques
et incite à chercher à découvrir la relation temporelle entre l’évolution de la défaillance organique et la mortalité.
PurposeThe multiple organ dysfunction (MOD) score and sequential organ failure assessment (SOFA) score are measures of organ dysfunction
and have been validated based on the association of these scores with mortality. We sought to compare the performance of the
SOFA and MOD scores in a large cohort of consecutive multisystem intensive care unit (ICU) patients.
MethodsProspective automated daily measurements of MOD and SOFA scores were performed in 1,436 patients admitted to a multisystem
ICU in the Calgary Health Region over a one-year period. Logistic regression modeling techniques were used to describe the
association of SOFA and MODS with mortality. Receiver operator characteristic (ROC) curves were used to assess the model’s
discriminatory ability.
ResultsFor ICU and hospital mortality, there was very little practical difference between the SOFA and MOD scores in their ability
to discriminate outcome as determined by the area under the ROC. However, compared to previous literature, the discriminatory
ability of both scores in this population was weak. As well, the calibration of the models was poor for both scores. The SOFA
cardiovascular component score performed better than the MOD cardiovascular component score in the discrimination of both
ICU and hospital mortality.
ConclusionsSOFA and MOD scores had only a modest ability to discriminate between survivors and non-survivors. These results question
the appropriateness of using organ dysfunction scores as a ’surrogate’ for mortality in clinical trials and suggest further
work is necessary to better understand the temporal relationship and course of organ failure with mortality.
Canadian Journal of Anaesthesia 04/2012; 52(3):302-308. · 2.35 Impact Factor
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ABSTRACT: Introduction p Pneumonia is an important cause of morbidity following severe traumatic brain injury (TBI). However, previous
studies have been limited by inclusion of specific patient subgroups or by selection bias. The primary objective of this study
wastoo describe the incidence, risk factors for, and outcome of ventilator-associated pneumonia in an unselected population-based
cohort of patients with severe TBI. An additional goal was to define the relationship of ventilator-associated pneumonia (VAP)
with nonneurological organ dysfunction.
Methods p A prospective, observational cohort study was performed at Foothills Medical Centre, the sole adult tertiary-care
trauma center servicing southern Alberta. All patients with severe TBI requiring ventilation for more than 48 hours between
May 1, 2000 and December 30, 2002 were included.
Results p A total of 60 patients (45%) acquired VAP for an incidence density of 42.7/1000 ventilator days. Patients with polytrauma
were at higher risk (risk ratio 1.7,95% confidence interval, 0.9–3.1) for development of VAP than those with isolated head
injury. Development of VAP was associated with a significantly greater degree of nonneurological organ svstem dysfunction.
Although VAP was not associated with increased hospital mortality, patients who developed VAP had a longer duration of mechanical
ventilation (15 versus 8 days, p < 0.0001), longer intensive care unit (17 versus 9 days, p < 0.0001) and hospital (60 versus 28 days, p=0.003) lengths of stay, and more often required tracheostomy (35 versus 18%, p=0.003).
ConclusionsVAP occurs frequently and is associated with significant morbidity in patients with severe TBI.
Neurocritical Care 04/2012; 5(2):108-114. · 2.47 Impact Factor
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ABSTRACT: Intensive care unit (ICU) beds, a scarce resource, may require prioritization of admissions when demand exceeds supply. We evaluated the effect of ICU bed availability on processes and outcomes of care for hospitalized patients with sudden clinical deterioration.
We identified consecutive hospitalized adults in Calgary, Alberta, Canada, with sudden clinical deterioration triggering medical emergency team activation between January 1, 2007, and December 31, 2009. We compared ICU admission rates (within 2 hours of medical emergency team activation), patient goals of care (resuscitative, medical, and comfort), and hospital mortality according to the number of ICU beds available (0, 1, 2, or >2), adjusting for patient, physician, and hospital characteristics (using data from clinical and administrative databases).
The cohort consisted of 3494 patients. Reduced ICU bed availability was associated with a decreased likelihood of patient admission within 2 hours of medical emergency team activation (P = .03) and with an increased likelihood of change in patient goals of care (P < .01). Patients with sudden clinical deterioration when zero ICU beds were available were 33.0% (95% CI, -5.1% to 57.3%) less likely to be admitted to the ICU and 89.6% (95% CI, 24.9% to 188.0%) more likely to have their goals of care changed compared with when more than 2 ICU beds were available. Hospital mortality did not vary significantly by ICU bed availability (P = .82).
