Kimball W R, Loring S H, Basta S J, De Troyer A, Mead J
J Appl Physiol (1985). 1985 May;58(5):1638-45. doi: 10.1152/jappl.1985.58.5.1638.
The influence of tonic inspiratory muscle activity on the relaxation characteristics of the chest wall, rib cage (RC), and abdominal wall (ABW) has been investigated in four highly trained subjects. Chest wall shape and volume were estimated with magnetometers. Pleural pressure (Pes) and abdominal pressure were measured with esophageal and gastric balloons, respectively. Subjects were seated reclining 30 degrees from upright, and respiratory muscle weakness was produced by pancuronium bromide until RC inspiratory capacity was decreased to 60% of control. Only minor changes were observed for Konno-Mead relaxation characteristics (RC vs. ABW) between control and paralysis. Similarly, although RC relaxation curves (RC vs. Pes) during paralysis were significantly different from control (P less than 0.05), the changes were small and not consistent. The differences between paralysis-induced changes in resting end-expiratory position of the chest wall and helium-dilution functional residual capacity (FRC) suggested changes in volume of blood within the chest wall. We conclude that 1) although tonic inspiratory activity of chest wall muscles exists, it does not significantly affect the chest wall relaxation characteristics in trained subjects; 2) submaximal paralysis produced by pancuronium bromide is likely to modify either spinal attitude or the distribution of blood between extremities and the thorax; these effects may account for the changes in FRC in other studies.
在四名训练有素的受试者中，研究了吸气肌紧张性活动对胸壁、胸廓（RC）和腹壁（ABW）松弛特性的影响。使用磁力计估计胸壁形状和容积。分别用食管气囊和胃气囊测量胸膜压力（Pes）和腹压。受试者以与直立位成30度角的姿势斜靠就座，并用潘库溴铵诱发呼吸肌无力，直至RC吸气容量降至对照值的60%。在对照和麻痹状态之间，Konno-Mead松弛特性（RC与ABW）仅观察到微小变化。同样，虽然麻痹期间的RC松弛曲线（RC与Pes）与对照有显著差异（P<0.05），但变化很小且不一致。胸壁静息呼气末位置的麻痹诱导变化与氦稀释功能残气量（FRC）之间的差异表明胸壁内血容量发生了变化。我们得出结论：1）虽然胸壁肌肉存在吸气紧张性活动，但在训练有素的受试者中，它不会显著影响胸壁松弛特性；2）潘库溴铵产生的次最大麻痹可能会改变脊柱姿势或肢体与胸部之间的血液分布；这些效应可能解释了其他研究中FRC的变化。
