Abstract:

Objective
 To determine the protective effect of extracorporeal circulation with autologous lung as oxygenator to lung function in dogs.Methods Twelve adult mongrel dogs were randomly divided into control group and experimental group.Cardiopulmonary bypass (CPB) using a membrane oxygenator (control group) or using the autologous lung (experimental group) for gas exchange was performed for 120 min in an alternating series of 12 mongrel dogs with the heart arrested for 90 min by crystalloid cardioplegia and 30 min reperfusion.Malondialdehyde (MDA) of lung tissue,alveolar-arterial oxygen gradient (P［A-a］O2),the ratio of white blood cells in BALf and lung function were measured at different time points （before CPB, 15 and 60 min after CPB）,lung biopsies were also made. Results The levels of airway resistance at  15 and 60 min after CPB in control group were higher than the airway resistance levels before CPB (P<0.05).The levels of airway resistance at  15 and 60 min after CPB in experimental group  were lower than those in control group at the same points (P<0.01).The levels of pulmonary vascular resistance at 15 and 60 min after CPB in each group were lower than the levels before CPB (P<0.01).The level at  15 and 60 min after CPB in control group  was higher than that  in experimental group  at the same points(P<0.05).The levels of PaO2/FiO2 at  15 and 60 min after CPB in each group were higher than the levels before CPB (P<0.01).The levels of PaO2/FiO2 at  15 and 60 min after CPB in control group   were lower than those  in experimental  group at the same points(P<0.05).The levels of P［A-a］O2 at  60 min after CPB in experimental group  were lower than those  in control group(P<0.001).The levels of MDA and neutrophil percentage in BALF at  90 min after CPB in  experimental group were lower than those 
 in control group (P<0.001,P<0.05).Morphological analysis revealed that  in  experimental group the  percentage of pathological lesions and alveolar hemorrhage grade values was lower than those in control group (P<0.001).
Conclusion Morphous and function have obvious changes in lungs after CPB.Extracorporeal circulation with autologous lung as oxygenator has  protective effect on  pulmonary morphous and function.

Key words: autologous lung;cardiopulmonary bypass;lung injury