Among hospitalized patients with sudden clinical deterioration, we noted a significant association between the number of ICU beds available and ICU admission and patient goals of care but not hospital mortality.
Archives of internal medicine 03/2012; 172(6):467-74. · 11.46 Impact Factor
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ABSTRACT: 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.
Prehospital Emergency Care 01/2012; 16(1):142-51. · 1.78 Impact Factor
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ABSTRACT: Background: Systolic pressure variation (SPV) predicts responsiveness to volume loading during mechanical ventilation and may be related to changes in LV preload and the resultant changes in stroke volume (SV). We, therefore, tested the relations between LV preload, output and SPV in an acute lung injury (ALI) model during mechanical ventilation.
Methods: ALI was created by oleic acidinfusion (0.07 ml/kg) in 8 anesthetized dogs. We measured LV, RV,
aortic, left atrial (LA) and pericardial pressures, LV area (ALVED) and SV during mechanical ventilation with positive end-expiratory pressures (PEEP) of 0, 6, 12 and 18 cmH2O at LV end-diastolic pressures of 5, 12 and 18 mmHg.
Results: Throughout these ranges of PEEPs and filling pressures, SPV was inversely related to LV preload [ALVED and transmural LV end-diastolic pressure; (PLVEDtm)] (r = −0.87 and r = −0.89, P <0.0001 respectively). Both preload measures were closely related to SV (both r = 0.90, P <0.0001). Changes in estimated PLVEDtm (LA end-diastolic pressure – RV end-diastolic pressure) matched changes in PLVEDtm (r = 0.95, P < 0.0001). Alternative measures of arterial pressure variation (pulse pressure variation, SV variation and delta down) behaved similarly when compared to SPV (r = 0.91, 0.97, and 0.78, P < 0.001, respectively).
Conclusions: The inverse relations between SPV and LV preload and output indicate that LV preload is a major determinant of SPV. An estimate of LV preload based on measurements from the flow-directed catheter (i.e., wedge pressure – right atrial pressure) may predict volume responsiveness in mechanically ventilated patients.
Journal of Clinical and Experimental Cardiology. 08/2011; 2(7):143.
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ABSTRACT: During mechanical ventilation, increased pulmonary vascular resistance (PVR) may decrease right ventricular (RV) performance. We hypothesized that volume loading, by reducing PVR, and, therefore, RV afterload, can limit this effect. Deep anesthesia was induced in 16 mongrel dogs (8 oleic acid-induced acute lung injury and 8 controls). We measured ventricular pressures, dimensions, and stroke volumes during positive end-expiratory pressures of 0, 6, 12, and 18 cmH(2)O at three left ventricular (LV) end-diastolic pressures (5, 12, and 18 mmHg). Oleic acid infusion (0.07 ml/kg) increased PVR and reduced respiratory system compliance (P < 0.05). With positive end-expiratory pressure, PVR was greater at a lower LV end-diastolic pressure. Increased PVR was associated with a decreased transseptal pressure gradient, suggesting that leftward septal shift contributed to decreased LV preload, in addition to that caused by external constraint. Volume loading reduced PVR; this was associated with improved RV output and an increased transseptal pressure gradient, which suggests that rightward septal shift contributed to the increased LV preload. If PVR is used to reflect RV afterload, volume loading appeared to reduce PVR, thereby improving RV and LV performance. The improvement in cardiac output was also associated with reduced external constraint to LV filling; since calculated PVR is inversely related to cardiac output, increased LV output would reduce PVR. In conclusion, our results, which suggest that PVR is an independent determinant of cardiac performance, but is also dependent on cardiac output, improve our understanding of the hemodynamic effects of volume loading in acute lung injury.
AJP Regulatory Integrative and Comparative Physiology 01/2011; 300(3):R763-70. · 3.34 Impact Factor
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ABSTRACT: The H1N1 pandemic has highlighted the importance of reliable and valid triage instruments. A Sequential Organ Failure Assessment score of >11 has been proposed to exclude patients from critical care resources quoting an associated mortality of >90%. We sought to assess the mortality associated with this Sequential Organ Failure Assessment threshold and the resource implications of such a triage protocol.
Retrospective cohort.
Three multisystem intensive care units.
Consecutive patients admitted from January 2003 to December 2008. Subsequently, a comparison H1N1 cohort was assembled consisting of all patients admitted in 2009 with confirmed H1N1.
None.
