الملخص
Objective To evaluate the effect of lung protective ventilation strategy on inflammatory responses in brain tissues of elderly patients requiring one-lung ventilation (OLV) during radical resection for esophagus cancer.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,were divided into volume-controlled ventilation (VCV) group (n =30) and VCV plus protective ventilation strategy group (PV group,n =30) using a random number table.In group VCV,the tidal volume was set at 10 ml/kg during two-lung ventilation (TLV) and at 7 ml/kg during OLV with inspiratory/expiratory ratio 1:2.In group PV,the tidal volume was set at 7 ml/kg during TLV and at 5 ml/kg during OLV with inspiratory/expiratory ratio 1:2 and positive end-expiratory pressure 5 cmH2O,and lung recruitment maneuver was performed every 45 min.End-tidal pressure of carbon dioxide was maintained at 35-45 mmHg,and bispectral index value at 40-60 in both groups.Before induction of anesthesia (T1),at 10 min of TLV (T2),at 30 min of OLV (T3),at 15 min after restoration of TLV (T4) and at 24 h after operation (T5),jugular bulb venous blood samples were taken for determination of serum glial fibrillary acid protein,tumor necrosis factor-α and interleukin-6 concentrations by enzyme-linked immunosorbent assay.The cognitive function was assessed using Mini-Mental State Examination before operation (T0),at T5 and at 3 and 7 days after operation (T6,7).The occurrence of postoperative delirium was recorded.Results Compared with group VCV,the serum concentrations of tumor necrosis factor-α,interleukin-6 and glial fibrillary acid protein were significantly decreased at T3-5,Mini-Mental State Examination scores were increased at T6,7,and the incidence of postoperative delirium was decreased in group PV (P<0.05).Conclusion The mechanism by which lung protective ventilation strategy decreases the development of postoperative cerebral dysfunction is related to reduction of inflammatory responses in brain tissues of elderly patients requiring OLV during radical resection for esophagus cancer.