Influence of general anesthesia combined with epidural block on arterial blood gas during one - lung ventilation in patients undergoing thoracic surgery

Abstract

Objective To evaluate the effects of general anesthesia combined with throacic epidural block on pulmonary gas ex-change during one-lung ventilation in patients undergoing thoracic surgery. Methods Eighty patients of ASA Ⅰ-Ⅱ undergoing electivethroacic surgery were randomly divided into two Groups (n = 40 ) receiving combined genera] anesthesia with throacic epidural block(group A ) or general anesthesia (group B ). MAP, HR, SpO2, PETCO2, VT, Paw were monitored at both bronps. Arterial andmixed vein blood gas were analyzed and Qs/Qt ,A-aDO2,Vd/Vt were calculated in both groups at 20 rain ( T1 ) before one-lung ventila-tion and 30 min( T2 ), 60 min( T3 ), as well as 120 min ( T4 ) after one-lung ventilation. Results In both groups, Paw and Qs/Qt in-creased while PaO2 decreased significantly at T2-4, ( P<0.05 ). At T2-4, Qs/Qt was significantly higher and PaO2 was significantly lowerin group A than that in group B. Conclusion During one-lung ventilation, general anesthesia combined with throacic epidural blockhas increased Qs/Qt ,A-aDO2 ,Vd/Vt and decreased PaO2. The patients should be monitored carefully during all the surgical procedure. Key words: one-lung ventilation ; general anesthesia ; epidural block ; pulmonary gas exchange ;