The effect of carotid chemoreceptor inhibition on exercise tolerance in chronic obstructive pulmonary disease: A randomized-controlled crossover trial
| Autor: | Eric Wong, Mohit Bhutani, M. Sean McMurtry, Michael K. Stickland, Sophie É Collins, Devin B. Phillips, Tracey L. Bryan |
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| Rok vydání: | 2019 |
| Předmět: |
Pulmonary and Respiratory Medicine
Mean arterial pressure medicine.medical_specialty Cardiac output Dopamine Exercise intolerance 03 medical and health sciences Pulmonary Disease Chronic Obstructive 0302 clinical medicine Internal medicine medicine Humans Lung volumes 030212 general & internal medicine COPD Cross-Over Studies Exercise Tolerance medicine.diagnostic_test business.industry medicine.disease Crossover study respiratory tract diseases Impedance cardiography 030228 respiratory system Cardiology Breathing medicine.symptom business |
| Zdroj: | Respiratory medicine. 160 |
| ISSN: | 1532-3064 |
| Popis: | Background Patients with chronic obstructive pulmonary disease (COPD) have an exaggerated ventilatory response to exercise, contributing to exertional dyspnea and exercise intolerance. We recently demonstrated enhanced activity and sensitivity of the carotid chemoreceptor (CC) in COPD which may alter ventilatory and cardiovascular regulation and negatively affect exercise tolerance. We sought to determine whether CC inhibition improves ventilatory and cardiovascular regulation, dyspnea and exercise tolerance in COPD. Methods Twelve mild-moderate COPD patients (FEV1 83 ± 15 %predicted) and twelve age- and sex-matched healthy controls completed two time-to-symptom limitation (TLIM) constant load exercise tests at 75% peak power output with either intravenous saline or low-dose dopamine (2 μg·kg−1·min−1, order randomized) to inhibit the CC. Ventilatory responses were evaluated using expired gas data and dyspnea was evaluated using a modified Borg scale. Inspiratory capacity maneuvers were performed to determine operating lung volumes. Cardiac output was estimated using impedance cardiography and vascular conductance was calculated as cardiac output/mean arterial pressure (MAP). Results At a standardized exercise time of 4-min and at TLIM; ventilation, operating volumes and dyspnea were unaffected by dopamine in COPD patients and controls. In COPD, dopamine decreased MAP and increased vascular conductance at all time points. In controls, dopamine increased vascular conductance at TLIM, while MAP was unaffected. Conclusion There was no change in time to exhaustion in either group with dopamine. These data suggest that the CC plays a role in cardiovascular regulation during exercise in COPD; however, ventilation, dyspnea and exercise tolerance were unaffected by CC inhibition in COPD patients. |
| Databáze: | OpenAIRE |
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