[Apneic anesthesia for microsurgery of the larynx under propofol anesthesia]

Apneic anesthesia with intermittent ventilation (AAIV) under inhalational anesthesia has been reported to improve visualization of the larynx with lack of vocal cord motion in laryngeal microsurgery. In this study, we evaluated AAIV using total intravenous anesthesia with propofol and fentanyl instead of inhalational anesthesia in 11 patients undergoing microsurgery of the larynx, and examined the effects of AAIV on respiration and circulation. Anesthesia was maintained with infusion of propofol 4-10 mg.kg-1.h-1 and intermittent administration of fentanyl and vecuronium intravenously. The lungs were ventilated with 100% oxygen, and the endotracheal tube was removed during the apneic period. AAIV provided the otorhinolaryngologist sufficient room in which to operate and an immobile field without complications in any of the patients. The number of periods of apnea (mean +/- SD) was 3.3 +/- 1.3, and the duration of apnea was 292 +/- 23 seconds. Neither blood pressure nor heart rate changed during the apneic periods. Arterial oxygen saturation measured using pulse oxymetry (Spo2) changed in none of the patients except an obese patient whose Spo2 declined to 90%. End-tidal carbon dioxide level increased for 14.9 mmHg immediately after apneic periods. Propofol vielded stable and adequate levels of anesthesia during apneic periods. We conclude that AAIV using constant monitoring of Spo2 is a useful and safe technique, and that propofol is a suitable anesthetic agent for AAIV.