Diaphragm fatigue following maximal ventilation in man
| Autor: | J Road, John Moxham, S Wragg, Gary H. Mills, C H Hamnegard, M Green, Björn Bake, Michael I. Polkey, J Moran, D Kyroussis |
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| Rok vydání: | 1996 |
| Předmět: |
Adult
Male Pulmonary and Respiratory Medicine business.industry Muscle Relaxation Respiration Diaphragm Diaphragmatic breathing Maximal Voluntary Ventilation Stimulation Middle Aged Electric Stimulation Isocapnic ventilation Diaphragm (structural system) Phrenic Nerve Contractility Reference Values Relaxation rate Anesthesia Muscle Fatigue Breathing Humans Medicine Respiratory system business |
| Zdroj: | European Respiratory Journal. 9:241-247 |
| ISSN: | 1399-3003 0903-1936 |
| DOI: | 10.1183/09031936.96.09020241 |
| Popis: | When highly motivated normal subjects perform maximal isocapnic ventilation, a substantial fall in ventilation is observed during the first minute associated with slowing of the maximum relaxation rate (MRR) of the inspiratory muscles. This suggests that these muscles are excessively loaded, raising the possibility that overt contractile failure of the diaphragm contributes to the fall in ventilation. We therefore investigated the effect of maximal isocapnic ventilation (MIV) on twitch transdiaphragmatic pressure (Pdi,Tw) elicited by cervical magnetic stimulation. We measured Pdi,Tw before and after 2 min MIV in nine normal subjects. Initial mean (SD) ventilation for the nine subjects was 196 (15) L.min-1 falling by 35% at 1 min. Pdi,Tw fell following MIV, at 10 min was reduced by 24%, and remained substantially reduced 90 min after MIV. No change in Pdi,Tw was observed during control studies in which subjects were studied with the same protocol but omitting MIV. We conclude that diaphragmatic contractility is reduced after 2 min maximal isocapnic ventilation and diaphragmatic fatigue may be a limiting factor in maximal ventilation in man. |
| Databáze: | OpenAIRE |
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