Pulmonary Protective Effect Of Pulmonary Protective Ventilation During Cardiopulmonary Bypass

Purpose: Retrospective analysis of pulmonary protective effect of pulmonary protective ventilation during cardiopulmonary bypass(CPB)was conducted to evaluate the protective effect of pulmonary protective ventilation on lung function and safety of clinical application in patients with lung injury after cardiopulmonary bypass(CPB).Methods: Patients undergoing primary cardiopulmonary bypass heart valve replacement from June 2015 to December 2017 in the Department of Thoracic Cardiac surgery,affiliated to the University of South China,were selected as the study subjects.The patients undergoing pulmonary protective ventilation under cardiopulmonary bypass were defined as the pulmonary protective ventilation group.Unprotected ventilation under cardiopulmonary bypass(CPB)was defined as the control group.The clinical data before,during and after CPB were collected and compared.The preoperative data included age,sex,body weight,past medical history and preoperative cardiac function.To collect the operation conditions including cardiopulmonary bypass time,aortic occlusion time,anesthesia time,etc.;collect the incidence of secondary thoracotomy,mortality and mobidity during hospitalization,heart,kidney,brain,lung and other viscer-related complications;collect the preoperative,intraoperative,and other organ related complications,The results of laboratory examination after operation,including blood routine,blood gas analysis,pulmonary alveolus-air oxygen partial pressure difference(A-a DO2)and respiratory index(RI),were calculated according to oxygen concentration,partial pressure of oxygen and partial pressure of carbon dioxide in blood gas analysis.Pulmonary function was evaluated by comparing the values of the alveolar-air oxygen partial pressure difference(A-a DO2)and respiratory index(RI).The Empowerstats statistical software was used to analyze the repeated measurement data,and the generalized additive mixed effect model was used to analyze the difference between the two groups(P < 0.05).Results: 121 patients were enrolled,including 57 patients in pulmonary protective ventilation group and 64 in control group.There was no significant difference in general data of patients before CPB.After cardiopulmonary bypass,blood gas analysis was conducted at different time after cardiopulmonary bypass(CPB).The pulmonary function of patients was evaluated by calculating the corresponding alveolar air-arterial oxygen partial pressure difference(A-a DO2)and respiratory index(RI).The results of statistical analysis showed that the lung protective ventilation group was compared with the routine group.At the same time point,there were significant differences in alveolar air-arterial oxygen partial pressure difference(A-a DO2)and respiratory index(RI)(P < 0.05)between the two groups,and acute renal insufficiency and low cardiac output syndrome were found in the two groups.There was no significant difference in the incidence of complications between the two groups(P > 0.05),but the incidence of secondary intubation and pulmonary infection in the pulmonary ventilation group was lower than that in the control group(P < 0.05),so was the morbidity of postoperative complications.Conclusions: In cardiac valve replacement under cardiopulmonary bypass(CPB),lung protective ventilation can significantly improve the pulmonary ventilation function of patients.It has obvious lung protective effect and does not increase the risk of low cardiac output syndrome,acute renal insufficiency and so on.The incidence of secondary intubation and pulmonary infection was significantly reduced.