Comparison of Two Methods of Bronchial Methacholine Provocation

Comparison of Two Methods of Bronchial Methacholine Provocation: PC 20 FEV1 Versus PD 20 FEV1

This study is meant to compare two routine diagnostic approaches in patients with bronchial asthma. Patients are challenged with methacholine in order to measure their bronchial response. We compare the evaluation of the effects of incremental concentrations versus incremental dosages.

Bronchial methacholine challenge is well established in asthma diagnostic and research purposes. ATS guidelines provide a short five-breath dosimeter protocol using a five-step dilution schedule. The Viasys APS system enables a feasible and less time consuming provocation with incremental dosages. In 48 young adults with bronchial hyperreactivity (BHR) the ATS-protocol with a five-step protocol using a single dilution of 16 mg/ml methacholine should be compared.

Inclusion Criteria:

• Informed consent
• Age 12-45 years
• Known bronchial hyperreactivity

Exclusion Criteria:

• Age < 12 > 45 years
• Clinical asthma requiring regular inhalation
• Vital capacity < 80%
• FEV1 < 75%
• Chronic disease conditions or infections
• Pregnancy
• Inhalative or systemic steroid use
• Substance abuse
• Incapability of understanding the study's purpose and performance