目的探讨不同机械通气策略对急性肺损伤(ALI)患者血液、呼吸动力学和氧代谢的影响。方法本组共26例ALI患者，对其中14例ALI评分值≥2.5者采用低潮气量+呼气末正压(PEEP)通气,并依次按0，5，10，15，20 cm H2O增加PEEP；对另外12例ALI评分值<2.5者最初采用辅助/控制通气(A/C)，并逐渐改为间歇辅助通气（SIMV）和压力支持通气（PSV）。通过Swan-Ganz导管获得血液动力学和氧代谢参数。结果 PEEP在 5～15 cm H2O范围内, 动脉血氧分压（PaO2）、氧合指数（PaO2／FiO2）、氧供给（DO2）和肺静态顺应性（Cst）随着PEEP的增高而逐渐增加（P<0.05）。在PEEP增加到20 cm H2O时心输出量（CO）和 Cst下降，外周循环阻力（SVR）、肺循环阻力（PVR）和气道峰值压（PIP）增加（P<0.05）。SIMV与A/C相比可显著增加DO2（P<0.05），PSV与A/C相比可明显降低PIP并使Cst增加(P<0.05)。SIMV和PSV方式均可降低SVR。结论对ALI不同时期选择不同的机械通气策略，可更好的增加氧供，减少对呼吸、血液动力学的影响。%Objective To explore the effects of different ventilation tactics on pneumodynamics, hemodynamics and metabolism of oxygen in patients with acute lung injury(ALI). Methods A total of 14 patients with ALI score≥2.5 were ventilated with low tidal and positive end expiratory pressure (PEEP). And the PEEP changed to 0, 5, 10, 15 and 20 cm H2O, respectively. Twelve patients with ALI score<2.5 were ventilated with A/C, synchronized intermittent mandatory ventilation (SIMV) and pressure support ventilation (PSV). The hemodynamics and the metabolism of oxygen parameters of the two groups were obtained through a Swan-Ganz tube. Results When the levels of PEEP were during 5 to 15 cm H2O, the partial pressure of oxygen in artery (PaO2), PaO2/FiO2, DO2 and the compliance static (Cst) increased gradually (P<0.05). The cardiac output (CO) and Cst decreased significantly when the PEEP was 20 cm H2O, at the same time, the pulmonary vascular resistance (PVR) and the systemic vascular resistance (SVR) increased (P<0.05). Compared with A/C model, DO2 increased under the SIMV. The peak inflating pressure (PIP) decreased under the PSV but Cst increased. Compared with the A/C model, SVR decreased significantly under the SIMV and PSV models. Conclusions It can better increase DO2 and decrease the bad effects of pneumodynamics and hemodynamic, when different ventilation tactics are chosen for the patients with ALI.
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