低潮气量加呼气末正压通气对急性肺损伤氧代谢的影响

Effect of low tidal volume with positive end-expiratory pressure on oxygen metabolism in patients with acute lung injury

目的 采用低潮气量加呼气末正压 (PEEP)通气 ,观察对急性肺损伤 (ALI)氧代谢的影响。方法 对 14例ALI患者 ,最初采用辅助 /控制 (A/C)通气 ,并逐渐增加PEEP ,每种方式 30min ,吸入氧浓度 (FiO2 )不变。利用Swan -Ganz导管获得氧代谢参数。结果 当PEEP 1 47kPa时 ,氧供给 (DO2 )最大 ,PEEP 1 96kPa时 ,DO2 下降(P <0 0 5 )。当PEEP在 0 49～ 1 47kPa范围内 ,对平均动脉压 (MBP)、肺动脉压 (PAP)和心脏射血指数 (CI)均无明显影响 (P >0 0 5 )。当PEEP增加到 1 96kPa时 ,CI降低。PEEP在 0 98和 1 47kPa时 ,肺静态顺应性 (Cst)稳定在 (33 6± 8 3)mL/cmH2 O水平 ,当PEEP 1 96kPa时 ,Cst下降 (P <0 0 5 )。结论 ALI采用低潮气量加适当PEEP可得到稳定的Cst,减少对血流动力学的影响 ,获得最大DO2 。

Objective To explore the effect of low tidal volume with positive end-expiratory pressure(PEEP) on oxygen metabolism in 14 acute lung injury(ALI) patients.Methods 14 patients with ALI were optimally ventilated by Assist and Control(A/C),and PEEP was increased gradually for 30min,respectively.The concentration of FiO 2 was kept constant.The parameters of oxygen metabolism were obtained by using Swan-Ganz catheter.Results At PEEP 1 47kPa,the maximal DO 2 was obtained,the DO 2 was decreased at PEEP 1 96kPa(P<0 05).MBP,PAP and CI were not significantly different from PEEP 0 49～1 47kPa(P<0 05).CI decreased at PEEP 1 96kPa(P<0 05).Cst was kept approximately(33 6± 8 3)mL/cmH 2O from PEEP 0 98 to 1 47kPa,but Cst was decreased at PEEP 1 96kPa(P<0 05).Conclusion The low tidal volume with a given PEEP can obtain constant Cst and reduce the effect on hemodynamics in patients with ALI,and obtain the maximal DO 2.ons were isolated directly from plasma by nonequilibrium density gradient centrifugation, and distributions of LDL subfractions were analyzed. The continuous monitoring of LDL oxidation by absorbance measurements at 234 nm was used to analyze the susceptibility of LDL subfractions to Cu 2+ mediated oxidation in patients with DM. It is showed that the frequency distributions of LDL subfractions had no different among simple DM, complicated DM patients and controls. The lag time in the test for LDL oxidizability in DM patients was significantly shorter than that in control. And the lag time in DM complication patients was the shortest. Circulating LDL isolated from DM patients was more susceptible to oxidation in vitro than that of controls. This may be associated with the high level of oxidative modificdtion LDL, and may also be associated with increased risk for coronary artery disease. Key words Diabetes mellitus Low density lipoprotein Subfractions Susceptibility to oxidation