Pharmacologic agents for the prevention and treatment of delirium in patients undergoing cardiac surgery: systematic review and metaanalysis.

OBJECTIVES: Postcardiac surgery delirium is associated with increased risks of morbidity, cognitive decline, poor health-related quality of life and mortality, and higher healthcare costs. We performed a systematic review of randomized controlled trials to examine the effect of pharmacologic agents for the prevention and the treatment of delirium after cardiac surgery.

DATA SOURCES: Electronic search on PubMed, Medline, Embase, Cochrane Central Register of Controlled Trials, ISI Web of Science, and CINAHL up to December 2013.

STUDY SELECTION: Randomized controlled trials of pharmacologic agents used for the prevention and the treatment of delirium after emergency or elective cardiac surgery in adults.

DATA EXTRACTION: We extracted data on patient population, pharmacologic agents, delirium characteristics, rescue treatment, length of stays in the ICU and hospital, and mortality. For each trial, we assessed the risk of bias domains and rated the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation approach.

DATA SYNTHESIS: Of the 13 studies (10 prevention and three treatment) involving 5,848 patients, one multicentered randomized controlled trial on prophylactic dexamethasone made up 77% of the total sample size. The use of pharmacologic agents (dexamethasone, rivastigmine, risperidone, ketamine, dexmedetomidine, propofol, and clonidine) reduced the risk of delirium (relative risk, 0.57; 95% CI, 0.40-0.80) with quality of evidence rated as moderate. There was high quality of evidence for no increased risk of mortality (relative risk, 0.89; 95% CI, 0.57-1.38) associated with the use of prophylactic pharmacologic agents. Metaanalysis of treatment trials was not undertaken because of high heterogeneity. In two small trials (total number of patients = 133), haloperidol did not appear to be effective in treating delirium.

CONCLUSIONS: Moderate to high-quality evidence supports the use of pharmacologic agents for the prevention of delirium, but results are based largely on one randomized controlled trial. The evidence for treating postcardiac surgery delirium with pharmacologic agents is inconclusive.