Ketamine - Propofol Duo Impresses for Procedural Sedation

ACEP News 
July 2009

Nausea or vomiting was experienced by 16% of the ketamine group and just 3% of patients on ketamine/propofol. 

By Bruce Jancin
Elsevier Global Medical News

NEW ORLEANS -- The combination of ketamine and propofol for pediatric procedural sedation in the emergency department results in less total sedation time, faster recovery, dramatically fewer side effects, and higher satisfaction scores than does the use of ketamine alone, according to a randomized, double-blind clinical trial.

"We feel that this study has a strong potential to change clinical practice in a meaningful way," Dr. Amit P. Shah said at the annual meeting of the Society for Academic Emergency Medicine.

Ketamine continues to be the most widely used first-line agent for pediatric procedural sedation in emergency departments (EDs), although propofol is gaining in popularity. But there are sound theoretical reasons to believe the two agents have synergistic benefits; for example, ketamine is an emetic, while propofol has been shown to have antiemetic properties.

For this reason, Dr. Shah and his coinvestigators at Children's Hospital of Western Ontario, London, organized a trial to compare ketamine plus propofol with ketamine alone.

Using dedicated research assistants and predetermined end points for sedation and recovery, the investigators studied 136 patients aged 2-17 years who presented to the hospital for treatment of an isolated orthopedic extremity injury requiring procedural sedation.

Participants randomized to ketamine received an initial dose of 1.0 mg/kg given over 30 seconds plus a placebo consisting of intravenous Intralipid, followed by ketamine at 0.5 mg/kg and placebo every 2 minutes as required to reach a predetermined sedation score. Patients assigned to ketamine/propofol received an initial dose of ketamine at 0.5 mg/kg and propofol at 0.5 mg/kg, followed by propofol at 0.5 mg/kg and saline placebo every 2 minutes as needed for sedation.

The primary study end point was total sedation time, defined as the lapsed time from the first sedative injection to a score of 8 or more on the Modified Aldrete Recovery Scale. Total sedation time averaged 15.2 minutes in the ketamine/propofol group, significantly less than the 18.7 minutes for ketamine alone.

Mean recovery time also was significantly faster with combined sedation: 11.4 minutes versus 15.6 minutes with ketamine alone.

But the most impressive finding was the striking difference in side effects, according to Dr. Shah. A total of 36% of ketamine-treated patients versus just 12% of those who got ketamine plus propofol experienced side effects. The major differences between the two regimens were in the domains of nausea or vomiting, which was experienced by 16% of the ketamine group and just 3% of patients on ketamine/propofol; agitation or hallucinations, which were reported by 13% of the ketamine group compared with 6% of the ketamine/propofol group; and pain upon injection, which occurred in 2.9% of the ketamine group but did not occur in anyone given the combined sedation.

Patients, physicians, and nurses all rated their satisfaction with sedation significantly higher on a 7-point scale with ketamine/propofol than with ketamine alone.

The incidence of respiratory adverse events was similar in both treatment groups. All respiratory complications were mild and were managed with oxygen or airway repositioning. In contrast, a recent meta-analysis suggests that the use of ketamine in combination with benzodiazepines results in slower recovery and more respiratory adverse events than occur with ketamine alone, according to Dr. Shah.

The trial received funding support from several Canadian nonprofit agencies.

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