Karen E A Burns

Université de Sherbrooke, Sherbrooke, Quebec, Canada

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Publications (77)369.63 Total impact

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  • Canadian respiratory journal: journal of the Canadian Thoracic Society 06/2014; · 1.29 Impact Factor
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    ABSTRACT: BACKGROUND:Noninvasive ventilation has been studied as a means of reducing complications among patients being weaned from invasive mechanical ventilation. We sought to summarize evidence comparing noninvasive and invasive weaning and their effects on mortality. METHODS:We identified relevant randomized and quasirandomized trials through searches of databases, conference proceedings and grey literature. We included trials comparing extubation and immediate application of noninvasive ventilation with continued invasive weaning in adults on mechanical ventilation. Two reviewers each independently screened citations, assessed trial quality and abstracted data. Our primary outcome was mortality. RESULTS:We identified 16 trials involving 994 participants, most of whom had chronic obstructive pulmonary disease (COPD). Compared with invasive weaning, noninvasive weaning significantly reduced mortality (risk ratio [RR] 0.53, 95% confidence interval [CI] 0.36 to 0.80), weaning failures (RR 0.63, 95% CI 0.42 to 0.96), ventilator-associated pneumonia (RR 0.25, 95% CI 0.15 to 0.43), length of stay in the intensive care unit (mean difference [MD] -5.59 d, 95% CI -7.90 to -3.28) and in hospital (MD -6.04 d, 95% CI -9.22 to -2.87), and total duration of mechanical ventilation (MD -5.64 d, 95% CI -9.50 to -1.77). Noninvasive weaning had no significant effect on the duration of ventilation related to weaning, but significantly reduced rates of tracheostomy (RR 0.19, 95% CI 0.08 to 0.47) and reintubation (RR 0.65, 95% CI 0.44 to 0.97). Mortality benefits were significantly greater in trials enrolling patients with COPD than in trials enrolling mixed patient populations (RR 0.36 [95% CI 0.24 to 0.56] v. RR 0.81 [95% CI 0.47 to 1.40]). INTERPRETATION:Noninvasive weaning reduces rates of death and pneumonia without increasing the risk of weaning failure or reintubation. In subgroup analyses, mortality benefits were significantly greater in patients with COPD.
    Canadian Medical Association Journal 12/2013; · 6.47 Impact Factor
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    ABSTRACT: Among critically ill patients with acute kidney injury, the impact of renal replacement therapy modality on long-term kidney function is unknown. Compared with conventional intermittent hemodialysis, continuous renal replacement therapy may promote kidney recovery by conferring greater hemodynamic stability; yet continuous renal replacement therapy may not enhance patient survival and is resource intense. Our objective was to determine whether continuous renal replacement therapy was associated with a lower risk of chronic dialysis as compared with intermittent hemodialysis, among survivors of acute kidney injury. Retrospective cohort study. Linked population-wide administrative databases in Ontario, Canada. Critically ill adults who initiated dialysis for acute kidney injury between July 1996 and December 2009. In the primary analysis, we considered those who survived to at least 90 days after renal replacement therapy initiation. Initial receipt of continuous renal replacement therapy versus intermittent hemodialysis. Continuous renal replacement therapy recipients were matched 1:1 to intermittent hemodialysis recipients based on a history of chronic kidney disease, receipt of mechanical ventilation, and a propensity score for the likelihood of receiving continuous renal replacement therapy. Cox proportional hazards were used to evaluate the relationship between initial renal replacement therapy modality and the primary outcome of chronic dialysis, defined as the need for dialysis for a consecutive period of 90 days. We identified 2,315 continuous renal replacement therapy recipients of whom 2,004 (87%) were successfully matched to 2,004 intermittent hemodialysis recipients. Participants were followed over a median duration of 3 years. The risk of chronic dialysis was significantly lower among patients who initially received continuous renal replacement therapy versus intermittent hemodialysis (hazard ratio, 0.75; 95% CI, 0.65-0.87). This relation was more prominent among those with preexisting chronic kidney disease (p value for interaction term = 0.065) and heart failure (p value for interaction term = 0.035). Compared with intermittent hemodialysis, initiation of continuous renal replacement therapy in critically ill adults with acute kidney injury is associated with a lower likelihood of chronic dialysis.
