Blanch L, Roussos C, Brotherton S, Michel R P, Angle M R
Critical Care Division, Royal Victoria Hospital, Montreal, Quebec, Canada.
J Appl Physiol (1985). 1992 Jul;73(1):108-16. doi: 10.1152/jappl.1992.73.1.108.
We examined the effects of positive end-expiratory pressure (PEEP) and tidal volume on the distribution of ventilation and perfusion in a canine model of asymmetric lung injury. Unilateral right lung edema was established in 10 animals by use of a selective infusion of ethchlorvynol. Five animals were tested in the supine position (horizontal asymmetry) and five in the right decubitus position (vertical asymmetry). Raising PEEP from 5 to 12 cmH2O improved oxygenation despite a redistribution of blood flow toward the damage lung and a consistent decrease in total respiratory system compliance. This improvement paralleled a redistribution of tidal ventilation to the injured lung. This was effected primarily by a fall in the compliance of the noninjured lung due to hyperinflation. The effects of higher tidal volume were additive to those of PEEP. We propose that the major effect of PEEP in inhomogeneous lung injury is to restore tidal ventilation to a population of alveoli recruitable only at high airway pressures.
我们在犬类非对称性肺损伤模型中研究了呼气末正压（PEEP）和潮气量对通气和灌注分布的影响。通过选择性输注ethchlorvynol在10只动物中建立单侧右肺水肿。5只动物处于仰卧位（水平不对称）进行测试，5只处于右侧卧位（垂直不对称）。将PEEP从5 cmH₂O提高到12 cmH₂O可改善氧合，尽管血流重新分布至损伤肺且总呼吸系统顺应性持续下降。这种改善与潮气量重新分布至损伤肺平行。这主要是由于非损伤肺因过度充气导致顺应性下降所致。较高潮气量的影响与PEEP的影响具有叠加性。我们提出，PEEP在不均匀性肺损伤中的主要作用是将潮气量恢复至仅在高气道压力下才可复张的肺泡群。
