Evaluation of respiratory disability in patients of respiratory diseases using relationships between ventilatory drive, ventilation and thoracic pump function during exercise
Kuno, K.; Ohi, M.; Mishima, M.; Chin, K.; Oku, Y.
Nihon Kyobu Shikkan Gakkai Zasshi 27(2): 131-136
1989
ISSN/ISBN: 0301-1542 PMID: 2747067 Document Number: 340200
We studied the parameters of breathing control during exercise in patients with respiratory diseases for the evaluation of respiratory disability. The ventilatory drive during the same load exercise was increased in patients with respiratory diseases compared with that in normal subjects. In addition, the ratio of ventilation to ventilatory drive during exercise was decreased in patients with respiratory diseases. Impairment of rapid thoracic movement was suggested to be one of the mechanical limitations for ventilation in these patients, based on the findings of smaller esophageal pressure fluctuations during maximum ventilation of 40 respirations per minute than that in normal subjects. Flow at 0.1 sec after initiation of inspiration was designated .ovrhdot.V0.1. The increase of the ratio of .ovrhdot.V0.1 at rest at that at maximum voluntary inspiration (.ovrhdot.V0.0 (rest)/.ovrhdot.V0.1 (max)) indicate the grade of respiratory disability showing the impossibility of rapid movement of thorax as a parameter of thoracic pump function. It was recognized that the decrease of .ovrhdot.VE/P0.1 during incremental exercise indicated ventilatory insufficiency.