Portable oxygen concentrator (POC) is a portable device used to provide oxygen therapy to people
requiring greater oxygen concentrations than the levels of ambient air. It is similar to a home oxygen concentrator, but is smaller in size and more mobile. The portable oxygen concentrator makes it easy for patients to travel freely; they are small enough to fit in a car and many concentrators are now FAA-approved for use on airplanes.
Portable oxygen concentrators operate on the same principle as a home domestic concentrator, pressure swing adsorption. The atmosphere contains around 21% oxygen; the remainder is nitrogen and a mixture of other gases. An internal air compressor forces this air through a system of chemical filters known as a molecular sieve. This filter is made up of silicate granules called Zeolite which attract (via molecular bond adsorption) nitrogen molecules onto their surfaces more strongly than they attract oxygen molecules – this sieves the nitrogen out of the air, concentrating the oxygen. Part of the oxygen produced is delivered to the patient; part is fed back into the sieves (at greatly reduced pressure) to flush away the accumulated nitrogen, preparing the granule surfaces for the next cycle. Through this process, the system is capable of producing medical-grade oxygen of up to 90% consistently. The latest models can be powered from mains electricity supply, 12v DC (car/boat/aircraft), and battery packs, freeing the patient from relying on using cylinders or other current solutions that put a restriction on time, weight, and size.
Most of the current portable oxygen concentrator systems provide oxygen on a pulse (on-demand) delivery. The system supplies a high concentration of oxygen and is used with a nasal cannula to deliver the oxygen to the patient.