Derksen F J, Robinson N E
Am J Vet Res. 1980 Nov;41(11):1756-61.
Pleural and esophageal pressures were compared in 6 standing sedated ponies. Pleural pressure was measured with blunt needles attached to transducers and inserted in the 10th intercostal space level with and 10 and 20 cm above the point of the shoulder. Two balloons (a condom and an esophageal balloon) attached to transducers measured esophageal pressure in the cranial, middle, and caudal portions of the thoracic part of the esophagus. Tidal volume was measured by integrating a flow signal derived from a pneumotachograph attached to an endotracheal tube inserted through a tracheostomy. Frequency responses of all measuring systems were matched. Frequency responses of all measuring systems were matched. The change in pleural pressure during respiration was greatest in the middle and ventral portions of the thorax, less in the dorsal portion of the thorax and in the middle and caudal portions of the thoracic part of the esophagus, and least in the cranial portion of the thoracic part of the esophagus. The type of esophageal balloon had no effect on the measured pressure change. Regional variations in esophageal or pleural pressure during breathing caused variations in the calculated dynamic compliance. Pleural pressure gradients of 0.33 cm of water/cm of descent and 0.484 cm of water/cm of descent were recorded in the dorsal and ventral halves of the thorax, respectively, and may result in regional variations in lung inflation similar to those observed in persons.
对6匹站立镇静的小马的胸膜压力和食管压力进行了比较。胸膜压力通过连接到换能器的钝针测量，并插入第10肋间水平以及肩部上方10厘米和20厘米处。两个连接到换能器的球囊（一个避孕套和一个食管球囊）测量食管胸部的头端、中部和尾端部分的食管压力。潮气量通过对来自连接到经气管切开术插入的气管内导管的呼吸速度描记器的流量信号进行积分来测量。所有测量系统的频率响应均匹配。呼吸过程中胸膜压力的变化在胸部的中部和腹侧部分最大，在胸部的背侧部分以及食管胸部的中部和尾端部分较小，而在食管胸部的头端部分最小。食管球囊的类型对测量的压力变化没有影响。呼吸过程中食管或胸膜压力的区域差异导致计算出的动态顺应性发生变化。在胸部的背侧和腹侧半部分别记录到0.33厘米水柱/厘米下降和0.484厘米水柱/厘米下降的胸膜压力梯度，这可能导致肺部充气的区域差异，类似于在人类中观察到的情况。
