Spirometry effects on conventional and multiple flow exhaled nitric oxide in children

Area of Science:

• Respiratory Medicine
• Pediatric Pulmonology
• Biomarkers

Background:

• Clinical guidelines suggest measuring exhaled nitric oxide (FeNO) before spirometry.
• Evidence on spirometry's carryover effect on FeNO is inconsistent.
• Limited research exists on spirometry's impact on multiple flow FeNO measures.

Purpose of the Study:

• To assess spirometry's carryover effect on FeNO at 50 ml/s, airway wall NO flux (J'awNO), and alveolar NO concentration (CANO).
• To evaluate these effects in a population-based sample of schoolchildren.

Main Methods:

• 1146 schoolchildren (ages 12-15) from the Southern California Children's Health Study participated.
• Participants underwent spirometry and multiple flow FeNO testing on the same day.
• Multiple linear regression analyzed FeNO measures in relation to spirometry order, adjusting for confounders.

Main Results:

• No spirometry carryover effect was observed in the overall sample.
• In children with asthma, FeNO, J'awNO, and CANO showed a trend towards lower values when measured within 6 minutes after spirometry.
• Specific reductions observed: FeNO (25.8%), J'awNO (15.1%), and CANO (0.43 ppb).

Conclusions:

• Measuring multiple flow FeNO before spirometry is advisable in clinical settings.
• For studies involving healthy children, pre-spirometry FeNO measurement may not be essential.
• Further research may clarify the clinical significance of spirometry's impact on FeNO in asthmatic children.