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Changes in airway resistance following nasal provocation
N T Littell1, C C Carlisle, R P Millman
1Department of Medicine, Rhode Island Hospital, Providence 02903.
The American Review of Respiratory Disease
|March 1, 1990
Summary
Nasal challenges did not trigger reflex bronchoconstriction in asthmatic patients. Methacholine
Area of Science:
- Respiratory Medicine
- Allergology
- Pulmonology
Background:
- The existence of a nasobronchial reflex, leading to bronchoconstriction from nasal stimulation, remains debated.
- Previous studies have been limited by experimental design flaws.
Purpose of the Study:
- To investigate the potential for nasal stimulation to induce reflex bronchoconstriction in asthmatic patients with allergic rhinitis.
- To clarify the mechanisms underlying changes in lower airway resistance following nasal challenges.
Main Methods:
- Double-blind, randomized nasal challenges were conducted in asthmatic patients and controls.
- Increasing concentrations of methacholine or histamine were administered via nasal pledgets.
- Nasal and lower airway resistance were measured, with and without phenylephrine premedication.
Main Results:
- Nasal challenges with methacholine and histamine significantly increased nasal resistance in both groups.
- Only methacholine administration led to an increase in lower airway resistance.
- Phenylephrine premedication blunted the methacholine-induced increase in lower airway resistance, suggesting systemic absorption.
Conclusions:
- The study does not support a nasobronchial reflex mediated by mechanical alteration of the nasal mucosa.
- Observed effects on lower airway resistance appear to be due to systemic absorption of the challenge agent, not a reflex.
- Findings suggest that nasal stimulation itself does not cause reflex bronchoconstriction in this patient population.