A CPAP machine is a small bedside device that blows air through a mask at a steady pressure, to keep a sleeping person's airway open. CPAP stands for continuous positive airway pressure. It is the most common treatment for obstructive sleep apnoea.
In obstructive sleep apnoea, the muscles of the throat relax during sleep, and the airway collapses. Breathing stops for ten seconds or more, and then restarts with a gasp or a snore. This can happen dozens of times an hour, all night. The number of such events per hour is called the apnoea-hypopnoea index, or AHI. It is measured in a sleep study, in which sensors record a person's breathing, oxygen and sleep through one night.
The machine has a quiet blower, a humidifier that adds water vapour so that the throat does not dry out, a hose, and a mask over the nose, or over the nose and mouth. The pressure is measured in centimetres of water, usually between 4 and 20. An auto-CPAP, also called APAP, changes the pressure through the night. Its software measures the air that the person breathes in and out, many times a second. It raises the pressure when it detects that the airway is starting to close.
Each morning, the machine sends a record of the night. The record goes out through a mobile connection built into the machine, managed through IoT connectivity, to the maker's cloud. It shows the hours of use, how much air leaked from the mask, the pressure and the AHI that remained. The doctor or the sleep clinic reads it on a website, through remote patient monitoring software. A summary can be added to the patient's clinic record.
Imagine a 50-year-old taxi owner in Ludhiana whose sleep study showed an AHI of 38, which is severe. He starts on an auto-CPAP. In the first week, the record shows that he used it for only 2 hours a night, with a large leak from the mask. The clinic calls him, and he changes to a mask of another size. A month later, he uses the machine for about 6.5 hours a night, and his remaining AHI is 3. Without the nightly record, the clinic would have learned none of this until his next visit.
In India, most patients buy their CPAP machine themselves. The software that sets the pressure and reports each night is regulated as part of the device, as software as a medical device explains.