ASV Failure Article - not ResMed Study

JDS74 · Post by **JDS74** » Mon May 18, 2015 10:18 am

Here is an interesting article of the failure to be effective of an ASV device with a patient with CHF, LVEF < 45% and central apnea.

http://www.ncbi.nlm.nih.gov/pmc/article ... .1.103.pdf

In this case, the ASV device successfully identified the central apnea but was unable to establish ventilation for the patient.

Krelvin · Post by **Krelvin** » Mon May 18, 2015 10:42 am

Journal of Clinical Sleep Medicine, Vol. 8, No. 1, 2012

Not sure it is really all that interesting since it only relates to a single person and is not actually a study and their conclusions were quite inconclusive. A followup study that tries to prove the hypothesis might be interesting to look at. Why would a person with a history of severe cardiac failure be looking at an article like this that is 2+ years old. They should be talking to their doctor.

An 80-year-old man with severe central sleep apnea due to Cheyne-Stokes breathing (AHI 41.2) caused by severe cardiac failure underwent a trial of adaptive servo-ventilation (ASV) by full face mask after failure of a fixed CPAP trial. Recommended procedure was closely followed and the ASV device activated normally during central apneas. Initial settings were EEP 5, PSmin 3, PSmax 15 on room air. The device did not capture the thorax or abdomen, as shown by lack of change in respiratory inductive plethysmography, despite expected mask pressure waveforms. Snoring was also detected during apneas with device activation. Desaturation continued, followed by arousals during hyperpnea. On the device, the patient clearly slept for 1-3 epochs during the central apneas only to awaken during hyperpnea. We hypothesize that the failure to capture may have resulted from “reverse” obstructive apnea, possibly due to glottic closure during ASV activation. We suggest that earlier manual adjustments to ASV in cases such as ours, prior to waiting for the recommended 20 to 40 min of sleep, may be appropriate in selected patients.

We also consider additional interventions that may increase the likelihood of a successful trial.

JDS74 · Post by **JDS74** » Mon May 18, 2015 12:45 pm

I found it interesting and I saw one of the authors as a patient so it had additional interest to me.
His supposition, which you highlighted, could be a contributing factor in the ResMed study. Hopefully, there will be additional studies trying to find out if this is a single unique case or something that has been under the radar.
New information is always helpful.

Morbius · Post by **Morbius** » Tue May 19, 2015 5:11 am

article wrote:We carefully followed the procedure recommended by the manufacturer.7

No, you didn't.

In the epochs presented, the abdominal and thoracic belt waveforms have become paradoxical, making this a "mixed" event (the latter portion being obstructive):

At that point, they should

protocol wrote:Increase EPAP by 1 cm H2O every 20 minutes until obstructive events are eliminated

OTOH, if his EF was 15%, maybe it was best that they didn't go down that road anyway.

Morbius · Post by **Morbius** » Tue May 19, 2015 6:05 pm

Morbius wrote:In the epochs presented, the abdominal and thoracic belt waveforms have become paradoxical, making this a "mixed" event (the latter portion being obstructive):

By paradoxical, we mean that in normal breathing, thoracic, abdominal and sum channels are all in sync. When obstruction occurs and breathing is attempted, thoracic effort rises, but since no air can be inhaled, the abdomen paradoxically sucks in and creates an opposite deflection. The sum channel (sum of the thoracic and abdominal belts) becomes dampened as the two waveforms begin to cancel each other out:

ASV Failure Article - not ResMed Study

ASV Failure Article - not ResMed Study

Re: ASV Failure Article - not ResMed Study

Re: ASV Failure Article - not ResMed Study

Re: ASV Failure Article - not ResMed Study

Re: ASV Failure Article - not ResMed Study