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Crit Care Med. 2008 Jan;36(1):94-9.

Informed consent in the critically ill: a two-step approach incorporating delirium screening.

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Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Ontario, Canada.



Sedation-agitation and delirium are common in critically ill patients and may be important barriers to informed consent. We describe a two-step process for informed consent and evaluate the natural history of patients' competency by repeated application of this process during their hospitalization.


Observational study.


Nine intensive care units (ICUs) in three teaching hospitals in Baltimore, MD.


One hundred fifty patients with acute lung injury.


Two-step process involving objective evaluation with Richmond Agitation-Sedation Scale (RASS) and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) (step 1), followed by traditional assessment for competency (step 2) in those patients passing step 1.


RASS and CAM-ICU assessments (during ICU stay, at consent and hospital discharge); cumulative proportion of patients providing consent at extubation and at ICU and hospital discharge. Of 150 patients, 86 (57%) survived and 77 (90% of survivors) provided consent. Patients were delirious/deeply sedated in 89% of daily assessments during mechanical ventilation. By extubation, 31 (44%) patients passed step 1 and 8 (11%) passed step 2 and were consented. By ICU and hospital discharge, these numbers were 50 (58%) and 18 (21%), and 81 (94%) and 67 (78%), respectively. The median (interquartile range) time to patient consent after acute lung injury diagnosis was 15 (9-28) days.


More than three fourths of critically ill patients are unable to provide informed consent throughout their ICU stay, even after extubation. Sedation-agitation and delirium are common barriers to consent. A two-step consent process, using validated instruments for sedation-agitation and delirium, provides a means of rapidly screening critically ill patients before a more detailed traditional assessment of competency is conducted.

[Indexed for MEDLINE]

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