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Flow limitation is not a condition that is looked at often by clinicians or doctors because it is not an important diagnostic for insurance, which targets actual apnea and hypopnea events. Flow limitation is important because it is actually airway restriction or obstruction that limits the peak flow through the airway. This makes it harder (more effort) to inhale and reduces the volume of air you respire (tidal volume). You can spot periods of flow limitation on your flow rate graph by looking at a zoomed image where you can see the individual respiratory waves. Where those waves change from normal rounded forms to ones that are flattened or downward sloping on top, that is what flow limitation looks like. As the body experiences greater flow limtation it will respond by arousing you to a lighter stage of sleep or awakening you to breath better. This is a Respiratory Event Related Arousal (RERA) and it leads to unsatisfying sleep and continuing daytime fatigue.
We have another member that has extreme flow limitation that shows this wave-form. Here is an example of her charts that shows that respiratory flow rate (black wavy line with inspiration above the red line and expiration below), and how we are using pressure support (mask pressure is the blue line, and pressure support is the increase in pressure for each inspiration) to try to treat it. Here is an example of her charts showing normal respiration going through a transition to extremely flow-limited. It's unlikely you will ever see this in your charts, but the flat or downward sloping inspiration waves are flow limitation, and we can see recovery-breaths after about 10 breaths (RERA).
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
01-15-2020, 03:49 PM (This post was last modified: 01-15-2020, 03:51 PM by mesenteria.)
RE: New APAP User
With great deference and respect to our esteemed Sleeprider, he intended RERA to be translated as "Respiration EFFORT-Related Arousal."
And, that's the whole point; with a flow restriction for whatever reason, it's harder to draw breath against it, and in some cases it leads to an arousal because of this intractable 'effort'.
I'll stick with what I said, however, I often say it the other way.
Quote:Respiratory event–related arousal (RERA) is an event in which patients have a series of breaths with increasing respiratory effort or flattening of the nasal pressure waveform leading to an arousal from sleep that does not otherwise meet the criteria for an apnea or hypopnea.
It is a breathing disorder characterized by obstructive upper airway airflow reduction (which does not meet the criteria of apnea or hypopnea), associated with increased respiratory effort that resolves with the appearance of arousals (RERAs).
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Last night I think looked good, but I do have a question. From 4:50 to about 5:30, my AHI jumped up a bit, but the pressure stayed at my min of 8. Why wouldn't the Auto function have bumped up the pressure to compensate, or am I not understanding how these machines work?
You folks know this stuff by heart, but I read every reply and have more questions. So I looked up Central events, and that’s my brain forgetting to tell me to breath? That’s scary. And CPAP does nothing for that?
Philips Respironics also calls CA events "clear airway", and at the level they occur in your therapy, they are insignificant. We often will hold a breath or not breath when we change position in bed, and sometimes the events occur during a sleep stage transition. Your respiration is maintained during sleep by your autonomic nervous system, and is "driven" by the balance of bicarbonate in your blood stream. When CO2 rises, it increases bicarbonate, and triggers faster or deeper respiration. During long apnea, it can also trigger adrenaline release and result in arousal to cause you to breathe. On the other hand, when CO2 levels drop, the respiratory drive also is reduced. This can cause you to skip a breath without any obstructive cause or distress. The body re-balances quickly and you resume normal spontaneous respiration. This is harmless, and your CPAP machine is programmed not to respond to it. Your CPAP machine is able to determine if an apnea is obstructive or clear, by testing the airway with a 1-cm pulse of air. If it is obstructive, the pressure will increase on the next breath; if it is clear airway there is no pressure change. You can see the pressure pulses on your chart on top of the flow-rate chart as black vertical lines. If you zoom into a close view of that pulse, you can see the breathing pause and the response or deflection of your airway during the pressure pulse.
This is nothing to be concerned about, and if you had frequent CA we would be the first to suggest changes to your therapy approach to mitigate it.
INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Machine: Resmed AirSense 10 AutoSet For Her Mask Type: Full face mask Mask Make & Model: Resmed f20 Humidifier: Resmed Integrated humidifier CPAP Pressure: 11/14 CmH2O CPAP Software: Not using software
Other Comments: I started CPAP in 2008. Totally blind since birth.
