Feno levels as an aid in the management of asthma
| Feno (ppb) | Range | Eosinophilic airway inflammation | Interpretation (as an aid in the management of asthma) | |
|---|---|---|---|---|
| Adults | Children | |||
| 5 10 15 20 25 | Low | Unlikely | If symptomatic, review diagnosis Neutrophilic asthma Anxiety/hyperventilation Vocal cord dysfunction Rhinosinusitis Gastro-oesophageal reflux | If symptomatic, review diagnosis Consider also: Wheezy bronchitis Cystic fibrosis Congenital abnormalities, e.g. airway malacia Primary ciliary dyskinesia |
| If asymptomatic and taking ICS: Implies good compliance with treatment.Reduce dose or, in case of low ICS dose,even withdraw ICS altogether | If asymptomatic and taking ICS: as for adults | |||
| 30 35 40 | Intermediate | Present but mild | If symptomatic, consider: Infection as reason for worsening High levels of allergen exposure Adding in other therapy apart from ICS(e.g. long acting β agonist) Consider ICS dose increase | If symptomatic (besides considerations in adults), consider: Possible inadequate ICS treatment (1) check compliance (2) check for poor inhaler technique and consider metered dose inhaler and spacer if patient is currently using a dry powder device |
| If asymptomatic No change in ICS dose if patient is stable | If asymptomatic: as for adults | |||
| 45 50 55 60 65 Higher levels | High (or rise of 60% or more since previous measurement) | Significant | If symptomatic, consider: Inadequate ICS treatment: (1) check compliance (2) check for poor inhaler technique (3) inadequate ICS dose Continuous high level allergen exposure Imminent exacerbation or relapse depending on history of individual patient. More likely if ICS dose is zero Steroid resistance (rare) | If symptomatic (besides considerations in adults) consider: Metered dose inhaler and spacer if patient is currently using a dry powder device |
| If asymptomatic No change in ICS dose if patient is stable | If asymptomatic: as for adults | |||