ST vs ASV - studies about risk

[Gideon]

To use ASV I believe the critical factor is LVEF Left Ventricle Ejection Factor.  Needs to be > 45% I think.

[Spy Car]

To use ASV I believe the critical factor is LVEF Left Ventricle Ejection Factor.  Needs to be > 45% I think.

Correct, but based on flawed data?

Here are some problems (deep problems) on the Serve-HF study from this article in the Canadian Respiratory Journal [emphasis added]:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676391/

There was substantial nonadherence to the study protocol: 29% of patients either discontinued or never used ASV, while 16% of patients randomly assigned to control crossed-over to positive airway pressure therapy. 

ASV compliance was low, averaging only 3.4 h per night one year postrandomization. This low adherence suggests that subjects remained exposed to CSA during a substantial length of time when ASV was not worn. 

A potential reason for low compliance was that 76% of treated subjects used a full face mask, which is generally less well tolerated than a nasal mask.

Second, the ASV device used has relatively high default pressures as part of its ventilation algorithm (minimum end-expiratory pressure of 5 cmH2O and minimum inspiratory pressure support of 3 cmH2O), making it more likely to induce hyperventilation and to lower cardiac output in those with normal or low left ventricular filling pressures than a device with lower default pressures.

Third, the reason for the increased mortality in the ASV group is not known.

So we have a population of people who used poorly set up devices (when they used them) for an average of hours that any doctor and insurance would count as "non-compliance."

Strikes me as "junk science" to base recommendations on such a flawed study, especially when the results were counter to the expected positive outcomes seen in clinical settings and in the metadata analysis.

How can the results be taken seriously when subjects averaged 3.4 hours per night using devices that were not optimally titrated?

Bill



 

[paulag1955]

After further review, I think over titration means over treating with pressure that is too high. And I totally asked this question in the wrong thread, because I saw it in an attachment linked to another thread. Oops.

[kiwii]

I recall a member that seemingly needed ASV due to centrals.  He was on CPAP and we had done all we could to optimize results.  Events were still around 12 AHI with a lot of centrals. His doctor put him on oxygen at 2.5 L/min and it all cleared up.  It can happen, I've seen it.
http://www.apneaboard.com/forums/Thread-...everything
https://www.ncbi.nlm.nih.gov/pubmed/8996011

This is very exciting news, thank you for the links.

The second one speaks specifically for eucapnic patients. I remember he said that my lung function tests would include some sort of induced challenge. I wonder if it is for exercise induced asthma.

What is of particular interest is that I've been told another condition I have (migraine equivalents) should clear up once the sleep apnea is successfully treated. Turns out the medicine I am taking to eliminate the vertigo & balance issues aggravates asthma.

My daytime symptoms of SA involve cognitive muzziness, confusion and exhaustion to such an extent that I cannot stand it, too tired to do anything and can't even entertain myself by watching TV or reading due to falling asleep; driving is out of the question, but that's okay because I'm too exhausted to go anywhere anyway. That isn't living, it's only existing (and poorly at that). That is how it was when I was at min EPAP of 6, with non-perfect sleep hygiene (unusually stressful stuff a family member is going thru). It isn't until I'm at 6.6 that I can get out of bed before lunchtime - and I'm normally a 'morning person'! If I'm using the Simplus, the settings need to be raised 1cm, but right now I'm enjoying the P10.

At min EPAP 7.0, I'm doing fine cognitively (mostly - can't always think of words). I'm working on my sleep hygiene, and I think if that is optimal, that I might be able to function better physically.

I am really eager to see what would happen if I include supplemental O2.

[SarcasticDave94]

To use ASV I believe the critical factor is LVEF Left Ventricle Ejection Factor.  Needs to be > 45% I think.

Yes, that is the correct threshold number. FWIW mine was a 55 so I was approved, obviously.

[ajack]

Let me throw in my 2c. ask your doctor, some stuff here isn't the same as the stuff I'm reading. I can be absolutely wrong too. I really find opinions can vary a lot on forums and one needs to sort out the grain, with the help of your medical team.

As best as I can figure it out so far.
An ASV treats PB and CS and adjusts each breath, this is where it differs from ST, the fine tuning of a breath. The back up for CA on an ASV only needs one pressure but it doesn't have that and is quickly raised to enough to ventilate the lung over several adjustment.

The ST doesn't treat PB and CS. It is epap ipap, with the timed breath, say backup RR12, 60sec divide by 12 so if you don't take a breath before 5 seconds the machine will make one for you. an asv and a st treats a CA exactly the same way. It provides enough PS to inflate the lung when a breath isn't take. Functionally it is exactly the same. The difference is the asv may take 3 quick pressure adjustments to get there. Those with asv will know this as you simple stop breathing to see this happen. Those that have used an ST will know that it is a bpap at the set PS/difference between epap/ipap. and won't do anything different till you don't take a breath within the prescribed time, every 5 seconds in this case. It will then give the full breath at the ipap pressure. every breath is a full breath, It doesn't give part breaths to make up a shortfall as the ASV does. If you take a half breath through PB, then the ASV will give you the other half. an ST will do nothing differnt, as it saw that you took a breath, that is all it cares about, that you take a breath.

[kiwii]

I have found on the wiki that PB = Periodic Breathing

What does CS stand for?

[DeepBreathing]

I have found on the wiki that PB = Periodic Breathing

What does CS stand for?

CS = Cheyne Stokes (usually CSR = Cheyne Stokes Respiration). It's a specific subset of PB and is often associated with heart failure. The wave form shows a gradually increasing airflow followed by a decreasing airflow, followed by a central apnea or hypopnea, followed by the gradual increase. (There is no sharp recovery breath like we see with obstructive events in periodic breathing). This is repeated over and over.

