par Sergysels, Roger 
;Degré, Serge ;Garcia-Herreros, P.
Référence Clinical Respiratory Physiology, 15, 1, page (57-73)
Publication Publié, 1979
;Degré, Serge ;Garcia-Herreros, P.Référence Clinical Respiratory Physiology, 15, 1, page (57-73)
Publication Publié, 1979
Article révisé par les pairs
| Résumé : | Ventilation was analysed during progressive and maximal exercise in 20 patients suffering from COLD and 15 normal subjects. The following equations were used: VE = VT x fv and VE = VT/TE x TE/Ttot. When VO2max.SL was below 1.5 l, patients with COLD develop hyperventilation with tachypnea at loads close to their VO2max.SL VT/TI (mean inspiratory flow) and VT/TE (mean expiratory flow) were higher at the same VO2 than in normals but TE/Ttot (expiratory time/total time for one cycle) remained in the normal range. Patients with COLD presented an upward shift of the end-expiratory level. The increase in VT/TI and in the occlusion pressure at 0.1 s (Whitelaw, 1975) suggests a high respiratory drive which is attributed to central or peripheral reflexes. The increase in VT/TE may be related to the end-expiratory level displacement but also to a more active expiration and perhaps to the preferential recruitment of fast lung units with high frequency breathing. The shortening of VT and tachypnea suggest a pulmonary reflex mechanism. Rapid shallow breathing at high lung volume may lead to mechanical advantages but, theoretically, has disadvantages for gas exchange. |