Sequential Organ Failure Assessment was collected daily by use of an electronic bedside clinical information system (n = 10,204 patients, 69,913 patient days). Mean admission Acute Physiology and Chronic Health Evaluation was 19.1. 13.4% of the cohort (9% of total patient days) had an initial Sequential Organ Failure Assessment of >11. Mortality in patients with an initial Sequential Organ Failure Assessment score of >11 was 59% (95% confidence interval: 56%, 62%). The mortality associated with an initial Sequential Organ Failure Assessment >11 across diagnostic categories varied from 29% for poisoning to 67% for neurologic patients. Hospital mortality exceeded 90% only when initial Sequential Organ Failure Assessment was >20 (0.2% of patients). H1N1 patients were younger, had a longer intensive care unit length of stay, and more commonly had a respiratory admission diagnosis than the nonH1N1 cohort. Hospital mortality in H1N1 patients with an initial Sequential Organ Failure Assessment score of >11 was 31% (95% confidence interval: 5%, 56%).
A Sequential Organ Failure Assessment score of >11 was not associated with a hospital mortality of >90% at any time during intensive care unit stay. Only a small proportion of patients have the extreme initial Sequential Organ Failure Assessment values associated with a hospital mortality of >90% limiting the usefulness of Sequential Organ Failure Assessment as a triage instrument for pandemic planning. Application of a Sequential Organ Failure Assessment threshold of >11 to the recent H1N1 pandemic would have excluded patients with a markedly lower mortality than seen in a large regional cohort of intensive care unit patients.
Critical care medicine 01/2011; 39(4):827-32. · 6.37 Impact Factor
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ABSTRACT: The effect of the long acting beta(2)-agonist/corticosteroid combination salmeterol-fluticasone propionate (SFC) on respiratory muscles and ventilation in severe COPD is unknown. As COPD hyperinflation worsens, diaphragm efficiency decreases, and a compensatory increase in chest wall inspiratory muscle activity occurs. If a bronchodilator successfully alleviates hyperinflation and improves diaphragm efficiency in severe COPD, then the extraordinary activation of the chest wall may be relieved. We examined directly the effect on the parasternal intercostal respiratory chest wall muscle and ventilation of four puffs of salmeterol 25 microg and fluticasone propionate 125 microg via the metered dose combination inhaler in 12 patients with severe Global Initiative on Obstructive Lung Disease stage III-IV COPD, mean FEV(1) = 0.91 L (32% predicted).
We measured parasternal intercostal electromyogram (EMG) recorded from implanted fine-wire electrodes, ventilation, and breathing pattern, during resting and CO(2)-stimulated breathing. Full pulmonary function tests were recorded at the beginning and end of the study.
In this patient group, severe airflow obstruction and hyperinflation were poorly reversible after SFC: FEV(1) increased 4.2%, functional residual capacity decreased 1.4%, and inspiratory capacity increased 5.9%. However, with SFC there was a significant increase in minute ventilation, tidal volume, and mean inspiratory flow. There was a very large decrease in directly recorded parasternal EMG, with parasternal EMG disappearing completely in some patients after SFC.
In severe COPD, with minimal change in hyperinflation or pulmonary mechanics, salmeterol-fluticasone induced a significant decrease in activity of the chest wall parasternal inspiratory muscle. This may be of practical benefit to reverse the extensive use of the chest wall muscles and alleviate dyspnea in severe COPD.
Chest 10/2009; 137(3):558-65. · 5.25 Impact Factor
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Stephen R Clark,
Adrienne C Ma,
Samantha A Tavener,
Braedon McDonald,
Zahra Goodarzi,
Margaret M Kelly,
Kamala D Patel,
Subhadeep Chakrabarti,
Erin McAvoy,
Gary D Sinclair,
Elizabeth M Keys,
Emma Allen-Vercoe,
Rebekah Devinney, Christopher J Doig,
Francis H Y Green,
Paul Kubes
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ABSTRACT: It has been known for many years that neutrophils and platelets participate in the pathogenesis of severe sepsis, but the inter-relationship between these players is completely unknown. We report several cellular events that led to enhanced trapping of bacteria in blood vessels: platelet TLR4 detected TLR4 ligands in blood and induced platelet binding to adherent neutrophils. This led to robust neutrophil activation and formation of neutrophil extracellular traps (NETs). Plasma from severely septic humans also induced TLR4-dependent platelet-neutrophil interactions, leading to the production of NETs. The NETs retained their integrity under flow conditions and ensnared bacteria within the vasculature. The entire event occurred primarily in the liver sinusoids and pulmonary capillaries, where NETs have the greatest capacity for bacterial trapping. We propose that platelet TLR4 is a threshold switch for this new bacterial trapping mechanism in severe sepsis.
