Prevention of air embolism with positive end expiratory pressure.

Pulmonary air embolism is recognized as a possible complication of neurosurgical procedures performed with the patient in the sitting position. A variety of preventive and therapeutic modalities have been proposed in the literature. We have used a consistent regimen consisting of precordial Doppler monitoring, measurement of end expiratory CO2, the semireclining position, and positive end expiratory pressure (PEEP). A right atrial catheter was not used. This approach has given good results in 81 patients; there was significant air embolism in only 1 case (1.2%). We believe that PEEP is as important in the prevention as it is in the treatment of pulmonary air embolism. By flexibly adjusting the level of PEEP, one may recreate the hemodynamic equivalent of the prone position, thereby eliminating the risk of venous air embolism and simultaneously the need for right heart catheterization.