Impact of quetiapine on resolution of individual delirium symptoms in critically ill patients with delirium: a post-hoc analysis of a double-blind, randomized, placebo-controlled study

Introduction: We hypothesized that delirium symptoms may respond differently to antipsychotic therapy. The purpose of this paper was to retrospectively compare duration and time to first resolution of individual delirium symptoms from the database of a randomized, double-blind, placebo-controlled study comparing quetiapine (Q) or placebo (P), both with haloperidol rescue, for critically ill patients with delirium. Methods: Data for 10 delirium symptoms from the eight-domain, intensive care delirium screening checklist (ICDSC) previously collected every 12 hours were extracted for 29 study patients. Data between the Q and P groups were compared using a cut-off P-value of <= 0.10 for this exploratory study. Results: Baseline ICDSC scores (5 (4 to 7) (Q) vs 5 (4 to 6)) (median, interquartile range (IQR)) and % of patients with each ICDSC symptom were similar in the two groups (all P > 0.10). Among patients with the delirium symptom at baseline, use of Q may lead to a shorter time (days) to first resolution of symptom fluctuation (4 (Q) vs. 14, P = 0.004), inattention (3 vs. 8, P = .10) and disorientation (2 vs. 10, P = 0.10) but a longer time to first resolution of agitation (3 vs. 1, P = 0.04) and hyperactivity (5 vs. 1, P = 0.07). Among all patients, Q-treated patients tended to spend a smaller percent of time with inattention (47 (0 to 67) vs. 78 (43 to 100), P = 0.025), hallucinations (0 (0 to 17) vs. 28 (0 to 43), P = 0.10) and symptom fluctuation (47 (19 to 67) vs. 89 (33 to 00), P = 0.04] and there was a trend for Q-treated patients to spend a greater percent of time at an appropriate level of consciousness (26% (13 to 63%) vs. 14% (0 to 33%), P = 0.17]. Conclusions: Our exploratory analysis suggests that quetiapine may resolve several intensive care unit (ICU) delirium symptoms faster than the placebo. Individual symptom resolution appears to differ in association with the pharmacologic intervention (that is, P vs Q, both with as needed haloperidol). Future studies evaluating antipsychotics in ICU patients with delirium should measure duration and resolution of individual delirium symptoms and their relation to long-term outcomes.