The effect of injection rate on etomidate-induced myoclonus. |
Sang Hwan Do, Sung Hee Han, Sang Hyun Park, Jin Hee Kim, Jin Young Hwang, Il Soon Son, Min Seok Kim |
1Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea. anesthesiology@snubh.org 2Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea. |
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Abstract |
BACKGROUND Etomidate frequently causes myoclonus. Since the myoclonus is caused by a transient disequilibrium due to etomidate exposure in the CNS, we hypothesized that a slow rate of injection of the drug may decrease the incidence of myoclonus. We conducted a prospective randomized study to compare the effect of two different types of the etomidate injection rate on the incidence and severity of myoclonus. METHODS Fifty patients were randomly assigned to the fast-injection group (group F) or slow-injection group (group S): Group F patients received etomidate (0.3 mg/kg) over ten seconds. The same dose was administered over two minutes for group S patients. The response to the injection of etomidate was graded on a four-point scale in a blinded manner. The time to loss of consciousness (LOC) was also recorded. RESULTS The incidence of myoclonus was significantly lower (P < 0.001) in group S patients; 84% and 28% in group F and group S patients, respectively. The myoclonus was also significantly less severe in group S patients (P < 0.001).
The time to LOC was significantly longer in group S patients (106 +/- 22 sec) than that of group F patients (49 +/- 18 sec, P < 0.001). CONCLUSIONS With same dose, a slower rate of injection resulted in a lower incidence of myoclonus and can effectively reduce myoclonus without the use of a pretreatment agent. |
Key Words:
etomidate; injection rate; myoclonus |
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