Corticosteroids and transition to delirium in patients with acute lung injury.

OBJECTIVE

Delirium is common in mechanically ventilated patients in the ICU and associated with short- and long-term morbidity and mortality. The use of systemic corticosteroids is also common in the ICU. Outside the ICU setting, corticosteroids are a recognized risk factor for delirium, but their relationship with delirium in critically ill patients has not been fully evaluated. We hypothesized that systemic corticosteroid administration would be associated with a transition to delirium in mechanically ventilated patients with acute lung injury.

DESIGN

Prospective cohort study.

SETTING

Thirteen ICUs in four hospitals in Baltimore, MD.

PATIENTS

Five hundred twenty mechanically ventilated adult patients with acute lung injury.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Delirium evaluation was performed by trained research staff using the validated Confusion Assessment Method for the ICU screening tool. A total of 330 of the 520 patients (64%) had at least two consecutive ICU days of observation in which delirium was assessable (e.g., patient was noncomatose), with a total of 2,286 days of observation and a median (interquartile range) of 15 (9, 28) observation days per patient. These 330 patients had 99 transitions into delirium from a prior nondelirious, noncomatose state. The probability of transitioning into delirium on any given day was 14%. Using multivariable Markov models with robust variance estimates, the following factors (adjusted odds ratio; 95% CI) were independently associated with transition to delirium: older age (compared to < 40 years old, 40-60 yr [1.81; 1.26-2.62], and ≥ 60 yr [2.52; 1.65-3.87]) and administration of any systemic corticosteroid in the prior 24 hours (1.52; 1.05-2.21).

CONCLUSIONS

After adjusting for other risk factors, systemic corticosteroid administration is significantly associated with transitioning to delirium from a nondelirious state. The risk of delirium should be considered when deciding about the use of systemic corticosteroids in critically ill patients with acute lung injury.