https://www.techdirt.com/articles/20200416/02595644310/over-the-air-updates-could-turn-millions-inexpensive-devices-into-much-needed-ventilators-to-treat-seriously-ill-covid-19.shtml

Last week we wrote about attempts to repair much-needed ventilators for serious coronavirus cases being stymied by manufacturers' refusal to allow hospital technicians to carry out the necessary work. Trammell Hudson, who describes himself as "a programmer, photographer, frequent hacker and occasional watchmaker", has come up with another approach to supplying ventilators to hospitals. It involves taking the inexpensive and widely-used Constant Positive Air Pressure (CPAP) devices typically used for sleep apnea, and turning them into emergency ventilators suitable for COVID-19 patients. These are known as Bi-level Positive Airway Pressure (BiPAP) machines. BiPAP devices are more sophisticated than CPAP ones: they apply higher pressure when the patient tries to breathe in, and lower pressure when they start to breathe out. In investigating the popular Airsense 10 CPAP device manufactured by ResMed, Hudson made a remarkable discovery:

Our work indicates that the actual difference between a low-end CPAP device and a high-end iVAPS [intelligent volume-assured pressure support] device is just a software upgrade. The CPAP machines have many of the same sensors as the more expensive models, and the Airsense 10 CPAP devices include in their firmware all of the other modes, such as iVAPS and BiPAP-ST [spontaneous/timed mode]. When we unlock that mode in software, the CPAP device functions like a much more capable and expensive iVAPS device.