Sevoflurane for controlled hypotension during spinal surgery: preliminary experience in five adolescents

The physical properties of sevoflurane suggest that it may be a suitable agent for controlled hypotension. With its low blood:gas partition coefficient of 0.69, it has a rapid onset of action making it easy to rapidly control blood pressure. The current report outlines preliminary experience with sevoflurane for controlled hypotension during posterior spinal fusion in five adolescents. The patients ranged in age from 12 to 16 years and in weight from 49 to to 72kg. The duration of controlled hypotension varied from two to three h. The expired sevoflurane concentration required to maintain the mean arterial pressure (MAP) at 55 to 65 mmHg varied from 2 to 4%. With sevoflurane, there was an increase in heart rate from baseline of 74 +/- 7 beats.min-1 to a maximum of 83 +/- 13 beats.min-1 (P = 0.038). One patient required three intravenous doses of esmolol (10mg each) for a heart rate in excess of 100 beats.min-1. Estimated blood loss varied from 300 to 850 ml. No patient received homologous blood. No excessive hypotension was noted with sevoflurane. No patient required calcium, alpha adrenergic agonists, or ephedrine for excessive hypotension. When controlled hypotension was no longer necessary, the sevoflurane concentration was decreased to 1%. After decreasing the sevoflurane to 1%, the time to return of the MAP to baseline varied from 4 to 8 min (5.6 +/- 1.8 min).