Murray J F
J Appl Physiol Respir Environ Exerc Physiol. 1978 Sep;45(3):442-50. doi: 10.1152/jappl.1978.45.3.442.
The effects of lung inflation from positive airway pressure (Paw) on pulmonary arterial pressure (Ppa) and the slope deltaPpa/deltaPaw were studied in normal dogs and dogs with pulmonary edema. Under base-line zone 2 conditions with the lungs perfused at constant flow (100 ml/kg per min) and vascular pressures measured relative to pleural (atmospheric) pressure, the slope deltaPpa/deltaPaw was nearly one (at Paw greater than or equal to 5 cmH2O). Pulmonary edema from high capillary pressure and oleic acid caused deltaPpa/deltaPaw and Ppa to decrease at high lung volumes and Ppa to increase at low lung volumes. These changes were not simulated by vasoactive drugs (adenosine and norepinephrine) but were reproduced by instilling dextran into the lungs and, in part, by occluding the right intermediate bronchus. In pulmonary edema the increased Ppa at low lung volumes is caused by the effects of decreases in the caliber of extra-alveolar vessels, by trapped air or liquid raising alveolar pressure, or by both; the decreased deltaPpa/deltaPaw and Ppa at high volumes is caused mainly by nonuniform distribution of driving pressures and blood flow.
在正常犬和患有肺水肿的犬中，研究了气道正压（Paw）引起的肺膨胀对肺动脉压（Ppa）以及斜率deltaPpa/deltaPaw的影响。在基线区域2条件下，以恒定流量（100 ml/kg每分钟）灌注肺，并相对于胸膜（大气）压力测量血管压力，斜率deltaPpa/deltaPaw接近1（Paw大于或等于5 cmH2O时）。高毛细血管压力和油酸引起的肺水肿导致在高肺容积时deltaPpa/deltaPaw和Ppa降低，而在低肺容积时Ppa升高。血管活性药物（腺苷和去甲肾上腺素）无法模拟这些变化，但向肺内注入右旋糖酐可重现这些变化，部分原因是通过阻塞右中间支气管。在肺水肿中，低肺容积时Ppa升高是由于肺泡外血管管径减小、被困空气或液体升高肺泡压力的影响，或两者共同作用所致；高容积时deltaPpa/deltaPaw和Ppa降低主要是由于驱动压力和血流分布不均所致。
