For Medicare to cover oxygen therapy, the qualifying blood gas study must be performed while the patient is in a chronic stable state. The term “chronic stable state” is defined as “…not during a period of acute illness or an exacerbation of their underlying disease.” In other words, all co-existing diseases or conditions that can cause hypoxia must be treated and the patient be in a chronic stable state before oxygen therapy is considered eligible for payment. This does not mean that patients with diseases such as obstructive sleep apnea (OSA) or pulmonary disease are unable to ultimately receive oxygen therapy, only that these diseases need to be controlled with the appropriate methods first, and then, if the patient remains hypoxemic, oxygen may be considered.
Example 2: In the case of obstructive pulmonary disease (e.g. asthma, emphysema, bronchitis), the patient should be managing their disease through the use of inhalers or a nebulizer, and an appropriate medication. Only after the underlying pulmonary disease is adequately treated and controlled may the patient be tested for oxygen. Again, the intent is to rule out all lesser forms of treatment before oxygen is considered.
Example 3: ER Visits. In the event a patient is taken to the emergency room and an underlying respiratory condition is identified, the blood gas study obtained during their visit may only be used if the patient is in a chronic stable state. In other words, the patient must not be having an acute episode and any causes of the underlying respiratory condition must be adequately treated and controlled before the test takes place. Most patients will not be in a chronic stable state during an ER visit and may need to be referred to their primary care physician to be qualified for oxygen after their visit.