肺复张策略救治急性肺损伤幼猪的实验研究

Recruitment maneuver in the treatment of young piglets with acute lung injury

摘要:

目的：通过急性肺损伤（ALI）幼猪模型，研究肺复张策略（RM）的可行性和有效性，并探讨其对损伤后肺组织修复的影响。方法：健康幼猪12只，注射内毒素（LPS）成模后，随机分为常规潮气量通气组（CON组）和小潮气量联合RM通气组（RM组），观察8 h，动态监测血液动力学、肺动态顺应性及血气分析指标，测定血浆、肺泡灌洗液中转化生长因子（TGF-β1）浓度，实时荧光定量PCR法检测TGF-β1在肺组织中的mRNA表达水平，并观察肺组织的病理学改变。结果：两组幼猪的心输出量和外周血管阻力指标差异无统计学意义；而RM组的血管外肺水指数在成模6 h以后，肺血管通透性指数于成模8 h时均较CON组明显下降（P＜0.05）；RM组的肺动态顺应性明显高于同时间点的CON组（P＜0.05）；RM组PaO2/FiO2值于成模2 h后明显高于CON组，而且RM组的肺泡-动脉氧分压差在成模2 h后即明显下降（P＜0.05）；RM组血浆、肺泡灌洗液中TGF-β1浓度及其在肺组织中的mRNA表达水平均低于相应CON组；RM组的肺泡扩张度明显高于CON组，而肺损伤评分明显下降（P＜0.05）。结论：RM可以改善ALI幼猪的气体交换和肺动态顺应性，且安全有效，能够扩张肺泡并减轻肺损伤程度，有助于改善损伤后的肺修复过程。

Abstract:

OBJECTIVE: To study the feasibility, efficiency and any benefits of recruitment maneuver (RM) in the facilitation of lung repair during recovery from ALI in acute lung injury (ALI) model of young piglets. METHODS: The piglet model of ALI was established by an intravenous injection of lipopolysaccharide (LPS). Twelve ALI piglets were randomly divided into two groups: conventional ventilation (CON) and RM with low tidal volume. Arterial blood gas, dynamic lung compliance (Cdyn) and systematic hemodynamics were monitored during the treatment. TGF-β1 levels in bronchoalveolar lavage fluid (BALF) and plasma were measured. The mRNA expression of TGF-β1 in the lungs was assessed by real time PCR. Lung tissue was examined for morphological changes. RESULTS: No significant difference was observed in cardiac output and peripheral vascular resistance (PVR) between the two groups. The extravascular lung water index (ELWI) from 6 hrs after ALI inducement and the pulmonary vascular permeability index (PVPI) 8 hrs after ALI inducement in the RM group decreased significantly compared with the CON group. Cdyn in the RM group increased quickly 1 hr after ALI inducement, and there was a significant difference between the two groups (P<0.05). P/F (ratio of PaO2 to FiO2) in the RM group was significantly higher than in the CON group from 2 hrs after ALI inducement (P<0.05). Alveolar-to-arterial oxygen difference in the RM group was obviously lower compared with the CON group from 2 hrs after ALI inducement (P<0.05). The levels of TGF-β1 in plasma and BALF and the mRNA expression of TGF-β1 in the lung tissue were lower than in the CON group. Volume density of alveolar aeration in the RM group was significantly higher than in the CON group, and the injury score in the RM group was lower (P<0.05). CONCLUSIONS: RM can improve gas exchange and Cdyn in the treatment of piglets with ALI. RM is a safe and effective approach to alveolar recruitment and can alleviate ventilation induced lung injury.