The dose-effect relationship of
mivacurium chloride on arterial blood pressure, heart rate, and plasma
histamine was determined in 97 consenting ASA physical status I-II patients receiving
nitrous oxide-
oxygen-
opiate-
barbiturate anesthesia. In the absence of surgical stimulation during steady state
anesthetic conditions with controlled ventilation, average maximum change in tachograph-counted heart rate was 7% or less after 10-15-s injection of
mivacurium at all doses from 0.03 to 0.30 mg/kg. Average peak change in mean arterial pressure measured via radial arterial
catheter was 7% or less after all doses from 0.03 to 0.15 mg/kg. Transient (0.2-4.5 min) decreases in arterial blood pressure were noted after 10-15-s injection in some patients at 0.20, 0.25, and 0.30 mg/kg. When they occurred, these changes were usually accompanied by facial
erythema lasting 2-5 min and were correlated with increases in plasma
histamine level (P less than 0.001). Facial
erythema, decrease in blood pressure, and elevation of
histamine level were all accentuated by increasing the dose of
mivacurium and by more rapid injection of the
drug. For example, mean blood pressure decreased an average of 13% after injection of
mivacurium 0.25 mg/kg over 10-15 s. In contrast, during administration over 30 and 60 s of this dose, arterial pressure decreased 7.6 and 1.5%, respectively (P less than 0.001, 10-15 s vs. 60-s injection). Average peak
histamine level, which increased to 132% of control after administration of 0.25 mg/kg over 10-15 s, did not change after injection over 60 s.(ABSTRACT TRUNCATED AT 250 WORDS)