[Prediction of lowest PaO2 during unilateral whole lung lavage in a patient with pulmonary alveolar proteinosis--unilateral ventilation with nitrogen].

Unilateral whole lung lavage (UWLL) was performed four times in a patient with pulmonary alveolar proteinosis. PaO2 was 94 Torr even under ventilation with 100% O2. Because of the difficulty in providing adequate arterial oxygenation, extracorporeal membrane oxygenation (ECMO) was indispensable in accomplishing the first right UWLL. During the second left UWLL, the left lung was ventilated with nitrogen (N2) and an attempt was made to predict the lowest PaO2 occurring during lavage in order to establish criteria for the use of ECMO during UWLL. When both lungs were ventilated with 100%. O2, PaO2 rose to 150 Torr. PaO2 fell to 65 Torr after ventilation of the left lung with N2 while the right lung was ventilated with 100% O2 for 7 minutes. The N2 was replaced with 100% O2 and ventilation was continued for another 10 minutes to wash the N2 out of the left lung. When the tracheal tube in the left lung was clamped for 7 minutes for degassing, PaO2 fell to 59 Torr. Subsequently 1,200 ml of physiological saline was injected into the left lung, and PaO2 rose to 155 Torr. A 6 Torr difference was found between the value of PaO2 under ventilation with N2 and that of degassing, but this difference was not statistically significant. The lowest PaO2 occurring during UWLL was considered to be predictable if the unilateral lung was ventilated with N2.