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06-05-2016, 05:44 AM
(06-05-2016, 05:44 AM)aergun Wrote: Hi, All
Highlight a 5 to 10 minute section of your top graph. This will expand the data below so that you can see the wave forms of the suspect Hypopneas. Looking at an individual breath, see if the wave form is flattened at the top. It might have a chair like appearance or look like a mountain with the top cut off. If it is "flattened" it is Obstructive. From AAST " http://www.aastweb.org/blog/scoring-obst...e-criteria
It is an Obstructive Hypopnea if ANY of the following are present:
Snoring during the event
An increase in the flatting of the nasal pressure flow or PAP flow signal
You can only call the event a Central Hypopnea if NONE of the above is present.
That's it! With a bit of practice and observation, you can identify the difference between the two and find the correct device modality and pressure for your patient.
Apnea Board Member RobySue has posted a Beginners Guide to Sleepyhead Software here: http://www.apneaboard.com/wiki/index.php...SleepyHead
Organize your Sleepyhead Charts
Post from Imgur
06-05-2016, 11:04 AM
Another characteristic of an Obstructive Apnea is that it ends with a sudden large increase in the Flow as we become aroused from sleep enough to gasp and take "recovery breaths" when no longer being choked by a collapsed airway. This makes the envelope of the Flow waveform have an arrowhead shape.
The Flow waveform shows the estimated rate of airflow into our lungs (positive Flow) and out from our lungs (negative Flow).
Similarly, also when other types of obstructive events end, such as Obstructive Hypopnea or RERA (Respiratory Effort Related Arousal), there will be sudden recovery breaths.
In addition, with an ASV machine like yours, during an Obstructive Apnea event the Pressure Support will soon reach its Max PS setting and the pressure will be alternating (at the backup respiration rate) between the EPAP pressure and the (EPAP + Max PS) pressure, but the Flow waveform will show no Flow (or very little Flow).
With an ASV machine like yours, during what would have been a Central Apnea or Central Hypopnea (which has been prevented by the backup respiration rate feature) the airway will be open, so there will be significant Flow while the machine is alternating between the EPAP pressure and the (EPAP + PS) pressure. Also, the PS might not not need to raise itself all the way to its Max PS value. Also, when the CA ends we will gradually and smoothly return to making our own effort to breathe, and the Flow waveform will not exhibit the sudden strong recovery breaths that are associated with the end of obstructive events.
So, the sign of a Central Apnea or Central Hypopnea which has been prevented from happening is a temporary increase in Pressure Support in order to do for us more or all of the work of breathing.
And, in general the apneas or hypopneas which occur during ASV therapy will be obstructive in type. (The most effective way to reduce the frequency and severity of obstructive events is usually to raise the Min EPAP setting.)
I am assuming here that the "Max PS" setting is large enough that the machine is allowed to do for us all the work of breathing, which usually requires the Max PS to be at least 9 or 10. If we have an unusual condition which impedes breathing, the Max PS may need to be significantly higher than 10, such as perhaps 15 or higher.
Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
06-13-2016, 05:32 AM
Thanks for answers.
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