Allergy.  1994 Dec;14(4):687-694.

Standardization of inhalation provocation tests: Comparisions of 2 min' tidal breathing and 5 vital capacity -inhalations by Pari- inhalier boy

• Choi BW
• Park IW
• Hue SH
• Kim SH
• Lee SP
• Sung YU
• Kang YJ

Abstract

BACKGROUND
Nonspecific bronchoprovocation tes-,s play an important roles in the assessment and diagnosis of asthma and now are used popularly in Korea. Results of inhalation provocation tests are quantitative, but a knowledge of what factors influence these results is essential to be comparable and reproducible from time to time and from laboratory to laboratory. The reponse to inhaled aerosol are influenced by a number of technical and nontechnical factors. The technical fctors include the method of aerosol generation and inhalation, of preparation and storage of test solutions, of measurement of the response, and of expression of results. Nontechnical factors include subject charactristics such as baseline airway caliber, medications, and enbironmental factors such as time of day, respiratory infection, and exposure to allergen. In this study, we evaluated the influence of method for inhalation(2 min tidal breathing versus 5 vital capacity breathing) on the response to inhaled methacholine when using Pari-inhalier boy nebulizer. METHODS: In 180 patients with suspected bronchial hyperreactivity in Chung-Ang University hospital, duplicate methaeholine inhalation test were performed under identical conditions, except for the method of inhalation which was 2 min tidal breathing(2 min-TB) in one test and 5 vital capacity breathing(5 VCB) in the other. The two methods of inhalation were cross checked in all patients with interval, 1 to 3 days. Baseline and postsaline FEV1 were also measured to compare effects by two inhalation methods. Methaeholine PC20 was calculated by linear interpolation between the last two data points on the dose-response curve, and the cut off value of bronchial asthma was 10mg/ml.
RESULTS
The rate of positive bronchopro-vocation test in 5 VCB was 18.9 %(34/180), which was significantly lower than 55.6 % (100/ 180) in 2 min-TB (p<0.01). Any patient, who was not provocated up to 10mg/ml of methacholine in 2 min-TB, was not provocated in 5 VCB. In 34 patients with positive bronchoprovocation in both inhalation methods, the mean PC20 in 5VCB(5VC-PC20) was 3. 37 mg/ml, being significantly higher than 0. 785mg/ml in 2min-TB(2min-PC20) (p<0.05). In 48 patients with 5VC-PC20<25 mg/ml, there was a significant positive correlation between 5VC-PC20 and 2 min-PC20 (R=0.524, p<0.001).
CONCLUSION
These results emphasize the importance of methods of inhalation in bronch-oprovocation tests if results done in different laboratory are to be compared.

MeSH Terms

Asthma
Bronchial Hyperreactivity
Bronchial Provocation Tests*
Diagnosis
Humans
Inhalation*
Korea
Male*
Methacholine Chloride
Nebulizers and Vaporizers
Respiration*
Vital Capacity*
Methacholine Chloride