16th February 2025

Flow-volume loops

A flow-volume loop is constructed from spirometry involving forced maximal inspiration and expiration. The cycle is clockwise, with an upward deflection indicating expiration and a downward indicating inspiration. The start point of maximal inspiration (total lung capacity, TLC) is the leftmost point of the loop, with the rightmost point representing the minimal lung volume (residual volume, RV).

References

• Chapman SJ, Robinson GV, Shrimanker R, Turnbull CD, Wrightson JM. Oxford handbook of respiratory medicine. 4th ed. London, England: Oxford University Press; 2021
• Bourke SJ. Respiratory medicine: Lecture notes, 10th edition: Lecture Notes. 10th ed. Hoboken, NJ: Wiley-Blackwell; 2022
• Bessant R et al. The pocketbook for PACES. London, England: Oxford University Press; 2012
• British Thoracic Society, Scottish Intercollegiate Guidelines Network. British guideline on the management of asthma. Thorax. 2014;69 Suppl 1:1–192
• Kaminsky DA. Overview of pulmonary function testing in adults [Internet]. McCormack MC, editor. UpToDate. 2022 [cited 2022 Dec 9]. Available from: https://www.uptodate.com/contents/overview-of-pulmonary-function-testing-in-adults
• McCormack MC. Diffusing capacity for carbon monoxide [Internet]. Stoller JK, editor. UpToDate. 2022 [cited 2022 Dec 9]. Available from: https://www.uptodate.com/contents/diffusing-capacity-for-carbon-monoxide