Dexmedetomidine-ketamine sedation among pediatric patients with Fallot tetralogy undergoing cardiac multislice spiral computed tomography

Background
The combination of dexmedetomidine and ketamine is feasible for pediatric procedural sedation, particularly in radiologic imaging studies.
Objective
The aim of the study was to investigate the sedative effects of ketamine-dexmedetomidine (KD) and ketamine-midazolam (KM) combinations on recovery time and adverse events in pediatric patients with uncorrected tetralogy of Fallot undergoing multislice spiral computed tomography (CT).
Patients and methods
A total of 40 American Association of Anesthesiologists III pediatric patients aged between 2 and 3 years with surgically uncorrected tetralogy of Fallot undergoing CT were randomly allocated into two equal groups. Patients in group KD received intravenous dexmedetomidine (1 µg/kg) over 15 min, followed by 1 mg/kg of ketamine infused slowly over 15 min. Patients in the group KM received 0.1 mg/kg bolus of midazolam over 15 min, followed by 1 mg/kg initial bolus of ketamine over 15 min, followed by waiting for 2 min to evaluate the sedative effect. After a Ramsay sedation score of 4 was reached, a rescue dose of 1 mg/kg of ketamine (maximum of 2 mg/kg) was administered to maintain an Ramsay sedation score of 4 in both groups. Recovery time; sedation scores, systolic blood pressure and diastolic blood pressure, and oxygen saturation at baseline, 3, 6, and 9 min after drug administration; the number of patients requiring additional ketamine; and the incidence of complications such as apnea, hypotension, and vomiting were recorded.
Results
Administration of KM compared with KD was associated with significantly larger number of patients requiring additional ketamine doses (=0.018) and a higher incidence of complications, such as tachyarrhythmia (<0.035), vomiting (<0.02), and agitation (<0.04) as well. There was no significant difference between both groups regarding recovery time, sedation scores, systolic blood pressure, diastolic blood pressure, and oxygen saturation.
Conclusion
Sedation using KD for cardiac multislice spiral CT displayed lower rescue doses of ketamine and less occurrence of complications with insignificant effect on the recovery time compared with KM sedation.