The fraction of exhaled nitric oxide (FeNO) is elevated in asthmatics compared to normal subjects. Many studies have demonstrated that FeNO correlates with other markers of airway inflammation. The purpose of this study was to assess the clinical utility of routine monitoring of FeNO in determining its ability to predict future asthma exacerbations compared with other standard clinical measures of spirometry, peak flows, quality of life score, medication usage, and symptoms. A convenience sample of 22 patients with moderate and severe-persistent asthma in the University of New Mexico Adult Asthma Clinic were evaluated during a routine clinic visit and then noted whether they had an exacerbation within 2 weeks of the initial appointment. Those with an exacerbation had a higher mean FeNO (29.67 ppb +/- 14.48) compared to those who did not (12.92 ppb +/- 5.17), p = 0.002. A nominal logistic regression model to determine those variables that predict asthma exacerbation found that FeNO was the only significant predictor, p = 0.03. Thus, FeNO appears to be a clinically useful tool to assess disease control in this population.

The In-Check-Dial (Alliance Tech Medical, Granburg, TX) was used to determine adequacy of inhalation techniques and teaching of two different devices. Retention of adequate techniques, was assessed in 234 moderate to severe asthmatics. Inhalation techniques were assessed at periodic follow-ups divided into less than 1 month return visit, between 1 and 3 months, 3 to less than 6 months, and 6 months to less than 1 year. Proper inhalation techniques worsened at greater than 3 months after the last instruction. The use of the In-Check-Dial is a useful tool in teaching proper technique and monitoring the patient's ability to correctly use inhalation devices.

To assess whether bronchial wall thickening during asthma exacerbations is due to active inflammation in severe asthmatics, we measured bronchial wall thickness and exhaled nitric oxide (FeNO) following treatment. Nine asthmatics were compared with seven controls with high-resolution computed tomography, spirometry, and FeNO measurements. The asthmatic bronchial wall area percent and FeNO was greater than controls. Following treatment, the FEV1 markedly improved, FeNO decreased modestly, and bronchial wall area percent did not change significantly. Bronchial wall thickening persisted after treatment of acute asthma exacerbation despite improvement in spirometry and decline in FeNO, possibly due to chronic airway remodeling.

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