Among critically ill, mechanically ventilated patients, continuous infusion of sedative-dose ketamine did not improve delirium- or coma-free days compared with continuous infusion of benzodiazepines. The median number of delirium- or coma-free days within the first 28 days was 1.2 for ketamine and 1.8 for benzodiazepines, a difference that was not statistically significant. Patients receiving ketamine spent less time at a desired sedation level, received more propofol and fentanyl, and had a longer intensive care unit stay. The findings suggest that ketamine offers no advantage over benzodiazepines for reducing delirium or coma in this population.
Among critically ill adults undergoing endotracheal intubation, acute cardiovascular dysfunction (hemodynamic instability or cardiac arrest) occurred at similar rates with etomidate and ketamine but was more frequent with propofol than with non-propofol sedation. Exploratory meta-analysis showed no statistically significant difference between etomidate and ketamine (odds ratio 1.05) or between etomidate and propofol (odds ratio 0.91). However, etomidate was associated with lower survival to hospital discharge compared to ketamine (odds ratio 0.76). Limited data for other outcomes such as acute kidney injury, delirium, or length of stay revealed no clear differences among the sedative agents.
Subanesthetic doses of ketamine improved specific depressive symptoms in critically ill intensive care unit patients without causing significant hemodynamic instability. In a retrospective study of 34 adults, including 18 solid organ transplant recipients, ketamine infusions (0.3-0.75 mg/kg over 40 minutes on three consecutive days) were associated with improvement in apparent sadness (90.0% vs 52.2%) and reported sadness (95.0% vs 59.1%). Among transplant recipients, improvement in apparent sadness remained significant (80.0% vs 41.7%). Heart rate increased transiently at 15-30 minutes post-infusion but returned to baseline by 60-90 minutes. Adverse effects included anxiety (12.5%), restlessness or agitation (10.4%), and dissociation (8.16%). These findings support ketamine's potential as a rapid-acting antidepressant in the ICU.