Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle Upon-Tyne, United Kingdom.
Northumbria Healthcare NHS Foundation Trust, North Tyneside General Hospital, Newcastle Upon-Tyne, United Kingdom.
J Appl Physiol (1985). 2021 Jul 1;131(1):401-413. doi: 10.1152/japplphysiol.00081.2021. Epub 2021 Jun 10.
We previously showed that use of portable noninvasive ventilation (pNIV) during recovery periods within intermittent exercise improved breathlessness and exercise tolerance in patients with COPD compared with pursed-lip breathing (PLB). However, in a minority of patients recovery from dynamic hyperinflation (DH) was better with PLB, based on inspiratory capacity. We further explored this using Optoelectronic Plethysmography to assess total and compartmental thoracoabdominal volumes. Fourteen patients with COPD (means ± SD) (FEV: 55% ± 22% predicted) underwent, in a balanced order sequence, two intermittent exercise protocols on the cycle ergometer consisting of five repeated 2-min exercise bouts at 80% peak capacity, separated by 2-min recovery periods, with application of pNIV or PLB in the 5 min of recovery. Our findings identified seven patients showing recovery in DH with pNIV (DH responders) whereas seven showed similar or better recovery in DH with PLB. When pNIV was applied, DH responders compared with DH nonresponders exhibited greater tidal volume (by 0.8 ± 0.3 L, = 0.015), inspiratory flow rate (by 0.6 ± 0.5 L/s, = 0.049), prolonged expiratory time (by 0.6 ± 0.5 s, = 0.006), and duty cycle (by 0.7 ± 0.6 s, = 0.007). DH responders showed a reduction in end-expiratory thoracoabdominal DH (by 265 ± 633 mL) predominantly driven by reduction in the abdominal compartment (by 210 ± 494 mL); this effectively offset end-inspiratory rib-cage DH. Compared with DH nonresponders, DH responders had significantly greater body mass index (BMI) by 8.4 ± 3.2 kg/m, = 0.022 and tended toward less severe resting hyperinflation by 0.3 ± 0.3 L. Patients with COPD who mitigate end-expiratory rib-cage DH by expiratory abdominal muscle recruitment benefit from pNIV application. Compared with the pursed-lip breathing technique, acute application of portable noninvasive ventilation during recovery from intermittent exercise improved end-expiratory thoracoabdominal dynamic hyperinflation (DH) in 50% of patients with COPD (DH responders). DH responders, compared with DH nonresponders, exhibited a reduction in end-expiratory thoracoabdominal DH predominantly driven by the abdominal compartment that effectively offset end-expiratory rib cage DH. The essential difference between DH responders and DH nonresponders was, therefore, in the behavior of the abdomen.
我们之前的研究表明，与唇缩拢呼吸（PLB）相比，在间歇性运动的恢复期使用便携式无创通气（pNIV）可改善 COPD 患者的呼吸困难和运动耐量。然而，根据吸气量，少数患者从动态过度充气（DH）中恢复时，PLB 效果更好。我们使用光电体积描记法进一步研究了这一点，以评估胸腹部的总容积和隔室容积。14 名 COPD 患者（平均值±标准差）（FEV：55%±22%预测值）以平衡顺序进行了两次在循环测功计上的间歇性运动方案，包括 5 次重复的 2 分钟运动，在 80%峰值容量下进行，每 2 分钟恢复期一次，在 5 分钟恢复期内应用 pNIV 或 PLB。我们的研究结果发现，有 7 名患者在应用 pNIV 时出现 DH 恢复（DH 应答者），而有 7 名患者在应用 PLB 时出现类似或更好的 DH 恢复。当应用 pNIV 时，与 DH 无应答者相比，DH 应答者的潮气量增加（增加 0.8±0.3 L，=0.015），吸气流量增加（增加 0.6±0.5 L/s，=0.049），呼气时间延长（增加 0.6±0.5 s，=0.006），呼吸时相延长（增加 0.7±0.6 s，=0.007）。DH 应答者的 end-expiratory 胸腹部 DH 减少（减少 265±633 mL），主要是由于腹部容积减少（减少 210±494 mL）；这有效地抵消了吸气末胸廓 DH。与 DH 无应答者相比，DH 应答者的体重指数（BMI）增加了 8.4±3.2 kg/m，=0.022，静息过度充气程度减轻（增加 0.3±0.3 L）。通过呼气腹部肌肉募集来减轻 end-expiratory 胸廓 DH 的 COPD 患者受益于 pNIV 的应用。与唇缩拢呼吸技术相比，在间歇性运动恢复期应用便携式无创通气可改善 50%的 COPD 患者（DH 应答者）的 end-expiratory 胸腹部动态过度充气（DH）。与 DH 无应答者相比，DH 应答者的 end-expiratory 胸腹部 DH 减少，主要是由于腹部容积减少，这有效地抵消了 end-expiratory 胸廓 DH。因此，DH 应答者和 DH 无应答者之间的主要区别在于腹部的行为。
