Effects Of Different Inspiratory Velocity During PCV On Respiratory Function And Inflammatory Factors In Patients With OLV

Objective:Observe the effect of different inspiratory flow rate on respiratory mechanics,blood gas analysis and inflammatory factors in patients with pressure controlled ventilation（PCV）mode during one-lung ventilation（OLV）,and to provide reference and basis for the setting of inspiratory flow rate in PCV during OLV.Methods:This study is a randomized single-blind prospective study of 75 patients with OLV from September 2018 to August 2019.The subjects were randomized to the inspiratory flow rate30L/min（group A）,50 L/min（group B）or 70 L/min（group C）after anesthesia and OLV.Respiratory mechanics,respiratory function,hemodynamics and blood gas parameters were compared between the three groups pre-OLV（T₀）and after 30（T₁）,60（T₂）,and 120（T₃）minutes of OLV.Center venous blood was collected to measure interleukin（IL）-6,IL-8,tumor necrosis factor（TNF）-α,and soluble intercellular adhesion molecule-1 levels.Observation of pulmonary complications and occurrence of acute respiratory distress syndrome（ARDS）3 days after operation.Results:Hemodynamic and General patient status were similar between the three groups（all P>0.05）.PaCO₂ was significantly lower in the Group B and group C compared with the Group A（P<0.05）;Compared with T₀,PaO₂ and SvO₂ were significantly lower at T₁,T₂,T₃ of the three groups（P<0.05）;PH,SaO₂and Hb were similar between the three groups（all P>0.05）.ΔVT was significantly higher in the Group B and group C compared with the Group A（P<0.05）;P_peakeak were similar between the three groups（all P>0.05）.PEEP was significantly higher in the Group B and group C compared with the Group A P<0.05);V_D/V_T was significantly decrease in the Group B and group C compared with the Group A（P<0.05）.Compared with T₀,Qs/Qt was significantly increased at T₁,T₂,T₃of the three groups（all P<0.05）,dynamic compliance was significantly increased at T₁,T₂,T₃ of the Group B and group C（all P<0.05）,PaO₂/FiO₂was significantly decrease at T₁、T₂、T₃ of the three groups（all P<0.05）.Compared with T₀,The concentrations of Il-6,Il-8,TNF-αand sICAM-1 were significantly increased at T₁,T₂,T₃ of three groups（P<0.05）,And group A and group B were significantly lower than those in group C（P<0.05）.The number of patients who had postoperative pulmonary complications（ppcs）or ARDS were similar between the three groups（all P>0.05）.Conclusion:In the PCV mode of OLV patients,when the inspiratory flow rate is set to 50 L/min,it can increase VT,reduce dying cavity rate,promote CO2 exchange,increase lung dynamic compliance without increasing lung inflammation.However,the inspiratory flow rate has no significant effect on oxygenation and intrapulmonary shunt,and it is not related to the incidence of postoperative PPCs and ARDS in OLV patients.