Interaction between the canine diaphragm and intercostal muscles in lung expansion
Interaction between the canine diaphragm and intercostal muscles in lung expansion
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DOI：
10.1152/japplphysiol.00632.2004
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发表时间：
2005-03-01
影响因子：
3.3
通讯作者：
De Troyer, A
中科院分区：
文献类型：
--
作者：
De Troyer, A
由吸气肋间肌引起的胸内压变化基本上是加性的，但这些肌肉与横膈膜之间的相互作用仍不确定。在本研究中，通过测量气道开放的变化来评估这种相互作用（DeltaPao）或经颅压（DeltaPtp）在迷走神经切断、膈神经切断的犬中自发吸气期间（孤立肋间收缩），在孤立矩形或斜坡刺激横断C-5膈神经根的外周端期间（单独的膈肌收缩）和在自发吸气期间叠加膈神经刺激（膈肌-肋间收缩组合）。在功能性残余容量下阻塞气管内导管时，在联合肌肉-肋间收缩期间的DeltaPao几乎等于由两个肌肉群单独收缩产生的DeltaPao的总和。而气管内管开放时，联合收缩时的DeltaPtp为单独DeltaPtp之和的123%（P < 0.001）。联合收缩时肺容积的增加量也是单个肺容积增加量之和的109%（P < 0.02）。腹压在联合收缩总是低于在单独的膈肌收缩。它的结论是，因此，犬膈肌和肋间肌在肺扩张过程中协同作用，这种协同作用主要是由于这样的事实，即肋间肌减少缩短的隔膜。然而，当肺维持在功能性残余容量时，协同作用被掩盖，因为在横膈膜收缩期间胸腔的更大刚度增强了由分离的横膈膜产生的DeltaPao，并且减少了由肋间肌肉产生的DeltaPao。
Changes in intrathoracic pressure produced by the various inspiratory intercostals are essentially additive, but the interaction between these muscles and the diaphragm remains uncertain. In the present study, this interaction was assessed by measuring the changes in airway opening (DeltaPao) or transpulmonary pressure (DeltaPtp) in vagotomized, phrenicotomized dogs during spontaneous inspiration ( isolated intercostal contraction), during isolated rectangular or ramp stimulation of the peripheral ends of the transected C-5 phrenic nerve roots ( isolated diaphragm contraction), and during spontaneous inspiration with superimposed phrenic nerve stimulation ( combined diaphragm-intercostal contraction). With the endotracheal tube occluded at functional residual capacity, DeltaPao during combined diaphragm-intercostal contraction was nearly equal to the sum of the DeltaPao produced by the two muscle groups contracting individually. However, when the endotracheal tube was kept open, DeltaPtp during combined contraction was 123% of the sum of the individual DeltaPtp ( P < 0.001). The increase in lung volume during combined contraction was also 109% of the sum of the individual volume increases ( P < 0.02). Abdominal pressure during combined contraction was invariably lower than during isolated diaphragm contraction. It is concluded, therefore, that the canine diaphragm and intercostal muscles act synergistically during lung expansion and that this synergism is primarily due to the fact that the intercostal muscles reduce shortening of the diaphragm. When the lung is maintained at functional residual capacity, however, the synergism is obscured because the greater stiffness of the rib cage during diaphragm contraction enhances the DeltaPao produced by the isolated diaphragm and reduces the DeltaPao produced by the intercostal muscles.