An Open Health Care UK project
A spirometer is a medical device to measure lung function. It determines how much air the lungs can hold and how effectively a patient can move air in and out.
Spirometers are used to diagnose and monitor a variety of lung diseases such as emphysema & chronic bronchitis.
For example, asthma patients are often asked to measure their lung function every morning and evening to monitor their response to changes in medication.
In cystic fibrosis sufferers, a 20% reduction in airflow is an indication for immediate hospital admission.
At home, a reading is usually taken by breathing into the mouthpiece of a handheld meter.
The value is read from the scale next to a sliding marker: this is time-consuming, unhygienic and error-prone
The most common device is called a pneumotachometer. These devices use pressure sensors to calculate to the flow rate of the air.
While pneumotachometers are accurate, they are costly and fragile and must be calibrated daily.
The Open Spirometer project aims to make accurate spirometry possible using just a microphone, such as one built into a mobile smartphone.
Earlier detection of issues can avoid the need for hospital admission, associated with a poorer prognosis as well as increased healthcare costs.
The increased convenience could encourage out-patients to measure their air flow more often, increasing the amount of data available to their doctors.
The widespread availability of smartphones will save time & funds spent purchasing and adjusting expensive hospital-based spirometers.