Measuring Offline eNO in children by chemiluminescence vs. electrochemical devices.

Exhaled nitric oxide (eNO), a noninvasive marker of airway inflammation, is employed in children using the "offline" technique. No studies in the literature compare the concordance and correlation between the two technologies used to measure eNO at tidal volume offline. 

A present study report the concordance and correlation of the eNO measured "offline" at tidal volume, using chemiluminescence (cl) vs. electrochemical devices (eq).

It included healthy children and those with a lung disease between 1 and 11 years of age and obtained their exhaled air sample at tidal volume by attaching a mask connected to a Mylar® bag.

 The study observed-

• Thirty-six children were enrolled. 
• The mean ± standard deviation (SD) age of the study population was 6 ± 2.6 years 
• 25% of the enrolled subjects were healthy, and the rest had lung disease. 
• The concordance correlation coefficient between the two measuring devices was 0.98, with a mean difference of 1.46 ± 3.5 ppb and 95% limits of agreement from -5.3 ppb to 8.3 ppb. 
• The linear regression model equation for the estimation of eNO was eNOcl = (eNOeq•1.0718) - 0.1343 (r2 = 0.97).

This study shows that electrochemical devices can measure eNO at tidal volume by the offline method. Furthermore, its results are interchangeable with those analyzed by chemiluminescence technology.

Bol Med Hosp Infant Mex. 2021;78(5):404-410. English. Doi: 10.24875/BMHIM.20000345. PMID: 34571514.