Multiple flow rate modelling of nitric oxide in COPD – methodological concerns

Abstract

Multiple flow rates FeNO data two-compartment mathematical modelling can estimate NO airway wall concentration (CawNO), airway wall diffusing capacity (DawNO), alveolar concentration (CalvNO) and maximal NO flux (JawNO). To compare modelling based on linear, non linear and mixed linear and non linear analyses in COPD. FeNO was measured using the Niox analyser (Aerocrine) at flow rates: 10, 30, 50, 100 and 200ml/s in 50 COPD patients and the data applied to 4 different methods. All methods showed that current smoking reduced CawNO. JawNO data differed between methods (Table 1). All the methods showed that current smoking did not affect CalvNO or DawNO. Comparison of the methods showed that CalvNO and DawNO data were significantly different between all methods, JawNO was different for most between method comparisons, while there was agreement between all the methods for CawNO. Smoking in COPD reduces CawNO , but not CalvNO and DawNO. JawNO, CalvNO and DawNO data are model dependent parameters. CawNO findings were model independent, and hence the most robust modelled parameter.