Mother's ResMed Astral 150 not keeping oxygen level high enough/what should I ask?

[Helena]

Mother's oxygen level stays high enough (93-98) on cannula with concentrator or tank.

When using ResMed Astral 150 (with full face mask), her oxygen level has started to not get high enough, (high 70's or 80's). The ResMed used to keep her oxygen levels high enough.

What ought I ask the RT from Apria and the RN from pulmonologist to make sure the ResMed ventilator gets checked out properly?

Thanks very much.


P. S. When her level is too low, I have her take long, deep breaths, and she adjusts her recliner so she is sitting up more. That only helps a little. If you have any other remedies, I would like to have more helps at hand.


Thank you very much.

[SarcasticDave94]

I don't know if you're already adding the oxygen into the Astral 150 (only the 150 has this) however that is what can be done with the correct oxygen hose. I'd probably start there, if oxygen isn't attached to the Astral 150 now.

It would likely just clip into the oxygen port. I do think there's settings regarding oxygen with the Astral 150, including adding an FIO2 sensor.

Page 21 of the Astral manual cautions to turn off oxygen, start Astral, then turn oxygen on. Reverse for turning off, ox off then Astral.

See images.

   

   

[Helena]

Sarcastic Dave, thanks for your kind help.

I forgot to write that the current oxygen input is through a valve at the back of the machine.

The Rt from Apria called and is overnighting an elbow fitting that will go on the front of the machine between the filter and the hose.

She is to use the cannula under the face mask until the adaptor arrives.

That is plan A.

[SarcasticDave94]

OK. The one on the back was what I was referring. It's likely down to see if the more direct method of oxygen brings levels up. Keep us updated and best wishes it works great.

[Sleeprider]

I don't think we can see data from the Astral 150, but there are several possibilities that SpO2 is not being maintained. In general, oxygenation is improved with increased PEEP (positive end expiratory pressure) provided by a ventilator, while CO2 exchange and ventilation is enhanced with pressure support or IPAP. When an oxygen bleed is used with a ventilator, we have to account for the dilution caused by excess flow that is vented from the mask vent. With a cannula, oxygen is delivered directly to the nose, but with any positive pressure device, that oxygen is highly diluted, meaning the fraction of inspired oxygen (FiO2) will be lower, even with higher bleed rates. We can roughly calculate the amount of oxygen that must be added to a circuit to achieve the FiO2 requirement, and we can titrate oxygen bleed rates by observing SpO2. You have clearly observed that more oxygen is needed, which means you need to turn up the bleed rate (oxygen delivery in Liters/minute) to a higher rate until SpO2 stabilizes above 90%. So it's possible machine settings are not optimized, and likely that the oxygen generator needs to be adjusted to provide a higher oxygen feed rate. I recommend you read our wiki on oxygen bleed with positive pressure to better understand how this works. https://www.apneaboard.com/wiki/index.ph..._with_CPAP