[Mexican consensus on fractional exhaled nitric oxide (FeNO) in asthma 2020].

The fractional exhaled nitric oxide (FeNO) is related to the level of eosinophilic inflammation in the airways and the levels of interleukin-13, as such it could be a diagnostic and monitoring tool in asthma. A working group was convened between pulmonologists, respiratory physiology experts, and allergists to establish criteria for the use of FeNO in asthma in Mexico. Through a simplified Delphi method and group discussion, seven key points regarding the use of FeNO were agreed upon. We agree that the measurement of FeNO serves for the diagnosis of asthma in specialized clinics, both in children and adults, as well as to determine the level of corticosteroid treatment. In severe asthma, we recommend FeNO for endotyping, for detecting poor therapeutic adherence, undertreatment, and the risk of crisis. We suggest FeNO can be used to determine the level of corticosteroid treatment and to identify patients at risk of loss of lung function. We also recommend it in adults to improve the selection of biological therapy and, in this context, we only suggest it in selected cases for children.