Diaz C E, Deoras K S, Allen J L
Department of Pediatrics, Temple University School of Medicine, Philadelphia, Pennsylvania.
Pediatr Pulmonol. 1993 Aug;16(2):89-95. doi: 10.1002/ppul.1950160203.
Patients with neuromuscular disease can display paradoxic motion of the rib cage (RC) and abdomen (AB), which increases the work of breathing and predisposes to respiratory muscle fatigue. Long-term mechanical ventilation can reverse chronic hypercapnea and decrease the work of breathing in these patients. Changes in chest wall motion (CWM) that occur during mechanical ventilation have not been studied. We have assessed CWM using a calibrated respiratory inductive plethysmograph before and during mechanical ventilation in 5 children and young adults with neuromuscular disease and paradoxic breathing at rest. Asynchrony of CWM was quantitated by measuring the phase shift, theta, between RC and AB motion (0 degree = synchronous motion, 180 degrees = paradoxic motion). The volume contribution of the paradoxing compartment to tidal volume (PC/VT) was calculated. Before mechanical ventilation, mean +/- SEM VT was 122 +/- 17 mL, theta was 131 +/- 15 degrees C, and PC/VT was -27 +/- 6%. During mechanical ventilation, VT increased to 274 +/- 47 mL (P < 0.05), theta decreased to 41 +/- 14 degrees (P < 0.05), and PC/VT increased to +39 +/- 9% (P < 0.02). We conclude that mechanical ventilation improves RC/AB asynchrony and reverses the negative contribution to tidal volume of the paradoxing compartment in children and young adults with neuromuscular disease. This implies that mechanical ventilation assumes most or all the role of the respiratory pump in these patients, which provides a rationale for the use of chronic or nighttime ventilation in the treatment of respiratory muscle fatigue. Assessment of CWM may be useful in the determination of optimal ventilator settings in this population.
患有神经肌肉疾病的患者可出现胸廓（RC）和腹部（AB）的反常运动，这会增加呼吸功并易导致呼吸肌疲劳。长期机械通气可逆转慢性高碳酸血症并减少这些患者的呼吸功。机械通气期间发生的胸壁运动（CWM）变化尚未得到研究。我们使用校准的呼吸感应体积描记器，对5名患有神经肌肉疾病且静息时存在反常呼吸的儿童和年轻人在机械通气前和通气期间的CWM进行了评估。通过测量RC和AB运动之间的相移θ来量化CWM的不同步性（0度 = 同步运动，180度 = 反常运动）。计算反常腔室对潮气量的容积贡献（PC/VT）。在机械通气前，平均±标准误潮气量（VT）为122±17 mL，θ为131±15摄氏度，PC/VT为 -27±6%。在机械通气期间，VT增加至274±47 mL（P < 0.05），θ降至41±14度（P < 0.05），PC/VT增加至 +39±9%（P < 0.02）。我们得出结论，机械通气可改善患有神经肌肉疾病的儿童和年轻人的RC/AB不同步性，并逆转反常腔室对潮气量的负性贡献。这意味着机械通气承担了这些患者呼吸泵的大部分或全部作用，这为使用慢性或夜间通气治疗呼吸肌疲劳提供了理论依据。评估CWM可能有助于确定该人群的最佳呼吸机设置。
