吸气末和呼气末压力对盐水冲洗诱导的肺损伤中肺泡复张和萎陷的影响——一项计算机断层扫描研究

Effects of end-inspiratory and end-expiratory pressures on alveolar recruitment and derecruitment in saline-washout-induced lung injury -- a computed tomography study.

作者信息

Luecke T, Roth H, Joachim A, Herrmann P, Deventer B, Weisser G, Pelosi P, Quintel M

机构信息

Department of Anesthesiology and Intensive Care, University Hospital of Mannheim, Faculty of Clinical Medicine, University of Heidelberg, Germany.

出版信息

Acta Anaesthesiol Scand. 2004 Jan;48(1):82-92. doi: 10.1111/j.1399-6576.2004.00265.x.

DOI:10.1111/j.1399-6576.2004.00265.x

PMID:14674978

Abstract

BACKGROUND

Lung protective ventilation using low end-inspiratory pressures and tidal volumes (VT) has been shown to impair alveolar recruitment and to promote derecruitment in acute lung injury. The aim of the present study was to compare the effects of two different end-inspiratory pressure levels on alveolar recruitment, alveolar derecruitment and potential overdistention at incremental levels of positive end-expiratory pressure.

METHODS

Sixteen adult sheep were randomized to be ventilated with a peak inspiratory pressure of either 35 cm H2O (P35, low VT) or 45 cm H2O (P45, high VT) after saline washout-induced lung injury. Positive end-expiratory pressure (PEEP) was increased in a stepwise manner from zero (ZEEP) to 7, 14 and 21 cm of H2O in hourly intervals. Tidal volume, initially set to 12 ml kg(-1), was reduced according to the pressure limits. Computed tomographic scans during end-expiratory and end-inspiratory hold were performed along with hemodynamic and respiratory measurements at each level of PEEP.

RESULTS

Tidal volumes for the two groups (P35/P45) were: 7.7 +/- 0.9/11.2 +/- 1.3 ml kg(-1) (ZEEP), 7.9 +/- 2.1/11.3 +/- 1.3 ml kg(-1) (PEEP 7 cm H2O), 8.3 +/- 2.5/11.6 +/- 1.4 ml kg(-1) (PEEP 14 cm H2O) and 6.5 +/- 1.7/11.0 +/- 1.6 ml kg(-1) (PEEP 21 cm H2O); P < 0.001 for differences between the two groups. Absolute nonaerated lung volumes during end-expiration and end-inspiration showed no difference between the two groups for given levels of PEEP, while tidal-induced changes in nonaerated lung volume (termed cyclic alveolar instability, CAI) were larger in the P45 group at low levels of PEEP. The decrease in nonaerated lung volume was significant for PEEP 14 and 21 cm H2O in both groups compared with ZEEP (P < 0.005). Over-inflated lung volumes, although small, were significantly higher in the P45 group. Significant respiratory acidosis was noted in the P35 group despite increases in the respiratory rate.

CONCLUSION

Limiting peak inspiratory pressure and VT does not impair alveolar recruitment or promote derecruitment when using sufficient levels of PEEP.

摘要

背景

已表明在急性肺损伤中，采用低吸气末压力和潮气量（VT）的肺保护性通气会损害肺泡复张，并促进肺泡萎陷。本研究的目的是比较两种不同吸气末压力水平在呼气末正压递增水平时对肺泡复张、肺泡萎陷和潜在过度膨胀的影响。

方法

16只成年绵羊在生理盐水冲洗诱导的肺损伤后，随机分为两组，分别接受35 cm H₂O（P35，低潮气量）或45 cm H₂O（P45，高潮气量）的吸气峰压通气。呼气末正压（PEEP）以每小时一档的方式从零（ZEEP）逐步增加至7、14和21 cm H₂O。潮气量最初设定为12 ml·kg⁻¹，根据压力限制进行调整。在每个PEEP水平进行呼气末和吸气末屏气时的计算机断层扫描以及血流动力学和呼吸测量。

结果

两组（P35/P45）的潮气量分别为：7.7±0.9/11.2±1.3 ml·kg⁻¹（ZEEP），7.9±2.1/11.3±1.3 ml·kg⁻¹（PEEP 7 cm H₂O），8.3±2.5/11.6±1.4 ml·kg⁻¹（PEEP 14 cm H₂O）和6.5±1.7/11.0±1.6 ml·kg⁻¹（PEEP 21 cm H₂O）；两组间差异P<0.001。在给定的PEEP水平下，呼气末和吸气末时两组的绝对未通气肺容积无差异，而在低PEEP水平时，P45组中潮气量诱导的未通气肺容积变化（称为周期性肺泡不稳定，CAI）更大。与ZEEP相比，两组在PEEP为14和21 cm H₂O时未通气肺容积的减少均有统计学意义（P<0.005）。P组45的过度膨胀肺容积虽小，但显著更高。尽管呼吸频率增加，但P35组仍出现明显的呼吸性酸中毒。