Fig. 9From: Measuring lung mechanics of expiratory tidal breathing with non-invasive breath occlusionExpiration is not an entirely passive process, as seen by non-linearity between flow and volume. This QV loop is the top half of the typically analysed spirometry QV loop, as only expiration is assessed. However, the end-expiratory portion shows a generally linear trend, indicating lung mechanics do not vary in this portionBack to article page