[Equipment] ASV Acquisition Guidance Requested

[ajack]

I'd go back to your doctor, or get a new one. You may be better with a st or a st-a ivaps/avaps. Or one of the next group in the line of home noninvasive ventilation, if you have a neuromuscular disease. ASV doesn't support a volume ventilation. It's for a normal functioning lung and respiratory system with disordered breathing. It isn't for copd, obesity or hypoventilation with CA either.

[DeepBreathing]

The Resmed machines (unlike your Respironics) don't have separate settings for rise, trigger and backup rate - it's all done automatically by the Pacewave algorithm.
https://www.google.com.au/url?sa=t&rct=j...o19Zyynoqw
This may or may not be an issue for your condition.

In comparing the S9 with the Aircurve, you should find out how many hours they have done. Some S9s would be over five years old, which is the notional life of the machine.

[Sleeprider]

I really don't want to get into the ST/ASV debate. If you are having good results with the Aircurve 10 ASV you are currently using, stick with it. You need treatment and a reasonable cost now. If I was considering a purchase from Supplier #2 and deciding between a VPAP Adapt and Aircurve 10 ASV, at a difference of $500, the newer Aircurve wins. Both will likely have the same warranty, but I do think the form factor and newer production date have enough advantages to warrant the difference. Considering the minimum price of a new machine at $3000, you will be getting a significant discount, and compared to the ridiculous price of your current supplier, it's only 30% of the price. You need to make a relatively fast decision to ensure the most savings and avoid more rental charges.

What is your current event rate on the ASV? Any chance you could post some Sleepyhead charts from the current machine?

[ajack]

I would want decent medical advice if I had a neuromuscular disease. It is serious stuff. 

This would exclude an ASV for consideration

http://erj.ersjournals.com/content/19/6/1194
Sleep breathing disorders in neuromuscular disease

The commonest form of sleep­ disordered breathing in patients with respiratory muscle weakness is hypoventilation due to reduced tidal volume, particularly during REM sleep 

[Sleeprider]

I would want decent medical advice if I had a neuromuscular disease. It is serious stuff.
http://erj.ersjournals.com/content/19/6/1194

The Dx of "severe CSA/Neuromuscular Disease in cervical spine" is frequently used to justify any prescription of a HCPCS Code E0471 device (Respiratory assist device, bi-level pressure (BiPAP) capability, WITH backup rate feature, used with noninvasive interface, e.g., nasal or facial mask (intermittent assist device with continuous positive airway pressure device)

The reason that language is used comes almost directly from the Medicare guidelines for prescribing these devices, and may actually be synonymous with complex apnea or central apnea when the cause of the central apnea syndrome is unknown.  It may indeed be a neurological issue, or related to the respiratory feedback mechanism that induces breathing or other unknown causes of CA.  We can't assume or interpret the meaning of this diagnosis without much more information; however we know he was prescribed ASV, which is apparently effective.  I'm not going to second guess that.

[ajack]

I would want a medical second opinion. We really don't know the level of treatment CT is getting with the ASV and an ASV isn't suited to a hypoventilation disease, it doesn't substitute for a ST or vaps, where a ST and vaps can substitute for an ASV
The machine he gets will need to treat him for the next 5 years or more till it needs replacing. CTcentral asked for opinions if his Neuromuscular Disease makes any difference and I gave mine from what I have read about going forward with this disease. 
he asked
"Do you all think there is anything I'm missing or else I should consider?  My dx is severe CSA/Neuromuscular Disease in cervical spine if that makes any difference."

[CTcentrals]

Good points, all. I appreciate the depth and seriousness of your considerations. Sleep doc is a pulmonologist and I have follow up appt middle of next month. I'm not aware of any respiratory muscle weakness, but there is a degree of spinal cord impingement damage that required 5-level laminectomy. I can post any indicator numbers that might help, but it might take me a bit to figure out how to post charts and would need to know what you think would be helpful.

Events for the last week (doesn't include UF2's of 50%=>7seconds that can be voluminous, can be clustered, or sparse and spread out):
.31
1.1
0.0
.25
.75
.51
.75

[Sleeprider]

I'm going to strongly disagree with ajack whom I respect and appreciate for his insightful view and helpfulness on the forum. Your results speak for themselves as showing excellent efficacy with ASV.

[ajack]

As it turns out when CT responded, saying his sleep doctor is a pulmonologist. We can assume, he would be well across what is needed.

I don't know how you can disagree with making sure CT is getting the right medical advice for his Neuromuscular Disease and pointing out that ASV isn't suitable for all problems. I certainly didn't hold myself as someone to advise on which machine to get. I don't think anyone can for complicated cases on a forum.