    Critical care medicine 11/2013; · 6.37 Impact Factor
  • European Journal of Intensive Care Medicine 10/2013; · 5.17 Impact Factor
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    ABSTRACT: To describe the attitudes and perceptions of intensive care unit (ICU) staff [critical care physicians and fellows (MDs), registered nurses (RNs), allied health discipline (HD) and managers] towards family presence at bedside rounds. We developed, tested and administered a questionnaire to the multidisciplinary staff. 24-Bed medical surgical ICU. 160/221 (72.4%) individuals responded, including 12 MDs, 95 RNs, 48 HD personnel, 4 managers and 1 unspecified. While most MDs strongly agreed and HD and management groups somewhat agreed, most RNs strongly disagreed with providing family members the option to attend rounds. Over 50% of respondents either strongly or somewhat agreed that the presence of family members prolongs rounds, reduces the medical education provided to the team and constrains delivery of negative medical information. Compared to MDs, RNs expressed greater reservation to family presence at rounds. Among RNs, more experienced RNs, expressed greater reservation with family presence during rounds. We found significant differences among the attitudes of health care providers towards family presence at bedside rounds with RNs, especially more experienced RNs, expressing the greatest reservation. Qualitative research is required to explore perceived and actual barriers to family member presence at rounds.
    Intensive & critical care nursing: the official journal of the British Association of Critical Care Nurses 08/2013;
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    ABSTRACT: Background Mechanical ventilation is a critical component of paediatric intensive care therapy. It is indicated when the patient’s spontaneous ventilation is inadequate to sustain life. Weaning is the gradual reduction of ventilatory support and the transfer of respiratory control back to the patient. Weaning may represent a large proportion of the ventilatory period. Prolonged ventilation is associated with significant morbidity, hospital cost, psychosocial and physical risks to the child and even death. Timely and effective weaning may reduce the duration of mechanical ventilation and may reduce the morbidity and mortality associated with prolonged ventilation. However, no consensus has been reached on criteria that can be used to identify when patients are ready to wean or the best way to achieve it. Objectives To assess the effects of weaning by protocol on invasively ventilated critically ill children. To compare the total duration of invasive mechanical ventilation of critically ill children who are weaned using protocols versus those weaned through usual (non-protocolized) practice. To ascertain any differences between protocolized weaning and usual care in terms of mortality, adverse events, intensive care unit length of stay and quality of life. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library, Issue 10, 2012), MEDLINE (1966 to October 2012), EMBASE (1988 to October 2012), CINAHL (1982 to October 2012), ISI Web of Science and LILACS. We identified unpublished data in the Web of Science (1990 to October 2012), ISI Conference Proceedings (1990 to October 2012) and Cambridge Scientific Abstracts (earliest to October 2012). We contacted first authors of studies included in the review to obtain further information on unpublished studies or work in progress. We searched reference lists of all identified studies and review papers for further relevant studies. We applied no language or publication restrictions. Selection criteria We included randomized controlled trials comparing protocolized weaning (professional-led or computer-driven) versus non-protocolized weaning practice conducted in children older than 28 days and younger than 18 years. Data collection and analysis Two review authors independently scanned titles and abstracts identified by electronic searching. Three review authors retrieved and evaluated full-text versions of potentially relevant studies, independently extracted data and assessed risk of bias. Main results We included three trials at low risk of bias with 321 children in the analysis. Protocolized weaning significantly reduced total ventilation time in the largest trial (260 children) by a mean of 32 hours (95% confidence interval (CI) 8 to 56; P = 0.01). Two other trials (30 and 31 children, respectively) reported non-significant reductions with a mean difference of -88 hours (95% CI -228 to 52; P = 0.2) and -24 hours (95% CI -10 to 58; P = 0.06). Protocolized weaning significantly reduced weaning time in these two smaller trials for a mean reduction of 106 hours (95% CI 28 to 184; P = 0.007) and 21 hours (95% CI 9 to 32; P < 0.001). These studies reported no significant effects for duration of mechanical ventilation before weaning, paediatric intensive care unit (PICU) and hospital length of stay, PICU mortality or adverse events. Authors' conclusions Limited evidence suggests that weaning protocols reduce the duration of mechanical ventilation, but evidence is inadequate to show whether the achievement of shorter ventilation by protocolized weaning causes children benefit or harm.
