Ventilation during total intravenous anaesthesia with ketamine.

Total intravenous anaesthesia with ketamine (TIVAK) is widely used throughout the world especially in precarious conditions. Although ketamine is usually considered to provide good respiratory function and may be used with spontaneous ventilation, recent studies have shown that desaturations may occur. Seventy-six adults and 64 children scheduled for peripheral surgery were randomly allocated to breathe spontaneously room air or 40% oxygen during TIVAK. Pulse oximetry was continuously assessed during anaesthesia and recovery. Desaturation (SpO2 < 92%) occurred immediately after induction in 20 adults breathing air and in only three adults breathing oxygen (P < 0.05). Respiratory abnormalities were sufficiently severe to warrant tracheal intubation in two patients. Desaturations were not observed during the recovery period. Very similar results were observed in children although desaturations observed after induction in paediatric patients breathing room air were less frequent than in adults occurring in only nine patients. These desaturations were also less severe and never required tracheal intubation. The high incidence of arterial desaturation observed immediately after induction of anaesthesia with intravenous ketamine should prompt anaesthetists to provide oxygen in every adult patient at least for the first 15 min. The large decrease in SpO2 sometimes observed requires that trained personnel be present and that equipment for tracheal intubation be available.