Key notes around fraction of exhaled nitric oxide marker in pneumonia

Abstract

Background Fractional exhaled nitric oxide (FeNO) is recognized as an airway inflammatory indicator for various respiratory insults like asthma, cystic fibrosis, and chronic obstructive pulmonary disease exacerbation.Aim To study the relation between FeNO level in exhaled breath and pneumonia types, nonventilator-associated pneumonia (VAP) [including community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and aspiration pneumonia (AsP)] and VAP, as well as relation to arterial oxygen tension/FiO2 ratio and the extent of radiological affection.Patients and methods A prospective cross-sectional study was conducted on 88 patients admitted to Mansoura University Children’s Hospital with pneumonia, either mechanically ventilated or not. FeNO level was measured during end-expiration via spirometry calibration syringe in VAP and by direct measurement in CAP, HAP, and AsP. Levels of FeNO were compared between patients in relation to different characteristics such as age, sex, arterial oxygen tension/FiO2 ratio, extent of radiological affection, and to a clinically modified PIRO (predisposition, insult, response, and organ dysfunction) score.Results FeNO level was higher in the expired air in VAP followed by AsP then HAP and lastly CAP (37.6, 33.4, 31.9, and 29.1 ppb, respectively; P=0.001). A statistically significant difference was detected among the four groups regarding FeNO level. Radiological grading of pneumonia was informative; grades III and IV showed higher percentage in total studied patients. There was statistically significant weak positive effect of modified PIRO score on FeNO level (r=0.255, P=0.017).Conclusion FeNO could be used as a beneficial airway inflammatory marker that is related to modified PIRO score in children but cannot identify pneumonia type.