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Crit Care Med. 2015 Mar;43(3):557-66. doi: 10.1097/CCM.0000000000000727.

Prevalence, risk factors, and outcomes of delirium in mechanically ventilated adults.

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1Department of Medicine and Interdepartmental Division of Critical Care, Mount Sinai Hospital and University of Toronto, Toronto, ON, Canada. 2Departments of Medicine, Clinical Epidemiology, and Biostatistics, McMaster University, St Joseph's Healthcare, Hamilton, ON, Canada. 3School of Pharmacy, Northeastern University, Boston, MA. 4Département de Médecine, Soins Intensifs, Hôpital Maisonneuve Rosemont, Université de Montréal, Montréal, QC, Canada. 5Departments of Medicine, Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada. 6Department of Critical Care, Hamilton Health Sciences, Hamilton, ON, Canada. 7Clinical Epidemiology Program, Ottawa Hospital Research Institute and Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada. 8Department of Medicine and Interdepartmental Division of Critical Care, University Health Network and University of Toronto, Toronto, ON, Canada. 9Department of Medicine, Mount Sinai Hospital, Toronto, ON, Canada. 10Division of Respirology, Interdepartmental Division of Critical Care, Faculty of Medicine, Toronto General Hospital, University of Toronto, Toronto, ON, Canada. 11Interdepartmental Division of Critical Care Medicine, Departments of Medicine and Physiology, University of Toronto, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada. 12Department of Medicine, Long Beach Memorial Medical Center, Long Beach, CA. 13Division of Critical Care Medicine and Center for Health Evaluation and Outcome Sciences, St. Paul's Hospital and University of British Columbia, Vancouver, BC, Canada. 14Departments of Medicine and Critical Care Medicine, Sunnybrook Hospital, Toronto, ON, Canada. 15Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada. 16Keenan Research Centre and the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada. 17Interdepartmental Division of Critical Care Medicine and the Institute of Health Policy Ma



Delirium is common during critical illness and associated with adverse outcomes. We compared characteristics and outcomes of delirious and nondelirious patients enrolled in a multicenter trial comparing protocolized sedation with protocolized sedation plus daily sedation interruption.


Randomized trial.


Sixteen North American medical and surgical ICUs.


Four hundred thirty critically ill, mechanically ventilated adults.


All patients had hourly titration of opioid and benzodiazepine infusions using a validated sedation scale. For patients in the interruption group, infusions were resumed, if indicated, at half of previous doses. Delirium screening occurred daily; positive screening was defined as an Intensive Care Delirium Screening Checklist score of 4 or more at any time.


Delirium was diagnosed in 226 of 420 assessed patients (53.8%). Coma was identified in 32.7% of delirious compared with 22.7% of nondelirious patients (p = 0.03). The median time to onset of delirium was 3.5 days (interquartile range, 2-7), and the median duration of delirium was 2 days (interquartile range, 1-4). Delirious patients were more likely to be male (61.1% vs 46.6%; p = 0.005), have a surgical/trauma diagnosis (21.2% vs 11.0%; p = 0.030), and history of tobacco (31.5% vs 16.2%; p = 0.002) or alcohol use (34.6% vs 20.9%; p = 0.009). Patients with positive delirium screening had longer duration of ventilation (13 vs 7 d; p < 0.001), ICU stay (12 vs 8 d; p < 0.0001), and hospital stay (24 vs 15 d; p < 0.0001). Delirious patients were more likely to be physically restrained (86.3% vs 76.7%; p = 0.014) and undergo tracheostomy (34.6% vs 15.5%; p < 0.0001). Antecedent factors independently associated with delirium onset were restraint use (hazard ratio, 1.87; 95% CI, 1.33-2.63; p = 0.0003), antipsychotic administration (hazard ratio, 1.67; 95% CI, 1.005-2.767; p = 0.047), and midazolam dose (hazard ratio, 0.998; 95% CI, 0.997-1.0; p = 0.049). There was no difference in delirium prevalence or duration between the interruption and control groups.


In mechanically ventilated adults, delirium was common and associated with longer duration of ventilation and hospitalization. Physical restraint was most strongly associated with delirium.

[Indexed for MEDLINE]

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