压力-容积曲线指导开胸手术患者个体化保护性单肺通气的效果

目的 评价应用动态压力-容积曲线(P-V曲线)设定开胸手术患者个体化的潮气量(VT)和呼气末正压(PEEP)行单肺通气(OLV)的效果.方法 择期行肺叶切除术患者25例,性别不限,年龄44～64岁,体重57～75 kg,ASA分级Ⅰ或Ⅱ级.常规双肺通气30 min后(T0)行OLV,按照动态P-V曲线低位拐点对应的压力(PLIP) +0.196 kPa设定PEEP,根据动态P-V曲线高位拐点对应的容量(VUTP)设定VT,通气30 min后(T1)将VT降至80％ VUIP,通气30 min后(T2)再将VT降至60％ VUIP,然后再通气30 min (T3).OLV期间吸呼比1∶1 ～2,通气频率14～20次/min,维持PETC02 4.67～6.00kPa.分别于T0-3时记录MAP、HR、CVP和气道峰压(Ppeak)、气道阻力(Rsw)、胸肺顺应性(CL),同时采集动脉和中心静脉血样,进行血气分析,记录pH值、PaO2和PaCO2,计算肺内分流率(Qs/Qt).结果 与T0时比较,T1-3时HR、Ppeak、Rsw和Qs/Qt升高,CL和PaO2降低,T1.2时CVP升高,T3时MAP和PaCO2升高(p＜0.05)；与T1时比较,T2.3时Ppeak和Rsw降低,T1.2时Pa02升高,Qs/Qt降低,T3时CVP降低,MAP和PaC02升高(P＜0.05).结论 根据80％ VUU确定VT,PuP +0.196 kPa确定PEEP,有助于改善开胸手术患者的氧合,对血液动力学无明显影响,是实现个体化保护性OLV的有效手段.

Individualized lung protective ventilation regimen based on pressure-volume curve for one lung ventilation in patients undergoing thoracic surgery

Objective To 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.Results HR,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.Conclusions Mechanical ventilation with VT set at 80％ of VUIPandPEEPatPUIP+0.196kPa provides best ventilatory efficacy for OLV in terms of PaO2 and hemodynamics.