Ketamine does not increase intracranial pressure, increase risk for death, or extend intensive care unit length of stay compared with drugs commonly used to intubate adult patients in the emergency department (ED), new data indicate.
In a systematic review, Lindsay Cohen, MD, from the Royal College Emergency Medicine Residency Training Program, University of British Columbia, Vancouver, Canada, and colleagues conclude that the intravenous induction agent should be routinely considered in life-threatening situations in EDs. Results of their study were published in the Annals of Emergency Medicine.
The authors said the misconceptions about ketamine come from studies more than 40 years old. This study reviewed 10 recent randomized controlled, prospective studies that met inclusion criteria, reporting on data from 953 patients.
“Apprehension for many years about ketamine’s effects on blood pressure or injured brains inhibited its use for intubation, especially in North America compared to Europe, but our review shows those concerns are likely overblown,” coauthor Corinne Hohl, MD, from the Department of Emergency Medicine at Vancouver General Hospital, British Columbia, Canada, said in a news release.
“In view of recent concerns about the potential negative effects of an alternative induction agent, etomidate, ketamine should be considered routinely in patients with life-threatening infections and more regularly for patients who have been ‘found down,’ or unconscious, before being transported to the ER,” she continues.
Only about 3% of ED intubations are performed using ketamine, the authors note. Most emergency physicians have chosen to use etomidate to intubate critically ill patients when traumatic or other neurologic injuries have not been ruled out, but in the last decade, induction doses of etomidate have been linked with transient adrenal dysfunction. As a result, interest in the use of ketamine in the management of undifferentiated critically ill patients has resurged.
The authors found that ketamine did not adversely affect patient outcomes. Studies found no difference in neurological outcomes for patients sedated with ketamine compared with patients sedated with fentanyl, sufentanil, remifentanil, or etomidate. Two randomized studies compared intensive care unit length of stay as an outcome. In 1 trial, patients with traumatic brain injury were exposed to prolonged ketamine or sufentanil infusions. In the other, patients undergoing elective open-heart surgery were exposed to intraoperative ketamine or remifentanil infusions. Neither study found a difference in length of stay.
Two randomized trials reported mortality data on 680 patients. One found no difference in 28-day mortality in undifferentiated critically ill patients who were intubated with either ketamine or etomidate. In the etomidate group, 35% of patients died compared with 31% of ketamine patients (95% confidence interval, −4 to 12 patients). The other trial found no difference in intensive care unit mortality in patients with severe traumatic brain injury who were sedated with ketamine compared with sufentanil.
Because EDs see a high volume of undifferentiated critically ill patients who need quick airway management, the study supporting the safety of ketamine, a sedative with a favorable hemodynamic profile, should be reassuring, the authors write.
However, they also note that the size of the studies constitutes a limitation.
“Our study is limited by the lack of large, well-designed, randomized, controlled trials addressing this topic. High-quality, adequately powered, randomized trials comparing induction agents with respect to patient-oriented outcomes are urgently needed to optimize treatment strategies for critically ill patients in the ED,” they write.