比较 ICU 机械通气急性低氧性呼吸衰竭患者食管压绝对值的 2 种校正方法。

Comparison of 2 correction methods for absolute values of esophageal pressure in subjects with acute hypoxemic respiratory failure, mechanically ventilated in the ICU.

机构信息

University of Lyon, Lyon, France.

出版信息

Respir Care. 2012 Dec;57(12):2045-51. doi: 10.4187/respcare.01883.

DOI:10.4187/respcare.01883

PMID:23233496

Abstract

BACKGROUND

A recent trial showed that setting PEEP according to end-expiratory transpulmonary pressure (P(pl,ee)) in acute lung injury/acute respiratory distress syndrome (ALI/ARDS) might improve patient outcome. P(pl,ee) was obtained by subtracting the absolute value of esophageal pressure (P(es)) from airway pressure an invariant value of 5 cm H(2)O. The goal of the present study was to compare 2 methods for correcting absolute P(es) values in terms of resulting P(pl,ee) and recommended PEEP.

METHODS

Measurements collected prospectively from 42 subjects with various forms of acute hypoxemic respiratory failure receiving mechanical ventilation in ICU were analyzed. P(es) was measured at PEEP (P(es,ee)) and at relaxation volume of the respiratory system Vr (P(es,Vr)), obtained by allowing the subject to exhale into the atmosphere (zero PEEP). Two methods for correcting P(es) were compared: Talmor method (P(pl,ee,Talmor) = P(es,ee) - 5 cm H(2)O), and Vr method (P(es,ee,Vr) = P(es,ee) - P(es,Vr)). The rationale was that P(es,Vr) was a more physiologically based correction factor than an invariant value of 5 cm H(2)O applied to all subjects.

RESULTS

Over the 42 subjects, median and interquartile range of P(es,ee) and P(es,Vr) were 11 (7-14) cm H(2)O and 8 (4-11) cm H(2)O, respectively. P(pl,ee,Talmor) was 6 (1-8) cm H(2)O, and P(es,ee,Vr) was 2 (1-5) cm H(2)O (P = .008). Two groups of subjects were defined, based on the difference between the 2 corrected values. In 28 subjects P(pl,ee,Talmor) was ≥ P(es,ee,Vr) (7 [5-9] cm H(2)O vs 2 [1-5] cm H(2)O, respectively), while in 14 subjects P(es,ee,Vr) was > P(pl,ee,Talmor) (2 [0-4] cm H(2)O vs -1 [-3 to 2] cm H(2)O, respectively). P(pl,ee,Vr) was significantly greater than P(pl,ee,Talmor) (7 [5-11] cm H(2)O vs 5 [2-7] cm H(2)O) in the former, and significantly lower in the latter (1 [-2 to 6] cm H(2)O vs 6 [4-9] cm H(2)O).

CONCLUSIONS

Referring absolute P(es) values to Vr rather than to an invariant value would be better adapted to a patient's physiological background. Further studies are required to determine whether this correction method might improve patient outcome.

摘要

背景

最近的一项试验表明，根据急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）患者的呼气末跨肺压（P（pl，ee））来设置呼气末正压（PEEP）可能会改善患者的预后。通过从气道压力中减去食管压力（P（es））的绝对值和 5 cm H（2）O 的不变值来获得 P（pl，ee）。本研究的目的是比较两种方法，根据得到的 P（pl，ee）和推荐的 PEEP，对绝对 P（es）值进行校正。

方法

前瞻性分析了 42 例接受机械通气的急性低氧性呼吸衰竭患者的测量值。在 PEEP（P（es，ee））和呼吸系统松弛容积 Vr（P（es，Vr））时测量 P（es），通过允许受试者呼气到大气中（零 PEEP）获得。比较了两种校正 P（es）的方法：Talmor 法（P（pl，ee，Talmor）= P（es，ee）-5 cm H（2）O）和 Vr 法（P（es，ee，Vr）= P（es，ee）-P（es，Vr））。原理是 P（es，Vr）是比应用于所有受试者的 5 cm H（2）O 不变值更基于生理的校正因子。

结果

在 42 例患者中，P（es，ee）和 P（es，Vr）的中位数和四分位间距分别为 11（7-14）cm H（2）O 和 8（4-11）cm H（2）O。P（pl，ee，Talmor）为 6（1-8）cm H（2）O，P（es，ee，Vr）为 2（1-5）cm H（2）O（P=0.008）。根据两种校正值的差异，定义了两组患者。在 28 例患者中，P（pl，ee，Talmor）≥P（es，ee，Vr）（分别为 7[5-9]cm H（2）O 和 2[1-5]cm H（2）O），而在 14 例患者中，P（es，ee，Vr）>P（pl，ee，Talmor）（分别为 2[0-4]cm H（2）O 和-1[-3 至 2]cm H（2）O）。P（pl，ee，Vr）在前者中显著大于 P（pl，ee，Talmor）（7[5-11]cm H（2）O 与 5[2-7]cm H（2）O），而在后者中显著低于后者（1[-2 至 6]cm H（2）O 与 6[4-9]cm H（2）O）。