A comparison of ketamine versus etomidate for procedural sedation for the reduction of large joint dislocations.

STUDY OBJECTIVES: Ketamine and etomidate are used for procedural sedation (PS) to facilitate the performance of painful procedures. We hypothesized that ketamine produces adequate and comparable sedation conditions for dislocated large joint reduction when compared to etomidate and results in fewer adverse events.

METHODS: This Institutional Review Board approved prospective trial compared a convenience sample of subjects, who were randomized to receive either ketamine or etomidate for PS to facilitate reduction of large joint dislocations. Following informed consent, subjects were assigned via a computer-generated algorithm to receive either etomidate (0.1 mg/kg) or ketamine (0.5 mg/kg) intravenously; if PS was not sufficient, subjects received repeat doses of etomidate or ketamine until adequate PS was achieved. The protocol's primary endpoint was a successful reduction of dislocated, large joints. Secondary endpoints included alteration in blood pressure, vomiting, recovery agitation, hypersalivation, laryngospasm, myoclonus, hypoxia, airway assistance with chin lift or jaw thrust, bag-valve-mask ventilation, endotracheal intubation, utilization of additional doses of ketamine or etomidate, and recovery time from sedation.

RESULTS: Total enrollment was eighty subjects, 46 in the ketamine cohort and 34 in the etomidate cohort. The two PS groups were comparable in terms of gender, age, and weight. There was no significant difference in the primary endpoint of large joint dislocation reduction between the ketamine and etomidate cohorts (46/46, 100%; 32/34, 94.1%; P - 0.1). Shoulder, hip, and ankle joints account for the majority of joint reductions in this trial. Titration of PS was necessary for almost half of each cohort as evidenced by the utilization of additional dosages of the sedative agents: ketamine (22/46, 47.8%) and etomidate (14/34, 41.2%; P - 0.56). Among secondary outcome variables, significant differences between ketamine and etomidate cohorts were myoclonus (1/46, 2.2%, 15/33, 45.5%; P - 0.0001), assisted ventilation with airway manipulation (3/45, 6.7%; 9/33, 27.3%; P - 0.01), and pulsoximetry desaturation < 90% (0/46; 7/34, 20.6%; P - 0.002). There was no significant difference in recovery time from PS between the ketamine and etomidate cohorts (11 min vs. 10 min; P - 0.69).

CONCLUSION: Ketamine produces PS conditions for successful large joint dislocation reduction that are adequate and comparable to etomidate. The increased likelihood of myoclonus, of the requirement for airway assistance, and of hypoxia observed with etomidate suggest potential benefits with the utilization of ketamine for PS for dislocated large joint reduction.