24-hour lung preservation with modified Euro-Collins (E-C) solution under hyperbaric oxygen (OHP) was studied in the canine single lung transplantation model. A prostaglandin I2 (PGI2) was administered before cardiac arrest by St. Thomas solution. Lungs were flushed with modified E-C solution, then heart and lungs were excised en-bloc and immersed in 4 degrees C modified E-C solution for 24 hours in control group (N = 5). In OHP group (N = 5), heart and lung block were preserved similarly in the control group but placed in hyperbaric chamber (mixed gas 95% O2, 5% CO2) under 2 atmospheres absolute pressure. In the hyperbaric chamber, the lungs were expanded continuously by pressure difference between the inside and the outside of the lung. The left lung was transplanted into recipient dog and reperfused for 3 hours. Pulmonary function was assessed serially by measuring oxygen and carbon dioxide tensions in arterial blood and pulmonary vascular resistance by clamping the right pulmonary artery for 5 minutes. ATP before and after preservation was measured. In the control group, PaO2, after 24 hours preservation followed by reperfusion, was 177 +/- 88 mmHg, but decreased to 75 +/- 34 mmHg at 3 hours of reperfusion and bloody foamy sputum appeared in 4 dogs. Alternatively, PaO2 was 256 +/- 58 mmHg at 3 hours of reperfusion and foamy sputum did not appear in OHP group. There was a significant difference between the 2 groups (p < 0.05). PaCO2 at 3 hours of reperfusion was 41 +/- 3 mmHg in the control group, and 31 +/- 2 mmHg in the OHP group (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)