Sarlabous Leonardo, Torres Abel, Fiz José A, Martínez-Llorens Juana M, Gea Joaquim, Jané Raimon
Institute for Bioengineering of Catalonia, Barcelona, Spain.
Center for Biomedical Research Network of Bioengineering, Biomaterials and Nanomedicine, Barcelona, Spain.
PLoS One. 2017 May 18;12(5):e0177730. doi: 10.1371/journal.pone.0177730. eCollection 2017.
There is a lack of instruments for assessing respiratory muscle activation during the breathing cycle in clinical conditions. The aim of the present study was to evaluate the usefulness of the respiratory muscle mechanomyogram (MMG) for non-invasively assessing the mechanical activation of the inspiratory muscles of the lower chest wall in both patients with chronic obstructive pulmonary disease (COPD) and healthy subjects, and to investigate the relationship between inspiratory muscle activation and pulmonary function parameters. Both inspiratory mouth pressure and respiratory muscle MMG were simultaneously recorded under two different respiratory conditions, quiet breathing and incremental ventilatory effort, in 13 COPD patients and 7 healthy subjects. The mechanical activation of the inspiratory muscles was characterised by the non-linear multistate Lempel-Ziv index (MLZ) calculated over the inspiratory time of the MMG signal. Subsequently, the efficiency of the inspiratory muscle mechanical activation was expressed as the ratio between the peak inspiratory mouth pressure to the amplitude of the mechanical activation. This activation estimated using the MLZ index correlated strongly with peak inspiratory mouth pressure throughout the respiratory protocol in both COPD patients (r = 0.80, p<0.001) and healthy (r = 0.82, p<0.001). Moreover, the greater the COPD severity in patients, the greater the level of muscle activation (r = -0.68, p = 0.001, between muscle activation at incremental ventilator effort and FEV1). Furthermore, the efficiency of the mechanical activation of inspiratory muscle was lower in COPD patients than healthy subjects (7.61±2.06 vs 20.42±10.81, respectively, p = 0.0002), and decreased with increasing COPD severity (r = 0.78, p<0.001, between efficiency of the mechanical activation at incremental ventilatory effort and FEV1). These results suggest that the respiratory muscle mechanomyogram is a good reflection of inspiratory effort and can be used to estimate the efficiency of the mechanical activation of the inspiratory muscles. Both, inspiratory muscle activation and inspiratory muscle mechanical activation efficiency are strongly correlated with the pulmonary function. Therefore, the use of the respiratory muscle mechanomyogram can improve the assessment of inspiratory muscle activation in clinical conditions, contributing to a better understanding of breathing in COPD patients.
在临床环境中，缺乏用于评估呼吸周期中呼吸肌激活情况的仪器。本研究的目的是评估呼吸肌机械肌电图（MMG）在非侵入性评估慢性阻塞性肺疾病（COPD）患者和健康受试者下胸壁吸气肌机械激活方面的有用性，并研究吸气肌激活与肺功能参数之间的关系。在安静呼吸和递增通气负荷这两种不同呼吸条件下，同时记录了13例COPD患者和7名健康受试者的吸气口压力和呼吸肌MMG。吸气肌的机械激活通过在MMG信号吸气时间上计算的非线性多状态莱姆尔 - 齐夫指数（MLZ）来表征。随后，吸气肌机械激活效率表示为吸气口压力峰值与机械激活幅度之间的比值。在整个呼吸方案中，使用MLZ指数估计的这种激活在COPD患者（r = 0.80，p<0.001）和健康受试者（r = 0.82，p<0.001）中均与吸气口压力峰值密切相关。此外，患者的COPD严重程度越高，肌肉激活水平越高（在递增通气负荷时的肌肉激活与第一秒用力呼气容积（FEV1）之间，r = -0.68，p = 0.001）。此外，COPD患者吸气肌机械激活的效率低于健康受试者（分别为7.61±2.06和20.42±10.81，p = 0.0002），并且随着COPD严重程度的增加而降低（在递增通气负荷时的机械激活效率与FEV1之间，r = 0.78，p<0.001）。这些结果表明，呼吸肌机械肌电图能很好地反映吸气努力，可用于估计吸气肌机械激活的效率。吸气肌激活和吸气肌机械激活效率均与肺功能密切相关。因此，呼吸肌机械肌电图的应用可以改善临床环境中吸气肌激活的评估，有助于更好地理解COPD患者的呼吸情况。
