RT Journal Article
SR Electronic
T1 The effect of oxygen and carbon dioxide cross-sensitivity sensor error in the Eco Medics Exhalyzer D device on measures of conductive and acinar airway function
JF ERJ Open Research
JO erjor
FD European Respiratory Society
SP 00614-2021
DO 10.1183/23120541.00614-2021
VO 8
IS 3
A1 Jack Bozier
A1 Edward Jeagal
A1 Paul D. Robinson
A1 G. Kim Prisk
A1 David G. Chapman
A1 Gregory G. King
A1 Cindy Thamrin
A1 Sandra Rutting
YR 2022
UL http://openres.ersjournals.com/content/8/3/00614-2021.abstract
AB Introduction The multiple breath nitrogen washout (MBNW) test provides important clinical information in obstructive airways diseases. Recently, a significant cross-sensitivity error in the O2 and CO2 sensors of a widely used commercial MBNW device (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) was detected, which leads to overestimation of N2 concentrations. Significant errors in functional residual capacity (FRC) and lung clearance index (LCI) have been reported in infants and children. This study investigated the impact in adults, and on additional important indices reflecting conductive (Scond) and acinar (Sacin) ventilation heterogeneity, in health and disease.Methods Existing MBNW measurements of 27 healthy volunteers, 20 participants with asthma and 16 smokers were reanalysed using SPIROWARE V 3.3.1, which incorporates an error correction algorithm. Uncorrected and corrected indices were compared using paired t-tests and Bland–Altman plots.Results Correction of the sensor error significantly lowered FRC (mean difference 9%) and LCI (8–10%) across all three groups. Scond was higher following correction (11%, 14% and 36% in health, asthma and smokers, respectively) with significant proportional bias. Sacin was significantly lower following correction in the asthma and smoker groups, but the effect was small (2–5%) and with no proportional bias.Discussion The O2 and CO2 cross-sensitivity sensor error significantly overestimated FRC and LCI in adults, consistent with data in infants and children. There was a high degree of underestimation of Scond but minimal impact on Sacin. The presence of significant proportional bias indicates that previous studies will require reanalysis to confirm previous findings and to allow comparability with future studies.O2 and CO2 cross-sensitivity sensor error in the Exhalyzer D device significantly overestimates FRC and LCI in adults, consistent with infants and children. Importantly, there was a high degree of underestimation of Scond, but minimal impact on Sacin. https://bit.ly/3HcH3Tp