    Cochrane database of systematic reviews (Online) 07/2013; · 5.70 Impact Factor
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    ABSTRACT: OBJECTIVE: The efficacy of systemic corticosteroids in many critical illnesses remains uncertain. Our primary objective was to survey intensivists in North America about their perceived use of corticosteroids in clinical practice. DESIGN: Self-administered paper survey. POPULATION: Intensivists in academic hospitals with clinical trial expertise in critical illness. MEASUREMENTS: We generated questionnaire items in focus groups and refined them after assessments of clinical sensibility and test-retest reliability and pilot testing. We administered the survey to experienced intensivists practicing in selected North American centres actively enrolling patients in the multicentre Oscillation for ARDS Treated Early (OSCILLATE) Trial (ISRCTN87124254). Respondents used a four-point scale to grade how frequently they would administer corticosteroids in 14 clinical settings. They also reported their opinions on 16 potential near-absolute indications or contraindications for the use of corticosteroids. MAIN RESULTS: Our response rate was 82% (103/125). Respondents were general internists (50%), respirologists (22%), anesthesiologists (21%), and surgeons (7%) who practiced in mixed medical-surgical units. A majority of respondents reported almost always prescribing corticosteroids in the setting of significant bronchospasm in a mechanically ventilated patient (94%), recent corticosteroid use and low blood pressure (93%), and vasopressor-refractory septic shock (52%). Although more than half of respondents stated they would almost never prescribe corticosteroids in severe community-acquired pneumonia (81%), acute lung injury (ALI, 76%), acute respiratory distress syndrome (ARDS, 65%), and severe ARDS (51%), variability increased with severity of acute lung injury. Near-absolute indications selected by most respondents included known adrenal insufficiency (99%) and suspicion of cryptogenic organizing pneumonia (89%), connective tissue disease (85%), or other potentially corticosteroid-responsive illnesses (85%). CONCLUSIONS: Respondents reported rarely prescribing corticosteroids for ALI, but accepted them for bronchospasm, suspected adrenal insufficiency due to previous corticosteroid use, and vasopressor-refractory septic shock. These competing indications will complicate the design and interpretation of any future large-scale trial of corticosteroids in critical illness.
    Canadian Anaesthetists? Society Journal 04/2013; · 2.31 Impact Factor
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    ABSTRACT: RATIONALE: Limited cross-sectional data exist to characterize the challenges of enrolling critically ill patients into research studies. OBJECTIVES: We aimed to describe recruitment practices, document factors that impact recruitment, and identify factors that may enhance future research feasibility. METHODS: We conducted a prospective, observational study of all critically ill adults eligible to participate in research studies at 23 Canadian intensive care units (ICUs). We characterized eligibility events into one of five consent outcomes, identified reasons why opportunities to recruit were missed or infeasible, and documented decision-maker's rationale for providing or declining consent. MEASUREMENTS AND MAIN RESULTS: Only 8.9% of eligible patients made decisions for themselves. In 453 eligibility events, consent was not required in 14 (3.1%), missed in 131 (28.9%), infeasible due to operational reasons in 129 (28.5%), obtained in 140 (30.9%) and declined in 39 (8.6%). Over half (57%) of all opportunities to recruit patients were missed or infeasible largely due to research team workload, limited availability, narrow time windows for inclusion, difficulties in contacting families, non-existent substitute decision makers (SDMs), physician refusals and protocols prohibiting co-enrollment. The rationale for providing consent differed between patients and SDMs. Greater research coordinator experience and site research volume were significant predictors of fewer declined consents. CONCLUSIONS: A large gap exists between eligibility and the frequency with which consent encounters occur in ICU research. Recruitment is susceptible to personnel availability, given the need to interact with SDMs, and to design and procedural inefficiencies that hinder recruitment. Current enrolment practices under-represent study populations.
