A sevoflurane induction of anesthesia with gradual reduction of concentration is well tolerated in elderly patients

Abstract

Purpose: To establish the appropriate inhalation induction technique using a high concentration of sevoflurane in the elderly. Methods: Forty-five patients, aged 70-79-yr-old, were randomly divided into three groups: I) Group I: anesthesia was induced with propofol 2 mg·kg-1 and sevoflurane 2% (n = 15); 2) Group II: anesthesia was induced with a three- minute inhalation of sevoflurane 8%; 3) Group III: anesthesia was induced with inhalation of sevoflurane using a gradual reduction technique (8, 6, 4% for each minute). In Groups II and III, a modified vital capacity inhalation induction was performed. Mean arterial pressure (MAP), heart rate (HR) and oxygen saturation (SpO2) were measured continuously during induction. In addition, induction time and adverse events related to anesthetic induction were recorded. Results: The induction time in Group I was significantly shorter than that in Groups II and III (P < 0.05). However, there was no difference in the induction time between Groups II and III. In Groups II and III, the majority of patients required additional breaths. In comparison with the other groups, stability of MAP was maintained in Group III. The variations of HR in all groups were small. During induction, no patient experienced a decrease in SpO2 below 96%, except for two patients in Group I. Severe respiratory adverse events were not observed. Other adverse events were similar in all groups. Conclusions: Our results suggest that a high concentration sevoflurane induction using a gradual reduction technique may be an acceptable alternative to standard iv induction in elderly patients.