反复的肺不张会加重机械通气期间的肺损伤。

Repeated derecruitments accentuate lung injury during mechanical ventilation.

作者信息

Suh Gee Young, Koh Youngmin, Chung Man Pyo, An Chang Hyeok, Kim Hojoong, Jang Woo Young, Han Jungho, Kwon O Jung

机构信息

Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Seoul, Korea.

出版信息

Crit Care Med. 2002 Aug;30(8):1848-53. doi: 10.1097/00003246-200208000-00029.

DOI:10.1097/00003246-200208000-00029

PMID:12163804

Abstract

OBJECTIVE

This study was performed to test the hypothesis that derecruitment itself might accentuate lung injury during mechanical ventilation.

SETTING

Randomized, controlled trial.

SETTING

Experimental laboratory.

SUBJECTS

New Zealand White rabbits (2.8-3.5 kg).

INTERVENTION

Twenty-four rabbits were ventilated in pressure-controlled mode with constant tidal volume (10 mL/kg). After lung injury was induced by repeated saline lavage (PaO2 <100 torr, 13.3 kPa), a pressure-volume curve was drawn to calculate the lower inflection point (Pflex), and randomization was done. The control group (n = 8) received ventilation with positive end-expiratory pressure (PEEP) fixed at Pflex for 3 hrs. The nonderecruitment group (n = 8) was ventilated at PEEP of 2 mm Hg (2.7 cm H2O) for the initial hour and then PEEP of Pflex for the remaining 2 hrs. The derecruitment group (n = 8) was ventilated for 3 hrs with six 30-min cycles consisting of 10 mins at PEEP of 2 mm Hg (2.7 cm H2O) and 20 mins at PEEP of Pflex to induce repeated derecruitments.

MEASUREMENTS AND MAIN RESULTS

Variables of gas exchange, mechanics, and hemodynamics were measured, and histologic evaluation was done. In the control group, Pao2 remained >500 torr (66.7 kPa) for 3 hrs. In the nonderecruitment group, PaO2 was 40 +/- 16 (mean +/- SD) torr (5.3 +/- 2.1 kPa) at 1 hr but increased to >500 torr (66.7 kPa) for the remaining 2 hrs after increase in PEEP to Pflex. In the derecruitment group, there was progressive decline in Pao2 with each derecruitment to 220 +/- 130 torr (29.3 +/- 17.3 kPa) at 3 hrs (p <.05 compared with other groups). Histologically there was more hyaline membrane formation in the derecruitment group compared with control (p <.05) and significantly higher mean bronchiolar injury score in the derecruitment group (1.92 +/- 0.78) than both control (0.50 +/- 0.50) and nonderecruitment (0.78 +/- 0.42) groups (p <.05).

CONCLUSION

Repeated derecruitments can accentuate lung injury during mechanical ventilation.

摘要

目的

本研究旨在验证机械通气期间肺复张不全本身可能会加重肺损伤这一假说。

设置

随机对照试验。

地点

实验实验室。

研究对象

新西兰白兔（体重2.8 - 3.5千克）。

干预措施

24只兔子采用压力控制模式通气，潮气量恒定（10毫升/千克）。在通过反复生理盐水灌洗诱导肺损伤（动脉血氧分压<100托，13.3千帕）后，绘制压力-容积曲线以计算下拐点（Pflex），然后进行随机分组。对照组（n = 8）以固定在Pflex的呼气末正压（PEEP）通气3小时。非复张不全组（n = 8）最初1小时以2毫米汞柱（2.7厘米水柱）的PEEP通气，随后2小时以Pflex的PEEP通气。复张不全组（n = 8）通气3小时，包括6个30分钟的周期，即2毫米汞柱（2.7厘米水柱）的PEEP通气10分钟，然后以Pflex的PEEP通气20分钟，以诱导反复的肺复张不全。

测量指标及主要结果

测量气体交换、力学和血流动力学变量，并进行组织学评估。对照组动脉血氧分压在3小时内保持>500托（66.7千帕）。非复张不全组在1小时时动脉血氧分压为40±16（均值±标准差）托（5.3±2.1千帕），但在将PEEP增加到Pflex后，剩余2小时内升至>500托（66.7千帕）。复张不全组在每次肺复张不全时动脉血氧分压逐渐下降，3小时时降至220±130托（29.3±17.3千帕）（与其他组相比，p<.05）。组织学上，复张不全组与对照组相比有更多的透明膜形成（p<.05），且复张不全组的平均细支气管损伤评分（1.92±0.78）显著高于对照组（0.50±0.50）和非复张不全组（0.78±0.42）（p<.05）。