Effects Of Different End-inspiratory Pause And Inspiration To Expiration Ratios On Respiratory Function In Patients With One-lung Ventilation

Objective: To investigate the effects of different end-inspiratory pause(EIP)and inspiration to expiration ratios(I?E)on respiratory function in patients undergoing thoracic surgery with one-lung ventilation.Methods: A total of 60 patients undergoing thoracic surgery with one-lung ventilation in the First Affiliated Hospital of Shihezi University School of Medicine were randomly divided into two groups: I?E=1?2(group A)and I?E=1?1(group B),(n=30).According to the different settings of EIP,the two groups were randomly divided into two subgroups(subgroup A1,A2 and B1,B2),(n=15).Subgroup A1 were ventilated in one-lung for each 30 min with different EIP in the order of0%,10% and 20%.Subgroup A2 were ventilated for each 30 min with different EIP in the order of0%,20% and 10%.Subgroup B1 were ventilated in one-lung for each 30 min with different EIP in the order of 0%,10% and 20%.Subgroup B2 were ventilated for each 30 min with different EIP in the order of 0%,20% and 10%.Hemodynamics and respiratory parmeters(Ppeak,Pplat,PEEP)were recorded,arterial and central venous blood was collected to analyze at initiating of one-lung ventilation(T1),30 min(T2),60 min(T3),90 min(T4)of one-lung ventilation.And we used these data to calculate the related respiratory function indicators(pulmonary dynamic compliance,dead space rate,Qs/Qt,Pa O2/Fi O2).Results: Both in group A and group B,with the EIP of 20%,the arterial CO2 partial pressure and the dead space rate decreased,Ppeak and PEEP increased compared with the EIP of 0% and 10%(P<0.05).Compared with group A,the Ppeak and Pplat were significantly lower and pulmonary dynamic compliance increased at the EIP of 0%,10% and 20% in group B(P < 0.05),and there was a increaseing trend of arterial CO2 partial pressure,but no statistical significance(P > 0.05).All patients' Ppeak,dead space rate and Qs/Qt increased,pulmonary dynamic compliance and Pa O2/Fi O2 were lower when they begin to be ventilated in one-lung(P<0.05).Conclusion: For patients undergoing thoracic surgery with one-lung ventilation,EIP of 20% is beneficial to dcrease of dead space rate and exchange of CO2;I?E of 1?1 can reduce Ppeak and Pplat,improve pulmonary dynamic compliance.Both of them have no significant effect on patients' hemodynamics.