Relationship between Fractional Exhaled Nitric Oxide and Forced Oscillometric Technique in the Assessment of Asthma

Abstract Background: Fractional exhaled nitric oxide (FeNO) and forced oscillometric technique (FOT) represent noninvasive and sensitive tools for measuring airway inflammation and resistance, respectively, but the studies that use FeNO and FOT to assess patients with asthma until now are few. Objective: This study aimed to evaluate the role of FeNO and FOT in the assessment of chronic asthma. Materials and Methods: This cross-sectional study involved 75 patients (10–70 years old) with chronic asthma who visited a private Spiro clinic in Al-Hilla City, Iraq, in the period from April 2022 to February 2023. They were examined by using the FeNO apparatus and FOT. Results: There were no significant differences between the patient and control group regarding age, gender, and body mass index. The study showed a significant relationship between expiratory flow rate and FeNO ( P = 0.000). There was also a significant relationship between large airway resistance (Rrs) and FeNO ( P = 0.008). In addition, there was a significant relationship between the resistance of small airways (as represented by Rrs19Hz) and FeNO level ( P = 0.04). The study also found a significant relationship between reactance and FeNO level ( P = 0.008). Conclusion: From the results, they conclude that the use of FOT and FeNO together gives considerable importance in the assessment of asthma.