The Efficacy of Ketamine in Pediatric Emergency Department Patients Who Present With Acute Severe Asthma

Abstract

We determine whether a continuous infusion of ketamine can decrease the severity of a moderately severe acute asthma exacerbation by a clinically significant 2 points using a 15-point Pulmonary Index scoring scale. A double-blinded, randomized, placebo-controlled trial was performed to evaluate patients aged 2 to 18 years who presented to a pediatric emergency department with an acute asthma exacerbation. Exclusion criteria included temperature greater than 39 degrees C (102 degrees F), focal infiltrate on radiograph, or any glucocorticoid use in the last 72 hours. Eligible patients received 3 treatments with albuterol, ipratropium bromide, and a dose of oral or parenteral glucocorticoids. If the Pulmonary Index score remained 8 to 14, enrollment proceeded. All enrolled patients received continuous nebulized albuterol at 10 mg/hour and were randomized to receive an intravenous bolus of 0.2 mg/kg of ketamine, followed by a 2-hour ketamine infusion at 0.5 mg/kg per hour or an equal-volume regimen with normal-saline placebo. A Pulmonary Index score was performed on patients at 0, 30, 60, 90, and 120 minutes. Sixty-eight patients were enrolled, with 33 randomized to the ketamine infusion and 35 randomized to placebo. Mean ages of patients enrolled, chronic severity of asthma, and duration of symptoms before presentation were similar between groups. At enrollment, the mean Pulmonary Index score in the placebo group was 10.3+/-1.1 versus 10.5+/-1.5 for the ketamine group (difference of means 0.2; 95% confidence interval [CI] -0.5 to 0.8). Sixty-two patients completed the entire 2-hour infusion protocol. No significant difference between groups was seen in rate of improvement in the Pulmonary Index score at completion. The mean decrease in the Pulmonary Index scores at the end of the infusion was 3.6+/-1.3 in the placebo group versus 3.2+/-2.0 in the ketamine group (difference of means 0.4; 95% CI -0.4 to 1.3). No short-term adverse effects necessitating discontinuation of the infusion or adverse behavioral impacts at 48 hours after discharge were noted. We conclude that ketamine given at 0.2 mg/kg followed by an infusion of 0.5 mg/kg per hour for 2 hours provided no incremental benefit to standard therapy in this cohort of children with a moderately severe asthma exacerbation.