Studies have disagreed as to the benefit of using exhaled nitric oxide to guide management of asthma in pregnancy. Powell et al randomized 220 pregnant women to be managed either according to symptoms (control) or by concentrations of exhaled nitric oxide (FENO).
Pregnant women whose asthma was managed by FENO had fewer asthma exacerbations during pregnancy (0.288 vs 0.615, with a number needed to treat of 6 to prevent an exacerbation, p=0.001). Quality of life was minimally improved by questionnaire. Strikingly, neonatal hospitalizations were also reduced (8 vs. 18, p<0.05).
Powell H et al. Management of asthma in pregnancy guided by measurement of fraction of exhaled nitric oxide: a double-blind, randomised controlled trial. Lancet 2011;378:983 – 990.
The use of exhaled nitric oxide concentration as a diagnostic and management tool in asthma is gaining currency — read the guideline in this month’s AJRCCM.