Meter, peak-flow
This hand-held device measures air flow (how fast air is blown out of the lungs).
Patients can use peak-flow meters to measure their own air flow regularly.
The use of a peak-flow meter allows patients to obtain a much earlier indication of an oncoming attack, for example, of exercise-induced asthma, a type of asthma typically triggered by exercise.
The 'peak flow' refers to the maximum flow rate of air breathed out during forced expiration.