Flow Limitation Index

[Ray]

What is a flow limitation, and what is the flow limitation index? I can't find a good definition.

[Stryker5777]

There are several definitions, one on this forum in the help section. Another is in the encore pro help files. I haven't really found an explaination medically what the consequences of flow limitations are. Does anybody know? Could enough negatively impact one's therapy?

Stryker5777

[Snoredog]

here are the definitions:

DEFINITIONS:
APNEA = cessation of airflow for 10 seconds or greater.
HYPOAPNEA =>50% decrease in airflow for 10 seconds or greater with a decrease in oxygen saturation of >3%.
APNEA/HYPOAPNEA INDEX (AHI) = apnea plus (+) hypoapnea/hour of sleep.
RESPIRATORY AROUSAL INDEX (RAI) = AHI +snoring related EEG arousals/hour of sleep.
AHI/RAI** Scale =<5 events /hour = (none); 5-15 events/hour = (mild); 15-30 events/hour = (moderate); >30 events/hour = (severe).
Respiratory related sleep fragmentation: Sleep arousals due to respiratory events or snoring.
Desaturation = Drop in O2 oximetry distribution saturation by 3% below average saturation.
SaO2 scale: >89%=(none); 85-89%=(mild);80-84%=(moderate); <80% (severe).
EPWORTH SLEEPINESS SCALE =<10=(does not indicate EDS (Excessive Daytime Somnolence));10-15=(indicates daytim somnolence-not excessive);>16 (indicates EDS).
RESPIRATORY EFFORT RELATED AROUSALS (RERAs)=Sleep Arousals due to respiratory events characterized by pressure flow limitations in the airflow indicator channel without significant O2 desaturations.
StageIII and StageIV are combined and referred to as Deep Sleep.
Sleep Efficiency = Normal is >80%


There are other definitions such as those found in EncorePro software but those are what the "machine" determines and not what the absm.org board has classified above.

A flow limitation is normally ignored in PSG scoring but it can be seen as an obstructive event being less severe than a Hypoapnea/Hypopnea to be classified.