Source:http://linkedlifedata.com/resource/umls/id/C0182123
UMD: Gas concentrators designed to increase the percentage of oxygen in a mixture of gases, usually air. Oxygen concentrators usually filter out nitrogen from atmospheric air, providing a gas mixture with a concentration of oxygen that is typically higher than 90%. An oxygen concentrator usually works by filtering out nitrogen (typically using absorption by a zeolite filter) and sending it back to the atmosphere; the remaining high-oxygen-concentration gas is delivered to the patient using a cannula and/or mask. Oxygen concentrators are available as stand-alone units and also as portable devices; they can deliver volumes up to five liter/minute and three liter/minute respectively. Oxygen concentrators are mainly used to supply oxygen therapy to patients by providing to the respiratory tract a gas mixture with a considerably higher concentration of oxygen than the usual concentration found in air (about 19%).