Romand J A, Donald F A, Suter P M
Department of Anesthesiology, University Hospital of Geneva, Switzerland.
New Horiz. 1994 Nov;2(4):457-62.
Development of acute lung injury (ALI) in the critically ill is associated with an array of abnormal interactions between the heart and lungs. Of these abnormalities, increased pulmonary vascular resistance (PVR) is common and seems to indicate a worse prognosis than when PVR is normal. Increased pulmonary artery pressure, which follows ALI in humans, has been attributed to many factors. Early in ALI, pulmonary artery hypertension (PAH) is secondary to an imbalance between the release of vasoactive mediators derived from arachidonic acid, endothelium-derived relaxing factor, and other metabolites. As ALI progresses, the combination of mechanical obstruction and severe regional hypoxic pulmonary artery vasoconstriction probably becomes the main factor responsible for PAH. In addition to these elements, in situ and peripherally derived thromboemboli can be seen in ALI, owing to diverse disturbances in the coagulation and fibrinolytic processes. The result is increased workload of the right ventricle which is caused by increased afterload and may induce hemodynamic disturbances that culminate in overt right ventricular failure. However, epidemiologic studies have demonstrated that death following ALI is more often the result of respiratory failure or sepsis. The absence of effective therapy for PAH in ALI might be explained by the pathophysiological and clinical course of the disease. A reasonable conclusion from the contributing elements cited above is that PAH complicating sepsis and trauma is simply a marker of the gravity of the systemic insult that leads to the development of ALI and probably not a separate process.
危重症患者急性肺损伤（ALI）的发生与心肺之间一系列异常相互作用有关。在这些异常情况中，肺血管阻力（PVR）增加很常见，而且与PVR正常时相比，似乎预示着更差的预后。人类发生ALI后出现的肺动脉压力升高，可归因于多种因素。在ALI早期，肺动脉高压（PAH）继发于源自花生四烯酸的血管活性介质、内皮源性舒张因子及其他代谢产物释放之间的失衡。随着ALI进展，机械性梗阻和严重的局部低氧性肺动脉收缩相结合可能成为PAH的主要成因。除了这些因素外，由于凝血和纤溶过程的多种紊乱，在ALI中还可见原位及外周来源的血栓栓塞。其结果是右心室工作负荷增加，这是由后负荷增加引起的，可能会诱发血流动力学紊乱，最终导致明显的右心室衰竭。然而，流行病学研究表明，ALI后的死亡更多是呼吸衰竭或脓毒症所致。ALI中PAH缺乏有效治疗方法，可能可以用该疾病的病理生理和临床病程来解释。从上述相关因素得出的一个合理结论是，脓毒症和创伤并发的PAH仅仅是导致ALI发生的全身性损伤严重程度的一个标志，可能并非一个独立的过程。
