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Reliability of the capsaicin cough reflex sensitivity test in healthy children

100%

Verechova S., Plevkova J., Javorka M., Hanacek J.

Journal of Physiology and Pharmacology. Supplement

2006

tom 57

nr 4

365-373

Testing cough reflex sensitivity (CRS) in children requires suitable methodology. A CRS test performed under control of inspiratory flow rate (IFR) shows excellent reliability in children, but it is difficult to perform, especially in younger children. The aim of the present study was to find whether the capsaicin CRS test performed without direct control of constant IFR in healthy children is reliable enough for practical use. The CRS test was performed in 27 healthy children, aged 7-17 yr three times within 8 days. Cough was induced by inhalation of capsaicin aerosol in doubling concentrations (0.61-1250 µmol/l) for 400 ms each. CRS was defined as the lowest capsaicin concentration that evoked 2 or more coughs (C2). Although the intraclass correlation coefficient values showed good to excellent reliability of this test, the within-subject standard deviation values revealed lower reliability of this method compared to the CRS test performed under control of IFR. From the results obtained it is reasonable to conclude that the method using uncontrolled IFR in CRS testing provides acceptable precision only when a bigger sample size is used or more tests are performed. Good to excellent reliability of this method was found in children with higher values of C2 and in those aged 13-17 yr.

Convergence of nasal and tracheal neural pathways in modulating the cough response in guinea pigs

76%

Plevkova J., Antosiewicz J., Verechova S., Poliacek I., Jakus J., Tatar M., Pokorski M.

Journal of Physiology and Pharmacology

2009

tom 60

nr 2

89-93

In the present study we investigated the possibility of central convergence of neural pathways coming from distant anatomical regions in modulating the cough response. We addressed this issue by inducing cough from the tracheo-bronchial region on the background of capsaicin-stimulated and mesocain-blocked nasal mucosa in 14 anesthetized guinea pigs. The control group consisted of 6 guinea pigs in which the active agents, capsaicin and mesocain, were substituted for by inert physiological saline. All animals were tracheostomized, and the larynx was disconnected from the proximal part of the trachea with preserved innervations, and all were subjected to the same protocol. Cough, induced by mechanical irritation of the tracheo-bronchial mucosa, was elicited three times: in the control condition, after intranasal capsaicin challenge, and after another capsaicin challenge preceded by intranasal instillation of a local anesthetic, mesocain. The main finding of the study was that the number of cough efforts per bout, assessed from positive deflections on the intrapleural pressure recordings, was significantly enhanced by intranasal capsaicin challenge and this effect was reversed by intranasal pretreatment with the anesthetic mesocain [2.1 ±0.2 (control) vs. 3.5 ±0.4 (capsaicin) vs. 2.2 ±0.2 (capsaicin after mesocain) (P<0.01)], with no appreciable changes in the magnitude of cough efforts. The cough response in the control group remained unchanged. We conclude that tracheo-bronchial cough may be modified by neural sensory input to the brain coming from nasal mucosa. Therefore, cough reflex is subject to central convergence of peripheral neural pathways originating at distant anatomical locations.

Ograniczanie wyników

1 Journal of Physiology and Pharmacology

1 Journal of Physiology and Pharmacology. Supplement

2 Plevkova J.

2 Verechova S.

1 Antosiewicz J.

1 Hanacek J.

1 Jakus J.

1 Javorka M.

1 Pokorski M.

1 Poliacek I.

1 Tatar M.

1 2009

1 2006

Wyniki wyszukiwania

Reliability of the capsaicin cough reflex sensitivity test in healthy children

Convergence of nasal and tracheal neural pathways in modulating the cough response in guinea pigs