Data questions

[Tigerlily]

These are basic questions...just trying to learn so I can understand my Sleepyhead data better.
Thanks in advance for bearing with this newbie! I like to ask lots of questions.

1) What is clear airway apnea? Is this central apnea? If the airway is not obstructed...?
2) Flow limitation, what is it exactly? I read the definition, but don't know how it is different than a hypopnea?
3) Pressure pulse...what is that?
4) RERA's...how exactly are these different than hypopnea's or flow limitation? Because they wake you up? How do you improve these numbers?
5) What is the difference between vibratory snore and vibratory snore #2?
6) What is the ideal for average leaks? I have no idea what's normal and acceptable vs. what is not.
7) What is PB under events?
On the leak graph, why are there 2 lines? One says leaks, and one says total leaks, what's the difference? I don't get it.

Ok.....I think that's it, I think that covers all my questions. For now.....

HAHAHA!!

[PolysomnoGuy]

1) What is clear airway apnea? Is this central apnea? If the airway is not obstructed...?

An apnea is detected when there is an 80% reduction in airflow from a baseline for at least 10 seconds if there is no airflow detected for 10 seconds. During the apnea, one or more pressure test pulses are delivered by the device. The device evaluates the response of the patient to the test pulse and assesses whether the apnea has occurred while the patient has a clear airway or an obstructed airway. The airway is determined to be clear if the pressure test pulse generates a significant amount of flow; otherwise the airway is determined to be obstructed.

2) Flow limitation, what is it exactly? I read the definition, but don't know how it is different than a hypopnea?

Flow Limitation is a partial obstruction of the airway as detected by a change in the shape of the flow signal.
The device looks for relative changes in the peak, flatness, roundness, or shape (skewness) of the inspiratory portion of the airflow waveform. These changes are observed both over a short period of time (groups of 4 breaths) and over a long period of time (several minutes). Statistical measures are used to help minimize false event detection while allowing the device to be sensitive to even small changes.
An hypopnea is indicated if there is approximately 40% reduction in airflow for a duration of between 10 and 60 seconds, compared to the average airflow over an extended period of several minutes.

3) Pressure pulse...what is that?

Small test probes or puffs of air to help the machine decide if the apnea event is obstructive in nature or clear airway in nature. This number can vary widely and is of no real critical consequence to therapy.

4) RERA's...how exactly are these different than hypopnea's or flow limitation? Because they wake you up? How do you improve these numbers?

Respiratory Event Related Arousal... a sequence of breaths characterized by increasing respiratory effort leading to an arousal from sleep, but which does not meet criteria for an apnea or hypopnea. Respiratory effort-related arousal..defined as an arousal from sleep that follows a 10 second or longer sequence of breaths that are characterized by increasing respiratory effort, but which does not meet criteria for an apenea or hypopnea. If this breath sequence is terminated by a sudden increase in airflow along with the absence of flow limitation, and the event does not meet the conditions for an apnea or hypopnea, a RERA is indicated.

5) What is the difference between vibratory snore and vibratory snore #2?

Vibratory snore is detected when a specific frequency is detected during the inspiratory portion of the patient's breath.

6) What is the ideal for average leaks? I have no idea what's normal and acceptable vs. what is not.

It varies from manufacturer to manufacturer on average we try to keep mask leaks as low as possible. On average below 30%.

7) What is PB under events?

Periodic Breathing is defined as a persistent waning and waxing breathing pattrn which repeats itself between 30 and 100 seconds. The nadir of the breathing pattern is characterized by at least a 40% reduction in airflow from an established baseline flow. The pattern must be present for several minutes before it can be identified as periodic breathing.

On the leak graph, why are there 2 lines? One says leaks, and one says total leaks, what's the difference? I don't get it.

Displays the average amount of time the patient spent with excessive air leakage that will compromise therapy. This could be the result of poor mask fitting.

[Pugsy]

Respironics machines report total leak...which is mask vent rate plus any excess leak.
So the top line in SleepyHead leak graph is the total leak rate.
The bottom line is an approx value of what excess leak might be.

[Tigerlily]

Thanks!!