Improved oxygenation during thoractomy with selective PEEP to the dependent lung.

In 22 patients during thoracotomy in the lateral position, the effects of selective positive end-expiratory pressure (PEEP) to the dependent lung while simultaneously ventilating the non-dependent lung at zero end-expiratory pressure (ZEEP) on (1) inspired O2 concentration required to maintain adequate Pao2 during thoractomy and 2) alveolar-arterial oxygen difference (AaO2D) while breathing 100 percent O2 at the end of thoractomy were examined and compared to ventilation of both lungs at ZEEP, Selective PEEP to the dependent lung resulted in adequate PaO2 with a lower inspired O2 concentration (44 +/- SD 6% versus 70 +/- SD 21%), and a smaller AsO2D while breathing 100 percent O2 189 +/- SD 31 versus 342 +/- SD 69 torr) at the end of thoracotomy.