Cardiovascular homeostasis during inhalational general anesthesia: a clinical comparison between sevoflurane and isoflurane

Abstract

Study Objective: To obtain more information on cardiovascular homeostasis and patient discharge from the recovery area after general anesthesia with either sevoflurane or isoflurane as the main anesthetic. Design: Prospective, randomized, multicenter study Setting: Inpatient anesthesia at 13 University Departments of Anesthesia. Patients: 247 ASA physical status I, II, and III patients, aged 18 to 85 years, receiving general anesthesia for elective urological, orthopedic, ENT, vascular, and low abdominal surgery. Interventions: General anesthesia was maintained using a 60% nitrous oxide in oxygen mixture with either isoflurane (n = 125) or sevoflurane (n = 122) adjusted according to hemodynamic variables. Measurements and Main Results: Occurrence of hypotension [systolic arterial blood pressure (SBP) decrease >30% from baseline], hypertension (SBP increase >30% from baseline), bradycardia [heart rate (HR) <50 bpm], or tachycardia (HR>100 bpm) provoked stepwise changes in the inspired concentration of the study drug. If this action proved to be ineffective after an adequate stabilization period, a specific treatment was given, and the need for pharmacological treatment was recorded as a hemodynamic side effect by an independent observer. No differences in duration of anesthesia were observed between sevoflurane (126 ± 76 min) and isoflurane patients (139 ± 60 min). Mean duration from anesthetic discontinuation to fulfillment of discharge criteria was shorter after sevoflurane (21 min; 25 th to 75 th percentiles: 27 to 13 min) than isoflurane (27 min; 25 th to 75 th percentiles: 17 to 35 min) ( p < 0.0005). Hemodynamic side effects requiring therapy occurred in 18 sevoflurane patients (14.6%) and 26 isoflurane patients (20.8%) (p = NS). The risk for hemodynamic side effects increased with age (>50 vs. ≤50 yrs: odds ratio 2.5; 95% CI 1.2 to 5.4; p = 0.015) and ASA physical status (III vs. I and II: odds ratio 2.2; 95% CI 0.9 to 5.7; p = 0.048). When only patients over 50 years of age were considered (72 in the sevoflurane group and 79 in the isoflurane group), the incidence of hemodynamic side effects was higher with isoflurane (29.1%) than with sevoflurane (15.2%) (odds ratio 2.3; 95% CI 1.0 to 5.2; p = 0.04). Conclusions: Sevoflurane provided equally safe and effective control of cardiovascular homeostasis as isoflurane, with a more rapid discharge from the recovery area. Interestingly, patients over 50 years of age showed a lower risk for hemodynamic side effects when receiving sevoflurane than isoflurane.