Comparative study of etomidate-alfentanil anesthesia with N2O/O2 or with air/O2

Systolic, diastolic blood pressures, heart rate, glycaemia, blood gases and clinical status were studied preinduction, 10' after anesthesia induction and intubation, 3', 30', 60' and 90' after surgical incision, when awake on the operating table and 60' after awakening in 20 hysterectomy patients. Etomidate (0.3 mg/kg + continuous infusion), alfentanil (75 micrograms/kg + increments of 15 micrograms/kg) anesthesia was used with a N2O/O2 mixture (10 pt) or with air/O2 (10 pt), both at a FIO2 = 0.33. This technique gave a smooth induction and recovery. Cardiovascular changes were moderate. The additional dose of alfentanil was 5.25 +/- 0.65 mg in the N2O/O2 group and 6.45 +/- 0.85 mg in the air/O2 group. The incidence of vomiting was 15%. Statistical analysis of both groups indicated no major difference between the two types of anesthesia, for the cardiovascular, acid base data and glycaemia. This technique is a simple and effective way of anesthetising patients, but from a clinical point of view the etomidate/alfentanil anesthesia combined with N2O/O2 gives better results than when combined with air/O2.