Controlled hypercapnia during one-lung ventilation in patients undergoing pulmonary resection

Background: In a pilot study, the haemodynamic and gas exchange effects of acute hypercapoia during one-lung ventilation in thoracotomy patients were investigated. The effects of normocapnic one-lung ventilation (OLV-N) on ha emodynamics and pulmonary gas exchange were compared with those of hypercap nic one-lung ventilation (OLV-H) in 14 patients undergoing pulmonary lobect omy. Methods: Hypercapnia was induced by decreasing tidal volume until PaCO2 inc reased to 8-9 kPa. During OLV, minute ventilation was reduced from 8.8 +/-1 .7 to 4.2 +/-0.71 min(-1). Results: Cardiac index (from 3.3 +/-0.6 to 3.9 +/-0.6 l min(-1), P <0.01) a nd pulmonary vascular resistance index (from 245 +/- 96 to 347 +/- 125 dyn s cm(-5) m(-2), P <0.05) increased during OLV-H, whereas systemic vascular resistance index decreased from 1952 +/- 403 to 1636 +/- 361 dyn s cm(-5) m (-2) (P <0.01). Pulmonary oxygenation remained unchanged. Conclusions: All patients had an uneventful course during OLV-H. The determ inants of pulmonary oxygenation during hypercapnic one-lung ventilation rem ain to be further elucidated.