Respiratory muscle dynamics and control during exercise with externally imposed expiratory flow limitation.

Details

Serval ID
serval:BIB_104426028E79
Type
Article: article from journal or magazin.
Collection
Publications
Title
Respiratory muscle dynamics and control during exercise with externally imposed expiratory flow limitation.
Journal
Journal of Applied Physiology
Author(s)
Aliverti A., Iandelli I., Duranti R., Cala S.J., Kayser B., Kelly S., Misuri G., Pedotti A., Scano G., Sliwinski P., Yan S., Macklem P.T.
ISSN
8750-7587 (Print)
ISSN-L
0161-7567
Publication state
Published
Issued date
2002
Volume
92
Number
5
Pages
1953-1963
Language
english
Abstract
To determine how decreasing velocity of shortening (U) of expiratory muscles affects breathing during exercise, six normal men performed incremental exercise with externally imposed expiratory flow limitation (EFLe) at approximately 1 l/s. We measured volumes of chest wall, lung- and diaphragm-apposed rib cage (Vrc,p and Vrc,a, respectively), and abdomen (Vab) by optoelectronic plethysmography; esophageal, gastric, and transdiaphragmatic pressures (Pdi); and end-tidal CO2 concentration. From these, we calculated velocity of shortening and power (W) of diaphragm, rib cage, and abdominal muscles (di, rcm, ab, respectively). EFLe forced a decrease in Uab, which increased Pab and which lasted well into inspiration. This imposed a load, overcome by preinspiratory diaphragm contraction. Udi and inspiratory Urcm increased, reducing their ability to generate pressure. Pdi, Prcm, and Wab increased, indicating an increased central drive to all muscle groups secondary to hypercapnia, which developed in all subjects. These results suggest a vicious cycle in which EFLe decreases Uab, increasing Pab and exacerbating the hypercapnia, which increases central drive increasing Pab even more, leading to further CO2 retention, and so forth.
Keywords
Abdominal Muscles/physiology, Adult, Carbon Dioxide/analysis, Carbon Dioxide/physiology, Diaphragm/physiology, Dyspnea/complications, Dyspnea/physiopathology, Exercise Test, Humans, Hypercapnia/etiology, Hypercapnia/physiopathology, Intercostal Muscles/physiology, Male, Muscle Contraction/physiology, Peak Expiratory Flow Rate/physiology, Physical Exertion/physiology, Pressure, Pulmonary Ventilation/physiology, Reference Values, Respiratory Muscles/physiology, Thorax/physiology, Tidal Volume/physiology, Work of Breathing/physiology
Pubmed
Web of science
Create date
19/09/2013 9:51
Last modification date
20/08/2019 12:37
Usage data