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Inhalative provocation test. When is it positive?
Scandinavian Journal of Respiratory Diseases. Supplementum
|January 1, 1979
Summary
Asthmatic patients
Area of Science:
- Pulmonary medicine
- Respiratory physiology
Background:
- Asthma management involves assessing airway hyperresponsiveness.
- Whole body plethysmography is a key diagnostic tool.
- Differentiating allergic and non-allergic airway responses is crucial.
Purpose of the Study:
- To establish reference ranges for airway resistance (R) and R/Rref quotient.
- To evaluate non-allergic provocation responses in asthmatic patients.
- To guide the safe and effective use of inhalative provocation tests.
Main Methods:
- Whole body plethysmography was used to measure airway resistance (R) and reference resistance (Rref).
- Patients underwent unspecific inhalative provocation.
- Initial R/Rref quotients were categorized (<2 and 2-5).
Main Results:
- Patients with initial R/Rref < 2 showed non-allergic reactions not exceeding 2.7.
- Patients with initial R/Rref between 2 and 5 reached R/Rref values up to 8.5.
- Higher initial R/Rref values correlated with greater non-allergic responses.
Conclusions:
- Recommends performing provocation tests only in patients with initial R/Rref < 2.
- This threshold helps distinguish allergic from non-allergic reactions.
- Avoids potentially harmful allergen-induced bronchospasm in susceptible individuals.