Rationale: Choice and intensity of early (first 48 h) sedation may affect short- and long-term outcome.
Objectives: To investigate the relationships between early sedation and time to extubation, delirium, and hospital and 180-day mortality among ventilated critically ill patients in the intensive care unit (ICU).
Methods: Multicenter (25 Australia and New Zealand hospitals) prospective longitudinal (ICU admission to 28 d) cohort study of medical/surgical patients ventilated and sedated 24 hours or more. We assessed administration of sedative agents, ventilation time, sedation depth using Richmond Agitation Sedation Scale (RASS, four hourly), delirium (daily), and hospital and 180-day mortality. We used multivariable Cox regression to quantify relationships between early deep sedation (RASS, -3 to -5) and patients' outcomes.
Measurements and main results: We studied 251 patients (mean age, 61.7 ± 15.9 yr; mean Acute Physiology and Chronic Health Evaluation [APACHE] II score, 20.8 ± 7.8), with 21.1% (53) hospital and 25.8% (64) 180-day mortality. Over 2,678 study days, we completed 14,736 RASS assessments. Deep sedation occurred in 191 (76.1%) patients within 4 hours of commencing ventilation and in 171 (68%) patients at 48 hours. Delirium occurred in 111 (50.7%) patients with median (interquartile range) duration of 2 (1-4) days. After adjusting for diagnosis, age, sex, APACHE II, operative, elective, hospital type, early use of vasopressors, and dialysis, early deep sedation was an independent predictor of time to extubation (hazard ratio [HR], 0.90; 95% confidence interval [CI], 0.87-0.94; P < 0.001), hospital death (HR, 1.11; 95% CI, 1.02-1.20; P = 0.01), and 180-day mortality (HR, 1.08; 95% CI, 1.01-1.16; P = 0.026) but not delirium occurring after 48 hours (P = 0.19).
Conclusions: Early sedation depth independently predicts delayed extubation and increased mortality, making it a potential target for interventional studies.