Assistance with IVAPS/BIPAP

[MattInMD]

Hello,

Some of this is probably beyond the scope of this board, but I was hoping to get some help interpreting these graphs.  In short, mom has severe kyphoscoliosis which limits her breathing.  She was hospitalized with severe hypercapnia 2.5 years ago and placed on NIV at night.  It worked well, mostly normalizing her CO2 levels over the next two years and eliminating all hypercapnic symptoms.  Six months ago she had emergency surgery for a bowel obstruction for which she had to be intubated.  She failed the extubation and eventually a tracheostomy was performed.  She regularly caps during the day (so breathing through her nose and mouth), but night has been a major issue.  The only way she could have the trach removed is if it can be capped at night and she succeeds with NIV again.  She has an Astral ventilator and uses IVAPS.  I changed the settings shortly after we came home after the hypercapnic episode because the settings they used were clearly wrong for mom.  As I said, she was fine over the next two years.  We tried those same settings with her capped and she wasn't feeling rested the next day.  The doctor made his own adjustments and things seemed to actually get worse.  We then tried a bipap mode, and everything looked great for the first couple hours and then turned into a mess and mom asked to go back on invasive ventilation.

Unfortunately I have to rely on Resscan.  The flow form when zoomed in is okay a lot of the time, but gets really rough occasionally.  It looks to me like mom's having an issue with the exhale.  It almost appears like she may need more EPAP, 8 cm H2O is actually a lot for mom to breathe against and I'm wondering if it in itself is restricting her exhale (her max strength with an Expiratory Muscle Trainer is between 15-20).  I used to go with 4 at home and mom frankly did better.  I'm also wondering how much is the trach itself and some secretions causing a flow restriction, but unfortunately I'm having trouble convincing the doctor to try a few things that would give us a better idea of how mom would respond without the trach.  I'm also not allowed to make changes to the Astral now while she's in the nursing facility, even though the doctor seems to be making things worse, but I can suggest changes if there's any recommendations.

I can only pull PDFs from Resscan.  The 1/31 graphs are with the hyperpowered IVAPS settings the doctor tried (mom was previously at 4.9 Va).  The 5/2 graphs are from the straight bipap, which looked fine for a while and then went haywire.  I also provided some closeups of the wave forms.  The invasive vent settings are for 350 tidal volume, but she appears to be all over the place with NIV.  I can provide more details or different days if requested.

Thank you,
Matt

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Here are the three flow chart examples.

[Sleeprider]

MattInMD, the OSCAR software works with various Resmed ST-A iVAPS devices, but I'm not sure about the Astral.  If there a SD card in the device it would be interesting to try to import the sleep data into OSCAR and see what kind of respiratory statistics we get.  Normally, the Oscar data gives us the tidal volume, minute vent, inspiratory and expiratory times, and other useful metrics, in addition to the graphs.

Based on what we see in your attachments, two different modes were  used. On 1/31 the device was set in IVAPS and on 2/2 it was on ST mode. The Va setting in ivAPS mode seems aggressive and she is experiencing a Vm between 5.8 and 9.4 L/min with pressures ranging from 14.4/5.8 to 24.2/8.0. That's a lot of PS at a very high respiratory rate of 20 bpm.  With iVAPS, her EPAP or PEEP ranged from 5.8 to 8.0, the median tidal volume was 366 and minute vent was 5.8 to 9.4.

In ST mode, there is not respiratory target, and pressure is constant, but timed at 20 bpm which allows NO OPPORTUNITY for spontaneous respiration. ST pressure is fixed at 16/6 , resulting in median tidal volume of 378 and  Mv of 6.0 to 11.6 L/min.

The flow wave from ResScamn shows a lot of cardiogenic oscillations that are actually fairly common, but seem more pronounced in this case. https://www.apneaboard.com/wiki/index.ph...cillations.

I don't have the necessary biometrics to suggest alternative settings, but I think you should read the recommendation on titrating iVAPS and perhaps go back to the more intelligent algorithm of iVAPS rather than ST, with a lower respiratory rate target or iBR setting appropriate to your mom. To help you discuss this intelligently with the doctor, take a look at the Resmed Sleep Lab Titration Guide starting at page 34.  https://www.resmed.com/us/dam/documents/...er_eng.pdf   Consider using the device to learn targets, follow the titration protocols and switch from fixed respiration to iBR. In your comments you indicate your mom is hypercapnic, and these settings are certainly ventilating her aggressively, but I'm concerned they go too far and prevent any spontaneous respiration. Especially in ST mode, that respiration rate should not be over 16 bpm.

