新生羔羊部分液体通气期间呼气末正压的血流动力学效应。

Hemodynamic effects of positive end-expiratory pressure during partial liquid ventilation in newborn lambs.

作者信息

Overfield D M, Bennett S H, Goetzman B W, Milstein J M, Moon-Grady A J

机构信息

Department of Pediatrics, Division of Neonatology, School of Medicine, University of California, Davis, CA 95616, USA.

出版信息

J Pediatr Surg. 2001 Sep;36(9):1327-32. doi: 10.1053/jpsu.2001.26360.

DOI:10.1053/jpsu.2001.26360

PMID:11528599

Abstract

BACKGROUND/PURPOSE: The aim of this study was to compare the effect of positive end-expiratory pressure (PEEP) application on hemodynamics, lung mechanics, and oxygenation in the intact newborn lung during conventional ventilation (CV) and partial liquid ventilation (PLV) at functional residual capacity (FRC). CV or PLV modes of ventilation do not affect hemodynamics nor the optimum PEEP for oxygenation.

METHODS

Seven newborn lambs (1 to 3 days old) were instrumented to measure pulmonary hemodynamics and airway mechanics. Each lamb was used as their own control to compare different modes of ventilation (CV followed by PLV) under graded variations of PEEP (4, 8, 12, and 16 cm H(2)O) on the influence on pulmonary blood flow and pulmonary vascular resistance.

RESULTS

There was a significant drop in pulmonary blood flow (PBF) from baseline (PEEP of 4 cm H(2)O on CV, 1,229 +/- 377 mL/min) in both modes of ventilation on a PEEP of 16 cm H(2)O (CV, 750 +/- 318 mL/min v PLV, 926 +/- 396 mL/min, respectively; P <.05). Peak inspiratory pressure (PIP) was higher on PLV at PEEP states of 4 cm H(2)O (16.5 +/- 1.3 cm H(2)O to 10.6 +/- 2.1 cm H(2)O; P <.05) and 8 cm H(2)O (18.8 +/- 2.2 cm H(2)O to 15.1 +/- 2.6 cm H(2)O; P <.05) when compared with CV. Conversely, PIP required to maintain the pCO(2) was lower on PLV at PEEP states of 12 (22.5 +/- 3.6 cm H(2)O to 24.2 +/- 3.8 cm H(2)O; P <.05) and 16 cm H(2)O (27.0 +/- 1.6 cm H(2)O to 34.0 +/- 5.9 cm H(2)O; P <.05).

CONCLUSIONS

Hemodynamically, CO is impaired at a PEEP above 12 cm H(2)O in intact lungs. PFC at FRC does provide an advantage in lung mechanics more than 10 to 12 cm H(2)O of PEEP by decreasing the amount PIP needed to achieve the similar levels of gas exchange and minute ventilation, implying a reduced risk for barotrauma with chronic ventilation. Thus, selection of the appropriate level of PEEP appears to be important if PLV is to be utilized at FRC. The best strategy for PLV, including the selection of PEEP, remains to be determined.

摘要

背景/目的：本研究旨在比较呼气末正压（PEEP）应用于功能残气量（FRC）时，在传统通气（CV）和部分液体通气（PLV）过程中，对完整新生羊肺的血流动力学、肺力学和氧合的影响。CV或PLV通气模式不影响血流动力学，也不影响氧合的最佳PEEP。

方法

对7只新生羔羊（1至3日龄）进行仪器安装以测量肺血流动力学和气道力学。每只羔羊自身作为对照，比较不同通气模式（先CV后PLV）在不同PEEP水平（4、8、12和16 cm H₂O）下对肺血流量和肺血管阻力的影响。

结果

在两种通气模式中，当PEEP为16 cm H₂O时（CV模式下从基线时的4 cm H₂O，肺血流量为1,229 ± 377 mL/min下降到750 ± 318 mL/min；PLV模式下从基线时的4 cm H₂O下降到926 ± 396 mL/min；P <.05），肺血流量（PBF）较基线均显著下降。在PEEP为4 cm H₂O（从16.5 ± 1.3 cm H₂O降至10.6 ± 2.1 cm H₂O；P <.05）和8 cm H₂O（从18.8 ± 2.2 cm H₂O降至15.1 ± 2.6 cm H₂O；P <.05）时，PLV模式下的吸气峰压（PIP）高于CV模式。相反地，在PEEP为12 cm H₂O（从22.5 ± 3.6 cm H₂O降至24.2 ± 3.8 cm H₂O；P <.05）和16 cm H₂O（从27.0 ± 1.6 cm H₂O降至34.0 ± 5.9 cm H₂O；P <.05）时，维持pCO₂所需的PIP在PLV模式下更低。

结论

从血流动力学角度来看，完整肺脏在PEEP高于12 cm H₂O时心输出量受损。在FRC水平下使用全氟碳化合物（PFC）在肺力学方面确实具有优势，可以降低达到相似气体交换和分钟通气水平所需的PIP量，这意味着长期通气时气压伤风险降低。因此，如果要在FRC水平下使用PLV，选择合适水平的PEEP似乎很重要。PLV的最佳策略，包括PEEP的选择仍有待确定。