[Protective effect of ventilation on warm ischemic lungs]

This study was undertaken to determine whether lung ventilation during warm ischemia provides a protective effect on lung preservation. The mongrel dogs were made left thoracotomy incision. Following a complete dissection of left pulmonary artery and vein, left lung was subjected to room temperature ischemia for 4 hours or 6 hours by clamping vasculature. Left lung was ventilated with oxygen or collapsed during warm ischemic period. The isolated ventilation of left lung was secured by ligation of left main bronchus over Carlens tube. After the ischemic period, blood supply of the left lung was reestablished by unclamping the pulmonary artery and vein. The contralateral pulmonary artery was ligated 10 min later, and blood gas, pulmonary pressure, and pulmonary shunt were monitored for additional 4 hours while left lungs ventilated with oxygen. In lungs collapsed during 4 hour ischemic period, massive pulmonary edema occurred within 30 minutes after reperfusion. Partial oxygen tension was only 63 mmHg at 1 hour after reperfusion. In contrast, lungs ventilated during 4 hours ischemic period did not manifest pulmonary edema, and PaO2 was 407 mmHg at 4 hours after reperfusion. The lungs collapsed during 6 hour ischemic period showed massive edema. When the lung was ventilated, the lung behaved variably but still better than the collapsed lungs. These results suggest that the ventilation of the lung during warm ischemia provide a protective effect.