Parasternal intercostal function during sustained hypoxia
| Autor: | Michael Ji, Tetsunori Ikegami, Estifanos Debru, Paul A. Easton |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of Applied Physiology. 132:622-631 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/japplphysiol.00771.2020 |
| Popis: | Ventilatory response to sustained isocapnic hypoxia in adult humans and other mammals is characterized by a biphasic pattern, with attenuation of neuromotor output to the diaphragm. However, there is no a priori reason that hypoxia-mediated attenuation of respiratory drive would be a common event among other respiratory muscles. At present, little is known about the function of the chest wall muscles during sustained hypoxia. As an obligatory inspiratory muscle with potential to act as a surrogate for neural drive to the relatively inaccessible costal diaphragm, parasternal intercostal has gained interest clinically: its function during a sustained hypoxic insult, as may occur in respiratory failure, warrants investigation. Therefore, in 11 chronically instrumented awake canines, we simultaneously recorded muscle length and shortening and electromyogram (EMG) activity of the parasternal chest wall inspiratory muscle, along with breathing pattern, during moderate levels of sustained isocapnic hypoxia lasting 20-25 min (mean 80 ± 2% oximeter oxygen saturation). Phasic inspiratory shortening and EMG activity of the parasternal intercostal were observed throughout room air and hypoxic ventilation in all animals. Temporal changes in parasternal intercostal shortening tracked the biphasic changes in ventilation during sustained hypoxia. Mean shortening and EMG activity of parasternal intercostal muscle increased significantly with initial hypoxia ( |
| Databáze: | OpenAIRE |
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