Wildhaber J H, Uhlig T, Sly P D
Department of Respiratory Medicine, Princess Margaret Hospital for Children, Perth, Western Australia.
Pediatr Pulmonol. 1998 Jan;25(1):45-51. doi: 10.1002/(sici)1099-0496(199801)25:1<45::aid-ppul5>3.0.co;2-n.
The aim of our study was to determine the effects of pulmonary vascular engorgement on airways and pulmonary tissues in juvenile animals before and after methacholine (Mch)-induced changes in lung function. Five anesthetized, paralyzed, and thoracotomized piglets were studied before and during pulmonary vascular engorgement, induced by inflating a left atrial balloon catheter and by calculating respiratory mechanics from measurements of airway opening (Pao) and alveolar pressures (PA), respiratory flow (V'), and volume (V) recorded during mechanical ventilation, using the multilinear regression technique. A maximal increase of 15 mmHg in pulmonary artery pressure (Ppa) resulted in a mean increase in total lung elastance (EL) of 28.6% and in total lung resistance (RL) of 14.9%. Mch increased EL by 21.7% and RL by 29.0%. Inflation of the left atrial balloon with an associated increase in Ppa by 15 mmHg in the presence of Mch resulted in an increase in EL by a further 12.4% (to 135.4% of baseline) and in RL by a further 9.0% (to 139.5% of baseline). The change in RL was associated with a qualitatively similar change in both tissue resistance (Vti) and airway resistance (Raw) before and after Mch-induced changes in lung function. We conclude that increasing pulmonary vascular pressures, by increasing left partial pressure, alters lung function in juvenile animals by altering the mechanical properties of both airways and lung tissues. The methods used in the present study allow a direct assessment of the site of action of vascular engorgement in the lungs and provide a useful model for studying this phenomenon further.
我们研究的目的是确定在乙酰甲胆碱（Mch）诱导肺功能变化前后，肺血管充血对幼年动物气道和肺组织的影响。对五只麻醉、麻痹并开胸的仔猪在肺血管充血前及充血期间进行了研究，通过向左心房插入球囊导管使肺血管充血，并利用多线性回归技术，根据机械通气期间记录的气道开口压力（Pao）、肺泡压力（PA）、呼吸流量（V'）和容积（V）测量值来计算呼吸力学。肺动脉压（Ppa）最大增加15 mmHg导致总肺弹性（EL）平均增加28.6%，总肺阻力（RL）平均增加14.9%。Mch使EL增加21.7%，RL增加29.0%。在存在Mch的情况下，左心房球囊充气使Ppa进一步增加15 mmHg，导致EL进一步增加12.4%（达到基线的135.4%），RL进一步增加9.0%（达到基线的139.5%）。在Mch诱导肺功能变化前后，RL的变化与组织阻力（Vti）和气道阻力（Raw）的定性相似变化相关。我们得出结论，通过增加左心房压力来增加肺血管压力，会通过改变气道和肺组织的力学特性来改变幼年动物的肺功能。本研究中使用的方法能够直接评估肺血管充血的作用部位，并为进一步研究这一现象提供了一个有用的模型。
