The Effects Of Continuous Positive Airway Pressure On Arterial Partial Pressure Of Oxygen And Pulmonary Shunt During One Lung Ventilation By Using The Self-Made Equipment

Objective:Although one lung ventilation (OLV) is frequently used for facilitating thoracic surgical procedures, arterial hypoxemia can occur while using one lung anesthesia. We evaluated the effects of CPAP in5cmH2O to the non-ventilating lung on arterial oxygenation and pulmonary shunt when using the self-made equipment during OLV.Methods:Forty patients that were scheduled for pulmonary lobectomy surgery were included in this study. AS A I-II level, age35to65years old, body mass index (BMI) of18-25kg/m2.They were randomly divided into2groups(each n=20):CPAP group(Group A)and control group(Group B).Two groups were performed by the same surgeon and anesthetist.In group A,CPAP in5cmH2O was administered to the non-ventilated lung by using the self-made equipment during OLV.The non-ventilated lung was kept open to the air during OLV in group B. Arterial and right atrium blood samples were taken for gas analysis after TLV for20mins but before open the thorax(Ti)and after OLV for 30mins(T2),60mins(T3). Following that, pulmonary shunt fraction (QS/QT) was calculated.Results:(1)There were no significant differences in general conditions in tow groups(P>0.05).(2)There were no significant differences in HR,MAP,PH and Hb in both groups (.P>0.05).(3)Compared with TLV,the Paw was significantly increased during OLV(P<0.001).(4)OLV significantly decreased arterial oxygen partial pressure (PaO2)(P<0.001)and increased Qs/Qt compared to TLV(P<0.001).(5)There were no significant differences of PaO2between tow groups at Ti(P>0.05). PaO2in group A were higher than group B at T2and T3(P<0.05).However,there were no significant differences of Qs/Qt between two groups at T1, T2and T3(P>0.05).Conclusions:This study suggests that OLV decreased arterial oxygen partial pressure (PaO2) and increased Qs/Qt.Using the self-made equipment to applied5cmH2O CPAP effectively improved arterial oxygenation during OLV,but it dose not affect the pulmonary shunt fraction (Qs/Qt).