BACKGROUND: There are a few reports with conflicting results regarding the potentiation of hypoxic pulmonary vasoconstriction (HPV) by repeated hypoxic challenges. The aim of this study was to determine if preoperative one lung ventilation (OLV) in the lateral position (LP) for a short time decreases the development of arterial hypoxemia and improves the level of arterial oxygenation via the potentiation of HPV in patients undergoing thoracic surgery with OLV.

METHODS: Forty patients were randomly divided into two groups according to presence or absence of preoperative OLV. Preoperative OLV in LP was achieved for 10 minutes with 100% O2 in group P (n = 20). Thereafter, the two lungs were again ventilated with 50% O2 until OLV with 100% O2 had been achieved. In group C (n = 20), the two lungs were continuously ventilated with 50% O2 until OLV with 100% O2 was achieved. The arterial blood samples were obtained 15 minutes after the two lung ventilation in the supine position (baseline) during preoperative OLV in LP, before pulmonary vein ligation, as well as before and after pulmonary artery ligation. The development of arterial hypoxemia (peripheral blood oxygen saturation in pulse oximetry < 95%) in patients undergoing thoracic surgery with OLV was also recorded.

RESULTS: Arterial hypoxemia during OLV was observed in 2 cases in group C and 3 cases in group P. There was a similar level of arterial oxygen tension during OLV between the two groups.

CONCLUSIONS: This study showed that the preoperative OLV in LP for 10 minutes neither potentiated the HPV response during OLV nor decreased the frequency of arterial hypoxemia during OLV.