Purpose: The purpose of this study was to evaluate rates of delirium or coma-free days between continuous infusion sedative-dose ketamine and continuous infusion benzodiazepines in critically ill patients. Materials and Methods: In this single-center, retrospective cohort adult patients were screened for inclusion if they received continuous infusions of either sedative-dose ketamine or benzodiazepines (lorazepam or midazolam) for at least 24 h, were mechanically ventilated for at least 48 h and admitted to the intensive care unit of a large quaternary academic center between 5/5/2018 and 12/1/2021. Results: A total of 165 patients were included with 64 patients in the ketamine group and 101 patients in the benzodiazepine group (lorazepam n = 35, midazolam n = 78). The primary outcome of median (IQR) delirium or coma-free days within the first 28 days of hospitalization was 1.2 (0.0, 3.7) for ketamine and 1.8 (0.7, 4.6) for benzodiazepines (p = 0.13). Patients in the ketamine arm spent a significantly lower proportion of time with RASS -3 to +4, received significantly higher doses and longer durations of propofol and fentanyl infusions, and had a significantly longer intensive care unit length of stay. Conclusions: The use of sedative-dose ketamine had no difference in delirium or coma-free days compared to benzodiazepines.
Keywords: benzodiazepines; delirium; ketamine; pharmacology; sedation.