This subject was still fresh in mind from the other forum about how the ASV is limited. One of the posters here wrote a detailed post on the thread titled...
Trilogy AVAPS vs ASV - Move the Debate Here

Most simply, in ASV mode there is NO target ventilation setting, but in AVAPS/iVAPS mode there is a target ventilation setting, and it plays a critical role in determining when an AVAPS machine steps in and how much additional pressure it provides to the patient.

It is true that in ASV mode the machine measures the tidal volume for the last several minutes so as to calculate the minute ventilation. And in ASV mode, the machine (internally) defines a target (minute) ventilation that is 90% of the moving average minute ventilation over the past several minutes. When the actual minute ventilation drops below that moving target, the machine decides you're in trouble and it starts to increase IPAP rather drastically until you start breathing more deeply on your own. In other words, in ASV mode, the machine expects the patient's last several minutes of regular breathing to reflect what the tidal volume and the minute ventilation should be at the current time.


In AVAPS mode, however, the target ventilation setting is a target for the desired tidal volume and this is usually based on the height and weight of the individual, but during a titration study the target ventilation setting can be adjusted to fit the patient's particular needs. (There is a protocol for adjusting it in the titration guidelines.) In the AVAPS algorithm enough pressure is applied to keep the actual tidal volume at or above the target ventilation setting at all times. In other words, the AVAPS does NOT use a running average of the tidal volume or minute ventilation, and the reason it does not use a running average is because the problem the patient is dealing with does not typically cause a very short term drop in minute ventilation, followed by hyperventilation, followed by more hypoventilation, etc. CSA is marked by this kind of hyperventilation-hypoventilation cycle; COPD and other restrictive respiratory problems are not. Rather a person with a restrictive respiratory problem has trouble maintaining an appropriate O2 saturation even during periods of normal breathing and their tidal volume may drop so slowly that it does not look like a hypopnea or the beginning of a CO2 undershoot/overshoot cycle (i.e. periodic breathing). So in essence the AVAPS doesn't trust the patient's last several minutes of regular breathing to necessarily reflect what the patient's current tidal volume ought to be.

Some useful links:

https://www.resmed.com/us/dam/documents/...lo_eng.pdf The Resmed titration guide. The discussion of Resmed's iVAPS algorithm starts on p. 25; the discussion of ASV starts on p. 27; an iVPAPS titration flow chart is found on p. 39, an ASV titration flow chart is found on p. 39, a sample iVAPS prescription can be found on p. 38, and a sample ASV Auto prescription can be found on p. 40. Information about billing codes for the VPAP ST-A starts on p. 45.

http://incenter.medical.philips.com/docl...%3d9792335 The PR titration guide. The discussion of ASV starts on p. 13; the discussion of AVAPS starts on p. 17; sample scripts for both ASV and AVAPS are found on p. 19.

http://www.saegeling-mt.cz/fileadmin/use...IntEng.pdf More detailed information about AVAPS---which patients it's for and explanation of how it helps their problems, from Philips Respironics

http://www.medtechnica.co.il/files/1402301644l44Ui.pdf Looks like a PowerPoint presentation with detailed information about properly titrating PR AVAPs machines, along with a pretty complete picture of what the Trilogy is capable of doing.

[Sleeprider]

ajack, I don't think he has neuromuscular disease at all, but that is a convenient Dx for the approval of an ASV. Even with spinal cord impingement, that is unlikely the source of central apnea, and a pulmonologist diagnosing a neurological disorder makes no sense at all. He has complex apnea or CPAP obstructive apnea that becomes central in the presence of PAP pressures. We see it here all the time. Whatever it takes to get insurance to approve reimbursement for the best treatment is what the docs do. It's like a dermatologist diagnosing a reimbursable skin condition so he can remove a wart or benign growth, or a urologist using the presence of blood traces in urine to justify cystoscopy (DAMHIK). So if a neurologist, neurosurgeon or orthopaedic is making this diagnosis, and making the link to CA, I'd buy it, but not a pulmonologist.

In most cases we never really know why people have central apnea, but we know how to treat it, and the kind of diagnoses that will get reimbursement for it. I seriously think that is the case here. A neurologist would more likely justify surgery to treat stenosis of the spine with impingement of the cervical spinal cord. MRI shows I have this same condition, but I have no symptoms. I know exactly what CTcentral is talking about, and it is extremely unlikely to be related to CA, although it makes a plausible argument for funding the treatment...and the treatment works.

An interesting side-note, an injury to the cervical spine like this actually can be helped with a soft cervical collar.