Predictors of adverse events with intramuscular ketamine sedation in children

Ketamine is a safe and effective sedative for emergency department procedures in children. However, the use of ketamine sometimes is associated with airway complications, emesis, and recovery agitation. We wished to identify predictors of these adverse events that clinicians might use to risk-stratify children who are candidates for ketamine sedation.

We analyzed data from 1,021 ED intramuscular ketamine sedations in children 15 years of age or younger at a university medical center and an affiliated county hospital over a 9-year period. Five potential predictor variables (age, gender, American Society of Anesthesiologists' [ASA] risk classification, quantity of first ketamine dose, and number of ketamine doses administered) were compared between children with and without complications. We used multiple logistic regression analyses to determine the association of these 5 variables with emesis and recovery agitation, and validated these analyses with bootstrap resampling techniques. We compared children with and without airway complications using univariate statistics alone, as there were too few patients with airway complications to support a multivariate analysis.

No study variables had significant univariate associations with airway complications (all P values >.40). We found emesis to be associated with increasing age in multivariate analysis (odds ratio [OR] 1.25 per year, bias-corrected 95% confidence interval [CI] 1.17 to 1.34, P<.001). The incidence of emesis was 12. 1% in children aged 5 years or older, and 3.5% in those younger than 5 years (Delta8.6%, 95% CI 4.9% to 12.1%). Recovery agitation was associated with the presence of an underlying medical condition (ie, ASA class > or =2, OR 3.05, bias-corrected 95% CI 1.65 to 7.30, P=.004) and inversely associated with increasing age (OR 0.79 per year, bias-corrected 95% CI 0.69 to 0.89, P<.001). The incidence of recovery agitation was 17.9% in ASA class 1 children and 33.3% in children in ASA class 2 or greater (Delta-15.4%, 95% CI 0.0% to -30. 7%). The incidence of recovery agitation was 12.1% in children aged 5 years or older, and 22.5% in those younger than 5 years (Delta-10. 4%, 95% CI -3.0% to -17.7%). Bootstrap resampling techniques validated the importance of the significant variables identified in the regression analyses.

No study variable was predictive of ketamine-associated airway complications. Emesis that occurred after ketamine administration was modestly associated with increasing age. Recovery agitation was modestly associated with decreasing age and the presence of an underlying medical condition. The discriminatory power of these variables was low enough as to be unlikely to alter clinical decisions regarding patient selection for ketamine administration. No evidence of a significant ketamine dose relationship was noted for airway complications, emesis, or recovery agitation.