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Comparing 6 and 10 sec exhalation time in exhaled nitric oxide measurements in children
M Koopman1, H G M Arets, C S P M Uiterwaal
1Department of Pediatric Pulmonology, University Medical Center Utrecht, Utrecht, The Netherlands. m.koopman-5@umcutrecht.nl
Insights
Shorter exhalation times for Fractional exhaled Nitric Oxide (FeNO) measurements are feasible for children. FeNO measurements at 6 seconds show good agreement with the standard 10 seconds, making them interchangeable.
Area of Science:
- Pediatric Pulmonology
- Respiratory Medicine
- Allergy and Immunology
Background:
- Standard Fractional exhaled Nitric Oxide (FeNO) measurement is 10 seconds.
- This duration is challenging for young children.
- A 6-second exhalation time for pediatric FeNO has lacked substantiation.
Purpose of the Study:
- To evaluate the agreement between 6-second (FeNO-6) and 10-second (FeNO-10) FeNO measurements.
- To assess children's preference for different exhalation times.
- To determine if FeNO-6 and FeNO-10 are interchangeable in pediatric populations.
Main Methods:
- FeNO was measured using the single-breath online (SBOL) technique in children aged 5-17.
- FeNO values were recorded with both 6-second and 10-second exhalation times in random order.
- Children's preferences were recorded and correlated with Forced Vital Capacity (FVC) values.
Main Results:
- No significant difference was found between median FeNO-6 (15.2 ppb) and FeNO-10 (13.6 ppb) (P = 0.259).
- The mean difference was -0.3 ppb, with limits of agreement from -5.8 ppb to +5.3 ppb.
- Sixty percent of children with FVC < 3 L preferred the 6-second method.
Conclusions:
- FeNO measurements at 6 and 10 seconds show good agreement and can be used interchangeably.
- A 6-second exhalation time is a viable alternative for pediatric FeNO measurements.
- Children with lower FVC values tend to prefer the shorter 6-second exhalation time.
Abstract:
Standard exhalation time for Fractional exhaled Nitric Oxide (FeNO) measurements is 10 sec but this is difficult for young children. Recommended exhalation time for children is 6 sec, but this was never substantiated in literature. We aimed to investigate the agreement between FeNO values measured with exhalation times of 6 and 10 sec and the preference of children for either method. The study population comprised children aged 5-17 years visiting the Pediatric Pulmonology outpatient clinic. FeNO values, measured during 6 (FeNO-6) and 10 (FeNO-10) sec (random order) using the single-breath online (SBOL) technique, were compared. Preferences for exhalation times were related to FVC values. Ninety-eight children (mean age 10.6 years) were included. Median FeNO-6 (15.2 ppb) and FeNO-10 (13.6 ppb) did not differ significantly (P = 0.259). Mean difference between FeNO-6 and FeNO-10 was -0.3 ppb, limits of agreement ranging from -5.8 ppb to +5.3 ppb. Sixty percent of children with a Forced Vital Capacity (FVC) less than 3 L preferred the FeNO-6 method. We found good agreement between FeNO-6 and FeNO-10, so they can be used interchangeably. An exhalation time of 6 sec was preferred by the majority of subjects with a FVC below 3 L.