    American Journal of Respiratory and Critical Care Medicine 03/2013; · 11.04 Impact Factor
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    ABSTRACT: OBJECTIVES:: While early mobilization is safe and enhances functional recovery in critically ill adults, rehabilitation practices in critically ill children are not well characterized. The objective of this study was to evaluate the knowledge, perceptions, and stated practices of early mobilization among physicians and physiotherapists practicing in Canadian pediatric critical care units. DESIGN AND MEASUREMENTS:: A self-administered survey was mailed to 102 physicians and 35 physiotherapists. Survey domains included barriers to early mobilization, the timing, nature and thresholds for rehabilitation, and staffing workload. We assessed for associations using chi-square tests. MAIN RESULTS:: The overall response rate was 64.2% (88 of 137), representing 59.8% (61 of 102) physicians and 77.1% (27 of 35) physiotherapists, respectively. Key institutional barriers to early mobilization included a lack of practice guidelines (75.4% physician, 48.1% physiotherapist respondents; p = 0.01) and the need for physician orders prior to initiating physiotherapy (26.2% physician vs. 55.6% physiotherapist, p = 0.008). Only 3.4% of respondents reported having local guidelines for early mobilization. Conflicting perceptions regarding the clinical thresholds for early mobilization and the safety of early mobilization were the most commonly reported patient-level barriers. Increasing illness severity was associated with decreased clinician comfort with early mobilization. Respiratory physiotherapy and passive range of motion were the most frequently applied rehabilitation interventions (77.8%), while pregait physiotherapy and ambulation were only sometimes or infrequently (70.4%) used. The type and extent of physiotherapy varied depending on the time of day and week. CONCLUSIONS:: There are numerous perceived institutional, patient- and provider-level barriers to early mobilization in Canadian pediatric critical care units, and diverse opinions on the appropriateness of early mobilization. Limited awareness of existing literature and the lack of practice guidelines on early mobilization are not surprising in light of the paucity of pediatric-specific evidence. These results strongly support the need for further research, evaluating the feasibility, safety, and efficacy of early mobilization in critically ill children.
    Critical care medicine 03/2013; · 6.37 Impact Factor
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    ABSTRACT: OBJECTIVE:: Little information exists to identify barriers to participation in pandemic research involving critically ill patients. We sought to characterize clinical research activity during the recent influenza A pandemic and to understand the experiences, beliefs, and practices of key stakeholders involved in pandemic research implementation. DESIGN:: Cross-sectional, provincial postal questionnaire. SETTING:: Level III ICUs. PARTICIPANTS:: ICU administrators and research coordinators. MEASUREMENTS:: We used rigorous survey methodology to identify potential respondents and to develop, test, and administer two-related questionnaires. MAIN RESULTS:: We analyzed responses from 39 research coordinators and 139 administrators (response rates: 70.9% and 73.2%, respectively). Compared with non-influenza A studies, influenza A studies were less likely to be randomized trials and most often investigator-initiated and peer-review funded. Whereas both respondent groups felt that pandemic research would be helpful in providing care during future pandemics, research coordinators placed significantly greater importance on their ICU's participation in pandemic research. Both respondent groups expressed a need for rapid approval processes, designated funding for research personnel, adequate funding for start-up and patient screening, preapproved template protocols and consent forms, and clearer guidance regarding co-enrollment. Research coordinators acknowledged a need for alternative consent models to increase their capacity to participate in future pandemic research. More administrators expressed willingness to participate in the next pandemic if the required research resources were made available to them. CONCLUSIONS:: Whereas research personnel and administrators support participation in pandemic ICU research, several modifiable barriers to participation exist. Pandemic research preparedness planning with regulatory bodies and dedicated funding to support research infrastructure, especially in community settings, are required to optimize future pandemic research participation.
