Research Article

Effect of maximal respiratory manoeuvres on bronchial sensitivity of asthmatic patients as compared to normal people.

Br Med J 1975; 1 doi: http://dx.doi.org/10.1136/bmj.1.5950.123 (Published 18 January 1975) Cite this as: Br Med J 1975;1:123
  1. J Orehek,
  2. P Gayrard,
  3. C Grimaud,
  4. J Charpin

    Abstract

    Cumulative dose-response curves to carbachol given by aerosol were established using plethysmographic measurements of specific airways resistance (SRaw) in 10 patients with asthma and five healthy subjects. Two experiments were performed--a control test and one in which maximal respiratory manoeuvres (MRM) (two maximal inspirations and two maximal expirations) were made before each carbachol inhalation. MRM did not modify the dose-response curves in the normal subjects. In the patients these manoeuvres enhanced the bronchoconstrictor effect of carbachol: curves were shifted to the left and the mean dose of carbachol producing a twofold increase in initial SRaw was decreased from 0.373 mg to 0.189 mg (P less than 0.001). Bronchial provocation tests using methods which require MRM--for example, forced expiratory volume at one second--could overestimate the bronchial sensitivity of patients with asthma.