Mayock D E, Badura R J, Watchko J F, Standaert T A, Woodrum D E
Pediatr Res. 1987 Feb;21(2):121-5. doi: 10.1203/00006450-198702000-00003.
The diaphragmatic force generation and electromyographic response to long-term (1 h) inspiratory resistive loading was examined in the newborn piglet during the 3rd postnatal wk of life. Minute ventilation decreased to approximately 50% of baseline level within 5 min of imposition of a severe resistive load and remained at this level for the duration of loading. The decrease in ventilation was secondary to a fall in tidal volume at a constant frequency. There was a significant increase in central nervous system output to the diaphragm as manifested by integrated diaphragmatic electromyogram. Progressive augmentation of this index of central drive continued throughout the period of loading. Functional residual capacity fell significantly by 60 min of inspiratory resistive loading. This strategy should allow greater force generation by placing the diaphragm at a more optimal length-tension relationship. However, the force generating capability of the diaphragm was compromised as assessed by force-frequency curve analysis. These results suggest that the diaphragm of the neonatal piglet fatigues during prolonged inspiratory resistive loading.
在新生仔猪出生后第3周的生命期内，研究了其膈肌力量产生以及对长期（1小时）吸气阻力负荷的肌电图反应。在施加严重阻力负荷后5分钟内，分钟通气量降至基线水平的约50%，并在负荷持续期间维持在该水平。通气量的下降是由于在恒定频率下潮气量的减少。通过整合膈肌肌电图显示，中枢神经系统对膈肌的输出显著增加。在整个负荷期间，这种中枢驱动指标持续进行性增强。吸气阻力负荷60分钟时，功能残气量显著下降。这种策略应通过使膈肌处于更优化的长度-张力关系来允许产生更大的力量。然而，通过力量-频率曲线分析评估，膈肌的力量产生能力受到损害。这些结果表明，新生仔猪的膈肌在长时间吸气阻力负荷期间会疲劳。
