Effect of lung protective ventilation regimen on regional cerebral oxygen saturation during one-lung ventilation in elderly patients undergoing radical esophagus cancer resection

Objective To investigate the effect of lung protective ventilation regimen on regional cerebral oxygen saturation(rSO2)during one-lung ventilation(OLV)in elderly patients undergoing radical esophagus cancer resection.Methods Forty ASA Ⅰ-Ⅲ patients,aged 65-76 yr,weighing 45-75 kg,undergoing radical esophagus cancer reseclion,were randomly divided into 2 groups(n =20 each):conventional ventilation group(group CV)and prolective ventilation regimen group(group PV).Anesthesia was induced with midaaolam 0.05 mg/kg,sufentanil 0.4 μg/kg,rocuronium 1 mg/kg and propofol 1.5 mg/kg and maintained with 2％ sevoflurane and intermittenl iv boluses of rocuronium 0.5 mg/kg.Double lumen tube was inserted.Correct positioning was verified by fiberoptic broncboscopy.The patients were mechanically ventilated.In group CV,PEEP was set at 0,Vt was set at 10 ml/kg,and I:E was set at 1:2 during two-lung ventilation(TLV)and OLV.In group PV,PEEP was set at 5 cm H2O,Vt was set at 6 ml/kg,and I:E was set at 1:2 during TLV and OLV.PETCO2 was maintained at 35-40 mn Hg in both groups.Arterial blood samples were taken before induction of anesthesia,at 10 min of TLV and at 30 min of OLV for blood gas analysis.Qs/Qt was calculated and rSO2 was recorded at the same time.Low rSO2 (rSO2 score ＞ 3000％)was recorded during OLV.Results Compared with group CV,PaO2 and rSO2 were significantly increased,and Qs/Qt was significantly decreased at 30 min of OLV,and the incidence of low rSO2 was significanfly decreased in group PV(P ＜ 0.05).Conclusion Lung protective ventilation regimen can improve oxygenation,decrease intrapulmonary shunt,and reduce the occurrence of low rSO2 during OLV in elderly patients undergoing radical esophagus cancer resection. Key words: Positive-pressure respiration; Tidal volume; Oximetry; Brain