Nature Medicine 05/2007; 13(4):463-9. · 22.46 Impact Factor
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ABSTRACT: Several hospitals have been developing programmes for organ donation after cardiac death. Such programmes offer options for organ donation to patients who do not meet brain-death criteria but wish to donate their organs after withdrawal of life-support. These programmes also increase the available organ pool at a time when demand exceeds supply. Given that potential donors are managed in intensive care units, intensivists will be key components of these programmes. Donation after cardiac death clearly carries a number of important ethical issues with it. In the present issue of Critical Care two established groups debate the ethical acceptability of using medications/interventions in potential organ donors for the sole purpose of making the organs more viable. Such debates will be an increasingly common component of intensivists' future practice.
Critical care (London, England) 02/2007; 11(2):211. · 4.61 Impact Factor
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ABSTRACT: The impact that physician trainees have on patient outcomes in academic adult medical/surgical intensive care units (ICUs) has not been adequately assessed.
All admissions to adult ICUs within the Calgary Health Region over a three-year period when a critical care medicine fellow (CCMF) was on service were compared to when an attending physician was alone on service. Primary outcomes were ICU and in-hospital mortality and length of stay (LOS).
CCMFs and attending physicians admitted 3,341 patients, while attending physicians alone admitted 3,224 patients. There was no difference in ICU or in-hospital mortality between the two groups; regression analysis determined CCMFs did not affect patient LOS.
In teaching hospitals with adult mixed medical/surgical ICUs, CCMFs do not have an effect on patient outcome or LOS. Improved patient outcomes at academic institutions previously attributed to the presence of CCMFs may instead be due to institution and patient-related factors.
Academic Medicine 11/2006; 81(10 Suppl):S1-4. · 3.52 Impact Factor
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ABSTRACT: Kidney dysfunction in the intensive care unit (ICU) results in increased morbidity, mortality, and health care costs; however, long-term mortality has not been described across strata of severity in kidney dysfunction.
The primary objective is to describe and assess factors associated with 1-year mortality in critically ill patients stratified by severity of kidney dysfunction during admission to the ICU. Kidney dysfunction is defined by peak serum creatinine values and stratified by: (1) no dysfunction (creatinine < 1.7 mg/dL [<150 micromol/L]), (2) mild dysfunction (creatinine, 1.7 to 3.4 mg/dL [150 to 299 micromol/L]), (3) moderate dysfunction (creatinine >or= 3.4 mg/dL [>or= 300 micromol/L]), (4) severe acute dysfunction requiring renal replacement therapy (acute renal failure), or (5) preexisting end-stage kidney disease. Population-based surveillance was of adult residents of the Calgary Health Region (population, 1 million) admitted to any multidisciplinary ICU and a cardiovascular surgery ICU from May 1, 1999, to April 30, 2002.
Of 5,693 admissions, 62% were men, median age was 64.9 years (interquartile range, 50.6 to 74.5 years), and mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 24.9 +/- 8.7 (SD). Case fatality rates stratified by renal dysfunction were 17% (763 of 4,411), 47% (370 of 790), 48% (77 of 160), 64% (153 of 240), and 40% (37 of 92) for no, mild, and moderate dysfunction; severe acute renal failure; and end-stage kidney disease, respectively. By means of multivariate analysis, 1-year mortality was associated independently with advancing age, medical diagnosis, higher APACHE II score, and presence and severity of kidney dysfunction, although no difference was evident comparing those with mild to moderate dysfunction. End-stage kidney disease was not associated independently with 1-year mortality.
Severity of kidney dysfunction in patients in the ICU is associated with an incremental increase in long-term mortality. Although patients classified with either mild or moderate kidney dysfunction had an increased risk for death, use of serum creatinine level alone was poor at discriminating long-term outcome, suggesting this measure alone should not be used for defining long-term prognosis.
American Journal of Kidney Diseases 10/2006; 48(3):402-9. · 5.43 Impact Factor
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ABSTRACT: Pneumonia is an important cause of morbidity following severe traumatic brain injury (TBI). However, previous studies have been limited by inclusion of specific patient subgroups or by selection bias. The primary objective of this study was to describe the incidence, risk factors for, and outcome of ventilator-associated pneumonia in an unselected population-based cohort of patients with severe TBI. An additional goal was to define the relationship of ventilator-associated pneumonia (VAP) with nonneurological organ dysfunction.
