Nebulised water as a bronchoconstricting challenge in infancy

Area of Science:

• Pediatric Pulmonology
• Respiratory Physiology
• Allergy and Immunology

Background:

• Infants with a history of wheeze often exhibit airway hyperresponsiveness.
• The role of inhaled water as a challenge agent in pediatric populations requires further elucidation.
• Understanding bronchoconstriction triggers is crucial for managing pediatric respiratory conditions.

Purpose of the Study:

• To investigate the pulmonary response to inhaled nebulized water in sedated infants with a history of wheeze.
• To assess the potential for a refractory period following repeated nebulized water challenges.

Main Methods:

• Pulmonary function was assessed using total body plethysmography in 100 sedated infants.
• Inhalation challenge was performed with nebulized distilled water.
• Specific airway conductance (sGaw) changes were measured to determine bronchoconstriction (>20% decrease).

Main Results:

• Fifty-one out of 88 infants (approximately 58%) showed a significant decrease in sGaw after nebulized water challenge.
• Only one infant responded to a prior nebulized saline challenge, suggesting water-specific reactivity.
• Repeated nebulized water challenges in a subset of infants indicated no significant refractory period, with 75% still responding after the second challenge.

Conclusions:

• Inhaled nebulized water is a potent stimulus for bronchoconstriction in approximately 60% of infants with a history of wheeze.
• The study suggests a lack of a significant refractory period to inhaled water challenge in this population.
• These findings highlight the utility of nebulized water as a challenge agent in pediatric respiratory assessments.