CONTINUOUS POSITIVE AIRWAY PRESSURE BY MASK IN PATIENTS AFTER CORONARY SURGERY

Thirty patients who underwent coronary artery bypass grafting were ran domized to receive 30% oxygen by mask either with an ambient airway pr essure or with 7.4 mmHg (1 kPa) continuous positive airway pressure (C PAP) for 8 h after extubation. Arterial blood oxygen tension (Pao(2)) decreased remarkably in the control group after extubation (from 19.2 +/- 5.3 kPa to 12.4 +/- 2.7 kPa) but less in the CPAP group (from 16.4 +/- 3.3 kPa to 14.0 +/- 2.1 kPa). On the second postoperative morning Pao(2) was equally low in both groups (control: 8.4 +/- 1.5 kPa, CPAP : 8.9 +/- 1.9 kPa). Ateleciatic areas were seen with similar frequency in both groups, 17% (whole material) on the first and 50% on the seco nd postoperative morning. Atelectasis was mere common in patients with internal thoracic artery grafting and/or pleural drainage. In conclus ion, CPAP therapy was well tolerated, and minimized the decrease in Pa o(2) after extubation, hut could not prevent the poor oxygenation or t he late development of atelectatic areas on the second postoperative d ay.