Comparative evaluation of cardiovascular effects of sevoflurane and isoflurane in patients with ischaemic heart disease undergoing non-cardiac surgery.

Twenty three adult patients with ischaemic heart disease undergoing elective non-cardiac surgery were studied. Induction of anaesthesia was similar for each patient and included thiopentone (4-5 mg/kg), morphine (0.1 mg/kg) and vecuronium (0.1 mg/kg). Additional morphine and vecuronium were used when necessary. All these patients were maintained with either sevoflurane (n=11) or isoflurane (n=12). The inhaled anaesthetics were titrated to achieve adequate clinical 'depth of anaesthsia' and to maintain mean arterial pressure within 20% of the pre-induction values. Heart rate, blood pressure and rate-pressure product were recorded during the maintenance phase of anaesthsia. ST-T changes were also monitored during this period. There was a tendency for heart rates to be significantly higher shortly after skin incision till the end of procedure in the isoflurane group, while in the sevoflurane group heart rate remained stable during the surgical procedure. Both systolic and diastolic blood pressure remained similar in both groups. The rate pressure product was higher in the isoflurane group than in the sevoflurane group at 30 min Post-incision. The data suggests that sevoflurane is not associated with untoward cardiovascular changes in ischaemic heart disease patients undergoing non-cardiac surgery.