Chest
Original ResearchCOPDEfficiency of Neural Drive During Exercise in Patients With COPD and Healthy Subjects
Section snippets
Subjects
Twelve male patients with moderate to severe COPD, aged 62.8 ± 10.3 years, with BMI 22.5 ± 3.0 kg/m2, participated in the study. All patients were clinically stable without clinically significant coexisting disease and had not had an acute exacerbation in the preceding month. No patients needed to receive supplemental oxygen at rest. Patients were allowed to take their usual medication, including inhaled bronchodilators. We also studied 12 age- (61.1 ± 7.2 years) and BMI- (22.3 ± 2.2 kg/m2)
Results
Maximal RMS of EMGdi was similar between patients with COPD and healthy subjects (245.5 ± 52.7 μV vs 210.6 ± 65.7 μV, P > .05). Neural drive as a percentage of maximal drive at rest was 18.9% ± 9.8% in patients with COPD and was significantly higher than that in healthy subjects (9.8% ± 3.2%, P < .01) (Table 1). Maximal EMG at rest was recorded from maximal inspiration from FRC to TLC in all but one patient with COPD. In contrast in normal subjects, maximal EMG was recorded during the maximal
Discussion
Our data confirm the known physiology of exercise and COPD; specifically, neural drive increases during exercise. We confirm our previous finding that, at end-exercise, EMGdi max is not reached. Additionally we show that the transmission of neural drive to ventilation is progressively impaired in COPD. Although this phenomenon has been previously explored, we believe this study is the first to quantify the problem.
Acknowledgments
Author contributions: Dr Qin: contributed to conception and design, analysis, and interpretation of data.
Dr Steier: contributed to conception and design, interpretation of data, and final approval of the version to be published.
Dr Jolley: contributed to conception and design, interpretation of data, and final approval of the version to be published.
Dr Moxham: contributed to conception and design, interpretation of data, and final approval of the version to be published.
Dr Zhong: contributed to
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2021, Respiratory Physiology and NeurobiologyNovel method for evaluating the upper airway resistance using the ratio of neural respiratory drive to flow in OSA
2020, Sleep MedicineCitation Excerpt :To some extent, efficiency of neural drive [13] measured by the ratio of minute ventilation to EMGdi(VE/EMGdi), representing the efficiency of lung ventilation, which means that a certain amount of ventilation generated by unit of EMGdi, can reflect total respiratory resistance. Our research [13] has reported that efficiency of neural drive could reflect the upper airway resistance if lung and chest wall mechanics and lower airway resistance would keep the same from wakefulness to sleep. OSA is characterized with the anatomical pharyngeal narrow and gradually increase in upper airway resistance from stable breathing to snoring and further hypopnea events [14,15].
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2015, Pulmonary Pharmacology and TherapeuticsElectrical activity of the diaphragm during progressive cycling exercise in endurance-trained men
2015, Respiratory Physiology and NeurobiologyCitation Excerpt :This method allows measuring directly at the diaphragm during actual exercise and thereby provide accurate assessment of the respiratory drive modulation during voluntary breathing (Qin et al., 2010). EADi has been used to measure the work of the diaphragm at different lung capacities (Beck et al., 1998), and fatigability during CO2 rebreathing efforts (Luo et al., 2001) or in whole body exercise during constant load cycling in elderly normal and COPD patients (Qin et al., 2010). So far, only Zhang et al. (2013) have measured EADi during progressive exercise to exhaustion.
Respiratory motor output during an inspiratory capacity maneuver is preserved despite submaximal exercise
2013, Respiratory Physiology and NeurobiologyCitation Excerpt :Therefore in the present study we adopted a novel approach by measuring the ability of the participants to voluntarily activate the diaphragm was assessed during a maneuver other than exercise (specifically the IC maneuver). We chose to normalize against the largest EMGdi obtained by any maneuver prior to or during exercise rather than that obtained from the IC maneuver at rest to make sure the data was normalized by a truly maximal EMG, in line with previous studies (Qin et al., 2010; Sinderby et al., 2001). The control condition of 60% of VO2max was chosen because exercise load lower than 85% of the maximum oxygen consumption is not thought to elicit diaphragm fatigue (Johnson et al., 1993; Babcock et al., 1995).
Funding/Support: This study was supported by the Chinese Natural Scientific Foundation [Grant 30770937] and International Collaboration Grant supported by Chinese Ministry of Science and Technology [Grant 2005DFA30910].
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).