Ketamine Sedation After Administration of Oral Contrast: A Retrospective Cohort Study

BACKGROUND: The American Academy of Pediatrics and American Society of Anesthesiologists have published consensus-based fasting guidelines intended to reduce the risk of pulmonary aspiration. The purpose of our study was to compare the rate of adverse events in patients sedated with ketamine within 2 hours of oral contrast intake to those who were nil per os (NPO). METHODS: A retrospective cohort review of a database of children between July 2008 and May 2011. The rate of adverse events in children sedated with ketamine after intake of oral contrast for an abdominal computed tomography were compared with those sedated without taking oral contrast. RESULTS: One hundred and four patients sedated for a computed tomography scan; 22 patients were sedated within 2 hours of taking oral contrast, and 82 were NPO. The 2 groups were comparable with regard to gender, race, and American Society of Anesthesiologists status. The mean (SD) time between the second dose of oral contrast and induction of sedation was 58 (24) minutes. Vomiting occurred in 4 of 22 patients in the oral contrast group (18%; 95% confidence interval 2%–34%) and 1 of 82 patients in the NPO group (1%; 95% confidence interval, 0%, 4%; P < .001). There was no difference in oxygen desaturation between the groups ( P = .6). CONCLUSIONS: Children who received oral contrast up to 58 minutes before ketamine sedation had a higher rate of vomiting than those who did not receive oral contrast. We did not identify cases of clinical aspiration, and the incidence of hypoxia between the 2 groups was not statistically significant. * Abbreviations: ASA : American Society of Anesthesiology CI : 95% confidence interval CT : computerized tomography GFV : gastric fluid volume NPO : nil per os/nothing by mouth