A bronchoalveolar lavage(BAL) is useful in diagnosing the etiology of bilateral pulmonary infiltrations, but may worsen the oxygenation and clinical status in severely hypoxemic patients. This study assessed the safety and efficacy of the continuous positive airway pressure(CPAP) using a conventional mechanical ventilator via a face mask as a tool for maintaining the oxygenation level during BAL.

Seven consecutive patients with the bilateral pulmonary infiltrates and severe hypoxemia (PaO₂/FIO₂ ratio ≤200 on oxygen 10 L/min via mask with reservoir bag) were enrolled. The CPAP 5-6 cmH₂O(F_IO₂ 1.0) was delivered through an inflatable face mask using a conventional mechanical ventilator. The CPAP began 10 min before starting the BAL and continued for 30 min after the procedure was completed. A bronchoscope was passed through a T-adapter and advanced through the mouth. BAL was performed using the conventional method. The vital signs, pulse oxymetry values, and arterial blood gases were monitored during the study.

(1) Median age was 56 years(male:female=4:3). (2) The baseline PaO₂ was 78±16 mmHg, which increased significantly to 269±116 mmHg(p=0.018) with CPAP. After the BAL, the PaO₂ did not decrease significantly but returned to the baseline level after the CPAP was discontinued. The SpO₂ showed a similar trend with the PaO₂ and did not decrease to below 90% during the duration of the study. (3) The PaCO₂ increased and the pH decreased significantly after the BAL but returned to the baseline level within 30 min after the BAL. (5) No complications directly related to the BAL procedure were encountered. However, intubation was necessary in 3 patients(43%) due to the progression of the underlying diseases.

In severe hypoxemic patients, CPAP using a face mask and conventional mechanical ventilator during a BAL might allow minimal alterations in oxygenation and prevent subsequent respiratory failure.