Portable oxygen concentrators (POCs) are devices developed in response to demand for a lightweight, portable source of supplemental oxygen.[1] Pulse dose delivery allows concentrators to deliver medical grade oxygen all day, every day while remaining convenient to carry.
Is Pulse Dose a More Efficient Form of Oxygen Delivery?
To understand the mechanics of pulse dose therapy, knowing the meaning of a few key terms is helpful.
An oxygen bolus is a single puff of air. The cycling phase is the moment between inhaling and exhaling.
Pulse dose flow oxygen therapy provides earlier delivery of the oxygen bolus into the inspiratory cycle, for more efficient oxygen delivery.[2]
An oxygen bolus delivered late in inspiration may be less effective in improving blood oxygen levels, as portions of the bolus may fall into the anatomical dead space.[3]
Pulse Dose Oxygen Delivery
Pulse dose mechanisms utilize an oxygen conserver and other technology to deliver oxygen to the patient based on breathing rate and other factors. The sensor determines when the patient begins inhaling and delivers the oxygen pulse/bolus at that moment, which is most productive[2], meaning the patient gets the oxygen they need, when they need it.
Pulse dosing is more akin to drinking water from a glass with a straw instead of a fountain. The intake will be based purely on the amount and intensity of sips. The bolus of pulse dose oxygen is measured in milliliters per breath, rather than liters per minute.[3]
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Continuous Oxygen Flow Delivery
The traditional home oxygen therapy is low-flow oxygen, comprising a continuous oxygen flow delivered from a stationary oxygen tank via nasal cannula.[4] Continuous flow (CF) delivers oxygen at a constant adjustable rate, regardless of the user’s breathing, measured in liters per minute.[5]
This method of delivery is simple but inherently inefficient. The oxygen delivered throughout expiration is wasted, with the exception of any oxygen which may ‘pool’ for subsequent inhalation, and may still be potentially wasted. Also wasted is the oxygen flow during late inhalation, which reaches only the conduit airways rather than gas-exchanging lung units.[4]
Think of it like a water fountain: If an individual stands in front of a water fountain flowing at 1 liter per minute, they don’t actually drink one full liter of water in a minute. The amount of water a person drinks is determined by the number of sips and the size of the sip. The rest of the water is not consumed. The same applies to continuous flow oxygen; the net amount of oxygen inhaled is a combination of the flow rate, the number of breaths and the size of the breaths.
If instead, the oxygen is delivered only intermittently, at those times productive for gas exchange, oxygen is conserved[4], and patients get the oxygen they need, when they need it.
The sensor determines when the patient begins inhaling and delivers the oxygen pulse/bolus at that moment, which is most productive[2], meaning the patient gets the oxygen they need, when they need it.
Inogen’s Intelligent Delivery Technology
Inogen® POCs feature proprietary Intelligent Delivery Technology, a reliable pulse-dose based algorithm designed to minimize missed breaths. Inogen’s Intelligent Delivery Technology is designed to deliver oxygen effectively and efficiently whether you are sleeping, at rest, or exerting yourself. With patented conserver technology, an Inogen® portable oxygen concentrator ensures oxygen is delivered within the first 250 milliseconds of inspiration, where oxygen has the most effect on lung gas exchange.
Portability of Pulse Dose Oxygen
Pulse dose oxygen can be delivered using a lightweight, battery powered oxygen concentrator which delivers an oxygen pulse only when an inhalation is detected. These portable devices provide a mobile oxygen source resulting in up to 12 hours of continuous use, depending on the model.[5]
Conclusion
Oxygen use has extended from inpatient to outpatient settings for patients with chronic pulmonary diseases and complications of hypoxemia. Pulse delivery of oxygen, such as that delivered by POCs, can provide prescribed oxygen needs in lightweight systems. Additionally, Inogen® oxygen concentrators may offer the patient one single solution[6] for long term oxygen therapy.
References
McCoy R. Oxygen-conserving techniques and devices. Respir Care. 2000 Jan:45(1):95-103; discussion 104, PMID: 10771785.
Tiep BL, Lewis MI. Oxygen conservation and oxygen-conserving devices in chronic lung disease. A review. Chest. 1987 Aug;92(2):263-72. doi: 10.1378/chest.92.2.263. PMID:3608597.
Questions about Portable Oxygen Concentrators COPD Foundation
This article was reviewed by Senior Director of Community Engagement and COPD360social Community Manager, Bill Clark, as well as certified staff Respiratory Therapists on January 23, 2020. Page accessed Jan 31,
2024. https://www.copdfoundation.org/COPD360social/Community/COPD-Digest/Article/232/Questions-about-Portable-Oxygen-Concentrators.aspx.
Martin DC. Contemporary portable oxygen concentrators and diverse breathing behaviours — a bench comparison. BMC Pulm Med. 2019 Nov
19;19(1):217. doi: 10.1186/s12890-019-0980-x. PMID: 31744499; PMCID: PMC6862795.
Hardavella G, Karampinis I, Frille A, Sreter K, Rousalova I. Oxygen devices and delivery systems. Breathe (Sheff). 2019 Sep;15(3):e108-e116. doi:
10.1183/20734735.0204-2019. PMID: 31777573; PMCID: PMC6876135.
Single solution encompasses both portable and stationary oxygen concentrators provided together
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What is Transient Nocturnal Desaturation?
Transient nocturnal desaturation, also known as nocturnal hypoxemia, is defined as a temporary drop in oxygen saturation during sleep. Patients diagnosed with sleep disordered breathing from chronic obstructive pulmonary disease (COPD) or obstructive sleep apnea (OSA) are at a greater risk for nocturnal desaturation. A substantial number of patients will have both COPD and OSA.[1]
Transient Nocturnal Desaturation is a significant problem in COPD, affecting a relatively large number of COPD patients. In fact, one study suggests that 27-70% of COPD patients with daytime oxygen saturation levels of 90-95% experience substantial desaturation at night, particularly during a period of sleep known as rapid eye movement (REM) sleep. In people with severe COPD, desaturation during sleep is even more profound than desaturation during exercise, which is also common.[2]
OSA is defined by intermittent collapse of the upper airway, which results in repetitive hypoxemia and arousal. It is estimated that OSA occurs in 4% of American men and 2% of women, meaning almost 10 million people in the United States are affected, although that is probably an underestimate. Obesity is a risk factor for the development of OSA. As obesity rates have risen over the last 15 years, the current prevalence of OSA is almost certainly much greater.[1]
A substantial number of patients will have both OSA and COPD. This “overlap syndrome” causes more severe nocturnal hypoxemia than either disease alone. This common combination of OSA and COPD has important implications for diagnosis, treatment, and outcome.[1]
Do I Need a Prescription to Buy a Portable Oxygen Concentrator?
When a patient first learns that they will require supplemental oxygen to improve their breathing, they are likely to have many questions. Patients often wonder about how to get their oxygen and what steps they will need to complete in order to get the oxygen delivery device they need. If your doctor has recommended supplemental oxygen therapy to you, read on to learn more about where to go from here.
What To Do With Your Oxygen Concentrator Parts When They’re No Longer Needed
If you use an oxygen concentrator, you will need to periodically replace some parts. Those parts need to be disposed of correctly or recycled when possible, so don’t throw them in the garbage. If you are finished with your oxygen concentrator, full units can often be donated. Let’s take a look at how to responsibly dispose of oxygen concentrator parts and units once you no longer need them.
