To clip or not to clip? Noseclips for spirometry

The use of noseclips for open-circuit spirometry is sporadic, despite guidelines encouraging their use. The authors aimed to evaluate whether noseclips significantly affected measurements of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) in children attending a tertiary, paediatric respiratory centre. Children attending the asthma and cystic fibrosis (CF) clinics were asked to perform two sets of spirometry, one with and one without noseclips in random order, 20-min apart. Paired data was obtained on 62 patients (32 asthma, 30 CF) with a median age of 11.4 yrs (range 7.2-17.2 yrs). There were no systematic differences in FEV1 or FVC measured with and without noseclips, although seven children (11%,) had clinically significant differences in FEV1 of >190 mL. There is no clear advantage to wearing noseclips when performing open-circuit spirometry. Individuals should be assessed to ascertain their optimal technique, which should then be used consistently in clinical practice. Noseclips should probably be retained for research protocols.