home study for centrals

[jerry1967]

Is there a home study to test for centrals? I know I get them from my sleepyhead studies and my Dr. wants me to test for a different machine.Can I do this testing with a home study?

[AlanE]

I doubt it can detect CA. You would need to monitor brain functions to determine if the reason you are not breathing (when not obstructed) is HA or CA.

[Sleeprider]

I'm certain that there are home sleep studies that differentiate between central and obstructive apnea, however the use of a clinical study with full PSG is nearly impossible to avoid if insurance coverage will be applied. Your Airsense 10 detects and reports central apnea, and that is a pretty good indicator or whether clinically important CA is present with CPAP pressure. If the objective is to determine whether CA is present in the absence of CPAP pressure, it may be sufficient for screening purposes to measure apnea (cessation of flow) with no respiratory effort (chest expansion). Some home studies do this, however you will never get approval for ASV on that basis. If insurance is not involved, then it's fairly easy to use an ASV, prescribed or not, to determine if it is effective in eliminating the central events Of course in that case you are assuming all the financial risk whether you work with your physician or not.

[AlanE]

Sorry to disagree. There is no CPAP machine that can determine if you are in central apnea. You may be confusing CA in CPAP machine world as "Central Apnea" when it is "Clear Airway". To determine clear airway the CPAP machine will send a pulse of air down the tube and meeting no resistance it assumes there is no obstruction and calls that a "clear airway". They will not use the term Central Apnea because it doesn't scan the brain.

[Sleeprider]

As I said, it's a screening tool, and not accepted for diagnostic purposes, particularly for insurance. It does tend to be a pretty good indicator, and I have no problems using the CPAP data to point a direction that CPAP is effective or not, or that central or complex apnea is likely present. "Clear airway" and "central apnea" are just semantic differentiation of a synonymous symptom. CPAP data certainly does not diagnose the cause.

[robertbuckley]

A home study, while not as fulsome as one performed in a sleep lab, detects and records centrals. In fact it will give you obstructive, central, hypopnea and RERA's and break them into whether in REM or non-REM and supine or non-supine, along with O2 sat levels, leg movements, heart rate and duration of time in each stage of sleep. Obviously, what a home study cannot provide is any form of titration which has to be done manually by the tech in the lab. IMHO with today's auto machines, titration in a lab to obtain optimal pressure settings will soon become a thing of the past. In the discussion above I think folks were confusing what our PAP machines can detect/reveal versus the "home study" from a sleep lab or maybe we should call it the "take-out PSG". Insurance companies today have actually become resistant to in-lab studies and are pushing for more home studies because of the cost difference.

[jerry1967]

So are clear airways the same as central or not?

[Sleeprider]

The machines have a certain error rate. Accuracy can be improved by analyzing pressure, flow rate, flow limitation, snore and patient history and making some judgements about factors associated with central or obstructive apnea. Central apnea onset can be related to many factors including CPAP pressure, medications, cardiac conditions, central nervous system disorders and more. CA is often registered during sleep disturbance in healthy individuals at low rates. High rates of CA over 15 AHI are rarely an error. Mid-range CA from 7-14 might be resolved through pressure and therapy changes. Low rates of CA from 2-7 seem to be more common and insurance won't cover it regardless of cause. Below CAI of 2/hour, CA may be simple sleep disturbance and movement and will generally be disregarded by professionals. CA is CA in most cases, but severity and cause are important.

[richb]

Central Apnea in the absence of Congestive Heart Failure often shows up as Central Hypopnea and Periodic Breathing in a sleep study in the absence of CPAP treatment.  Effort is usually present during periodic breathing and cessation of effort is often brief during Central hypopneas.   What is of concern is the desaturation of blood O2 as measured by a Pulse Oximeter.  The Central Apnea can be caused by a malfunction of the CO2 measuring system primarily located in the Carotid Body or by a malfunction in the brain stem where the brain interprets signals from the Carotid Body and signals the body to breathe.  A stroke victim with sudden onset Central Apnea would be an example of the brain malfunction type.  Our CPAP machines tend to wash out CO2 from our blood making Central Apnea worse in those with serious Carotid Body malfunction.  We often note that some individuals are more sensitive to CO2 washout and require machine adjustments to minimize this effect.  In those with more serious Central Apnea ASV machines are the only treatment that works without additional medication.  The one victim of stroke and sudden onset Central Apnea that I know is successfully treated with an ASV machine.  

Rich

[richb]

I did some "sleep study" experimentation using one of the CPAP machines that I had before getting my ASV machine.  At what would have been therapeutic settings (pressures above 8cm H2O I had very high AHI (above 40) consisting of CAs and Cheyne Stokes Respiration.  Below 5 cm H20 I had primarily Hypopneas and Periodic Breathing.  The Hypopneas had the waveform characteristic of Central Hypopnea (normal breaths in miniature).  I had no Obstructive events at either setting.

Rich