Home oxygen therapy under Medicare. A primer.

Medicare recently implemented a new, strict, and complex home oxygen policy and a new oxygen prescription form. Unfortunately, the lack of instructions for the form has led to confusion, frustration, and suboptimal treatment. Long-term oxygen therapy prolongs survival, ameliorates hypoxic organ dysfunction, and improves exercise endurance. Indications for therapy include hypoxemia caused by cardiopulmonary diseases, hypoxemia that occurs with sleep or exercise, and hypoxemic organ dysfunction. Patients should be stable and have an arterial blood oxygen tension (PaO2) of 55 mm of mercury (7.3 kPa) or less or arterial blood oxygen saturation (SaO2) of 88% or less. There should be evidence of hypoxic organ dysfunction when the (PaO2) is 56 to 59 mm of mercury (7.4 to 7.8 kPa) or the SaO2 is 89%. A medical review by the insurance carrier is required if oxygen is to be prescribed when hypoxemia is less severe--if the PaO2 is 60 mm of mercury (8.0 kPa) or more or if the SaO2 is 90% or more. The instructions for oxygen flow, duration, and equipment must be explicit to ensure adequate therapy. An oxygen concentrator with a small oxygen cylinder portable system fulfills most needs. Oxygen cylinders may be used at low flows for patients who require therapy only during sleep or where electrical power is unreliable. A liquid oxygen system may be prescribed for active patients. Portable equipment should be provided in addition to stationary equipment when patients have resting hypoxemia. Portable equipment alone is sufficient when there is exercise-related hypoxemia with normal oxygenation at rest. Newly developed oxygen-conserving devices may offer longer ambulatory times and possibly lower operating costs. When home oxygen therapy is started in the hospital, the Certificate of Medical Necessity should be completed and patients should be trained to use the equipment before discharge.