急性呼吸窘迫综合征患者的呼吸力学和计算机断层扫描评估肺复张：两者之间的关系是什么？

Lung Recruitment Assessed by Respiratory Mechanics and Computed Tomography in Patients with Acute Respiratory Distress Syndrome. What Is the Relationship?

机构信息

1 Dipartimento di Anestesia, Rianimazione ed Emergenza-Urgenza, Fondazione IRCCS Cà Granda - Ospedale Maggiore Policlinico, Milano, Italy.

2 Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milano, Italy; and.

出版信息

Am J Respir Crit Care Med. 2016 Jun 1;193(11):1254-63. doi: 10.1164/rccm.201507-1413OC.

DOI:10.1164/rccm.201507-1413OC

PMID:26699672

Abstract

RATIONALE

The assessment of lung recruitability in patients with acute respiratory distress syndrome (ARDS) may be important for planning recruitment maneuvers and setting positive end-expiratory pressure (PEEP).

OBJECTIVES

To determine whether lung recruitment measured by respiratory mechanics is comparable with lung recruitment measured by computed tomography (CT).

METHODS

In 22 patients with ARDS, lung recruitment was assessed at 5 and 15 cm H2O PEEP by using respiratory mechanics-based methods: (1) increase in gas volume between two pressure-volume curves (P-Vrs curve); (2) increase in gas volume measured and predicted on the basis of expected end-expiratory lung volume and static compliance of the respiratory system (EELV-Cst,rs); as well as by CT scan: (3) decrease in noninflated lung tissue (CT [not inflated]); and (4) decrease in noninflated and poorly inflated tissue (CT [not + poorly inflated]).

MEASUREMENTS AND MAIN RESULTS

The P-Vrs curve recruitment was significantly higher than EELV-Cst,rs recruitment (423 ± 223 ml vs. 315 ± 201 ml; P < 0.001), but these measures were significantly related to each other (R(2) = 0.93; P < 0.001). CT (not inflated) recruitment was 77 ± 86 g and CT (not + poorly inflated) was 80 ± 67 g (P = 0.856), and these measures were also significantly related to each other (R(2) = 0.20; P = 0.04). Recruitment measured by respiratory mechanics was 54 ± 28% (P-Vrs curve) and 39 ± 25% (EELV-Cst,rs) of the gas volume at 5 cm H2O PEEP. Recruitment measured by CT scan was 5 ± 5% (CT [not inflated]) and 6 ± 6% (CT [not + poorly inflated]) of lung tissue.

CONCLUSIONS

Respiratory mechanics and CT measure-under the same term, "recruitment"-two different entities. The respiratory mechanics-based methods include gas entering in already open pulmonary units that improve their mechanical properties at higher PEEP. Consequently, they can be used to assess the overall improvement of inflation. The CT scan measures the amount of collapsed tissue that regains inflation. Clinical trial registered with www.clinicaltrials.gov (NCT00759590).

摘要

背景

急性呼吸窘迫综合征（ARDS）患者的肺可复张性评估对于制定复张手法和设置呼气末正压（PEEP）可能很重要。

目的

通过呼吸力学和 CT 来确定肺可复张性的测量值是否具有可比性。

方法

在 22 例 ARDS 患者中，通过使用基于呼吸力学的方法（1）两条压力-容积曲线（P-Vrs 曲线）之间的容积增加；（2）根据预计呼气末肺容积和呼吸系统静态顺应性（EELV-Cst，rs）测量和预测的容积增加，在 5 和 15 cm H2O PEEP 下评估肺复张：以及 CT 扫描（3）非充气性肺组织（CT [不充气]）减少；（4）非充气性和充气不良组织（CT [不充气+不良充气]）减少。

测量和主要结果

P-Vrs 曲线募集量明显高于 EELV-Cst，rs 募集量（423 ± 223 ml 比 315 ± 201 ml；P < 0.001），但这两种测量方法具有显著相关性（R（2）= 0.93；P < 0.001）。CT（不充气）募集量为 77 ± 86 g，CT（不充气+不良充气）为 80 ± 67 g（P = 0.856），这两种测量方法也具有显著相关性（R（2）= 0.20；P = 0.04）。呼吸力学测量的募集量为 5 cm H2O PEEP 时的气体量的 54 ± 28%（P-Vrs 曲线）和 39 ± 25%（EELV-Cst，rs）。CT 扫描测量的募集量为肺组织的 5 ± 5%（CT [不充气]）和 6 ± 6%（CT [不充气+不良充气]）。

结论

呼吸力学和 CT 测量（在相同术语下，“募集”）两种不同的实体。基于呼吸力学的方法包括在更高 PEEP 时进入已经开放的肺单位的气体，从而改善其机械特性。因此，它们可用于评估充气的整体改善。CT 扫描测量充气恢复的塌陷组织量。在 www.clinicaltrials.gov （NCT00759590）上进行了临床试验注册。