Pathological Change Of Pulmonary After Ventilation Combined With Hypothermia Via Lung On Canines With Acute Respiratory Distress Syndrome

Objective: To investigate the pathological change of pulmonary after ventilation combined with hypothermia via lung on canines with acute respiratory distress syndromeMethods: Eighteen healthy mutts after anesthesia were induced with oleic acid to be acute respiratory distress syndrome models. The models were prepared and then randomly divided into three groups, each with six, namely: conventional mechanical ventilation group (Group A, normal control group); Low-volume low-pressure mechanical ventilation group (Group B); local hypothermia with low-volume low-pressure ventilation group (Group C).By close observation at three time points: 1, 2, 3-hour after treatment, we measured lung surface temperature (Tl), blood temperature (Tb),. In addition, 3 ml blood samples were taken from a femoral artery at four time points: after model without treatment, 1, 2, 3-hour after treatment. Serum was analysed for tumor necrosis factor (TNF-α), interleukin --6 (IL-6) levels by radioimmunoassay(RIA).All mutts were killed after the experiment,The lower parts of the left lungs were taken out after clamping the endotracheal catheter at the end of expiration.And histopathologic appearance of lung tissue was analyzed by light microscopy.Results: (1) Tl, Tb levels at the 3rd hour after treatment in Group C decreased remarkably (P<0.05), while the temperature changes in Group A, B had no significance in statistics.(2);Cumulative mean histology scores showed a lower score in Group B, C compared with GroupA (P<0.05). (3)The histology score of atelectasis, intra-alveolar, edema intra-alveolar and hemorrhage perivascular edema in groupA was highest among three groups,which in group C was the lowest(P<0.01).(4)In the serum, TNF-α, IL-6 levels were higher in Group A than in Group B, C(P <0.05), and higher in Group B than in Group C(P <0.05).Conclusion: these findings show that the combination of local hypothermia and protective ventilation in the lung can inhibit the TNF-α, IL-6 levels and attenuate injury in lung tissues in oleic acid-induced ARDS canine models. Furthermore, we provide new ideas to improve the prognosis of ARDS in the future.