Minimizing perioperative hypoxemia does not affect postpneumonectomy lung growth.

Abstract

The effects of preventing the acute hypoxemia common during lung resection on postpneumonectomy lung growth were investigated. Rats that had undergone translaryngeal tracheal intubation and were supported with intermittent positive-pressure ventilation during pneumonectomy (IPPV) were compared with those allowed to breathe room air spontaneously via the natural airway (SV). A pulse oximeter was used to document intraoperative and postoperative oxygen saturation (SaO2). Almost all SV animals became acutely hypoxemic during thoracotomy [SaO2 less than 50% for 2.5 +/- 0.5 min (8/9), less than 30% for 1.7 +/- 0.4 (8/9)], whereas IPPV animals largely maintained oxygenation [SaO2 less than 50% for 0.3 +/- 0.2 min (8/13), less than 30% for 0.05 +/- 0.05 min (1/13)]. Direct measurements of oxygen saturation correlated well with the pulse oximeter (slope of regression line = 0.90, correlation 0.91), and arterial blood gases showed the SV group to be hypercapneic and acidotic as well as hypoxemic during lung removal. These abnormalities resolved soon after chest closure. Intubated animals had mild postextubation hypoxemia that normalized within 3 h of surgery. Two weeks postoperative, there were no differences in lung mass or content of water, RNA, DNA, and protein between the two groups.