A home oxygen concentrator is a medical device specifically designed to provide supplemental oxygen therapy to individuals with respiratory conditions like Chronic Obstructive Pulmonary Disease (COPD) or severe asthma. These machines draw in the surrounding air and increase the oxygen concentration before delivering it to the user through a nasal cannula or mask. The purpose of this device is to raise the oxygen level in the user’s blood, which has dropped below normal. Unlike traditional oxygen tanks that store compressed gas or liquid oxygen, the concentrator actively produces the oxygen on demand from the air around it. This process makes the use of supplemental oxygen in a home environment more practical and less reliant on frequent resupply deliveries.
How Home Oxygen Concentrators Function
The technical process that enables oxygen concentration is known as Pressure Swing Adsorption (PSA) technology. This method relies on the principle that different gases in the air can be selectively adsorbed onto a solid material under pressure. Ambient air, which is approximately 21% oxygen and 78% nitrogen, is drawn into the concentrator by a compressor and filtered to remove impurities. The air is then pushed into a series of chambers, often two columns, that contain an adsorbent material.
These chambers, known as sieve beds, are packed with tiny pellets of zeolite, a synthetic mineral that acts as a molecular sieve. When the air is compressed and forced into the first sieve bed, the zeolite preferentially attracts and traps the nitrogen molecules. This action allows the oxygen to pass through, resulting in an oxygen-enriched gas that is typically 90% to 95% pure. The concentrated oxygen is collected in a reservoir before being delivered to the patient.
The “swing” in PSA refers to the alternating cycle between the two sieve beds. While one bed is adsorbing nitrogen under high pressure, the other undergoes regeneration by having its pressure lowered. This pressure reduction causes the zeolite to release the trapped nitrogen, which is then vented back into the surrounding air. The system continuously cycles between these adsorption and desorption phases, ensuring a steady, continuous supply of concentrated oxygen.
Stationary Versus Portable Models
Oxygen concentrators are categorized into two main types based on their size, power source, and intended use: stationary and portable models. Stationary concentrators are larger, heavier units designed for use within the home and require continuous power from a wall outlet. These units are capable of delivering higher flow rates of oxygen, often up to 10 liters per minute (LPM), using a continuous flow method. Continuous flow provides a constant, uninterrupted stream of oxygen at a fixed rate, regardless of the user’s breathing pattern.
Portable Oxygen Concentrators (POCs) are significantly smaller, lighter, and are designed to run on rechargeable batteries, which allows the user mobility outside the home. POCs often utilize a more efficient delivery method called pulse dose. Pulse dose delivery is a system that detects when the user begins to inhale and releases a burst, or bolus, of oxygen at that precise moment.
The pulse dose method conserves oxygen and significantly extends the battery life of the portable unit. While the continuous flow method is generally recommended for patients requiring a stable, high volume of oxygen, especially for overnight use, pulse dose is preferred by active individuals for its enhanced portability and efficiency. Some portable units offer both delivery options, although the continuous flow setting may be limited to lower flow rates compared to a stationary machine.
Practical Use and Safety Considerations
Setting up a home oxygen concentrator typically involves plugging the unit directly into a grounded electrical outlet, avoiding the use of extension cords or power strips. The oxygen tubing is connected to the outlet port on the machine, and if a humidifier bottle is prescribed, the tubing connects to that first. Users must then set the flow rate exactly as prescribed by their doctor, using the flowmeter knob on the device.
Routine Maintenance
Routine user maintenance is necessary to ensure the machine functions efficiently and safely. This includes:
- Regularly inspecting and cleaning the external air filters on the concentrator, often with warm, soapy water, especially in dusty environments.
- Checking the nasal cannula or mask tubing for cracks, wear, or kinks.
- Replacing the tubing every few months, or immediately if damaged.
- Keeping the exterior surface of the machine clean with a damp cloth.
The primary safety concern when using concentrated oxygen is the increased risk of fire, as oxygen causes combustible materials to burn much faster and hotter. Users must strictly adhere to a “no smoking” rule near the equipment and keep the concentrator at least 10 feet (about 3 meters) away from any open flames, heat sources, or sparking electrical devices like space heaters or hair dryers. Petroleum-based products, oils, and greases should never come into contact with the oxygen equipment, as they pose a flammability hazard.
Concentrators require electricity to operate, so a backup plan for power outages is a necessity for continuous oxygen users. This often involves having a reserve supply of traditional oxygen cylinders or a battery backup system, which should be discussed with the healthcare provider and equipment supplier. Modern concentrators are equipped with alarms to signal issues like a machine malfunction or a drop in oxygen purity below 80%. If a yellow or red indicator light appears or an alarm sounds, the user should immediately switch to their backup oxygen supply and contact their supplier or doctor.