[A comparison of the effects of 50 % oxygen combined with CPAP to the non-ventilated lung vs. 100 % oxygen on oxygenation during one-lung ventilation]. / Oxygenierung während Ein-Lungen-Ventilation: Ein Vergleich von FiO.

OBJECTIVE: In a prospective, randomised, double-blind study the effects of FiO (2) of 0,5 with CPAP and a FiO (2) of 1.0 without CPAP on oxygenation and pulmonary shunt during one-lung ventilation (OLV) were examined. METHODS: In 20 patients undergoing thoracotomy (ASA II/III) two sequential ventilation methods were used during OLV: a) FiO (2) of 1.0 (OLV-100) and b) a FiO (2) of 0.5 in N (2)O combined with CPAP of 5 cm H (2)O to the non-ventilated lung (OLV-CPAP), whereby the sequence in 10 patients was OLV-CPAP followed by OLV-100; and the opposite in the remaining 10 patients. Operating conditions were graded by the surgeon. RESULTS: OLV-CPAP was associated with a better oxygenation and a lower shunt compared to OLV-100 (paO (2) : 198 +/- 40 mmHg vs 181 +/- 38 mmHg; p < 0.05 and Qs/Qt: 30 +/- 6 % vs. 34 +/- 8 %; p < 0.01, respectively). The different sequence of the ventilation methods did not cause significant differences in the results. The surgical conditions were not impaired by the CPAP of 5 cm H (2)O. CONCLUSION: The application of low FiO (2) with CPAP provided a better oxygenation and a lower pulmonary shunt during the OLV compared to high FiO (2) without CPAP.