OCDs are available and their use is growing in the home care market because of economic factors associated with LTOT, but this trend has evolved with little clinical research. There is great variability among the oxygen control systems, and physicians need to test patients on each device, at each activity level the patient is capable of in the home, and to write a prescription for each activity level. OCDs should be used because of the patient benefits of improved activity and compliance with a 24-hour prescription, and the economic benefit associated with reduced delivery of oxygen. Clinicians and patients need to be thoroughly familiar with the oxygen system they are using and to understand its capabilities and limitations. More research is required to evaluate the application and effectiveness of and the differences between products and outcomes of OCDs used in home care. Equivalency between CFO and OCDs should not be necessary because of the differences between these delivery methods and the great variability of products.