Effects of lung-protective ventilation on cerebral oxygen metabolism and postoperative cognitive function in elderly patients requiring one-lung ventilation / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effects of lung-protective ventilation on the cerebral oxygen metabolism and postoperative cognitive function in elderly patients requiring one-lung ventilation (OLV).Methods Sixty patients of both sexes,aged 65-80 yr,weighing 45-75 kg,of American Society of Anesthesiologists physical status Ⅱ or Ⅲ,scheduled for elective radical resection for esophageal cancer performed via video-assisted thoracoscope with general aneshesia,were divided into 2 groups (n =30 each)using a random number tablevolume-controlled ventilation group (group VCV) and protective ventilation group (group PV).In group VCV,the tidal volume (VT) was set at 10 ml/kg during two-lung ventilation (TLV) and at 7 ml/kg during OLV.In group PV,the VT was set at 7 ml/kg during TLV and at 5 ml/kg during OLV with positive end-expiratory pressure of 5 cmH2O,and lung recruitment maneuver was performed every 45 min with inspiratory pressure at 15,20 and 25 cmH2O,PEEP 5 cmH2O,3 breaths per pressure,5 s/breath.Before induction of anesthesia (T1),at 10 min of TLV (T2),at 30 min of OLV (T3) and at 15 min after restoration of TLV (T4),blood samples were taken from the radial artery and jugular bulb for blood gas analysis,and pH value,arterial oxygen partial pressure (PaO2),arterial carbon dioxide partial pressure (PaCO2),arterial oxygen saturation (SaO2) and jugular venous oxygen saturation (SjvO2) were recorded.Oxygenation index (OI),intrapulmonary shunt (Qs/Qt),arteriovenous blood O2 content difference (Da-jvO2) and cerebral O2 extraction rate (CERO2) were calculated at the same time.Cognitive function was assessed using Mini-Mental State Examination at 7 days and 1 month after operation,and the development of postoperative cognitive dysfunction was recorded.Results PaO2,DajvO2,CERO2 and Qs/Qt were significantly higher and SjvO2 and OI were lower at T2-4 than at T1 in two groups (P＜0.05).PaO2,SjvO2 and OI were significantly lower and Qs/Qt and CERO2 were higher at T3 than at T2,and Da-jvO2 was higher at T3-4 than at T2 in two groups (P＜0.05).Compared with group VCV,PaO2,PaCO2,SjvO2 and OI were significantly increased and Qs/Qt,Da-jvO2 and CERO2 were decreased at T3,the Mini-Mental State Examination scores were increased on postoperative day 7,and the incidence of postoperative cognitive dysfunction was decreased in group PV (P＜O.05).Conclusion Lungprotective ventilation is helpful in improving postoperative brain function of elderly patients requiring OLV.