Neuromuscular blocking drugs may have variable effects on heart rate (HR) and blood pressure.
Rapacuronium is a rapid-acting, steroidal-derived neuromuscular blocking
drug whose hemodynamic effects have not been characterized. We studied the effects of 1, 2, and 3 mg/kg
rapacuronium on histamine release, HR, and blood pressure in 47 ASA physical status II or III adult patients after the induction of
anesthesia with
etomidate/
fentanyl/N2O. Plasma
histamine concentrations were measured before induction and immediately before and 1, 3, and 5 min after the rapid administration of
rapacuronium. Mean arterial pressure (MAP) decreased after
rapacuronium administration, but there were no significant differences among the groups for changes in HR or MAP, and there was no correlation between changes in MAP or HR and increases in
histamine levels. There were no changes in HR or MAP among five patients who had significant (> or = 1 ng/mL) increases in
histamine from baselin. Seven patients had
bronchospasm without increases in plasma
histamine levels.
Rapacuronium 2-3 mg/kg increased plasma
histamine levels. However, clinically significant
histamine-related sequelae did not occur in this population with 1- to 3-mg/kg doses of
rapacuronium, and cardiovascular changes were not directly correlated with histamine release.
Rapacuronium administration can produce
hypotension via mechanisms that do not seem to be related to histamine release.
IMPLICATIONS:
Rapacuronium, a new steroidal-derived muscle relaxant, may release
histamine and produce slight changes in blood pressure and heart rate after administration.