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The Differences Between Pulse Dose and Continuous Flow Oxygen

Nov 25, 2019
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The information on this page is not meant to replace a medical evaluation or information from your doctor. Always consult your doctor for medical advice and guidance. 

When you are prescribed supplemental oxygen by your doctor, you’ll likely discuss what type of device best fit your needs. You might have heard your doctor use the phrases “pulse dose” and “continuous flow,” but may not understand the significance of these terms. 

We’ve put together this article to help you understand what these terms mean as they relate to delivering oxygen via a portable oxygen concentrator. Our goal is to empower you to make an informed decision as to what delivery method is suitable for your therapy.

Before making any big decisions as to which supplemental oxygen device to use, be sure to explore the differences between pulse dose and continuous flow oxygen and talk to your doctor about which one is right for you.

What is Pulse Dose?

Pulse dose also known as “on demand” is based on breathing and inhaling. Oxygen is delivered to the patient based on breathe rate and other factors (varies based on device model). With pulse dose the patient’s inhalation triggers the delivery of the bolus (dose) of oxygen. The bolus is delivered in the first part of the breath, when it’s most needed.1

Think of a pulse dose concentrator as a glass of water with a straw. The intake is based on both the amount and intensity of the ‘sip’ that is taken by the patient.  

There are oxygen patients who use a portable oxygen concentrator with pulse dose delivery during the day and a stationary concentrator with continuous flow oxygen at night. These patients often have shallow breathing during sleep or sleep apnea. Speak to your doctor about your oxygen therapy needs during sleep versus while awake.

Additionally there are oxygen patients who solely use their pulse dose delivery portable oxygen concentrator 24/7. In comparison to a stationary concentrator, the benefits these patients may experience include a more comfortable oxygen delivery experience, a more quiet concentrator, less electricity usage in their home, and a unit that is easier to carry around their household. 

There are oxygen concentrators that have both continuous flow and pulse dose oxygen delivery. These units are typically heavier (10+ pounds). 

What is Continuous Flow? 

Contrary to pulse dose, the better known continuous flow is a bit less sophisticated and is delivered at a constant rate, regardless of the patient’s breathing. Oxygen delivery throughout the entire breath cycle with continuous flow can be considered wasted due to the functional limits of the lungs.1

Think of continuous flow oxygen concentrators as a water fountain. If you were to stand in front of a water fountain and let it flow at 1 liter per minute, you wouldn’t actually drink the entire liter of water. 

Instead, the amount of water that you drink is dependent upon the number and size of sips you take. A lot of  water ends up being wasted. This is the same for continuous flow oxygen concentrators.

Below are devices that deliver continuous flow. These units are heavier and therefore harder to move around with than a portable oxygen concentrator. 


The Bottom Line

Ultimately, you deserve a device that’ll allow you to live your life to the fullest. This means providing you the oxygen you need, so you can participate in the activities you enjoy. Many portable oxygen concentrator patients love the flexibility and mobility their device offers such as spending more time with family and friends, travelling on an airplane, or spending time outdoors without having to transport heavy equipment. 

The Oxyensure portable oxygen concentrator is a pulse dose oxygen delivery device that gives you the freedom you are looking for from your oxygen equipment.

Additional Information on Oxygen Delivery 

In the 1980s pulse dose concentrators were created to solve for the need to deliver oxygen more efficiently. This was done by delivering oxygen solely during the first part of inhalation, which eliminated the waste of oxygen during exhalation. An article from the International Journal of Chronic Obstructive Pulmonary Disease states:

POCs depend on these efficiency gains to reduce size and extend operating times to achieve ambulatory systems that are patient friendly, thereby improving adherence. However, these devices have also created confusion related to oxygen delivery, prescriptions, device selection, understanding patient versus product capabilities, and reimbursement for long-term oxygen treatment. 

In terms of scripting oxygen therapy, pulse dose therapy delivers a bolus of oxygen per breath, sized in milliliters. The better understood continuous flow administration of oxygen is prescribed in liters per minute

Additionally the settings on a portable oxygen concentrator do not necessarily correlate with liter flow amounts. I.e. The amount of oxygen delivered on setting 4 on a portable oxygen concentrator is not necessarily equivalent to the delivery of 4 L/min of oxygen on a stationary unit.2

Each portable oxygen concentrator has a different max output of oxygen in ml/min. The max oxygen output on the device, the number of settings on the device and the user’s breath rate will determine the size of the bolus that is delivered each breath. It is always recommended that each patient is titrated on the specific portable oxygen concentrator they are going to use. 

Get Your Own Portable Oxygen Concentrator

Oxyensure offers a free solution finder to help you find a device/accessories package and payment plan that works for your budget. Get the freedom and mobility you, or your loved one, deserves!


  1. Chen, John Z et al. (2017, August 24). Comparison of pulsed versus continuous oxygen delivery using realistic adult nasal airway replicas. Retrieved from
  2. Katz, Ira et al. (2016, September 29). An in silico analysis of oxygen uptake of a mild COPD patient during rest and exercise using a portable oxygen concentrator. Retrieved from


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