RE: Oxygenation with BIPAP

[Sleepy Willy]

I was having a fight with my F30I the other night, as it's nearing its EOL and the air was shooting past the end of my nose.

I ripped off the F30I, which caused my sleep monitor to immediately start bitching about my O2 levels. So I put on my portable O2 concentrator which only puts out 1 lpm, at a reasonable noise level. I checked my Sleep Monitor the next day and my average O2 levels were 94%. My average O2 levels are never 94%. If I wear the BIPAP without O2, my levels are about 92%. If I wear the BIPAP with O2 (2 lpm) my O2 levels are 93%. How can 1 lpm be raising me to 94%.

I surmised that the BIPAP must be wasting a lot of the oxygen, through leaks and whatever you lose out of the exhaust ports. I asked the sleep doctor and he gave me a long winding story about the BIPAP altering your breathing patterns, so your body got less benefit from the oxygen. OK, I believe about 10% of that. I asked a sleep technologist I know and he basically said that if I had my large concentrator feeding 2 lpm to the BIPAP, I could only expect to get about .5 lpm to my body, which lines up with my real world experience. I guess my real question is why is this rocket science, if these people have any real world experience. The DME did not mention this, the sleep doctor seemed unaware of the loss factor and my other Respirologist made no mention of it, although to be fair, his prescription was only for my walk test.

Any experience with this or comments?

[Sleeprider]

When using oxygen with xPAP, the trick is to get the "fraction of inspired oxygen" FiO2 to a level that is sufficient to maintain your SpO2 and overcome the effects of dilution. I wrote the wiki on this topic and included the method for calculating FiO2 considering CPAP flow and mask venting. The problem is you have at least 30 L/minute of excess air in xPAP to satisfy respiratory requirements and avoid rebreathing expired CO2. With a cannula you get highly concentrated oxygen, even with a relatively low flow rate, but with CPAP you may need 3 to 4 times as much oxygen flow to match the FiO2 of a cannula, due to dilution of the oxygen with positive air pressure. http://www.apneaboard.com/wiki/index.php..._with_CPAP

[Sleepy Willy]

I have a Respironics EverFlo 5 lpm oxygen concentrator and a portable OxyGo Next. 

I have to set the EverFlo to at least 4 lpm to achieve 93% average oxygen saturation with my BIPAP machine. Although my prescription is 1 lpm from the walk test. The sleep technician said they call this washout, as some of the oxygen is lost in the BIPAP exhaust. 

The weird thing is that if I use the OxyGo Next at 1 lpm I can achieve 94% average oxygen saturation using a nasal cannula. I've also tried the EverFlo at 4 lpm using a nasal cannula and I still usually only get 93% average oxygen saturation. I just had a nap with the OxyGo Next at 1 lpm and my average oxygen saturation was 95%. The other odd thing is that the O2 graph was fairly flat, it's normally fairly spikey, with or without the BIPAP. My lowest O2 was 91% and my 'O2 Score' was 9.9. I nearly always spend some time below 90%, although the BIPAP helps and the BIPAP with O2 helps more.

It was a GOOD nap BTW.

My question is why does the EverFlo seem to perform so poorly compared to the OxyGo Next. I realize that one is pulsed, while the other is continuous flow, but I would expect the continuous flow to provide better results. The EverFlo is new as far as I know and it doesn't have any warning lights.

[Sleepy Willy]

Thanks, 4 times was the number that was quoted to me.

Now if I could figure out why my OxyGo Next performs better a 1 lpm than my EverFlo at 4 lpm, both with a cannula.

[Sleeprider]

Well, I hope the wiki article was helpful, but I have no deal why there is a difference between OxyGo and EvenFlo. With first-hand experience you are much better equipped to answer that.

[zellem]

I think you should contact the provider and see if the sieve beds are working.

[Sleepy Willy]

Thanks,

I told them I wanted it tested.

[Jeff8356]

Now if I could figure out why my OxyGo Next performs better a 1 lpm than my EverFlo at 4 lpm, both with a cannula.

Were the tubing lengths and canula's the same?

Here are the specs for both concentrators:

Everflo:  
Oxygen concentration = 93% (+/- 3%)  90-96% from 0.5 LPM to 5 LPM

OxyGo:
Oxygen concentration = 90% (-3%/+6%)  87.3%-95.4% at all settings

Getting it checked/serviced is a good idea.

[Sleepy Willy]

Were the tubing lengths and canula's the same?

Here are the specs for both concentrators:

Everflo:  
Oxygen concentration = 93% (+/- 3%)  90-96% from 0.5 LPM to 5 LPM

OxyGo:
Oxygen concentration = 90% (-3%/+6%)  87.3%-95.4% at all settings

Getting it checked/serviced is a good idea.

No, the tubing for the EverFlo is 25' longer and it includes a water trap or I end up breathing water. I was considering buying a longer cannula for the EverFlo and eliminating the water for a test run. The OxyGo is not humidified and it does not seem to bother me.

[jimbo1199]

I have the luxury of two machines (Airsense 10 with oxy-climateline) and Dreamstation (new) with Pressure valve and O2 injector 
The Dilution effect is very apparent ..
Using my Apple Watch - a straight canula gives me 94-95 with 3 litres / min
The Airsense 10 in any configuration gives me  <90% at 4litres/min with F30 mask
The Dreamstation with Amara View 4litres/min, heated tube Phillips CPAP line pressure O2 Backflow preventer valve ,O2 injector  and unheated final tube to mask small bore tube gives me 94% with Amara View                    -         and 90% with F30!! without the small bore final tube
Flex level ?? currently set to 3
the Amara View metric in Oscar has a flow rate of +23.3 to -35.3 band, but the F30 seems wider

I felt that the F30 purge system was causing rebreathing without sufficient bleed off. The Amara creates quite a gale (use spectacles at night if it gets in your eyes)
The Amara View has the short small bore final tube
The Oxy-climateline is a much larger bore tube

As my InOgen Home Oxygen concentrator is a long way from the bedroom the lack of an easy control to turn it off (and on) is a real pain. yes I use flash back preventers

Is the small bore final delivery tube the secret of success.

Thoughts please.