Oxygen Conservation and Oxygen- conserving Devices in Chronic Lung Disease* A

The efficacy of long-term oxygen therapy for hypoxemic COPD patients is well established. However, oxygen is expensive and the portability of home oxygen is limited by the weight and bulk of the oxygen source. As a result, there has been a recent surge of interest in creating oxygen-conserving devices and methods. The efficiency of oxygen therapy can be improved over steady flow delivery by focusing oxygen delivery to early inspiration. Three meth-ods for improving oxygen delivery efficiency-trans-HIsi-oRIc PERSPECTIVEJoseph Priestly discovered in 1774 that by focusing the sun’s rays on mercuric oxide using a lens, he could liberate oxygen gas in glass tubes under water.’ He wrote: “The feeling ofit to my lungs is not sensibly different from that ofcommon air, but I fancied that my breast felt light and easy for some time afterward. Who can tell but that, in time, this pure air may be a fashionable article of luxury.” Thomas Beddoes,2 who founded the Pneumatic Institution in Bristol, England in 1798, used oxygen to treat a variety ofmaladies. He was probably the first to make medical use of the newly-discovered gas for a variety of conditions. J. S. Haldane used oxygen to treat chlorine poisoning during World War He suggested that oxygen should be used continuously if benefit is to be derived. Oxygen was not used systematically in the treatment of patients until the 1920s when the late Alvan L. Barach, considered by many to be the father of modern oxygen therapy, began using it to treat patients with 5 He noted that patients improved faster