[ajack]

To use ASV I believe the critical factor is LVEF Left Ventricle Ejection Factor.  Needs to be > 45% I think.

Correct, but based on flawed data?

Here are some problems (deep problems) on the Serve-HF study from this article in the Canadian Respiratory Journal [emphasis added]:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676391/

There was substantial nonadherence to the study protocol: 29% of patients either discontinued or never used ASV, while 16% of patients randomly assigned to control crossed-over to positive airway pressure therapy. 

ASV compliance was low, averaging only 3.4 h per night one year postrandomization. This low adherence suggests that subjects remained exposed to CSA during a substantial length of time when ASV was not worn. 

A potential reason for low compliance was that 76% of treated subjects used a full face mask, which is generally less well tolerated than a nasal mask.

Second, the ASV device used has relatively high default pressures as part of its ventilation algorithm (minimum end-expiratory pressure of 5 cmH2O and minimum inspiratory pressure support of 3 cmH2O), making it more likely to induce hyperventilation and to lower cardiac output in those with normal or low left ventricular filling pressures than a device with lower default pressures.

Third, the reason for the increased mortality in the ASV group is not known.

So we have a population of people who used poorly set up devices (when they used them) for an average of hours that any doctor and insurance would count as "non-compliance."

Strikes me as "junk science" to base recommendations on such a flawed study, especially when the results were counter to the expected positive outcomes seen in clinical settings and in the metadata analysis.

How can the results be taken seriously when subjects averaged 3.4 hours per night using devices that were not optimally titrated?

Bill



 

Yelling doesn't make your point stronger. I disagree with it, the experts found those people with low ejection factor died on asv, low EF had a 500% greater risk of death. It isn't in dispute, the experts won't support you opinion.  I don't know why this is so hard for you at accept, unless you have a low EF and you have self prescribed an ASV and you need it to be true?
your own report says it's compelling, but it shouldn't prevent further reseach, from the links below, you will see that this is happening, but they won't be putting low EF in to ASV studies, it's unethical and no authority would approve such a study.
"As compelling as the SERVE-HF data appear, they raise a number of issues that should not preclude completion of other trials of devices for therapy of CSA or OSA in HFrEF patients."

Without spending a weeks looking at reports. This is the experts on ASV, giving lectures to other professional sleep doctors. The include numerous reports in their lectures, including the resmed one that is being talked about here and was cancelled part way through, because of the unacceptable death rate with those with low EF.

new horizons with ASV
https://www.youtube.com/watch?v=Nr08K5IfzzY&t=2250s

 management of OSD with ASV
https://www.youtube.com/watch?v=EmHy_FO8T0I&t=1614s

[Spy Car]

To use ASV I believe the critical factor is LVEF Left Ventricle Ejection Factor.  Needs to be > 45% I think.

Correct, but based on flawed data?

Here are some problems (deep problems) on the Serve-HF study from this article in the Canadian Respiratory Journal [emphasis added]:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676391/

There was substantial nonadherence to the study protocol: 29% of patients either discontinued or never used ASV, while 16% of patients randomly assigned to control crossed-over to positive airway pressure therapy. 

ASV compliance was low, averaging only 3.4 h per night one year postrandomization. This low adherence suggests that subjects remained exposed to CSA during a substantial length of time when ASV was not worn. 

A potential reason for low compliance was that 76% of treated subjects used a full face mask, which is generally less well tolerated than a nasal mask.

Second, the ASV device used has relatively high default pressures as part of its ventilation algorithm (minimum end-expiratory pressure of 5 cmH2O and minimum inspiratory pressure support of 3 cmH2O), making it more likely to induce hyperventilation and to lower cardiac output in those with normal or low left ventricular filling pressures than a device with lower default pressures.

Third, the reason for the increased mortality in the ASV group is not known.

So we have a population of people who used poorly set up devices (when they used them) for an average of hours that any doctor and insurance would count as "non-compliance."

Strikes me as "junk science" to base recommendations on such a flawed study, especially when the results were counter to the expected positive outcomes seen in clinical settings and in the metadata analysis.

How can the results be taken seriously when subjects averaged 3.4 hours per night using devices that were not optimally titrated?

Bill



 

Yelling doesn't make your point stronger. I disagree with it, the experts found those people with low ejection factor died on asv, low EF had a 500% greater risk of death. It isn't in dispute, the experts won't support you opinion.  I don't know why this is so hard for you at accept, unless you have a low EF and you have self prescribed an ASV and you need it to be true?

Without spending a weeks looking at reports. This is the experts on ASV, giving lectures to other professional sleep doctors. The include numerous reports in their lectures, including the resmed one that is being talked about here.

new horizons with ASV
https://www.youtube.com/watch?v=Nr08K5IfzzY&t=2250s

 management of OSD with ASV
https://www.youtube.com/watch?v=EmHy_FO8T0I&t=1614s

Yelling? Who is yelling?

I put the direct quotes in bold to clearly differentiate the journal article from my own words.

The bolded words are from an article by experts and they cast grave doubt on this study's legitimacy.

Other experts have based their recommendations on a single study where the average usage was 3.4 hours per night using non-optimized machines. 

If you are OK with this rate of compliance (which is considered non-compliance in medical/legal settings) then we have a difference of opinion. 

I think the study is too flawed to take seriously when it runs counter to meta-analysis data and clinical observations that show the benefits of ASV in the same population groups.

I'd like to see a proper study where users actually used their machines and used optimized settings and were not forced to use FFMs.

Who includes people who are non-compliant in their machine usage, to study said machines? It does not compute.

Bill