CPAPtalk.com

Kitmastin wrote:We also offer free CEU credits for clinicians who participate in the courses on http://www.devilbissclinicaleducation.com site.

Thank you for the feedback on the audio recordings. We are looking at alternatives to record the audio for our webinars. In addition, we will be adding additional educational courses within the next few months.

As, always - we are listening. Feel free to offer up any comments or suggestions.

• the audio quality on the second was reasonable, but the sound was very weak.
  Please note that there is a major time lag between the audio and the appearance of case study charts it the second webinar. That makes the last part of the presentation almost impossible to follow - a pity because it is interesting to hear the analysis.
  The scoring for the second quiz is totally messed up - (check the first question and you will see that immediately).

Kitmastin wrote:We're glad that you find the webinars useful. We are working on a fix for the audio issues and should have them repaired in the next month. If you have any other suggestions - courses you would like to see presented, etc...please let me know. You can always email me at Kristin.Mastin@DeVilbisshc.com.

Thanks again for the feedback.

Kit,
According to the webinars, Devilbiss assumes a drop in flow of more than 95% is central, and it will not respond to those apneas. Can you point us to studies supporting those assumptions?
Do you have info about the percentages of false positive and false negatives when that rule is used?

Thank you

yardbird wrote:Your data looks almost exactly like mine. Last night I had ZERO apneas recorded and I think that's a first for me. However I had a LOT of hypopnea events and they wake me up so I need to track them down. I also think it's important to know what a particular setting MEANS if we're going to make changes. The way I'm reading the Advanced Menu options seems to be indicating that the percentage setting is is a figure representing how far below normal flow we must fall before registering as an event.

For example (just tossing out easy numbers, not meant to be representative of actual):

Let's say our normal flow is 100

Default Hypopnea% is 50%
I read this as: Respiratory flow must drop to 50% of normal and stay at or below 50% of normal for the time specified in Hypopnea Duration. Default for that is 10 seconds.
So respiratory flow of 50 for 10 seconds registers as a Hypopnea event.

If we change Hypopnea% to 40% and change nothing else.
Respiratory flow must fall 40% from normal for 10 seconds. This means you still HAVE 60% respiratory flow. You've made the machine more sensitive because now your respiratory flow only needs to drop 40% from normal instead of having to drop to 50% below normal.

If we change Hypopnea% to 60% and change nothing else.
Respiratory flow must fall 60% from normal for 10 seconds. This means you still HAVE 40% respiratory flow. You've made the machine less sensitive because now your respiratory flow needs to drop 60% from normal before registering an event.

So the apnea% or the hypopnea% are not percentages of what you HAVE, but rather percentages of how far you have fallen off of the normal.

A hypopnea% setting of 40% would be telling the machine that if I reach a respiratory flow that is down 40% from my normal (not 40% OF my normal), start working on this as a hypopnea event. A hypopnea setting of 50% would ignore that same scenario and wait until I've reached a 50% reduction from normal before reacting.

So LOWERING that percentage number makes the machine more sensitive, and RAISING it makes the machine less sensitive to these events.

Now here's a bigger question...
If the machine pressure is set, such that I have ZERO apnea events recorded, but lots of hypopnea events. Do I want to CHASE the hypopnea events by making these small and granular adjustments or do I do something much simpler and INCREASE my low pressure setting in an effort to keep the airway splinted open and PREVENT the hypopnea events?

natediggidydogg wrote:

yardbird wrote:Your data looks almost exactly like mine. Last night I had ZERO apneas recorded and I think that's a first for me. However I had a LOT of hypopnea events and they wake me up so I need to track them down. I also think it's important to know what a particular setting MEANS if we're going to make changes. The way I'm reading the Advanced Menu options seems to be indicating that the percentage setting is is a figure representing how far below normal flow we must fall before registering as an event.

For example (just tossing out easy numbers, not meant to be representative of actual):

Let's say our normal flow is 100

Default Hypopnea% is 50%
I read this as: Respiratory flow must drop to 50% of normal and stay at or below 50% of normal for the time specified in Hypopnea Duration. Default for that is 10 seconds.
So respiratory flow of 50 for 10 seconds registers as a Hypopnea event.

If we change Hypopnea% to 40% and change nothing else.
Respiratory flow must fall 40% from normal for 10 seconds. This means you still HAVE 60% respiratory flow. You've made the machine more sensitive because now your respiratory flow only needs to drop 40% from normal instead of having to drop to 50% below normal.

If we change Hypopnea% to 60% and change nothing else.
Respiratory flow must fall 60% from normal for 10 seconds. This means you still HAVE 40% respiratory flow. You've made the machine less sensitive because now your respiratory flow needs to drop 60% from normal before registering an event.

So the apnea% or the hypopnea% are not percentages of what you HAVE, but rather percentages of how far you have fallen off of the normal.

A hypopnea% setting of 40% would be telling the machine that if I reach a respiratory flow that is down 40% from my normal (not 40% OF my normal), start working on this as a hypopnea event. A hypopnea setting of 50% would ignore that same scenario and wait until I've reached a 50% reduction from normal before reacting.

So LOWERING that percentage number makes the machine more sensitive, and RAISING it makes the machine less sensitive to these events.

Now here's a bigger question...
If the machine pressure is set, such that I have ZERO apnea events recorded, but lots of hypopnea events. Do I want to CHASE the hypopnea events by making these small and granular adjustments or do I do something much simpler and INCREASE my low pressure setting in an effort to keep the airway splinted open and PREVENT the hypopnea events?

BE VERY CAREFUL HERE. YOUR ABOVE CALCULATIONS ARE EXACTLY THE OPPOSITE OF WHAT THEY SHOULD BE.

Changing hypoapnea to 40% makes the machine LESS sensitive to the event.
Changing hypoapnea to 60% makes the machine MORE sensitive to the event

Here's why: look at the "apnea" options. We have 0% - 20%. That means an apnea can be defined by 0% of normal breathing volume (a true apnea) to 20% of normal breathing volume. The same rules apply to hypoapneas: setting at 60% (instead of 50%) means we are adjusting the machine so that it defines hypoapneas as 60% normal breathing volume. We are making the machine more sensitive bc it is now responding to an smaller event.