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Published on: June 11, 2014
Methodological aspects of exhaled nitric oxide measurements in infants
Carmelo Gabriele1, Els C van der Wiel, Eveline M Nieuwhof
1Department of Pediatric Respiratory Medicine, Erasmus Medical Centre, Sophia Chldren's Hospital, Rotterdam, The Netherlands.
Insights
Lung function tests and sedation do not affect fractional exhaled nitric oxide (FE(NO)) in infants. Breastfeeding also has no impact, but oral FE(NO) is lower than mixed nasal and oral measurements.
Area of Science:
- Pediatric Pulmonology
- Respiratory Physiology
- Biomarker Measurement
Background:
- Fractional exhaled nitric oxide (FE(NO)) measurements are influenced by pre-test conditions in adults.
- Limited data exists on factors affecting FE(NO) in infants, particularly those with airway diseases.
Purpose of the Study:
- To investigate the impact of lung function tests (LFT), sedation, nasal contamination, and breastfeeding on FE(NO) in infants.
- To assess the reproducibility of FE(NO) measurements in healthy infants.
Main Methods:
- FE(NO) was measured off-line using a facemask during tidal breathing in sedated infants with airway diseases and unsedated healthy infants.
- FE(NO) was compared before and after LFT, before and during sedation, and before and after breastfeeding.
- Oral vs. mixed (nasal+oral) FE(NO) and short-term reproducibility were also evaluated.
Main Results:
- No significant difference in FE(NO) was observed before and after LFT or before and during sedation in infants with airway diseases.
- Oral FE(NO) values were significantly lower than mixed FE(NO) values (p < 0.001).
- Breastfeeding did not affect FE(NO) values, and short-term reproducibility in healthy infants was satisfactory (ICC = 0.94).
Conclusions:
- LFT and sedation do not appear to influence FE(NO) measurements in infants with airway diseases.
- Oral FE(NO) measurement is lower than mixed measurement, and breastfeeding is not a confounding factor.
- FE(NO) measurement in infants demonstrates good short-term reproducibility.
Abstract:
Guidelines for the measurement of fractional exhaled nitric oxide (FE(NO)) recommend refraining from lung function tests (LFT) and certain foods and beverages before performing FE(NO) measurements, as they may lead to transiently altered FE(NO) levels. Little is known of such factors in infants. The aim of the present study was to evaluate whether forced expiratory maneuvers, sedation, nasal contamination, and breastfeeding affect FE(NO) values in infants. FE(NO) was measured off-line during tidal breathing by means of a facemask covering nose and mouth. FE(NO) measurements were performed in 45 sedated infants (mean age 12.1 months) who underwent LFT because of airway diseases and in 83 unsedated healthy infants (mean age 4.3 months). In infants with airway diseases, no difference was found in FE(NO) values before and 5 min after LFT (n = 19 infants, p = 0.7) and FE(NO) values before sedation did not differ from FE(NO) values during sedation (n = 10 infants, p = 0.2). Oral FE(NO) values were significantly lower than mixed (nasal + oral) FE(NO) (n = 42 infants, p < 0.001). FE(NO) values before and 5 min after breastfeeding were not different (n = 11 healthy infants, p = 0.57). The short-term reproducibility in healthy infants (n = 54) was satisfactory (intraclass correlation coefficient = 0.94). We conclude that, in infants with airway diseases, LFT prior to FE(NO) measurement did not influence FE(NO) values and FE(NO) values did not change after sedation. Oral FE(NO) values were significantly lower than mixed (oral + nasal) FE(NO), and breastfeeding did not influence FE(NO). Short-term reproducibility in awake healthy infants was good.
