Temporal hemodynamic effects of permissive hypercapnia as associated with ideal PEEP in ARDS
Temporal hemodynamic effects of permissive hypercapnia as associated with ideal PEEP in ARDS
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DOI：
10.1164/ajrccm.156.5.9604081
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发表时间：
1997-11-01
影响因子：
24.7
通讯作者：
Amato, MBP
中科院分区：
文献类型：
--
作者：
Carvalho, CRR;Barbas, CSV;Amato, MBP
允许性高碳酸血症（PHY）和高PEEP水平（PEEPIDEAL）的相关使用最近被认为是急性呼吸窘迫综合征（ARDS）肺保护入路（LPA）的一部分。然而，这种关联所产生的净血流动力学效应尚不清楚。我们分析了48例ARDS患者（平均年龄34 +/- 13岁）的时间血流动力学影响，重点关注其即时（1小时后），早期（前36小时）和晚期（第2 -7天）的后果。25例患者接受lpa，联合使用允许性高碳酸血症（PHY）， VT < 6 ml/kg，扩张压高于PEEP < 20 cm H2O， PEEP高于静态吸气P-V曲线（P-FLEX）下拐点2 cm H2O，对照组23例接受常规机械通气。LPA立即启动，导致心率（p = 0.0002）、心输出量（p = 0.0002）、氧输送(（D) / o(2)I, p = 0.0003）和混合静脉Po-2 （p = 0.0006）立即增加，维持全身耗氧量（p = 0.52）。肺动脉压平均升高（平均升高8.8 mm Hg, p < 0.0001），肺血管阻力无明显变化（p = 0.32）。心脏充盈压力升高（p < 0.001），全身血管阻力下降（p = 0.003）。所有这些变化在前36小时内逐渐减弱，尽管持续高碳酸血症。血浆乳酸在LPA早期呈进行性下降，而对照组没有（p < 0.0001）。晚期未见LPA对血流动力学的影响，肾功能得以保留。一项多变量分析表明，这些急性高动力效应与呼吸性酸中毒有关，没有归因于高PEEP的抑制作用。相反，高平台压与心血管抑郁有关。因此，只要同时施加足够低的扩张压力，突然安装PHY和PEEPIDEAL会引起短暂的高动力状态和肺动脉高压，而不会对年轻的ARDS人群产生有害后果。
The associated use of permissive hypercapnia (PHY) and high PEEP levels (PEEPIDEAL) has been recently indicated as part of a lung-protective-approach (LPA) in acute respiratory distress syndrome (ARDS). However, the net hemodynamic effect produced by this association is not known. We analyzed the temporal hemodynamic effects of this combined strategy in 48 patients (mean age 34 +/- 13 yr) with ARDS, focusing on its immediate (after 1 h), early (first 36 h), and late (2nd-7th d) consequences. Twenty-five patients were submitted to LPA-with the combined use of permissive hypercapnia (PHY), VT < 6 ml/kg, distending pressures above PEEP < 20 cm H2O, and PEEP 2 cm H2O above the lower inflection point on the static inspiratory P-V curve (P-FLEX)-and 23 control patients were submitted to conventional mechanical ventilation. LPA was initiated at once, resulting in an immediate increase in heart rate (p = 0.0002), cardiac output (p = 0.0002), oxygen delivery ((D) over dot o(2)I, p = 0.0003), and mixed venous Po-2 (p = 0.0006), with a maintained systemic oxygen consumption (p = 0.52). The mean pulmonary arterial pressure markedly increased (mean increment 8.8 mm Hg; p < 0.0001), but the pulmonary vascular resistance did not change (p = 0.32). Cardiac filling pressures increased (p < 0.001) and the systemic vascular resistance fell (p = 0.003). All these alterations were progressively attenuated in the course of the first 36 h, despite persisting hypercapnia. Plasma lactate suffered a progressive decrement along the early period in LPA but not in control patients (p < 0.0001). No hemodynamic consequences of LPA were noticed in the late period and renal function was preserved. A multivariate analysis suggested that these acute hyperdynamic effects were related to respiratory acidosis, with no depressant effects ascribed to high PEEP levels. In contrast, high plateau pressures were associated with cardiovascular depression. Thus, as long as sufficiently low distending pressures are concomitantly applied, the sudden installation of PHY plus PEEPIDEAL induces a transitory hyperdynamic state and pulmonary hypertension without harmful consequences to this young ARDS population.