The measurement of nonspecific bronchial hyperreactivity is valuable for diagnosis and management of bronchial asthma. Methacholine or histamine is used for the pharmacologic provocation test. Usually a methacholine bronchial provocation test is performed by a dosing technique with counted number of breaths. A dosimeter is indispensable in the dosing technique. Recently a timed tidal breathing technique which dose not need an expensive dosimeter was introduced. We measured the degree of nonspecific bronchial hyperreactivity to histamine using a simple timed tidal breathing technique.

Forty two healthy volunteers, 12 patients with bronchial asthma(BA), 10 patients with rhinitis(RH) and 10 patients with upper respiratory infection(URI) participated in the study. The subject's nose was clipped and inhalation continued during tidal breathing for 2 minutes via a face mask. FEV1 was measured at 30 seconds, 90 seconds after inhalation and inhalation of next solution was continued until there was a fall in FEV1 of 20%. Histamine PC20 was defined as the concentration at 20% fall of FEV1 and it was obtained from the log dose-response curve by linear interpolation.

Inhalation of serial dilution of histamine could be performed in all patients without significant side of effects. The geometric mean±standard deviation of histamine PC20 in healthy volunteers is 8.27±2.22mg/ml, BA group 0.33±3.02mg/ml, RH group 0.85 ±3.24mg/ml, and URI group 1.47±1.98mg/ml.

Histamine bronchial provocation test using timed tidal breath method is a simple and suitable tool for management of patients with bronchial hyperreactivity.