Flow and Flow Limitation graphs; need help

Can someone please direct me to a source of information that will help me understand and analyze Flow and Flow Limitation detailed graphs. I have the clinical manual but it is of little help. Thanks in advance.

KatieW wrote:viewtopic.php?f=1&t=57594&st=0&sk=t&sd= ... limitation

Thanks, KatieW,

I just spent awhile reading the material in that post and have NO IDEA what these engineers are talking about, lol. If I understood anything about what they are discussing, it's that no one understands the graphs and what they mean. I won't worry about it anymore.

jonnybee wrote:Can someone please direct me to a source of information that will help me understand and analyze Flow and Flow Limitation detailed graphs. I have the clinical manual but it is of little help. Thanks in advance.

Are you interested in more than the ResMed definitions?

Flow
Flow is an estimate of the airflow entering the lungs. It is derived by taking the total flow and
then removing the leak and mask vent flow components.

Flow Limitation
Flow Limitation is a measure of partial upper airway obstruction. This measure is based on the shape of the inspiratory flow–time curve. When using a mathematical representation of the shape of the breath (flow time curve) to indicate the state of the upper airway, a "round" shape denotes an open patent airway while a "flattened" shape indicates a flow limited airway.


Hypopnoea
A hypopnoea is an episode of shallow breathing during sleep. A hypopnoea is scored when there is a reduction in
breathing by 50% of baseline breathing with partial upper airway obstruction for 10 seconds or more. The event is scored
after 10 seconds of the hypopnoea.

jonnybee wrote:no one understands the graphs and what they mean.

What's not to understand?

Rounded = Good

Flattened = Bad

S8 and Earlier Algorithm = "Flattening Index" & Good on Top



S9 Algorithm = "Flow Limitation" & Good on Bottom:

jonnybee wrote:...these engineers...

Another engineer experimenting with "Flattening Index":

jonnybee, I just now noticed your signature line. That's one lucky dog to have been found by you. You're a good person.

Back to the flow limitations stuff... all the breaths in my normal breathing are pretty much flow limited -- like the middle squiggle in the fuschia colored pics from ResMed that NotMuffy posted. I do fine somewhat "flow limited", so I don't worry about it.

But I make sure not to wear socks to bed.