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

TLDR

The study aimed to determine whether the duration of ICU delirium independently predicts long‑term cognitive impairment in mechanically ventilated patients. A prospective cohort of 126 mechanically ventilated medical ICU patients, with daily delirium assessments and cognitive testing at 3 and 12 months, had a median age of 61, 51 % admitted with sepsis/ARDS, and a median delirium duration of 2 days. At 3 and 12 months, 79 % and 71 % of survivors exhibited cognitive impairment (62 % and 36 % severely impaired), and after adjusting for confounders, each additional day of delirium independently predicted worse cognition (p = 0.02 at 3 mo, p = 0.03 at 12 mo), whereas ventilation duration was not associated.

Abstract

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.Prospective cohort study.Medical intensive care unit in a large community hospital in the United States.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.Of 126 eligible patients, 99 survived>or=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).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.