Global strategy for asthma management and prevention. National Heart, Lung, and Blood Institute (U.S.) - Federal Government Agency [U.S.] World Health Organization - International Agency. 1995 Jan (revised 2005). 184 pages. NGC:004592
Excerpts from GINA Guidelines:
Figure 1-6: Key Mediators of Asthma. Nitric oxide (NO), a potent vasodilator, is produced predominantly from the action of inducible nitric oxide synthase in airway epithelial cells107. Exhaled NO is increasingly being used to monitor the effectiveness of asthma treatment, because of its reported association with the presence of inflammation in asthma108.
"Non-invasive markers of airway inflammation. The evaluation of airway inflammation associated with asthma may be undertaken by examining spontaneously produced or hypertonic saline-induced sputum for eosinophilic or neutrophilic inflammation30. In addition, levels of exhaled nitric oxide (FeNO)31 and carbon monoxide (FeCO)32 have been suggested as non-invasive markers of airway inflammation in asthma. Levels of FeNO are elevated in people with asthma (who are not taking inhaled glucocorticosteroids) compared to people without asthma, yet these findings are not specific for asthma. Neither sputum eosinophilia nor FeNO has been evaluated prospectively as an aid in asthma diagnosis, but these measurements are being evaluated for potential use in determining optimal treatment33,34.
Asthma Control. Asthma control may be defined in a variety of ways. In general, the term control may indicate disease prevention, or even cure. However, in asthma, where neither of these are realistic options at present, it refers to control of the manifestations of disease. Ideally this should apply not only to clinical manifestations, but to laboratory markers of inflammation and pathophysiological features of the disease as well. There is evidence that reducing inflammation with controller therapy achieves clinical control, but because of the cost and/or general unavailability of tests such as endobronchial biopsy and measurement of sputum eosinophils and exhaled nitric oxide30-34, it is recommended that treatment be aimed at controlling the clinical features of disease, including lung function abnormalities. Figure 2-5 provides the characteristics of controlled, partly controlled and uncontrolled asthma. This is a working scheme based on current opinion and has not been validated."
References
30. Pizzichini MM, Popov TA, Efthimiadis A, Hussack P, Evans S, Pizzichini E, et al. Spontaneous and induced sputum to measure indices of airway inflammation in asthma. Am J Respir Crit Care Med 1996;154(4 Pt 1):866-9.
31. Kharitonov S, Alving K, Barnes PJ. Exhaled and nasal nitric oxide measurements: recommendations. The European Respiratory Society Task Force. Eur Respir J 1997;10(7):1683-93.
32. Horvath I, Barnes PJ. Exhaled monoxides in asymptomatic atopic subjects. Clin Exp Allergy 1999;29(9):1276-80.
33. Green RH, Brightling CE, McKenna S, Hargadon B, Parker D, Bradding P, et al. Asthma exacerbations and sputum eosinophil counts: a randomised controlled trial. Lancet 2002;360(9347):1715-21.
34. Smith AD, Cowan JO, Brassett KP, Herbison GP, Taylor DR. Use of exhaled nitric oxide measurements to guide treatment in chronic asthma. N Engl J Med 2005;352(21):2163-73.
108. Smith AD, Taylor DR. Is exhaled nitric oxide measurement a useful clinical test in asthma? Curr Opin Allergy Clin Immunol 2005;5(1):49-56.