Effects of Differential Lung Ventilation with Positive End-Expiratory Pressure on Ischemia-Reperfusion Lung Injury in Dogs

Abstract

Background : Ischemia-reperfusion injury and ventilation/perfusion mismatch are the major complication of lung transplantation. Application of positive end-expiratory pressure(PEEP) on reperfused lung can prevent hypoxemia, because it increases functional residual capacity and improves oxygenation without contralateral dynamic hyperexpansion. To identify which differential lung ventilation with PEEP reduces ischemia-reperfusion lung injury, PaO2, intrapulmonary shunt, pulmonary compliance and water content of lung tissue were measured and compared with those of conventional two lung ventilation. Methods : Nineteen Korean mongrel dogs were included for study. Double lumen endotracheal tube was inserted via tracheostomy site. Femoral arterial catheter and Swan-Ganz catheter were inserted for hemodynamic data and thoracotomy was done. The right pulmonary artery, vein, and main bronchus were clamped for 90 minutes and released to produce unilateral warm ischemia-reperfusion lung injury. In control group(C), conventional two lung ventilation was applied, and in experimental group(P), the right lung was ventilated with 10 cmH2O PEEP independent of the left lung. PaO2, intrapulmonary shunt, pulmonary compliance and water content of lung tissue were measured. Result : At 60 min after reperfusion, PaO2 in group P was higher than in group C(512.4±58.8 mmHg vs 263.6±165.8 mmHg), and intrapulmonary shunt was smaller(9.8±3.4 vs 25.9±11.3%). Dynamic and static pulmonary compliance in group P were higher than in group C(42.3±9.4, 95.2±14.7 vs 29.2±1.4, 60.2±17.1 dyne·sec/cm5). Water content of the right lung in group P was lower than in group C(81.1±1.6 vs 85.1±3.9%). Conclusion : In conclusion, these data suggest that application of positive end-expiratory pressure on reperfused lung is more effective to improve ventilation/perfusion mismatch and oxygenation, so it is thought to be a good treatment for ischemia-reperfusion lung injury. (Korean J Anesthesiol 1998; 35: 242∼251)