BACKGROUND: During one-lung ventilation (OLV) for thoracic surgery, hypoxic pulmonary vasoconstriction (HPV) may reduce the venous admixture and ameliorate the decrease in arterial oxygenation by diverting blood from the non-ventilated to the ventilated lung. Volatile anesthetics (halothane, enflurane, isoflurane, desflurane and sevoflurane) have been shown to depress the HPV with essentially the same potency in vitro. However, clinical studies suggest that isoflurane and sevoflurane provide superior arterial oxygenation during OLV over halothane or enflurane. However, these have not been compared with desflurane. This study compared the effects of desflurane with those of isoflurane on oxygenation & shunt during two lung ventilation (TLV) and OLV in human volunteers. METHODS: Twenty adults who needed OLV with minimal trauma to the nonventilated lung (esophageal surgery) were randomly assigned to receive either 1 MAC desflurane (n = 10) or 1 MAC isoflurane (n = 10) with 100% oxygen in separate groups. Systemic and pulmonary hemodynamic data were recorded, and blood gas values were obtained 30 min after TLV and OLV in lateral position. RESULTS: Reductions in PaO2 (445.2 +/- 72.3 to 125.9 +/- 52.5 and 483.2 +/- 86.2 to 110. 2 +/- 39.8 mmHg, in desflurane and isoflurane respectively) and increases in shunt fraction (Qs/Qt%; 17.2 +/- 3.8 to 33.1 +/- 5.7, 13.4 +/- 4.5 to 32.5 +/- 4.1, in desflurane and isoflurane respectively) at 30 min after the start of OLV were observed, but there were no differences between the groups. The other blood gas data (PaCO2, PCO2, pH, Hb, CaO2, CO2) and systemic and pulmonary hemodynamics (mean arterial blood pressure, heart rate, cardiac output, mean pulmonary arterial pressure, central venous pressure) did not change 30 min after the start of OLV in the two groups. CONCLUSIONS: In clinical practice, there was no difference between desflurane and isoflurane for OLV was no difference in the arterial blood oxygenation and the intrapulmonary shunt.