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A Conway Morris,
N Anderson,
M Brittan,
T S Wilkinson,
D F McAuley,
J Antonelli,
C McCulloch,
L C Barr,
K Dhaliwal,
R O Jones,
C Haslett,
A W Hay,
D G Swann,
I F Laurenson,
D J Davidson,
A G Rossi, T S Walsh,
A J Simpson
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A Conway Morris,
N Anderson,
M Brittan,
T S Wilkinson,
D F McAuley,
J Antonelli,
C McCulloch,
L C Barr,
K Dhaliwal,
R O Jones,
C Haslett,
A W Hay,
D G Swann,
I F Laurenson,
D J Davidson,
A G Rossi, T S Walsh,
A J Simpson
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ABSTRACT: BACKGROUND: /st>Nosocomial infection occurs commonly in intensive care units (ICUs). Although critical illness is associated with immune activation, the prevalence of nosocomial infections suggests concomitant immune suppression. This study examined the temporal occurrence of immune dysfunction across three immune cell types, and their relationship with the development of nosocomial infection. METHODS: /st>A prospective observational cohort study was undertaken in a teaching hospital general ICU. Critically ill patients were recruited and underwent serial examination of immune status, namely percentage regulatory T-cells (Tregs), monocyte deactivation (by expression) and neutrophil dysfunction (by CD88 expression). The occurrence of nosocomial infection was determined using pre-defined, objective criteria. RESULTS: /st>Ninety-six patients were recruited, of whom 95 had data available for analysis. Relative to healthy controls, percentage Tregs were elevated 6-10 days after admission, while monocyte HLA-DR and neutrophil CD88 showed broader depression across time points measured. Thirty-three patients (35%) developed nosocomial infection, and patients developing nosocomial infection showed significantly greater immune dysfunction by the measures used. Tregs and neutrophil dysfunction remained significantly predictive of infection in a Cox hazards model correcting for time effects and clinical confounders {hazard ratio (HR) 2.4 [95% confidence interval (CI) 1.1-5.4] and 6.9 (95% CI 1.6-30), respectively, P=0.001}. Cumulative immune dysfunction resulted in a progressive risk of infection, rising from no cases in patients with no dysfunction to 75% of patients with dysfunction of all three cell types (P=0.0004). CONCLUSIONS: /st>Dysfunctions of T-cells, monocytes, and neutrophils predict acquisition of nosocomial infection, and combine additively to stratify risk of nosocomial infection in the critically ill.
BJA British Journal of Anaesthesia 06/2013; · 4.24 Impact Factor
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ABSTRACT: Revision hip arthroplasty (RHA) is associated with high rates of allogeneic blood transfusion (ABT). We aimed to determine factors associated with ABT in patients undergoing RHA in Scottish hospitals, with particular focus on perioperative cell salvage (PCS).
A prospective observational cohort study of RHA procedures performed in 11 hospitals over 7 months was performed. We recorded predefined patient, surgery-related, and blood conservation factors that may influence perioperative ABT, together with postoperative haemoglobin (Hb) data and ABTs to day 7. We explored factors with strongest independent association with ABT during the perioperative period using multiple regression analysis.
Two hundred and ten cases were studied, of whom 58% received ABTs (mean 1.8 units), most of which (52%) occurred on the day of surgery. Eighty-eight (42%) patients received PCS, of whom 68 had red cells re-infused [mean re-infusion volume 312 ml (1st, 3rd quartile: 260, 363 ml)]. In unadjusted comparisons, patients receiving PCS had lower intraoperative (9% vs 40%) and total (55% vs 63%) exposure to ABTs. The mean (95% confidence interval) theatre blood loss was 1013 (899-1128) ml and was higher for combined femoral/acetabular revision and femoral revision than other categories. The mean postoperative Hb transfusion trigger was 80 g litre(-1). In multivariable models, preoperative Hb [odds ratio (OR) 0.35; P<0.001], patient weight (OR 0.96; P=0.004), operating theatre blood loss (OR 1.002; P<0.001), and re-infusion of PCS blood (OR 0.31; P=0.02) were independent predictors of ABT exposure.
