Spirometry

Welcome to today's Knowledge Nugget. During this episode, we will dive in and explore the most essential information surrounding spirometry in detail. The content of this video will cover the broader definition of spirometry, its categorization into different test types, and the most relevant practices and applications of spirometry.

During a spirometric examination, the breath of the subject travels from a specially fitted mouthpiece into the so-called spirometer, or measuring device. This process is performed under resting conditions or in combination with CPET. The outcome of the measurement gives us information about the respiratory capacity and flow of the lungs. In other words, it assesses how well the lungs function by measuring how much air a person can inhale or exhale, in combination with the speed and force of those movements.

The main maneuvers of spirometry are listed in this table, starting off with the vital capacity test, which is mostly used on patients with respiratory limitations, where no forcing of the breathing maneuver is required. On the contrary, the forced vital capacity requires maximum effort from the subject during exhalation. And lastly, the maximum voluntary ventilation demands that a subject breathe in and out as much and as fast as possible for 15 seconds. By conducting these maneuvers, clinicians or sports physicians can [as part of their overall assessment] diagnose a series of chronic lung conditions.

Here we see a graphical representation of the forced vital capacity and the performance of static lung volumes. This respiratory curve can later on be combined with the respiratory recordings during a stress test, the so-called exercise flow-volume loops, thus providing us with a conclusive picture of the dynamics of respiration under stress. By observing the ventilation curve for any disturbances of the loop, we could potentially diagnose stress-induced asthma [in combination with further diagnostics].

To conclude, spirometry is a diagnostic approach to assess and identify limitations of the lungs. It can either take place in a resting state or be implemented within an exercise condition. Spirometry is also used to [help] confirm whether a specific therapy or treatment has a positive effect on the breathing condition. Thank you for joining.