A prospective, observational cohort study was performed at Foothills Medical Centre, the sole adult tertiary-care trauma center servicing southern Alberta. All patients with severe TBI requiring ventilation for more than 48 hours between May 1, 2000 and December 30, 2002 were included.
A total of 60 patients (45%) acquired VAP for an incidence density of 42.7/1000 ventilator days. Patients with polytrauma were at higher risk (risk ratio 1.7, 95% confidence interval, 0.9-3.1) for development of VAP than those with isolated head injury. Development of VAP was associated with a significantly greater degree of nonneurological organ system dysfunction. Although VAP was not associated with increased hospital mortality, patients who developed VAP had a longer duration of mechanical ventilation (15 versus 8 days, p < 0.0001), longer intensive care unit (17 versus 9 days, p < 0.0001) and hospital (60 versus 28 days, p = 0.003) lengths of stay, and more often required tracheostomy (35 versus 18%, p = 0.003).
VAP occurs frequently and is associated with significant morbidity in patients with severe TBI.
Neurocritical Care 02/2006; 5(2):108-14. · 2.47 Impact Factor
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ABSTRACT: Meta-analyses have been suggested to be the highest form of evidence available to clinicians to guide clinical practice in critical care. The purpose of this study was to systematically evaluate the quality of meta-analyses that address topics pertinent to critical care.
To identify potentially eligible meta-analyses for inclusion, a systematic search of Medline, EMBASE and the Cochrane Database of Systematic Reviews was undertaken, using broad search terms relevant to intensive care, including: intensive care, critical care, shock, resuscitation, inotropes and mechanical ventilation. Predetermined inclusion criteria were applied to each identified meta-analysis independently by two authors. To assess report quality, the included meta-analyses were assessed using the component and overall scores from the Overview Quality Assessment Questionnaire (OQAQ). The quality of reports published before and after the publication of the QUOROM statement was compared.
A total of 139 reports of meta-analyses were included (kappa = 0.93). The overall quality of reports of meta-analyses was found to be poor, with an estimated mean overall OQAQ score of 3.3 (95% CI; 3.0-3.6). Only 43 (30.9%) were scored as having minimal or minor flaws (>5). We noted problems with the reporting of key characteristics of meta-analyses, such as performing a thorough literature search, avoidance of bias in the inclusion of studies and appropriately referring to the validity of the included studies. After the release of the QUOROM statement, however, an improvement in the overall quality of published meta-analyses was noted.
The overall quality of the reports of meta-analyses available to critical care physicians is poor. Physicians should critically evaluate these studies prior to considering applying the results of these studies in their clinical practice.
Critical care (London, England) 11/2005; 9(5):R575-82. · 4.61 Impact Factor
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ABSTRACT: The multiple organ dysfunction (MOD) score and sequential organ failure assessment (SOFA) score are measures of organ dysfunction and have been validated based on the association of these scores with mortality. We sought to compare the performance of the SOFA and MOD scores in a large cohort of consecutive multisystem intensive care unit (ICU) patients.
Prospective automated daily measurements of MOD and SOFA scores were performed in 1,436 patients admitted to a multisystem ICU in the Calgary Health Region over a one-year period. Logistic regression modeling techniques were used to describe the association of SOFA and MODS with mortality. Receiver operator characteristic (ROC) curves were used to assess the model's discriminatory ability.
For ICU and hospital mortality, there was very little practical difference between the SOFA and MOD scores in their ability to discriminate outcome as determined by the area under the ROC. However, compared to previous literature, the discriminatory ability of both scores in this population was weak. As well, the calibration of the models was poor for both scores. The SOFA cardiovascular component score performed better than the MOD cardiovascular component score in the discrimination of both ICU and hospital mortality.
SOFA and MOD scores had only a modest ability to discriminate between survivors and non-survivors. These results question the appropriateness of using organ dysfunction scores as a 'surrogate' for mortality in clinical trials and suggest further work is necessary to better understand the temporal relationship and course of organ failure with mortality.
Canadian Journal of Anaesthesia 04/2005; 52(3):302-8. · 2.35 Impact Factor
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ABSTRACT: To describe the incidence of non-neurologic organ dysfunction and its association with outcome in patients with severe traumatic brain injury admitted to intensive care.
Observational cohort study.