PCS is an effective blood conservation strategy for RHA, especially for patients with preoperative anaemia, low body weight, or both.
BJA British Journal of Anaesthesia 01/2012; 108(1):63-71. · 4.24 Impact Factor
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ABSTRACT: Ventilator-associated pneumonia is the most common intensive care unit-acquired infection. Although there is widespread consensus that evidenced-based interventions reduce the risk of ventilator-associated pneumonia, controversy has surrounded the importance of implementing them as a "bundle" of care. This study aimed to determine the effects of implementing such a bundle while controlling for potential confounding variables seen in similar studies.
A before-and-after study conducted within the context of an existing, independent, infection surveillance program.
An 18-bed, mixed medical-surgical teaching hospital intensive care unit.
All patients admitted to intensive care for 48 hrs or more during the periods before and after intervention.
A four-element ventilator-associated pneumonia prevention bundle, consisting of head-of-bed elevation, oral chlorhexidine gel, sedation holds, and a weaning protocol implemented as part of the Scottish Patient Safety Program using Institute of Health Care Improvement methods.
Compliance with head-of-bed elevation and chlorhexidine gel were 95%-100%; documented compliance with "wake and wean" elements was 70%, giving overall bundle compliance rates of 70%. Compared to the preintervention period, there was a significant reduction in ventilator-associated pneumonia in the postintervention period (32 cases per 1,000 ventilator days to 12 cases per 1,000 ventilator days; p<.001). Statistical process control charts showed the decrease was most marked after bundle implementation. Patient cohorts staying ≥6 and ≥14 days had greater reduction in ventilator-associated pneumonia acquisition and also had reduced antibiotic use (reduced by 1 and 3 days; p=.008/.007, respectively). Rates of methicillin-resistant Staphylococcus aureus acquisition also decreased (10% to 3.6%; p<.001).
Implementation of a ventilator-associated pneumonia prevention bundle was associated with a statistically significant reduction in ventilator-associated pneumonia, which had not been achieved with earlier ad hoc ventilator-associated pneumonia prevention guidelines in our unit. This occurred despite an inability to meet bundle compliance targets of 95% for all elements. Our data support the systematic approach to achieving high rates of process compliance and suggest systematic introduction can decrease both infection incidence and antibiotic use, especially for patients requiring longer duration of ventilation.
Critical care medicine 06/2011; 39(10):2218-24. · 6.37 Impact Factor
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ABSTRACT: To investigate ward-based rehabilitation after critical illness and undertake a pilot study exploring the feasibility of delivering enhanced physiotherapy and nutritional rehabilitation.
Service evaluation (part A) and pilot feasibility randomized controlled trial (part B).
Hospital inpatient wards following discharge from intensive care.
Part A involved 24 people with an intensive care stay of four days or more. Part B involved 16 participants randomized into a control (n = 8) or intervention (n = 8) group.
Part A defined the current 'standard' physiotherapy and nutritional interventions. In part B the control group received this 'standard' service while the intervention group received this 'standard' service plus enhanced rehabilitation.
Part A collected process outcomes of current interventions and outcomes that included calorie and protein intake and the Rivermead Mobility Index. In part B process outcomes determined differences between groups. Outcomes included those undertaken in part A plus an incremental shuttle test, handgrip dynamometry and visual analogue scales.
Part A found low levels of ward-based physiotherapy (walking and transfer practice once per week) and dietetic input (0.8 visits per week). Part B found an increased frequency of both physiotherapy (P = 0.002) and dietetic (P = 0.001) visits in the intervention group. Physical and nutritional outcomes were suitable for use after critical illness, but no statistically significant differences were found between groups. Power calculations indicated 100 participants per group would be required for a definitive study.
This feasibility pilot work has informed the design of a larger study to evaluate enhanced rehabilitation following critical illness.
