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Delirium as a predictor of long-term cognitive impairment in survivors of critical illness

Girard, Timothy D. MD, MSCI; Jackson, James C. PsyD; Pandharipande, Pratik P. MD, MSCI; Pun, Brenda T. MSN; Thompson, Jennifer L. MPH; Shintani, Ayumi K. PhD, MPH; Gordon, Sharon M. PsyD; Canonico, Angelo E. MD; Dittus, Robert S. MD, MPH; Bernard, Gordon R. MD; Wesley Ely, E. MD, MPH

doi: 10.1097/CCM.0b013e3181e47be1
Continuing Medical Education Articles

Objective: To test the hypothesis that duration of delirium in the intensive care unit is an independent predictor of long-term cognitive impairment after critical illness requiring mechanical ventilation.

Design: Prospective cohort study.

Setting: Medical intensive care unit in a large community hospital in the United States.

Patients: Mechanically ventilated medical intensive care unit patients who were assessed daily for delirium while in the intensive care unit and who underwent comprehensive cognitive assessments 3 and 12 mos after discharge.

Measurements and Main Results: Of 126 eligible patients, 99 survived ≥3 months after critical illness; long-term cognitive outcomes were obtained for 77 (78%) patients. Median age was 61 yrs, 51% were admitted with sepsis/acute respiratory distress syndrome, and median duration of delirium was 2 days. At 3-mo and 12-mo follow-up, 79% and 71% of survivors had cognitive impairment, respectively (with 62% and 36% being severely impaired). After adjusting for age, education, preexisting cognitive function, severity of illness, severe sepsis, and exposure to sedative medications in the intensive care unit, increasing duration of delirium was an independent predictor of worse cognitive performance—determined by averaging age-adjusted and education-adjusted T-scores from nine tests measuring seven domains of cognition—at 3-mo (p = .02) and 12-mo follow-up (p = .03). Duration of mechanical ventilation, alternatively, was not associated with long-term cognitive impairment (p = .20 and .58).

Conclusions: In this study of mechanically ventilated medical intensive care unit patients, duration of delirium (which is potentially modifiable) was independently associated with long-term cognitive impairment, a common public health problem among intensive care unit survivors. (Crit Care Med 2010; 38:1513–1520

Assistant Professor of Medicine (TDG), Division of Allergy, Pulmonary, and Critical Care Medicine and Center for Health Services Research in the Department of Medicine, Vanderbilt University School of Medicine; Geriatric Research, Education and Clinical Center Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, TN; Assistant Professor of Medicine and Psychiatry (JCJ), Division of Allergy, Pulmonary, and Critical Care Medicine and Center for Health Services Research in the Department of Medicine, Department of Psychiatry, Vanderbilt University School of Medicine; Research Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System, Nashville, TN; Associate Professor of Anesthesiology and Critical Care (PPP), Anesthesia Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System; Division of Critical Care in the Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN; Research Coordinator (BTP), Division of Allergy, Pulmonary, and Critical Care Medicine in the Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN; Biostatistician III (JLT), Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN; Associate Professor of Biostatistics (AKS), Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN; Assistant Clinical Professor of Psychiatry (SMG), Psychiatry Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN; Physician (AEC), Department of Medicine, Saint Thomas Hospital, Nashville, TN; Professor of Medicine and Director (RSD), Geriatric Research, Education and Clinical Center Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System; Center for Health Services Research, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN; Professor of Medicine and Associate Vice Chancellor for Research (GRB), Division of Allergy, Pulmonary, and Critical Care Medicine in the Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN; Professor of Medicine and Associate Director for Research (EWE), Geriatric Research, Education and Clinical Center Service, Department of Veterans Affairs Medical Center, Tennessee Valley Healthcare System; Division of Allergy, Pulmonary, and Critical Care Medicine and Center for Health Services Research in the Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN.

This research was supported by the Saint Thomas Foundation (Nashville, TN), National Institutes of Health (AG001023, AG034257, HL007123, and RR024975), Veterans Affairs Tennessee Valley Geriatric Research, Education, and Clinical Center (GRECC), Hartford Geriatrics Health Outcomes Research Scholars Award Program, and Vanderbilt Physician Scientist Development Program. These sponsors had no role in study design, data collection, analysis, and interpretation, or publication of results. The researchers were all independent from the sponsors.

For information regarding this article, E-mail: timothy.girard@vanderbilt.edu

© 2010 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins