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Comparative bronchial responses to hyperosmolar saline and methacholine in asthma
L P Boulet1, C Legris, L Thibault
1Centre de Pneumologie, Hôpital Laval, Ste-Foy, Quebec, Canada.
Thorax
|December 1, 1987
Summary
This study compared airway responsiveness in asthma patients using hyperosmolar saline and methacholine. Results show that the airway response to hyperosmolar saline is distinct from the response to methacholine.
Area of Science:
- Pulmonary Medicine
- Respiratory Physiology
Background:
- Asthma is characterized by airway hyperresponsiveness.
- Methacholine challenge is a standard method to assess airway responsiveness.
- Hyperosmolar stimuli may also induce bronchoconstriction in asthmatics.
Purpose of the Study:
- To compare airway responsiveness to ultrasonically nebulized hyperosmolar saline versus methacholine in asthma.
- To establish a quantitative method for assessing airway response to hyperosmolar saline.
Main Methods:
- Twenty asthmatic subjects underwent random, blinded challenges with hyperosmolar saline and methacholine.
- Dose-response curves were generated for both stimuli.
- Airway responsiveness was measured by the concentration or osmolarity causing a 20% fall in forced expiratory volume in one second (FEV1).
Main Results:
- Hyperosmolar saline challenge was well-tolerated and repeatable.
- A significant correlation was not found between the osmolarity causing a 20% fall in FEV1 (PO20) and the methacholine concentration causing a 20% fall in FEV1 (PC20).
- The peak bronchoconstrictor effect of hyperosmolar saline occurred at 3 minutes and lasted a mean of 50 minutes.
Conclusions:
- Inhaled hyperosmolar saline provides a distinct measure of airway responsiveness compared to methacholine in asthma.
- This new quantitative method for hyperosmolar saline challenge offers a different perspective on airway reactivity in asthma.