Clinical Rehabilitation 06/2010; 24(6):489-500. · 2.12 Impact Factor
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ABSTRACT: The aim of this study was to describe current blood conservation practice during revision hip surgery in Scotland and document practice variation. Revision hip surgery is associated with a high likelihood of blood transfusion. A decrease in the proportion of patients requiring blood transfusion has been documented, but the reasons for this are unclear. Various blood conservation practices are available to clinicians, but the extent to which these are used in Scottish hospitals is not known. A cross-sectional postal survey was sent to all consultant orthopaedic surgeons and consultant anaesthetists participating in revision hip surgery in Scottish hospitals. Responses were received from 92 of 120 (77%) surgeons, and 174 of 216 (81%) anaesthetists (62/92). A total of 62 of 92 (67%) surgeons and 78 of 174 (45%) anaesthetists surveyed participated in revision hip surgery. Blood conservation practice varied widely: 34 of 78 (44%) anaesthetists routinely assessed revision hip patients >or=1 week prior to surgery; 10 of 62 (16%) surgeons and 24 of 78 (31%) anaesthetists routinely used cell salvage; 7 of 78 (9%) anaesthetists and 2 of 62 (3%) surgeons routinely used tranexamic acid; and 45 of 62 (73%) surgeons use a transfusion protocol. A wide variation in the use of blood conservation strategies exists during revision hip surgery in Scotland.
Transfusion Medicine 10/2008; 18(5):296-301. · 1.14 Impact Factor
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ABSTRACT: Our intensive care unit has been treating comatose patients, following an out-of-hospital cardiac arrest, with therapeutic hypothermia since 2002. In all, 139 out-of-hospital cardiac arrest patients were admitted in the 4-year period 2002-5. Of these, 27% had a favourable outcome (discharged home or to rehabilitation). Forty-one per cent of patients presenting with ventricular fibrillation (VF) and 7% of non-VF patients had a favourable outcome. No patient with an estimated time from collapse to first attempt at cardiopulmonary resuscitation over 12 min survived to hospital discharge. Twenty-two per cent of patients over 70 years were discharged home, suggesting age was not a barrier to surviving out-of-hospital cardiac arrest. The introduction of a therapeutic hypothermia clinical pathway, at the end of 2003 improved the efficiency of cooling. The percentage of patients cooled to below 34 degrees C within 4 h increased from 15 to 51% and those cooled for more than 12 h increased from 30 to 83%.
Anaesthesia 02/2008; 63(1):15-9. · 2.96 Impact Factor
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ABSTRACT: Preoperative investigation and treatment of anaemia is recommended before orthopaedic surgery. We measured the prevalence of anaemia among admissions presenting for elective major joint arthroplasty (MJA), assessed their transfusion requirements, and investigated factors associated with perioperative blood transfusion.
All admissions to a dedicated elective orthopaedic hospital during 2000-2001 were studied. The patients' database was merged with the haematology and transfusion databases. Population estimates for different types of anaemia and their blood transfusion requirements were generated using local reference ranges (males <130 g litre(-1); females <115 g litre(-1)).
One thousand three hundred and twenty-two admissions were included; haematology data were complete for 1142 (544 primary hip, 490 primary knee, 77 revision hip, 31 revision knee). About 19.6% were anaemic [7.1% haemoglobin (Hb) <110 g litre(-1); 1.6% Hb<100 g litre(-1)]. Overall, 21.3% of admissions were transfused (mean 0.58 units per case: 95% CI 0.50-0.61). For anaemic admissions, 42.0% were transfused (mean 1.11 units per case: 95% CI 0.90-1.32). Mean red cell use for admissions with normocytic normochromic anaemia (12.7% of admissions) and hypochromic anaemia (4.6%) was 1.04 (95% CI 0.78-1.31) and 1.14 (95% CI 0.71-1.57) units per admission, respectively. Factors strongly associated independently with transfusion were preoperative haemoglobin </=110 g litre(-1) [odds ratio: 13.92 (95% CI 7.77-24.9) and revision hip surgery (OR: 17.80 (9.59-33.02)].
The prevalence of preoperative anaemia among admissions undergoing elective MJA is approximately 20%. Patients most likely to avoid transfusions with preoperative intervention are those with low haemoglobin undergoing revision hip surgery.
