A stationary oxygen concentrator like the Philips Respironics EverFlo is a staple of supplementary home oxygen therapy. Oxygen concentrators are sometimes called oxygen generators or oxygen machines. Oxygen concentrators entrain air, filter it through a sieve bed to remove other gases, and collect the leftover oxygen for delivery to the patient. The air around us is 21% oxygen, 78% nitrogen, and 1% a mix of argon and carbon dioxide (and some other trace gases). By eliminating the nitrogen, the concentrator continually collects concentrated oxygen.
The stationary oxygen concentrator is an oxygen factory. It can process up to ten liters per minute of air to ensure there is always supplementary oxygen available for the patient. Stationary oxygen concentrators process air about ten times faster than portable concentrators. As a result, they can meet the needs of sicker patients more effectively than portable oxygen concentrators. Since the concentrator is continually filtering air, there is no worry about running out before the next tank delivery. All oxygen concentrators require electricity.
Medical grade oxygen delivered from tanks or liquid systems at home or in the hospital is close to 99% oxygen. Concentrators provide oxygen-enriched gas that is closer to 85%-95% oxygen. The reduced oxygen percent is because the scrubbing of nitrogen is not 100% perfect. Technical specifications for a concentrator list the range of oxygen concentrations that the generator produces. Devices have a range because the actual efficiency of the scrubbing depends on how high the flow rate is and how fast the patient is breathing. When the demand is higher, the machine pushes it through the filter faster, which decreases the concentration.
Some devices include a monitor that measures the fraction of delivered oxygen and send an alert if it drops below a set percentage. On the Philips Respironics EverFlo, this feature is called the Oxygen Percentage Indicator (OPI). The EverFlo is available with or without the OPI feature. Due to these operational differences, a patient may need a slightly higher flow rate from a concentrator than required in the hospital or from a tank of oxygen. Oxygen users must also think about flow rate settings differently with an oxygen concentrator. Hospital oxygen devices and oxygen from a tank typically deliver at a continuous flow rate. Concentrators can deliver continuous flow oxygen as well, but they also have pulse dose flow settings. Pulse dosing only delivers supplementary oxygen when the patient inhales. Pulse dosing conserves the supplemental oxygen for use when it is needed. Settings for the pulse dose rates are device-specific. The pulse dose setting on one concentrator does not equate to the same pulse dose setting on another model of oxygen concentrator.
Patients and caregivers should learn to monitor whether there is an appropriate amount of oxygen in the blood. Pulse oximetry is a type of monitoring that can be used at home or on the go. A small sensor slips over the finger and measures oxygen saturation in the blood at that moment. The physician should tell the patient and caregivers what the ideal oxygen saturation value is. Since different devices deliver different percentages of oxygen and use different scales of flow, pulse oximetry is useful for titrating flow from each device to get the best results from the supplemental oxygen therapy. Fatigue, confusion, dizziness, and shortness of breath are other symptoms that may indicate the patient is not getting enough oxygen. Monitoring symptoms and using a pulse oximeter is also crucial during different types of activity. Oxygen levels may drop more during more vigorous activities and sleep. Consequently, patients may need increased delivery rates.
The oxygen concentrator delivers oxygen to the patient via a nasal cannula or a mask. Supplemental oxygen can also be bled into CPAP or BiPAP machines to provide oxygen therapy during sleep therapy. Humidifier bottles filled with sterile water can be attached to the concentrator. Humidification adds moisture to the inhaled gas to reduce nasal dryness.
Oxygen concentrators should be centrally located to allow the patient to get to as many locations in the house as possible. Stationary oxygen concentrators are heavy, but very long tubing is available to allow the oxygen user to go from room to room without moving any equipment. The longer the tubing, the more the odds are that the pulse dose flow rate may need to be increased to keep up with the patient’s needs. Most concentrators are also on wheels so that they can be moved as needed. It may be necessary, for example, to locate the oxygen concentrator downstairs during the day and upstairs at night.
Oxygen concentrators emit a low hum. Most people get used to the white noise of the concentrator quickly, but some people find it helpful to park it outside the bedroom door and use longer tubing. This placement reduces noise during sleep for the user and the sleeping partner. Local emergency services should be notified when a household has a home oxygen user. Notification allows the local EMS to know where to triage support during a power outage or other disaster. CPAPman sells a variety of supplies needed to keep home oxygen delivery safe and trouble-free, including nasal cannulas, oxygen tubing, pulse oximeters, and oxygen adapters for CPAP machines.