Fitting J W, Easton P A, Grassino A E
J Appl Physiol (1985). 1986 Feb;60(2):670-7. doi: 10.1152/jappl.1986.60.2.670.
Respiratory muscle length was measured with sonomicrometry to determine the relation between inspiratory flow and velocity of shortening of the external intercostal and diaphragm. Electromyographic (EMG) activity and tidal shortening of the costal and crural segments of the diaphragm and of the external intercostal were recorded during hyperoxic CO2 rebreathing in 12 anesthetized dogs. We observed a linear increase of EMG activity and peak tidal shortening of costal and crural diaphragm with alveolar CO2 partial pressure. For the external intercostal, no consistent pattern was found either in EMG activity or in tidal shortening. Mean inspiratory flow was linearly related to mean velocity of shortening of costal and crural diaphragm, with no difference between the two segments. Considerable shortening occurred in costal and crural diaphragm during inspiratory efforts against occlusion. We conclude that the relation between mean inspiratory flow and mean velocity of shortening of costal and crural diaphragm is linear and can be altered by an inspiratory load. There does not appear to be a relationship between inspiratory flow and velocity of shortening of external intercostals.
采用超声测量法测量呼吸肌长度，以确定吸气流量与肋间外肌和膈肌缩短速度之间的关系。在12只麻醉犬进行高氧二氧化碳再呼吸期间，记录膈肌肋部和脚段以及肋间外肌的肌电图（EMG）活动和潮气量缩短情况。我们观察到，随着肺泡二氧化碳分压升高，膈肌肋部和脚段的EMG活动及潮气量峰值缩短呈线性增加。对于肋间外肌，无论是EMG活动还是潮气量缩短，均未发现一致的模式。平均吸气流量与膈肌肋部和脚段的平均缩短速度呈线性相关，两段之间无差异。在对抗阻塞的吸气努力过程中，膈肌肋部和脚段出现了明显的缩短。我们得出结论，平均吸气流量与膈肌肋部和脚段的平均缩短速度之间的关系是线性的，并且可以通过吸气负荷改变。吸气流量与肋间外肌缩短速度之间似乎没有关系。
