[The development and safety of cough provocation test by capsaicin inhalation].
OBJECTIVE
To assess the application and the safety of capsaicin cough provocation test by dosimeter method.


METHODS
Capsaicin inhalation cough challenge test by dosimeter method was performed on 60 healthy volunteers (group A), 11 subjects with upper respiratory infection (group B), 10 patients with gastroesophageal reflux cough (group C) and 10 patients with asthma (group D). Each subject inhaled doubling concentrations of capsaicin (1.95, 3.90, 7.80, 15.6, 31.2, 62.5, 125, 250, 500, 1,000 micromol/L) by a breath-activated dosimeter until the concentration inducing five or more coughs (C(5)) was reached. The lg C(5) was calculated as the cough reflex sensitivity. General lung ventilation and impedance with impulse oscillometry were measured before and after the cough provocation test.


RESULTS
There was no serious side effect of the test in all subjects; two subjects complained of slight nausea; one of heartburn, and three of hoarseness. Before the provocation the values of FEV(1) in group A, B, C and D were (3.6 +/- 0.5) L, (3.7 +/- 0.7) L, (2.7 +/- 0.8) L and (2.1 +/- 0.8) L, compared with (3.6 +/- 0.5) L, (3.7 +/- 0.8) L, (2.6 +/- 0.7) L and (2.1 +/- 0.8) L after the test, the differences being not significant (all P > 0.05). Compared with the measurements after provocation, Zrs was (2.6 +/- 0.8) mm Hg.L(-1).s(-1) vs (2.7 +/- 0.8) mm Hg.L(-1).s(-1) in group A, (2.5 +/- 0.5) mm Hg.L(-1).s(-1) vs (2.6 +/- 0.3) mm Hg.L(-1).s(-1) in group B, (2.7 +/- 0.7) mm Hg.L(-1).s(-1) vs (2.7 +/- 0.7) mm Hg.L(-1).s(-1) in group C, (3.3 +/- 1.5) mm Hg.L(-1).s(-1) vs (3.7 +/- 2.0) mm Hg.L(-1).s(-1) in group D, the differences showed no significance (all P > 0.05 respectively). The lg C(5) value was 2.45 +/- 0.46 in group A, 2.51 +/- 0.20 in group B, 1.52 +/- 0.70 in group C, 2.34 +/- 0.56 in group D. Compared with group A, B and D, the lg C(5) value in group C was significantly different (all P < 0.01 respectively). The lg C(5) value showed no significant difference among group A, group B and group D (all P > 0.05).


CONCLUSIONS
Capsaicin inhalation cough provocation test by dosimeter method is a safe and specific tool for measuring cough reflex sensitivity.
Chen
Ru-chong
RC
Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical College, Guangzhou 510120, China.
Lai
Ke-fang
KF
Liu
Chun-li
CL
Luo
Wei
W
Zheng
Jing-ping
JP
Zhong
Nan-shan
NS
D000281:Administration, Intranasal; D000293:Adolescent; D000328:Adult; D016535:Bronchial Hyperreactivity / Q000139:chemically induced; D001985:Bronchial Provocation Tests / Q000009:adverse effects* / Q000379:methods; D002211:Capsaicin / Q000009:adverse effects*; D003371:Cough / Q000139:chemically induced* / Q000175:diagnosis / Q000209:etiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D012449:Safety; D055815:Young Adult
D002211:Capsaicin