    Critical care medicine 02/2013; · 6.37 Impact Factor
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    ABSTRACT: OBJECTIVES:: Accurate prognostic information in patients with severe traumatic brain injury remains limited, but mortality following the withdrawal of life-sustaining therapies is high and variable across centers. We designed a survey to understand attitudes of physicians caring for patients with severe traumatic brain injury toward the determination of prognosis and clinical decision making on the level of care. DESIGN, SETTING, AND PARTICIPANTS:: We conducted a cross-sectional study of intensivists, neurosurgeons, and neurologists that participate in the care of patients with severe traumatic brain injury at all Canadian level 1 and level 2 trauma centers. INTERVENTION:: None. MEASUREMENTS:: The main outcome measure was physicians' perceptions of prognosis and recommendations on the level of care. MAIN RESULTS:: Our response rate was 64% (455/712). Most respondents (65%) reported that an accurate prediction of prognosis would be most helpful during the first seven days. Most respondents (>80%) identified bedside monitoring, clinical exam, and imaging to be useful for evaluating prognosis, whereas fewer considered electrophysiology tests (<60%) and biomarkers (<15%). In a case-based scenario, approximately one third of respondents agreed, one third were neutral, and one third disagreed that the patient prognosis would be unfavorable at one year. About 10% were comfortable recommending withdrawal of life-sustaining therapies. CONCLUSIONS:: A significant variation in perceptions of neurological prognosis and in clinical decision making on the level of care was found among Canadian intensivists, neurosurgeons, and neurologists. Improved understanding of the factors that can accurately predict prognosis for patients with traumatic brain injury is urgently needed.
    Critical care medicine 02/2013; · 6.37 Impact Factor
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    ABSTRACT: PURPOSE: To identify factors associated with decisions to withdraw life-sustaining therapies in patients with severe traumatic brain injury (TBI). MATERIALS AND METHODS: We conducted a 2-year multicenter retrospective cohort study (2005-2006) in mechanically ventilated patients aged 16 years and older admitted to the intensive care units (ICUs) of six Canadian level I trauma centers following severe TBI. One hundred and twenty charts were randomly selected at each center (n = 720). Data on ICU management strategies, patients' clinical condition, surgical procedures, diagnostic imaging, and decision to withdraw life-sustaining therapies were collected. The association of factors pertaining to the injury, interventions, and management strategies with decisions to withdraw life-sustaining therapies was evaluated among non-survivors. RESULTS: Among the 228 non-survivors, 160 died following withdrawal of life-sustaining therapies. Patients were predominantly male (69.7 %) with a mean age of 50.7 (±21.7) years old. Brain herniation was more often reported in patients who died following decisions to withdraw life-sustaining therapies (odds ratio [OR] 2.91, 95 % confidence interval [CI] 1.16-7.30, p = 0.02) compared to those who died due to other causes (e.g., cardiac arrest, shock, etc.). Epidural hematomas (OR 0.18, 95 % CI 0.06-0.56, p < 0.01), craniotomies (OR 0.12, 95 % CI 0.02-0.68, p = 0.02), and other non-neurosurgical procedures (OR 0.08, 95 % CI 0.02-0.43, p < 0.01) were less often associated with death following withdrawal of life-sustaining therapies than death from other causes. CONCLUSIONS: Death following decisions to withdraw life-sustaining therapies is associated with specific patient and clinical factors, and the intensity of care.
    Neurocritical Care 10/2012; · 3.04 Impact Factor
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    ABSTRACT: PURPOSE: We undertook this study to characterize the epidemiology of acute kidney injury (AKI) in Canadian critical care units. We aimed to identify predictors of mortality for patients diagnosed with AKI. METHODS: We conducted a prospective cohort study of consecutive patients admitted to critical care units at five Canadian hospitals over a 30-day period. Each patient was followed until hospital discharge or for a maximum of 30 days. The serum creatinine criteria for the Acute Kidney Injury Network (AKIN-SCr) system were used to identify, classify, and characterize patients who developed AKI. We used multivariable logistic regression to predict 30-day mortality among patients with AKI. RESULTS: We identified 603 patients, 161 (26.7%) of whom developed AKI. Compared to patients without AKI, those with AKI were more likely to die (29.2% vs 8.6%, P < 0.001). The risk of death increased with increasing AKIN-SCr stage (P < 0.001). In all, 19 patients (11.8% of those with AKI) commenced dialysis a median of one day (interquartile range, one to two days) after AKI diagnosis. At AKI diagnosis, the blood urea nitrogen (BUN) level (adjusted odds ratio [OR] 1.68, 95% confidence interval [CI] 1.01 to 2.79/10 mmol·L(-1)) and serum bicarbonate (adjusted OR 0.88, 95% CI 0.81 to 0.95/1 mmol·L(-1)) were associated with 30-day mortality and predicted death with an area under the receiver-operating characteristic curve of 0.79 (95% CI 0.71 to 0.86). CONCLUSIONS: Acute kidney injury is a common complication of critical illness in Canada. The development of even the mildest stage of AKI is associated with a substantially higher risk of death. At AKI diagnosis, routine clinical data may be helpful for predicting adverse outcomes.