BJA British Journal of Anaesthesia 12/2007; 99(6):801-8. · 4.24 Impact Factor
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BJA British Journal of Anaesthesia 10/2006; 97(3):278-91. · 4.24 Impact Factor
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ABSTRACT: The database of a multicentre cohort study was analysed to determine the impact of intensive care unit (ICU) organ failures and their association with ICU mortality using sequential organ failure assessment (SOFA). A consecutive sample of 873 adult patients with a non-neurological diagnosis was identified. SOFA scores were measured every 24 h of ICU stay. The odds of ICU death within 7 days doubled (95% CI 1.3-2.9) for a 5-unit increase in total SOFA score at admission, p < 0.001. However ICU death after 7 days was not associated with total SOFA score at admission, p = 0.36. Compared to patients with a day 6 total SOFA score = 5, there was a 1-unit (95% CI 0.8-3.1) increase in the odds ratio of ICU death after 7 days with every 5-unit increase in SOFA score on day 6, p = 0.009. Continuous assessments of organ failures during an ICU admission are more useful than scores measured at admission to determine outcome and to compare ICUs.
Anaesthesia 08/2006; 61(8):731-8. · 2.96 Impact Factor
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ABSTRACT: There are few data measuring rates of contact by healthcare workers (HCWs) with intensive care unit (ICU) patients (direct contacts) and their immediate environment (indirect contacts), or estimates of the time needed for 100% hand hygiene compliance. We measured this using a prospective trained observer study in a 12-bedded UK adult general ICU admitting > 600 mixed medical/surgical patients annually. HCWs were observed in ICU bed spaces for 1-h periods by a single researcher using a pre-determined plan, such that all 12 beds were observed for similar times and throughout the day. Mean daily rates of direct and indirect contact between HCWs and ICU patients were calculated. Observed post-contact hand hygiene compliance was also measured. Numbers of contacts/day that were or were not followed by hand hygiene, and estimates of the time needed daily for 100% compliance were calculated. On average, each patient was contacted directly 159 [95% confidence intervals (CI) 144-178] times and contacted indirectly 191 (95% CI 174-210) times/day. Observed post-contact hand hygiene rates were 43% for direct contacts and 12% for indirect contacts. Staff contacting more than one patient during routine care, who carry the highest risk of transmitting infection between patients, made, on average, 22 direct and 107 indirect contacts without adequate hand hygiene/patient/day. One hundred percent hand hygiene compliance by all healthcare workers would require about 230 min/patient/day (100 min for direct and 130 min for indirect contacts).
Journal of Hospital Infection 03/2006; 62(3):304-10. · 3.39 Impact Factor
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ABSTRACT: Restrictive transfusion triggers are safe for most critically ill patients, but doubts exist for patients with ischaemic heart disease (IHD). We investigated the prevalence of reported IHD at admission to the intensive care unit (ICU) and investigated how this influenced red cell transfusion triggers. We also compared observed practice with the clinicians' responses to clinical scenarios.
We studied 1023 sequential ICU admissions over 100 days to 10 Scottish ICUs. Daily haemoglobin, red cell transfusion, and haemorrhage data were available for 99.4% of 5638 ICU patient days. We recorded if IHD was recorded in clinical records at ICU admission. We grouped admissions as having a non-cardiac primary ICU diagnosis and no documentary evidence of IHD (Group 1, n=697), a non-cardiac primary ICU diagnosis with evidence of IHD (Group 2, n=213), or a cardiac primary ICU admission diagnosis (Group 3, n=113). We examined pre-transfusion haemoglobin concentration (Hb) for transfusion episodes not associated with haemorrhage. Clinical transfusion scenarios were sent to intensivists in the ICUs after data collection, which were designed to explore the clinicians' attitude to transfusion triggers in patients with IHD.
