Deep inspiration-induced bronchoprotection is stronger than bronchodilation

Nicola Scichilone, Trisevgeni Kapsali, Solbert Permutt, Alkis Togias

Research output: Contribution to journalArticle

Abstract

We have previously shown that in healthy subjects, deep inspiration (DI) has not only a bronchodilatory but also a bronchoprotective effect that is absent in asthmatic subjects. We conducted the study reported here to test the hypothesis that the bronchoprotective effect is stronger than the bronchodilatory effect, and to determine the extent to which these two effects are related. Ten healthy subjects underwent provocations in which single doses of methacholine, previously shown to reduce FEV1 by 10% to 20% (Dose 1) and by 20% to 40% (Dose 2) were administered after a 20-min period devoid of DI. To measure the bronchodilator effect, DIs were performed immediately after the first spirometry after methacholine, and were followed by another lung function test. To measure their bronchoprotective effect, DIs were performed before administration of a single dose of methacholine, and the FEV1 after methacholine was compared with that of another single-dose challenge in which DIs were not included. From these outcomes, bronchodilation and bronchoprotection indices were constructed and compared with each other. At Dose 1 (mild obstruction), the ability of DIs to reverse methacholine-induced obstruction was equal to their ability to prevent it (bronchodilation index [BDI] versus bronchoprotection index [BPI]: 1.62 ± 0.21 versus 2.02 ± 0.40 [mean ± SEM], p = 0.26). At Dose 2, the relative potency of both the bronchodilating and bronchoprotective effects of DIs increased, but bronchoprotection was significantly stronger (BDI versus BPI: 3.40 ± 0.43 versus 6.98 ± 1.42, p = 0.02). Correlation analysis of the two indices indicated that as the BPI increased, the BDI reached a plateau. We conclude that in healthy humans, the bronchoprotective effect of lung inflation is stronger than the bronchodilatory effect.

Original languageEnglish (US)
Pages (from-to)910-916
Number of pages7
JournalAmerican journal of respiratory and critical care medicine
Volume162
Issue number3 I
DOIs
StatePublished - Jan 1 2000

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ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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