Individualized lung protective ventilation regimen based on pressure-volume curve for one lung ventilation in patients undergoing thoracic surgery / 中华麻醉学杂志

ABSTRACT

ObjectiveTo evaluate the effectiveness of setting PEEP and tidal volume (VT ) according to pressure-volume (P-V) curve during one lung ventilation (OLV) in patients undergoing thoracic surgery.Methods Twenty-five ASA Ⅰ or Ⅱ patients of both sexes aged 44-64 yr weighing 57-75 kg undergoing lobectomy under general anesthesia were enrolled in this study.Double-lumen tube was inserted.Correct positioning was verified by flberoptic bronchoscopy.The patients were mechanically ventilated.P-V curve was measured by SSS system during OLV.Lower inflection point (LIP)and upper inflection point (UIP) were determined.The pressure at LIP (PLIP) and volume at UIP (VUIP) were measured.Bilateral lungs were ventilated for 30 min (T0) at first before OLV was started.PEEP was set at PLIP + 0.196 kPa and VT was set at VUIP,and the patients were ventilated for 30 min (T1).VT was then reduced to 80％ of VUIP.OLV was performed for another 30 min (T2).VT was then further reduced to 60％ of VUIP and the patients were ventilated for 30 min (T3).PEr CO2 was maintained at 4.67-6.00 kPa.Arterial blood and central venous samples were taken at T0-3.Blood gas analysis was performed.Qs/Qt was calculated.MAP,HR,CVP,peak airway pressure (Peak),airway resistance (Rsw) and lung compliance (CL) were measured and recorded at T0-3.ResultsHR,Ppeakk,Rsw and Qs/Qt were significantly increased while CL and PaO2 decreased at T1-3,CVP was significantly increased at T1.2 and MAP and PaCO2 were increased at T3 as compared with the baseline values at T0.Ppeak and Rsw were significantly decreased at T2.3 and PaO2 was significantly increased while Qs/Qt decreased at T2,CVP was decreased,MAP and PaO2 were increased at T3 as compared with the values at T1.ConclusionsMechanical ventilation with VT set at 80％ of VUIPandPEEPatPUIP+0.196kPa provides best ventilatory efficacy for OLV in terms of PaO2 and hemodynamics.