    Canadian Anaesthetists? Society Journal 07/2012; 59(10):934-942. · 2.31 Impact Factor
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    ABSTRACT: The optimal timing for starting renal replacement therapy (RRT) in patients with acute kidney injury (AKI) is unknown. Defining current practice is necessary to design interventional trials. We describe the current Canadian practice regarding the timing of RRT initiation for AKI. An observational study of patients undergoing RRT for AKI was undertaken at 11 intensive care units (ICUs) across Canada. Data were captured on demographics, clinical and laboratory findings, indications for RRT, and timing of RRT initiation. Among 119 consecutive patients, the most common ICU admission diagnosis was sepsis/septic shock, occurring in 54%. At the time of RRT initiation, the median and interquartile range (IQR) serum creatinine level was 322 (221-432) μmol·L(-1). The mean (SD) values for other parameters were as follows: Sequential Organ Failure Assessment (SOFA) score 13.4 (4.1), pH 7.25 (0.15), potassium 4.6 (1.0) mmol·L(-1). Also, 64% fulfilled the serum creatinine-based criterion for Acute Kidney Injury Network (AKIN) stage 3. Severity of illness, measured using Acute Physiology and Chronic Health Evaluation (APACHE II) and SOFA scores, did not correlate with AKI severity as defined by the serum creatinine-based AKIN criteria. Median (IQR) time from hospital and ICU admission to the start of RRT was 2.0 (1.0-7.0) days and 1.0 (0-2.0) day, respectively. Patients admitted to an ICU who were started on RRT generally had advanced AKI, high-grade illness severity, and multiorgan dysfunction. Also, they were started on RRT shortly after hospital presentation. We describe the current state of practice in Canada regarding the initiation of RRT for AKI in critically ill patients, which can inform the designs of future interventional trials.
    Canadian Anaesthetists? Society Journal 06/2012; 59(9):861-70. · 2.31 Impact Factor
  • Clarence Chant, Karen E A Burns
    Annals of internal medicine 05/2012; 156(10):JC5-6. · 13.98 Impact Factor
  • American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California; 05/2012
  • American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California; 05/2012
  • American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California; 05/2012
  • Critical Care 03/2012; 16(1). · 4.93 Impact Factor

Publication Stats

1k Citations
369.63 Total Impact Points

Institutions

  • 2011–2013
    • Université de Sherbrooke
      • • Department of Medicine
      • • Étienne-Le Bel Clinical Research Center
      Sherbrooke, Quebec, Canada
  • 2009–2013
    • St. Michael's Hospital
      Toronto, Ontario, Canada
  • 2011–2012
    • Laval University
      • Département d'Anesthésiologie
      Québec, Quebec, Canada
  • 2007–2012
    • University of Toronto
      • Division of Critical Care Medicine
      Toronto, Ontario, Canada
  • 2000–2010
    • London Health Sciences Centre
      • Division of Critical Care
      London, Ontario, Canada
  • 2004–2009
    • McMaster University
      • • Department of Medicine
      • • Department of Clinical Epidemiology and Biostatistics
      Hamilton, Ontario, Canada
  • 2005
    • The University of Western Ontario
      • Division of Critical Care Medicine
      London, Ontario, Canada
  • 2002–2003
    • University of Pittsburgh
      • • Department of Critical Care Medicine
      • • Division of Transplantation
      Pittsburgh, PA, United States