Low Oxygen Levels On VPAP

[Sleeprider]

I hope it all works out for you fairly quickly. The ideas above are all things you can consider and discuss for longer-term treatment.

[thibaulthib]

Hi all,

I confirm that the Lumis 150 ST has iVAPS mode (I've tried it).

Airbus, if you don't suffer from Central nor complex apneas, I would suggest you disable ST mode and only use S mode.

Quick question: what is your backup rate set in the machine? I suspect that it is way too close (or even higher) than your natural respiratory rate, which causes the machines to trigger too many breaths. Because if we really believe the 1% spont trigger, it would mean that without the VPAP, you would not be able to initiate a single breath on your own, which I doubt !

Your backup rate should be 2-4 breath below you natural respiratory rate. I'm personally using ST mode, and I've set my backup rate 5 breath below my natural one. I would propose you to start with backup rate = natural respiratory rate - 4


Thibault

[ardenum]

Philips Everflo costs ~500 EUR brand new in Germany.

https://www.philips.com.au/healthcare/pr...ncentrator

[airbusA346]

Hi all,

I confirm that the Lumis 150 ST has iVAPS mode (I've tried it).

Airbus, if you don't suffer from Central nor complex apneas, I would suggest you disable ST mode and only use S mode.

Quick question: what is your backup rate set in the machine? I suspect that it is way too close (or even higher) than your natural respiratory rate, which causes the machines to trigger too many breaths. Because if we really believe the 1% spont trigger, it would mean that without the VPAP, you would not be able to initiate a single breath on your own, which I doubt !

Your backup rate should be 2-4 breath below you natural respiratory rate. I'm personally using ST mode, and I've set my backup rate 5 breath below my natural one. I would propose you to start with backup rate = natural respiratory rate - 4


Thibault

The reason I've been put on ST mode is because I don't take enough breaths myself while asleep, which means I retain carbon dioxide.

My back up rate is currently 18.  Back in March 18, when I was switched from APAP to the Lumis it was 15 and since then it has been raised to it's current level (it's been at 18 since the end of June).

[thibaulthib]

1) Do you mind sharing:
- your height in cm
- your weight in kg
- the current overnight average tidal volume

We will be able to determine if the backup rate is too high or not.

2) Can you also share with us:
- Which spontaneous trigger mode you are set on: default, high, very high, low, very low?
- Which spontaneous cycle mode you are set on: default, high, very high, low, very low?
- Which rise time: none, 100ms, 200ms, 250ms, 300ms, etc?

Thibault

[airbusA346]

1) Do you mind sharing:
- your height in cm
- your weight in kg
- the current overnight average tidal volume

We will be able to determine if the backup rate is too high or not.

2) Can you also share with us:
- Which spontaneous trigger mode you are set on: default, high, very high, low, very low?
- Which spontaneous cycle mode you are set on: default, high, very high, low, very low?
- Which rise time: none, 100ms, 200ms, 250ms, 300ms, etc?

Thibault

- Height is 182.88cm
- Weight is 102.5kg
- Median tidal volume for last week was 820mL

- Spontaneous trigger is medium
- Spontaneous cycle mode is medium
- Rise time is 200ms

[Sleeprider]

The reason I've been put on ST mode is because I don't take enough breaths myself while asleep, which means I retain carbon dioxide.

My back up rate is currently 18.  Back in March 18, when I was switched from APAP to the Lumis it was 15 and since then it has been raised to it's current level (it's been at 18 since the end of June).

If your problem is central apnea (not taking enough breaths), the answer is ASV (adaptive servo ventilation). It resolves both obstructive and central apnea as well as maintains respiratory volume.  The problem with your current therapy is the 16 cm of pressure support completely suppresses your own respiratory drive. The ASV will provide only as much pressure support as you need, only when you need it, and it is smart enough to maintain your respiratory rate and volume.  I just can't emphasize enough how wrong and unatural your therapy is.

[airbusA346]

The reason I've been put on ST mode is because I don't take enough breaths myself while asleep, which means I retain carbon dioxide.

My back up rate is currently 18.  Back in March 18, when I was switched from APAP to the Lumis it was 15 and since then it has been raised to it's current level (it's been at 18 since the end of June).

If your problem is central apnea (not taking enough breaths), the answer is ASV (adaptive servo ventilation). It resolves both obstructive and central apnea as well as maintains respiratory volume.  The problem with your current therapy is the 16 cm of pressure support completely suppresses your own respiratory drive. The ASV will provide only as much pressure support as you need, only when you need it, and it is smart enough to maintain your respiratory rate and volume.  I just can't emphasize enough how wrong and unatural your therapy is.

I've never been diagnosed with central apnoea, just obstructive.  As far as I understand, my natural respiratory drive decreases too much during sleep.  

I don't think ASV is widely used in the UK... I might be wrong though...

[thibaulthib]

- Height is 182.88cm
- Weight is 102.5kg
- Median tidal volume for last week was 820mL

- Spontaneous trigger is medium
- Spontaneous cycle mode is medium
- Rise time is 200ms

Thanks!

Resmed titration guide recommends to set Target Va such that Vt is equal to 6ml/kg IBW. You can find this info page 38 for the iVAPS titration protocol. And you may assume that this info is valid for ST titration protocol too.

Link to the titration: https://www.resmed.com/us/dam/documents/...er_eng.pdf

According to your height (183cm), and based on the IBW, you should be targeting a tidal volume of 468ml: https://www.mdcalc.com/endotracheal-tube...calculator

According to me, if you get dizzy/drowsy/light headed, it's because you probably hyperventilate by having BOTH a too high tidal volume and the fact that your machine literally forces you to breath ALL the time.

Another issue I've found out is that, while the VPAP is forcing you to breath, if you are "not in sync", the Lumis will never be able to make you "entirely breath". If you just lower the backup rate to 14, and increase the sensitivity of the spontaneous trigger to very high, you will already see a noticeable difference (positive, of course). A backup rate of 18 with a tidal volume of 800ml is, sportive! lol! 

Let's make you breath on your own a bit, I'm sure you wouldn't mind haha. Let's start to make minor changes which will definitely help you from tonight onwards, without taking ANY risk:
- Set the spontaneous trigger to very high (= making the VPAP very sensitive to detect any inhale attempt)
- Set the backup rate to 14 (= because we set up a spontaneous trigger to very high)
- Set the rise time to 350ms (=because 26/9 with 200ms is just like a massive hit in your face)
- Set your IPAP/EPAP to 25/9

Let us know tomorrow how it goes, I wouldn't be surprised that it improves your condition !

Cheers

[airbusA346]

I forgot to mention another reason I was put onto the Lumis was to give my body a rest during the night.