Home oxygen therapy (HOT) provides supplemental oxygen to patients at home to treat conditions causing low blood oxygen levels. Ordering and receiving this therapy is complex, requiring coordination between the prescribing physician, the patient, the Durable Medical Equipment (DME) supplier, and the insurance payer. This guide outlines the steps necessary to ensure a patient receives appropriate and authorized home oxygen.
Establishing Medical Necessity and the Initial Prescription
The initial step in obtaining home oxygen is the physician’s determination of medical necessity, which must be supported by objective clinical testing. This evidence typically involves measuring the patient’s oxygen levels while they are in a chronic stable state, meaning they are not experiencing an acute illness like pneumonia. The most common standard for coverage is a resting arterial oxygen pressure (PaO2) at or below 55 millimeters of mercury (mm Hg) or a pulse oximetry saturation (SpO2) at or below 88% while breathing room air.
Patients who do not meet these severe resting criteria may still qualify if their PaO2 is 56-59 mm Hg or SpO2 is 89% and they have additional complications like cor pulmonale or polycythemia. Testing may also be required during exercise or sleep to prove the need for nocturnal or exertional oxygen. For example, a patient may qualify for oxygen only during activity if their SpO2 drops to 88% or less during a six-minute walk test.
Once medical necessity is established, the physician writes a detailed prescription, which acts as the initial order for the DME supplier. This order must be specific, indicating the precise flow rate, usually measured in liters per minute (LPM), and the required duration of use. The prescription will specify if the oxygen is to be used continuously (24 hours a day), only at night (nocturnal), or solely during periods of physical exertion.
Documentation Required for Payer Approval
Obtaining financial coverage for home oxygen is often the greatest challenge, as payers like Medicare and private insurers require extensive documentation to authorize payment. The clinical evidence gathered by the physician, such as the qualifying SpO2 or PaO2 test results, must be formally submitted to the payer for review. This submission process is managed by the DME supplier.
A Certificate of Medical Necessity (CMN), often using the CMS-484 form for Medicare patients, is a central component of this documentation. The CMN formalizes the physician’s prescription and certifies that the patient meets the established coverage criteria for the equipment. Additionally, a Detailed Written Order (DWO) must be completed and signed by the prescribing physician, and the patient must have had a face-to-face visit with their treating provider within 30 days prior to the initial certification.
The medical record submitted must show that alternative treatments, such as inhalers or other medications, were tried or considered and deemed clinically ineffective before resorting to oxygen therapy. Coverage is not indefinite; for Medicare, initial coverage is limited, and the patient must undergo periodic recertification to continue receiving the equipment. This recertification often involves a repeat blood gas study performed between 61 and 90 days after the start of therapy to confirm the continued need for oxygen.
Selecting and Coordinating Equipment Delivery
The Durable Medical Equipment (DME) supplier provides the physical equipment and coordinates its delivery and setup. The choice of equipment is a collaborative decision based on the patient’s prescribed flow rate, mobility, and lifestyle. The three main types of oxygen systems are concentrators, compressed gas cylinders, and liquid oxygen systems.
Oxygen concentrators are the most common choice, operating by filtering nitrogen from ambient air to deliver a concentrated oxygen supply. Stationary concentrators are large, plug into a standard wall outlet, and can deliver high, continuous flow rates up to 10-15 LPM, making them suitable for homebound patients with high oxygen needs. Portable oxygen concentrators (POCs) are smaller, battery-operated units that offer mobility but provide a lower maximum flow rate, often using a pulse dose delivery that releases oxygen only upon inhalation.
Compressed gas cylinders, or oxygen tanks, store oxygen under high pressure and are available in various sizes for stationary or portable use. While portable tanks are useful for short outings, they require frequent refills from the supplier.
Liquid oxygen systems store oxygen at very low temperatures, allowing for a high volume of oxygen to be stored in a relatively small space. These systems utilize smaller portable reservoirs that the patient can refill at home from the main unit.
Once the appropriate system is selected, the DME supplier delivers the equipment and provides instruction to the patient and caregivers. This instruction covers the proper use of the nasal cannula or mask, troubleshooting alarms, and the schedule for maintenance and refills. The supplier coordinates directly with the prescribing physician to ensure the equipment settings match the order.
Home Safety and Usage Guidelines
Once the oxygen equipment is set up in the home, safety protocols must be followed because oxygen supports combustion, causing materials to burn more intensely and quickly. The most important rule is that no smoking or open flames are permitted near the oxygen equipment. Post “No Smoking” signs in and outside the home.
All heat sources, including gas stoves, candles, and electrical appliances, must be kept five to six feet away from the oxygen unit. Avoid using oil-based products, petroleum jelly, or aerosol sprays near the equipment, as these materials can ignite easily. Oxygen tanks must be secured upright to prevent them from falling over, which could damage the valve and cause a rapid release of oxygen.
Concentrators must be plugged directly into a wall outlet and never into an extension cord, which can pose a fire hazard due to electrical overload. Proper ventilation is required, so the unit should be kept several inches away from walls, curtains, or furniture to allow air to flow freely. Patients must use the prescribed flow rate without adjustment, as changing the flow rate without a physician’s order can be dangerous, potentially leading to carbon dioxide retention in some lung conditions.