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Pulse and Continuous flow: Understanding the differences in portable oxygen technology.

If you are new to oxygen therapy, or even an existing user, you’ve probably discovered that portable oxygen concentrators vary greatly in size and weight. The main reasons for this are varying capacity’s and whether it’s able to deliver continuous flow. In this article we explain the difference between “pulse flow” and “continuous flow” oxygen as well as the pro’s and con’s behind each when it comes to finding a portable oxygen solution.

Let’s start with Continuous flow…

As the name suggests, it is a constant delivery of Oxygen at a steady flow rate and is measured in litres per minute. Anyone who is using oxygen will be prescribed a continuous flow rate in litres per minute. Most, if not all home oxygen concentrators and cylinders provide a continuous flow and is administered through a nasal cannula or a mask. However, when it comes to getting out and about, only a handful of portable oxygen concentrators facilitate a continuous flow setting – and, at best, can only achieve a fraction of the capacity compared to a home oxygen system. The reasons for this are simple – A home oxygen concentrator is built with larger components to deal with the continual production of oxygen at higher flows. In a portable oxygen system, the internal workings are made smaller and therefore there is often a compromise on continuous flow – and this is where “pulse flow” comes in.

Pulse flow

The portable oxygen concentrator (POC) is a technology that has seen great technological advances and benefits in recent years. Devices have got smaller with capacity becoming larger meaning more oxygen users can escape the confinement of the home and be more mobile. A portable oxygen concentrator is designed to be discreet wearable technology and thanks to pulse flow delivery, this has been made possible. As an example, our smallest and lightest POC available, the INOGENONE G4, weighs just a little over a bag of sugar with 3 pulse settings (we’ll explain the pulse settings below) – 10 years ago this was unheard of which is testament to where portable oxygen technology is heading. To briefly explain, pulse flow delivery is an oxygen conserving system that only produces oxygen on-demand. In layman's terms, the POC delivers a short burst of oxygen every time you inhale through a nasal cannula and works consistently in tandem with your breathing. As human biology will dictate, when exhaling, you can’t inhale at the same time. This may seem like an obvious statement but where there is a continuous oxygen supply, whilst exhaling oxygen is wasted. This generally defines the logic behind why pulse flow oxygen delivery exists and how devices have been allowed to be made so small and compact. POC’s have settings that closely match the prescribed Litres per minute. For example, setting 2 on a pulse flow device roughly equates to a prescription of 2 litres per minute. The benefits of pulse flow oxygen delivery makes way for smaller, wearable oxygen-producing devices with rechargeable batteries, long operation time and the biggest benefit of all… freedom & independence. However, not all portable oxygen concentrators are the same. Some have more sophisticated technologies. Some have bigger capacity. Some have better battery operation time and some have a continuous flow option as well as pulse flow delivery, although these are not as portable. We have written an article here to help you find the best solution for you. As mentioned above, Portable oxygen concentrators that offer a continuous flow setting often come with a compromise. They are often weightier, certainly not wearable and using this setting will inevitably give you less time on the battery before needing access to a power source. But on the flip side, for anyone who is reliant on continuous flow (for example sleep apnoea sufferers) this type of portable oxygen concentrator offers the best of both worlds. We hope this article has explained the main differences between the flow types and how they differ in portable oxygen technology. If you’d like to know more or discuss your requirements, why not give us a call. We are friendly team of respiratory professionals who have the time to chat about your needs and help with finding the right solution for you.

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