Previous myocardial infarction was documented in 159 (16%), cardiac failure in 142 (14%), and angina in 167 (16%). Overall, 28.8% of admissions had >/=1 of these documented. The adjusted mean (se) pre-transfusion Hb concentrations varied across the groups. These were 74 (2.2) g litre(-1) in Group 1, 77 (2.3) g litre(-1) in Group 2, and 79 (3.1) g litre(-1) in Group 3 (P=0.003 across the groups). There was concordance between observed practice and responses to the scenario similar to Group 1, but discordance for patients with IHD (Groups 2 and 3). In scenario responses, intensivists stated these patients should have significantly higher transfusion triggers than were actually observed (median [IQR] response for both groups: 90 [80-100] g litre(-1)).
About 29% of patients admitted to Scottish ICUs had documented IHD, which was associated with small adjustments to Hb transfusion triggers. In response to scenarios, clinicians believe that patients with IHD require higher transfusion triggers than are observed in practice.
BJA British Journal of Anaesthesia 05/2005; 94(4):445-52. · 4.24 Impact Factor
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ABSTRACT: Controversy exists regarding the optimal method of managing intensive care unit (ICU)-acquired infection. Antibiotic prescriptions in 177 sequential admissions to our ICU, which collected twice-weekly screening samples, were audited. Seventy-seven percent of patients received at least one antibiotic prescription, and 45% of patients received at least one prescription for suspected or proven sepsis. Of the 353 antibiotic prescriptions audited, 86 were prophylactic and 61 were first prescribed prior to ICU admission. One hundred and eighty-three were prescribed for sepsis; of these, 108 (59%) were empirical prescriptions and only 21% of these were subsequently changed. For the 75 prescriptions for specific organisms, 28% targeted organisms isolated at least four days previously. Clinicians in our ICU reviewed the data and reached consensus that screening was associated with decision making that did not represent current evidence-based practice, because empirical prescriptions were rarely changed or stopped on the basis of new samples, and those prescribed for confirmed infection frequently targeted organisms isolated before the septic episode. After our audit, we stopped regular collection of screening samples and used more targeted and invasive sampling, in response to clinical suspicion, to guide therapy and maintain data concerning local microbial epidemiology.
Journal of Hospital Infection 03/2005; 59(2):90-5. · 3.39 Impact Factor
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ABSTRACT: There is increasing evidence that weaning protocols improve outcome from mechanical ventilation, but it is unclear how best to implement such protocols in large intensive care units. We evaluated a checklist of simple bedside criteria to determine whether it could be used reliably to predict successful discontinuation of mechanical ventilation.
We carried out a prospective observational cohort study in a 12-bedded general intensive care unit (ICU). We developed a checklist of metabolic, cardiorespiratory and neurological criteria that suggested that patients should start the weaning process. We performed daily assessments throughout ICU stay and recorded whether the criteria were met. Ultimate ventilator independence was used as the reference standard.
We studied 325 sequential admissions to the ICU. Data were available for 98% of patients; 97% of admissions were mechanically ventilated on admission to ICU. Overall, 205 of the 308 ventilated patients (67%) achieved ventilator independence during ICU admission; the other patients died or were transferred ventilated to other ICUs. Eighty-three per cent of the patients who achieved ventilator independence met the set criteria. Fulfilling the criteria was a moderately strong predictor of ultimate ventilator independence: specificity 89%, positive predictive value 94%, positive likelihood ratio (LR) 7.6. When we analysed data by the day from admission on which patients were examined, the test was a strong predictor of subsequent ventilator independence when criteria were met by day 1 (LR 11.1) or day 2 (LR 6.9), but weaker when met by more than/equal to 4 days (LR <3). Patients who met criteria after more than/equal to 4 days often had prolonged weaning and a high incidence of re-intubation. Patients who achieved ventilator independence without fulfilling the criteria (n=35) had a short duration of mechanical ventilation (median 2 days, interquartile range 1-3 days). The most frequent reason for failing criteria before ventilator independence was a Pa(O(2))/FI(O(2)) ratio less than 24 kPa (49% of cases).
A simple checklist can assist nurse assessment of suitability for weaning and could be used as a trigger to commence a weaning protocol. The day on which criteria are met is a useful way of stratifying patients for likely patterns of weaning.
