Hypotension is common after mivacurium injection in healthy patients. This hemodynamic event had not been investigated in hypertensive patients characterized by more intense hemodynamic instability. In this open-label, multicenter, randomized, and controlled study, we sought to determine whether mean arterial blood pressure (MAP) and heart rate variations were larger in hypertensive versus normotensive patients after a bolus dose of mivacurium injected over 10 or 30 s. After the induction of anesthesia with fentanyl and etomidate, normotensive (n = 149) and hypertensive (n = 57) patients received a single dose of mivacurium 0.2 mg/kg injected over 10 or 30 s by random allocation. Heart rate and MAP were recorded electronically. The incidence of hypotension (defined as a 20% MAP decrease from the control value before mivacurium injection) was 21% and 36% (10-s injection) or 11% and 10% (30-s injection) in the Normotensive and Hypertensive groups, respectively. In Hypertensive patients, the maximum decrease in MAP was significantly greater when mivacurium was injected over 10 s compared with 30 s: 20% vs 11%, respectively (P = 0.002). This difference was not observed in Normotensive patients. Hypotension after rapid (e.g., 10 s) mivacurium injection was more frequent and more pronounced in Hypertensive than in Normotensive patients.
Implications: When mivacurium (0.2 mg/kg) is injected rapidly (e.g., 10 s) the incidence and the intensity of hypotension are greater in hypertensive patients than in healthy patients.