脉压变异对急性肺损伤机械通气患者血流动力学变化的临床价值

The Clinical Value of Pulse Pressure Variation to Monitor the Fluid Responsiveness and Effects of PEEP in Ventilated Patients with Acute Lung Injury

目的研究脉压变异(ΔPP)是否可反映呼气末正压(PEEP)及液体复苏对血流动力学的影响。方法选择ALI需要机械通气的患者20例。所有患者镇静并应用容量控制通气模式,潮气量=8mL/kg,吸气/呼气=1:2,维持PaCO2在35～45mmHg;随机先后设定PEEP为5cmH2O及15cmH2O;应用经肺热稀释法监测血流动力学变化;当PEEP导致心排指数(CI)下降>10%时,予羟乙基淀粉(HES)500mL进行液体复苏,并监测CI及ΔPP的变化。结果20例机械通气的患者均先后应用5cmH2O和15cmH2O的PEEP。PEEP15时CI较PEEP5时显著降低(P<0.05),ΔPP显著增加(P<0.05)。其中14例患者应用PEEP15时导致CI下降>10%,予羟乙基淀粉(HES)进行液体复苏,CI从(3.01±0.57)L.min-1.m-2升高至(3.62±0.68)L.min-1.m-2(P<0.01),ΔPP从(17±3)%降至(10±2)%(P<0.01)。PEEP15导致的CI变化与PEEP5时ΔPP值相关(r=-0.91,P<0.01),并与PEEP15导致的ΔPP增加相关(r=-0.79,P<0.01);而且液体复苏导致CI变化与复苏前ΔPP值相关(r=0.96,P<0.01),并与液体复苏导致的ΔPP降低相关(r=-0.95,P<0.01)。结论对于ALI进行机械通气应用PEEP的患者,ΔPP是预测并评价PEEP及液体复苏时血流动力学变化简便且有效的指标。

Objective To investigate whether pulse pressure variation （△PP） reflect the effects of PEEP and fluid resuscitation （FR） on hemodynamic effects. Methods Twenty critical patients with acute lung injury was ventilated with volume control （ VT = 8 mL/kg, Ti/Te = 1 ： 2 ）, and PaCO2 was kept at 35 to 45 mm Hg. PEEP was setted as 5 cm H2O and 15 cm H2O in randomized order. Hemodynamic parameters including cardiac index, pulse pressure, central venous pressure, etc. were monitered by PiCCO system. Measurements were performed after the application of 5 cm H2O PEEP （PEEP5 group）and 15 cm H2O PEEP （PEEP15 group ） respectively. When the PEEP-induced decrease in cardiac index （ CI ） was 〉 10%, ts were also performed after fluid resuscitation. Results Compared with PEEPs group, CI was decreased significantly in PEEPIs group（ P 〈0.05 ）, and APP was increased significantly（ P 〈0. 05 ）. In 14 patients whose PEEP-induced decrease in CI was 〉 10%, fluid resuscitation increased CI from （3. 01 ± 0. 57 ） L · min^ -1 · m^ -2 to （ 3.62 ± 0. 68 ） L ·min^ -1· m^ -2 （ p 〈 0. 01 ） , and decreased APP from （ 17 ± 3 ） % to （10±2）% （P 〈0. 01 ）. PEEP15-induced decrease in CI was correlated negatively with APP on PEEP5 （r = - 0.91, P 〈 0.01 ） and with the PEEP1s-induced increase in △PP （ r = - 0. 79, P 〈 0. 01 ）. FR-induced changes in CI correlated with APP before FR （r = 0. 96, P 〈 0. 01 ） and with the FR-induced decrease in △PP （r = - 0. 95, P 〈 0. 01 ）. Conclusions In ventilated patients with ALI, APP may be a simple and useful parameter in predicting and assessing the hemodynamic effects of PEEP and FR.