[Effect of small-dose of ephedrine administered prior to induction of anesthesia on the onset time of succinylcholine]

ABSTRACT

Onset of action of relaxants is influenced by cardiac output and muscle blood flow. Ephedrine increases blood flow to muscles and may shorten the onset of action of succinylcholine. The aim of the study was to evaluate the effect of small-dose of ephedrine administered prior to rapid-sequence induction of anesthesia on the onset time of succinylcholine for endotracheal intubation. In this randomized clinical trial, 50 patients scheduled for elective gynecologic surgeries in Alzahra hospital in Tabriz 1385, were selected. In these patients ephedrine, 70 micro g/kg [study group, n=30], or saline [placebo group, n=30] was administered 3 minutes before induction of anesthesia with thiopentone/fentanyl. Succinylcholine, 0.6 mg/kg, was administrated to facilitate the tracheal intubation. Onset of succinylcholine, intubating conditions and hemodynamic variables were recorded in the subjects. Fasciculation was absent in 60% [36] of the patients. No significant differences were found between the onsets of fasciculation between two groups. Moreover, the difference in duration of fasciculation in two groups was not significant. Onset time of succinylcholine was significantly shorter in study group [19.53 +/- 3.91second], compared with placebo group [25.87 +/- 7.11second] [p<0.0001]. Patients in study group were intubated in 47.07 +/- 4.51 seconds compared with 58.73 +/- 9.04 seconds in placebo group [p<0.0001]. Intubation conditions were similar in both groups. Heart rate was slightly increased in study patients in the first and 3rd minutes after ephedrine administration, but there was no significant difference in systolic blood pressure values compared with the baseline value between two groups. The onset time of succinylcholine is shortened with small-dose of ephedrine pretreatment without significant adverse heamodynamic effects