Foothills Medical Centre, which is the only neurosurgical service in southern Alberta (population approximately 1.3 million).
Patients were 209 consecutive patients with severe traumatic brain injury.
None.
Non-neurologic organ dysfunction was measured by the maximum modified multiple organ dysfunction score. Organ system failure was defined as a component score of >/=3 on any day during the patient's intensive care unit stay. One hundred and eighty-five patients (89%) developed dysfunction of at least one non-neurologic organ system. Ninety-six organ system failures were identified in 74 patients (35%). Respiratory failure was the most common non-neurologic organ system failure, occurring in 23% of patients, whereas cardiovascular failure occurred in 18%. Eight patients (4%) had failure of the coagulation system. One patient had renal failure, whereas no patient developed hepatic failure. In a multivariate model, non-neurologic organ dysfunction was independently associated with hospital mortality (odds ratio for hospital mortality, 1.63; 95% confidence interval, 1.34, 1.98 for one maximum modified multiple organ dysfunction score point). Non-neurologic organ dysfunction was also independently associated with dichotomized Glasgow Outcome Score, as a measure of neurologic outcome (odds ratio for unfavorable neurologic outcome, 1.53; 95% confidence interval, 1.22, 1.98 for one maximum modified multiple organ dysfunction score point). The timing of the organ dysfunction did not appear to be important in the prediction of outcome.
Non-neurologic organ dysfunction is common in patients with severe traumatic brain injury and is independently associated with worse outcome.
Critical Care Medicine 03/2005; 33(3):654-60. · 6.33 Impact Factor
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ABSTRACT: The long-term mortality outcome associated with sepsis and septic shock has not been well defined in a nonselected critically ill population. This study investigated the occurrence and the role of bloodstream infection (BSI) associated sepsis and septic shock at time of intensive care unit (ICU) admission on the 1-year mortality of patients admitted to a regional critical care system.
Population-based inception cohort in all adult multidisciplinary and cardiovascular ICUs in the Calgary Health Region (population approx. 1 million) between 1 July 1999 and 31 March 2002.
Adults (>/=18 years; n=4,845) who had at least one ICU admission to CHR ICUs.
In 251 (5%) patients there was BSI-associated sepsis at presentation to ICU, and 159 of these also had septic shock. The 28-day, 90-day, and 1-year mortality rates overall were 18%, 21%, and 24%: 23%, 30%, and 36% for BSI-associated sepsis without shock, and 51%, 57%, and 61% with shock, respectively. Surgical diagnosis, BSI-associated sepsis, and increasing age were independently associated with late (28-day to 1-year) mortality whereas higher APACHE II and TISS scores were associated with reduced odds in logistic regression analysis.
BSI-associated sepsis and septic shock are associated with increased risk of mortality persisting after 28-days up to 1 year or more. Follow-up duration beyond 28 days better defines the burden of illness associated with these syndromes.
Intensive Care Medicine 03/2005; 31(2):213-9. · 5.40 Impact Factor
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ABSTRACT: The cardiac effects of positive pressure ventilation and positive end-expiratory pressure are incompletely understood. External constraint due to increased intrathoracic pressure decreases left ventricular end-diastolic volume; the effects on venous return and ventricular interaction are less clear. Phasic changes in inferior vena caval flow, end-diastolic ventricular dimensions and output were measured in seven anesthetized, ventilated normal dogs. During inspiration, caval flow, right ventricular diameter and output decreased; end-diastolic transseptal pressure gradient, septum-to-left ventricular free wall diameter, left ventricular area (ie, left ventricular volume index) and output increased despite the decreased sum of the septum-to-free wall diameters. The reverse occurred during expiration. Increased positive end-expiratory pressure decreased the left ventricular area, but the end-expiratory right ventricular diameter was unchanged. At given airway pressures, right ventricular diameter was greater at higher positive end-expiratory pressures, suggesting that a leftward septal shift (direct ventricular interaction) added to the effect of external constraint on left ventricular end-diastolic volume. In conclusion, positive pressure ventilation reduced right ventricular end-diastolic volume during inspiration and increased the transseptal pressure gradient, which shifted the septum rightward, increasing left ventricular end-diastolic volume and output. The reverse occurred during expiration. Positive end-expiratory pressure constrained left ventricular filling and decreased left ventricular end-diastolic volume further by a leftward septal shift.
The Canadian journal of cardiology 02/2005; 21(1):73-81. · 3.36 Impact Factor
