Agreement Between the 6 Seconds and 10 Seconds Exhalation Modes When Measuring Fractional Exhaled Nitric Oxide in Children Aged 4-6 Years With the NIOX VERO Device

Abstract

SESSION TITLE: Pediatrics SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: NIOX VERO has the capability to measure fractional exhaled nitric oxide (FeNO) using both the 6 second (6s) and the 10 second (10s) exhalation modes. ATS/ERS 2005 guidelines for measurement of FeNO in children require exhalation of at least 4 seconds for children <12 years of age and >6 seconds for children >12 years of age. This study was undertaken to compare results of FeNO measurements performed using the 6s and 10s exhalation modes in children 4-6 years of age. METHODS: This was a randomized, multi-center, single-visit study with healthy and asthmatic children 4 to 6 years of age. Subjects were randomized to perform FeNO measurements starting with either the 6s or 10s exhalation mode. Data are presented in which the degree of agreement of FeNO measurements using the 6s and the 10s exhalation modes was assessed by weighted Deming regression analysis. RESULTS: The total population (n=247) consisted of 137 (55.5%) males, had a mean height of 112.8 cm, and was composed of 73 four year olds (4yo), 87 five year olds (5yo) and 87 six year olds (6yo). 105 subjects completed one FeNO measurement in either mode (20 4yo, 40 5yo, 45 6yo). An additional 88 subjects completed one FeNO measurement in either mode but were discontinued because enrollment into the low FeNO group (<20 ppb) was met (25 4yo, 30 5yo, 33 6yo). 54 subjects were unable to complete any FeNO measurements (28 4yo, 17 5yo, 9 6yo). There were 83 subjects that completed one FeNO measurement in both modes. Average FeNO values for the 6s (21.3 ppb) and the 10s (21.0 ppb) modes were comparable and paired differences between the replicates centered around zero for each age group. The 4yo mean paired difference was -0.3 (n=13, SD=1.58, median=0.0). The 5yo mean paired difference was 0.5 (n=31, SD=3.61, median=0.5). The 6yo mean paired difference was 0.4 (n=39, SD=3.70, median=0.5). Of the 83 subjects, 68 completed two FeNO measurements in both modes. Average FeNO values for the 6s (21.1 ppb) and the 10s (20.7 ppb) modes were comparable and paired differences between the replicates centered around zero for each age group. The 4yo mean paired difference was 0.4 (n=9, SD=0.74, median=0.0). The 5yo mean paired difference was 0.6 (n=27, SD=3.28, median=0.5). The 6yo mean paired difference was 0.1 (n=32, SD=3.99, median=0.3). The estimated intercept and slope from the weighted Deming regression modeling 6s mode FeNO results as a function of the 10s mode FeNO results were not significantly different from 0 and 1.0, respectively. Average bias in the predicted 6s mode FeNO results expressed as a percent of the 10s mode FeNO result was low (1.03%), and the bias at the 35 ppb cut-off value (0.391) was significantly less than 7 ppb (20% of 35 ppb; p<0.0001). FeNO values were within the tolerance limits at the 35 ppb cut-off value for 65/68 subjects (95.6%). There were no reported adverse events or serious injuries. CONCLUSIONS: The results of this study demonstrate that the degree of agreement between the 6s and 10s modes was high and that the NIOX VERO was safe in children 4-6 years of age. CLINICAL IMPLICATIONS: Performing FeNO measurements to assess TH2 inflammation in the airway using the 6s mode is a feasible option and can provide valuable information in the management of asthma in children 4-6 years of age. DISCLOSURE: Kathy Rickard: Employee: salary Margot MacDonald-Berko: Employee: salary Robert Anolik: Grant monies (from industry related sources): contract for study-related tasks Neal Jain: Grant monies (from industry related sources): contract for study-related tasks, Consultant fee, speaker bureau, advisory committee, etc.: contract for advisory board and speaker fees Craig La Force: Grant monies (from industry related sources): contract for study-related tasks, Consultant fee, speaker bureau, advisory committee, etc.: contract for speaker fees Richard Wasserman: Grant monies (from industry related sources): contract for study-related tasks The use of the NIOX VERO 6s exhalation mode and the use of the NIOX VERO in children younger than 7 years of age are uses not yet cleared by the FDA. However, the results of this study have been submitted to the FDA for 510k and clearances may be obtained prior to the CHEST meeting.