my sleep study says negative for obstructive sleep apnea?

3 Comments

1. Jacob Smith says:

   August 26, 2010 at 10:58 am

   ask the doc, who knows, i’m not trying to spook you, the study might be wrong, ask them to retake it, or they put you under some sort of strong drug, that may be to keep you sleeping
2. