Ask the Expert: Lung function measurement

Abstract

1. According to 2005 American Thoracic Society (ATS)/European Respiratory Society guidelines [1], the use of a nose-clip or manual occlusion of nares is recommended.... This refers to spirometry. Previous guidelines stated that for dynamic tests, a nose-clip was not necessary, as there should be little time-delay from maximal inspiration to insertion of mouthpiece and maximal exhalation to end-expiration; however, in practice, this is not always case. My opinion is that use of nose-clips rules out air leak from nose, which may not be apparent to operator, and which may cause underestimation of measured values. It also prevents patient from taking a second inspiration through nose in middle of a test, and thus giving inaccurate forced vital capacity (FVC) values. Some of my colleagues who routinely test children often make a game of child holding their own nose while doing test, and so it becomes more fun than uncomfortable hospital rules! This can be done, provided child keeps his elbows at his side and not raised; alternatively, ask a parent to do it. I think advantages outweigh disadvantages.