Regional Trauma Services, Foothills Medical Centre, 1403 29 Street NW, Calgary, Alberta, Canada.
Crit Care. 2010;14(4):232. doi: 10.1186/cc9099. Epub 2010 Aug 27.
Prone ventilation (PV) is a ventilatory strategy that frequently improves oxygenation and lung mechanics in critical illness, yet does not consistently improve survival. While the exact physiologic mechanisms related to these benefits remain unproven, one major theoretical mechanism relates to reducing the abdominal encroachment upon the lungs. Concurrent to this experience is increasing recognition of the ubiquitous role of intra-abdominal hypertension (IAH) in critical illness, of the relationship between IAH and intra-abdominal volume or thus the compliance of the abdominal wall, and of the potential difference in the abdominal influences between the extrapulmonary and pulmonary forms of acute respiratory distress syndrome. The present paper reviews reported data concerning intra-abdominal pressure (IAP) in association with the use of PV to explore the potential influence of IAH. While early authors stressed the importance of gravitationally unloading the abdominal cavity to unencumber the lung bases, this admonition has not been consistently acknowledged when PV has been utilized. Basic data required to understand the role of IAP/IAH in the physiology of PV have generally not been collected and/or reported. No randomized controlled trials or meta-analyses considered IAH in design or outcome. While the act of proning itself has a variable reported effect on IAP, abundant clinical and laboratory data confirm that the thoracoabdominal cavities are intimately linked and that IAH is consistently transmitted across the diaphragm--although the transmission ratio is variable and is possibly related to the compliance of the abdominal wall. Any proning-related intervention that secondarily influences IAP/IAH is likely to greatly influence respiratory mechanics and outcomes. Further study of the role of IAP/IAH in the physiology and outcomes of PV in hypoxemic respiratory failure is thus required. Theories relating inter-relations between prone positioning and the abdominal condition are presented to aid in designing these studies.
俯卧位通气（PV）是一种在危重病中经常改善氧合和肺力学的通气策略，但并不总能提高生存率。虽然与这些益处相关的确切生理机制尚未得到证实，但一个主要的理论机制与减少腹部对肺部的侵犯有关。与此同时，人们越来越认识到腹腔内高压（IAH）在危重病中的普遍作用，IAH 与腹腔内容量或因此腹壁顺应性之间的关系，以及在急性呼吸窘迫综合征的肺外和肺内形式之间腹部影响的潜在差异。本文回顾了与使用 PV 相关的报告数据，以探讨 IAH 的潜在影响。虽然早期作者强调了将重力从腹部腔卸载以释放肺基底的重要性，但当使用 PV 时，这一警告并没有得到一致的认可。为了理解 IAP/IAH 在 PV 生理学中的作用而需要的基本数据通常没有被收集和/或报告。没有随机对照试验或荟萃分析考虑到 IAH 在设计或结果中的作用。虽然俯卧位本身对 IAP 的影响具有可变的报告，但大量的临床和实验室数据证实，胸腹腔是紧密相连的，IAH 始终通过横膈膜传递——尽管传递比例是可变的，并且可能与腹壁的顺应性有关。任何与俯卧位相关的干预措施，如果对 IAP/IAH 有次要影响，很可能会极大地影响呼吸力学和结果。因此，需要进一步研究 IAP/IAH 在低氧性呼吸衰竭中 PV 的生理学和结果中的作用。提出了与俯卧位定位和腹部状况之间相互关系相关的理论，以帮助设计这些研究。
