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British Lung Foundation
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Liquid Oxygen pulse or continuous flow

Hi All

Hope your all keeping nice and warm. Just a little query I have been giving liquid oxygen a try the last two weeks and finding it ok good to have an endless supply at the ready which is wonderful as some may remember I am at present being screened for lung valve so lots of hospital visits and quite a few hours out of the house so thought the liquid oxygen would give me better back up. Can someone explain to me why we have pulse and continuous flow offered I understand that the oxygen supply in the canister will last twice as long when on pulse but is there a reason why one is better than the other for any other reasons . I have also been looking at portable concentrators which of course are battery operated but most seem to be on pulse rather than on continuous flow which is what I use as a rule and as I use it on Number 4 it chows oxygen pretty fast. Just looking for others views tips and hints learning as I go.

Thanks All

Pauline X

5 Replies

I am on liquid oxygen unfortunatley. I cant use pulse same as you I am on 4 when moving about so definitley uses more oxygen. Really wish I could use pulse life would be a lot simpler Take care x



Continuous supply delivers oxygen on the exhale, as well as on the inhalation, so there is a considerable wastage.

Pulse delivers only on inhalation. Although more efficient it’s not suitable for everyone.

Testing with your respitory nurse is the only sure method of deciding what’s most suitable.

The more lightweight concentrators are being offered by oxygen providers, if suitable speak to your respitory nurse.

I use 4lpm on pulse using cylinders, when out and about I use a Imogen G3 self purchase.

The same model which goes to 5lpm is the one offered by several providers.


Thanks so much Stone a little clearer now good to have the tip off regards to the portable concentrators the respiratory nurse did tell me to be cautious as you say if and when I buy I shall check more details. I have tried the pulse method on my liquid oxygen cylinder and don’t find it too bad but haven’t tried it out and about yet. Thanks once again for your advice hope your keeping well.

Pauline 🙂


The difference, as stone says, comes down to waste though the waste is often overstated (by POC manufacturers). It's quite lengthy /complex to explain the issue (anatomic reservoir) but if you are interested I can dig out an explanation.

Hopefully, you will be able to compare the difference for yourself. I guess you are testing either the Helios Marathon or the larger Helios systems?. I found that the highest pulse on the Marathon (4 or 5 - can't remember) was less effective than 4LPM continuous which was unfortunate as O2 savings were considerable.

I see you mention you are on setting 4 continuous which suggest to me that your prescription is 4 LPM continuous. If that is the case be aware that many (all?) of the small electronic portables (up to 10lb) may not be any use to you and even the larger ones (suitcase type - 20lb proving 3LPM) may not be much use either. I have an Inogen G3 (7lb) and found that even on setting 5 it provided less benefit than I got from 4LPM continuous (closer to 2-3LPM continuous). I also have access to an Devibilis iGO (20lb - 3 LPM continuous and setting 6 pulse) and that struggles to provide as much benefit as I get from 4LPM continuous O2 from either a cylinder or a Helios Marathon liquid O2 system.

Others find same issue as me but other get more benefit from POCs. Make sure you test before you buy if you have to buy the POC yourself.


Many Thanks Salmo

Between yourself and Stones explanation I feel a little wiser I will try pulse on my liquid oxygen at home. Would love a portable And you have given me plenty to think about thanks so much for the advice given test before you buy I think is the way to go.

Keep Well

Many Thanks Pauline 🙂


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