The Study Of The Correlation Between P_etCO₂and PaCO₂on One Lung Ventilation During Thoracic Surgery

Objective:To compare the impacts of Pressure controlled ventilation（PCV） and volumecontrolled ventilation（VCV） on the correlation between P_etCO₂and PaCO₂during One-lungventilation for Thoracic surgery.Method:40ASA Ⅰ～Ⅱelderly patients（age46～78years） in the same surgeon undergoingOLV during thoracic surgery were been chosen,and were randomly divided into2groups （A、B） with20subjects in each group.After intubation,all patients were mechanically ventilatedwith IPPV model.Group A: the parameter of TLV were VTon10ml/kg,respiratory frequencyon10bite per min,I:E on1:2,FiO₂on100%,and oxygen flow on2L/min.Group B: theparameter of TLV were adjusted the airway pressure to VTon10ml/kg,respiratory frequencyon10bite per min,I:E on1:2,FiO₂on100%,and oxygen flow on2L/min,1min before OLV（T₀）, PaCO₂、 P_etCO₂and hemodynamic indexes（HR,SBP,DBP and MAP,etc） wererecorded.After OLV, PaCO₂, P_etCO₂,and hemodynamic indexes（HR,SBP,DBP and MAP,etc）of Group A（VCV,VTon8ml/kg,Rf on12bpm）,Group B（PCV,the pressure was maintainingVTon8ml/kg,Rf on12bpm） were recorded,.Results: The statistical analysis show that compare with the two group,the same time point（butT₀）,P_etCO₂were statistical differene （P<0.05）, PaCO₂were statistical differene（P<0.05）.compare with T₀and T₁、T2、T3,the two group P_etCO₂and PaCO₂were statisticaldifferene （P<0.05）.The correlation coefficient between P_etCO₂and PaCO₂is larger at eachtime point during PCV than VCV on OLV.Either PCV and VCV,the correlation coefficientbetween P_etCO₂and PaCO₂is getting smaller during OLV for a long time.Conclusion:1.the change of P_etCO₂and PaCO₂is less during PCV than VCV on OLV.2.During OLV in Thoracic surgery,PCV is superior to VCV on the correlationbetween P_etCO₂and PaCO₂.3. PaCO₂is needed to monitor intermittent during OLV for a long time.