[MattInMD]

Sleeprider,

Thanks for the response. Unfortunately there's no port for an SD card and Resscan is less than ideal imo. I did follow the recommended titration protocol in the past and arrived at 4.9-5.5. It was at 4.9, and the doctor decided a 20% hike would be worth a try, hence the 6 volume assurance. Mom agreed it felt too strong. Typically the 20 iBR results in a BURR of closer to 14 unless mom zonks out completely. I'm actually not sure why it says the BURR in ST mode was 20 because it was 15 when I left. I'll bring up your comments to the doctor. Have you seen anyone who has very weak expiratory muscles struggle with higher levels of EPAP? The autoEPAP keeps wanting to crank up the pressures but it eventually reaches a point where mom struggles to exhale, which is why the max EPAP is capped under 10. I'm not sure if it's a legitimate closure of the airway or if it's detecting diminished effort and thinks it's an apnea. We tried correcting chin tuck with padding under the chin but didn't have much success in improving the numbers.

-Matt

[SarcasticDave94]

Just a quick comment, Astral I don't think is yet OSCAR chart compatible. However, setting ought to be similar to ST-A in iVAPS, more settings to check though. I'll see if I can pop up a few settings screenshots via ResMed clinical manual.

[Sleeprider]

Expiration is mostly a passive release of inspired air rather than something that is forced by muscular effort. With COPD and other restrictive pulmonary conditions, more time needs to be allowed for expiration. Your flow rate charts lack a timeline, so it's hard to know what rate we're looking at there, but the pattern looks normal with a fairly long expiration cycle. Jay51 and SarcasticDave94 are both well-versed and interested in adavanced PAP. Feel free to send them a PM asking them for ideas here. Is there a reason you went to ST mode on 2/2?

[SarcasticDave94]

Here's a few shots of the clinical for Astral including iVAPS specifically with settings ranges in the table page 79. First is reminder how to access clinical menu and exit same. Pg 15, 16. Others are iVAPS settings.

[MattInMD]

The ST mode was really just a trial to see what would happen because the pressures were swinging so dramatically in IVAPS and we wanted to see if she'd maintain a steadier tidal volume.  An issue I had in the past is that at the particular recommended volume assurance, mom could spend part of the night hyperventilating at 30 RR and IVAPS would accept it was adequate volume and deliver little pressure, so I found I had to up the minimum PS a bit just to make sure it delivered enough air to slow her breathing down.  ST mode bypasses that issue, but may not be as comfortable or supply enough volume when she's in a deep sleep.

Here's 1/16.  Only a few brief leaks to cause interference.  Minute volume is consistent, but it still concerns me how much the tidal volume and RR bounced around.  EPAP stayed under 5 for about two hours and then rode the max EPAP until the hour..  The report also lists Va at 4.8, which I know is incorrect.  AHI was 0.9 which doesn't seem bad, but she didn't feel well the next day.

[SarcasticDave94]

PS, the Astral ventilators have a USB port on the back for data storage. No SD card.

[SarcasticDave94]

A question on Ti. Min and Ti. Max, they're equal it seems at 0.8. In normal circumstances, this may need a bit of a spread between them, a window for inhale to happen. Equal .8 sec isn't much of a window to fit inhale. Any thoughts on increasing Ti. Max closer to 2.0 sec.?

This is under the area:
"Inspiratory Phase Duration Settings"

It could be the RR 20 is high, doesn't this set up a timed breath only, no spontaneous, state? What is the actual respiratory respiration rate?

Feel free to comment Sleeprider.

[Sleeprider]

Consider this a question not a recommendation. In all the charts the Ti min and Ti max are the same at 0.8. Have you ever tried a longer TiMax? I think you are cycling her too fast by cutting off IPAP and while her median expiratory time is long enough, I think a more normal breath could be assured with Ti min 0.8, Ti max 1.6.