P. Couture et al., HEMODYNAMIC INTERACTION OF HIGH-DOSE FENTANYL AND INCREASING DOSES OFVECURONIUM IN PATIENTS UNDERGOING MYOCARDIAL REVASCULARIZATION, Acta anaesthesiologica Scandinavica, 40(1), 1996, pp. 32-38
Background. Bradyarrhythmia has been reported with vecuronium when giv
en with high dose narcotics. We hypothesized that if the bradycardic r
esponse is dependent on a vagal reaction mediated by narcotics, it sho
uld be independent of the vecuronium dose. A dose-related response of
vecuronium on heart rate (HR) would be in favour of a chronotropic act
ion of this agent. Methods, We examined three induction techniques usi
ng high doses of fentanyl in which vecuronium was given in increasing
doses. In addition, a reference group received a low dose of atracuriu
m. Forty patients scheduled for elective CABG surgery were anaesthetiz
ed with fentanyl (50 mu g/kg) given over 5 min, and were randomly assi
gned to receive either 0.056, 0.14, 0.28 mg/kg of vecuronium or 0.28 m
g/kg of atracurium. Haemodynamic measurements were obtained at the fol
lowing intervals: before induction (time 0), after the administration
of fentanyl (at 5 min), and 1, 2 and 5 min after tracheal intubation (
at 10, 11 and 15 min). Results. In vecuronium-treated groups, there we
re significant decreases in HR, mean arterial pressure, and cardiac ou
tput (P<0.05). There were no differences between the three vecuronium
groups. Although the atracurium-treated group displayed no significant
haemodynamic changes, 2 patients of this group developed HR <40 bpm.
Conclusions. Over the range of vecuronium doses studied, we observed a
reduction in HR during induction for CABG surgery with high doses of
fentanyl and vecuronium. This effect was not dose dependent and is lik
ely related to a direct effect of a high-dose narcotic technique and/o
r due to a vagal stimulation regarding the airway procedure.