Adjunctive atropine versus metoclopramide: can we reduce ketamine-associated vomiting in young children? a prospective, randomized, open, controlled study.

Pediatric procedural sedation and analgesia (PPSA) with ketamine administration occurs commonly in the emergency department (ED). Although ketamine-associated vomiting (KAV) is a less serious complication of ketamine administration, it seems to be cumbersome and not uncommon. The authors evaluated the incidence of KAV and the prophylactic effect of adjunctive atropine and metoclopramide in children receiving ketamine sedation in the ED setting.This prospective, randomized, open, controlled study was conducted in children receiving ketamine sedation in the ED of a university-affiliated, tertiary hospital with 85,000 ED visits, including 32,000 pediatric patients from October 2010 to September 2011. The primary outcome was a measure of the incidence of KAV in the ED and after discharge according to the adjunctive drug administered. Secondary outcome measures included the time to resumption of a normal diet after ketamine sedation.Of the 1,883 children administered ketamine for primary wound repair during the study period, a convenience sample of 338 patients aged 4 months to 5 years was enrolled. The incidences of KAV were 28.4% in the ketamine alone group, 27.9% in the ketamine with adjunctive atropine group, and 31.2% in the ketamine with adjunctive metoclopramide group (p = 0.86). The vomiting rate after discharge was 9.2% in the ketamine alone group. The nothing-by-mouth (NPO) status before sedation did not influence the incidence of KAV in any of the groups. Mean times to resumption of normal diet after ketamine administration were 7 hours 59 minutes in the ketamine alone group, 7 hours 35 minutes in the ketamine with atropine group, and 8 hours 1 minute in the ketamine with metoclopramide group (p = 0.64). In this study, a high rate (28.4%) of KAV was observed, consistent with prior reports using the intramuscular (IM) route. However, the authors were unable to reduce KAV using adjunctive atropine or metoclopramide. Parents or caregivers should be given more detailed discharge instructions about vomiting and diet considering the relatively long time to resuming a normal diet after ketamine sedation and the fact that KAV often occurred after ED discharge.