Ketamine for continuous sedation of mechanically ventilated patients

Context: Long-term sedation with midazolam or propofol has been demonstrated to have serious adverse side effects, such as toxic accumulation or propofol infusion syndrome. Ketamine remains a viable alternative for continuous sedation as it is inexpensive and widely available, however, there are few analyses regarding its safety in this clinical setting. Objective: To review the data related to safety and efficacy of ketamine as a potential sedative agent in mechanically ventilated patients admitted to the intensive care unit (ICU). Materials and Methods: This was a single-center retrospective study from September 2011 to March 2012 of patients who required sedation for greater than 24 hours, in whom ketamine was selected as the primary sedative agent. All patients greater than 18 years of age, regardless of admitting diagnosis, were eligible for inclusion. Patients that received ketamine for continuous infusion but died prior to receiving it for 24 hours were not included. Results: Thirty patients received ketamine for continuous sedation. In four patients, ketamine was switched to another sedative agent due to possible adverse side effects. Of these, two patients had tachydysrhythmias, both with new onset atrial fibrillation and two patients had agitation believed to be caused by ketamine. The adverse event rate in our patient population was 13% (4/30). Conclusions: Among ICU patients receiving prolonged mechanical ventilation, the use of ketamine appeared to have a frequency of adverse events similar to more common sedative agents, like propofol and benzodiazepines.