Sevoflurane versus isoflurane in patients undergoing valvular cardiac surgery

To determine if sevoflurane provides hemodynamic and recovery characteristics comparable to isoflurane in patients undergoing surgery for valvular heart disease.

A prospective crossover, dose-response study using sevoflurane and isoflurane before the start of surgery, followed by randomization to sevoflurane or isoflurane for surgery with blinded assessment for recovery.

Tertiary referral cardiac center.

Twenty-seven patients scheduled for elective valve surgery. Surgery consisted of 18 aortic valve and 12 mitral valve replacements, of which 3 patients had 2 valves replaced; 1, tricuspid repair; and 8, coronary artery bypass procedures.

A pulmonary artery catheter was used to obtain a complete hemodynamic profile during the dose-response study before surgery. Transesophageal echocardiography was used to confirm the diagnosis, and electrocardiography monitored for myocardial ischemia.

Both agents showed similar hemodynamic effects at 0.5 and 1.0 minimum alveolar concentration. There was a tendency to decreases in heart rate, blood pressure, and cardiac output, whereas filling pressures remained stable with each volatile agent. Electrocardiography did not detect ischemic changes. Times to eye opening and extubation were similar with both agents, with sevoflurane tending to be earlier than isoflurane.

Sevoflurane showed a tendency to lower heart rates and cardiac index compared with isoflurane. Eye opening and extubation were slightly earlier. These findings were not statistically significant, however.