BJA British Journal of Anaesthesia 07/2004; 92(6):793-9. · 4.24 Impact Factor
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ABSTRACT: Anaemia is a common finding in critically ill patients. There are often multiple causes. Obvious causes include surgical bleeding and gastrointestinal haemorrhage but many patients have no overt bleeding episodes. Phlebotomy can be a significant source of blood loss. In addition, critically ill patients have impaired erythropoiesis as a consequence of blunted erythropoietin production and direct inhibitory effects of inflammatory cytokines. The ability of a patient to tolerate anaemia depends on their clinical condition and the presence of any significant co-morbidity; maintenance of circulating volume is of paramount importance. There is no universal transfusion trigger. Current guidelines for critically ill and perioperative patients advise that at Hb values <70 g/L red blood cell transfusion is strongly indicated and at Hb values >100 g/L transfusion is unjustified. For patients with Hb values in the range 70 to 100 g/L the transfusion trigger should be based on clinical indicators. Most stable critically ill patients can probably be managed with a Hb concentration between 70 and 90 g/L. Uncertainties exist concerning the most appropriate Hb concentration for patients with significant cardio-respiratory disease.
Blood Reviews 12/2003; 17(4):195-208. · 5.36 Impact Factor
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T S Walsh
BJA British Journal of Anaesthesia 08/2003; 91(1):120-31. · 4.24 Impact Factor
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BJA British Journal of Anaesthesia 07/2003; 90(6):719-22. · 4.24 Impact Factor
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ABSTRACT: We measured oxygen consumption using a new noninvasive modular metabolic monitor, M-COVX trade mark, in ventilated critically ill patients. Oxygen consumption was measured continuously as part of routine monitoring for up to 24 h following mechanical ventilation in 27 patients admitted to a general intensive care unit. We explored several possible sources of error. Most errors related to inaccurate tidal volume measurement, which resulted in rejection of a median 14% (interquartile range 8-34%) of data. Water accumulation in the pneumotachograph was responsible and occurred more frequently with water bath humidifiers. After manual removal of erroneous data mean oxygen consumption values were virtually identical to calculated values in 24 of 27 patients. We conclude that in most ventilated patients averaging of continuous oxygen consumption data with the M-COVX module results in small errors.
Anaesthesia 06/2003; 58(5):455-60. · 2.96 Impact Factor
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ABSTRACT: The Transfusion Requirements In Critical Care (TRICC) study found that critically ill patients tolerate a restrictive haemoglobin transfusion threshold. We investigated red-cell transfusion practice since publication of the TRICC study in a large Scottish teaching hospital intensive care unit (ICU).
We prospectively collected daily data for a 6-month period on haemoglobin concentrations, red-cell transfusions and indications for transfusions, throughout ICU stay for all patients who stayed for longer than 24 h in the ICU.
A total of 176 patients were studied, who utilized 1237 ICU days. Of these 176 patients, 52% received red-cell transfusions. A haemoglobin concentration of < or = 9 g/dl was measured in 55% of patients; this occurred by day 1 and day 2 in 52% and 77% of these cases, respectively. Overall the haemoglobin concentration was < or = 9 g/dl for 45% of all patient days. Total red-cell use was 3.1 units per admission (0.47 units per patient day). Only 18% of transfusion episodes were required as a result of haemorrhage. For 'non-haemorrhage' transfusion episodes, the median pretransfusion haemoglobin concentration was 7.8 g/dl (interquartile range: 7.4-8.4 g/dl), and 64% of transfusion episodes were for 2 units.
Clinicians in our centre were conservative, in keeping with recent transfusion guidelines, but deviated from the TRICC protocol by transfusing at haemoglobin concentrations of between 7 and 9 g/dl, rather than below 7 g/dl, and by prescribing 2 unit transfusions. Significant numbers of red-cell units are still used in the critically ill.
Vox Sanguinis 05/2003; 84(3):211-8. · 2.86 Impact Factor
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BJA British Journal of Anaesthesia 11/2002; 89(4):537-40. · 4.24 Impact Factor
