March 24, 2026

Pulse Dose vs Continuous Flow Oxygen. What’s the Difference?

Are you uncertain whether pulse-dose or continuous-flow oxygen is the right choice for you? Discover how each of these different oxygen delivery methods work, what pulse-dose settings means in terms of litres per minute, and the reason continuous-flow is the best choice for overnight oxygen therapy.

Pulse-Dose and Continuous-Flow Oxygen: What’s the difference?

I've you've recently been prescribed supplemental oxygen therapy, one of the first things you will almost certainly ask yourself is: What is pulse-dose as opposed to continuous-flow, and which do I need?

Most prescriptions are written using litres per minute, and this causes people choosing between oxygen concentrators to think that continuous-flow is their only option.

However, medical-grade pulse-dose devices are also very common and in most cases, suitable. Especially in portable oxygen concentrators.

In this article, we'll help you understand the difference between these two types of oxygen supply will do away with a lot of the worries relating to portable oxygen concentrators and their flow rates.

What Does “Litres Per Minute” (LPM) Actually Mean?

Oxygen delivered at a set rate is measured in litres per minute. If a person is prescribed 2 LPM, the machine supplies 2 litres of oxygen every minute, consistently, while switched on.

That is, the oxygen is delivered continuously, whether someone inhales or exhales. While 'pulse-dose' oxygen concentrators, work differently.

These do not provide a continuous steady stream of oxygen, but give a specific quantity, or a ‘pulse’ or ‘bolus’ of oxygen when a breath begins.

For this reason, the settings on pulse dose machines, commonly from 1 to 5, do not relate to litres per minute. Instead, they indicate the size of the oxygen pulse with each breath, and are not a constant rate.

How Continuous Flow Oxygen Works

Continuous flow oxygen is, simply, an ongoing, unbroken, even supply.
It is something of what you’d get when drinking from a fountain, assuming the fountain is on, the water runs all the time, most of it wasted.

As oxygen gets delivered during both inhalation and exhalation, continuous flow is usually what doctors prescribe:

While you’re asleep
If your health condition requires a good deal of oxygen
When you need the oxygen to be given at a consistent rate.

Stationery home oxygen concentrators, such as the Kingon P2-SOC, are designed to give this sort of dependable, continuous oxygen supply.

How Pulse Dose Oxygen Works

Oxygen given in pulses is much like drinking via a straw. Oxygen is given only when you breathe in, and very little is wasted.

The Kingon oxygen concentrators picks up the first part of an inhale via a nasal tube, then provides a definite quantity of oxygen at the very start of the breath, and then stops.

This timing allows pulse systems to conserve oxygen and battery power, because of this, portable concentrators like the Kingon P2-E series, are more compact, weigh less and are good for people who are on the move.

However, pulse dose depends on breath detection.
You need to:

Be using a nasal cannula
Be breathing through your nose
Generate sufficient inspiratory effort for the device to detect the breath.

If no breath is detected for a period (for example, approximately 60 seconds), the P2-E alerts the user and enters a timed smart auto-dose pattern until breathing is detected again.

This safeguard maintains intermittent delivery until normal breathing resumes.

Can Pulse Dose Be Compared to 2 LPM?

It's a common question asked at the start of oxygen therapy. Although pulse-dose delivery isn’t measured the same as litres a minute, we can work out the relationship between them.

As an example:

At level 2, the Kingon P2-E gives a pulsed dose or bolus of roughly 420 millilitres/min
On the other hand, 2 litres per minute of ongoing flow provides 2,000 millilitres/min, all the time across the full breathing cycle. Including breathing in and when you’re breathing out.

Clearly, 420 mL isn’t 2,000 mL.

So, if setting 2 can appear to achieve the same result as being set to 2 LPM, what is happening?

The big thing to remember is when the oxygen is given. Pulse delivery puts oxygen into the lungs at the start of a breath, the part of breathing where oxygen transfer into the bloodstream is most effective

Continuous flow delivers oxygen constantly when the device is in operation, even during expiration. Over one minute, 2 LPM continuous flow supplies 2,000 millilitres of oxygen.
But only a part of that minute is active inspiration.

Below is a visual overview to help illustrate what’s taking place.

Put simply, pulse-dose devices concentrates oxygen and delivers a bolus (a puff) of oxygen when inhalation is detected, instead of spreading it out over the whole minute.

Nevertheless, how well the two delivery methods match up relies on how much air a person breathes in, how well the nasal prongs fit, the way they breathe, and what illness they have.

When deciding on portable oxygen concentrator, the pulse-dose flow setting should match the minimum equivalent LPM (litres per minute) prescribed by your doctor.

Why Continuous Flow Is Often Recommended Overnight

For some people, the way we breathe changes when we go to sleep.

Many individuals will start to breathe via the mouth, and the effort of each breath may become reduced, with the breathing possibly being irregular.

As pulse-dose oxygen concentrators rely on sensing breath taken through the nose, they aren’t, as a rule, appropriate for nocturnal use, unless they have been particularly assigned, and a clinical evaluation carried out.

What If You Need Oxygen During the Day and at Night?

Some people require:

Pulse delivery for daytime mobility
Continuous flow for overnight therapy

Hybrid systems such as the Kingon P2-TOC provide both pulse dose and continuous flow capability in one transportable device. This allows flexibility while still ensuring the delivery mode aligns with prescription requirements.