Warm or cold ischemia in animal models of lung ischemia-reperfusion injury

Objective: Experiments were designed to compare large animal models for lung ischemia-reperfusion injury using either 90 minutes' warm or 24 hours' cold ischemia. Methods: In 6 pigs, the left lung was perfused in situ with cold LPD solution. Reperfusion was started after 90 min of warm ischemia. The left lung of 6 donor pigs was perfused with LPD solution and the lung transplanted after 24 hours of cold storage into 6 recipient pigs. In both groups the right pulmonary artery and main bronchus were clamped after reperfusion of the left lung. Bronchoalveolar lavage (BAL) was obtained before ischemia and after 2 h of reperfusion. Hemodynamic and respiratory parameters were monitored. Surfactant activity was determined from the BAL in a pulsating bubble surfactometer. Results: Moderate lung injury was evident after reperfusion, but without any significant differences between groups. Surfactant composition and function were mildly impaired after reperfusion in both groups. Conclusions: Our results suggest that short periods of warm ischemia might be accepted as an accelerated model for ischemia-reperfusion injury of the lung after cold storage.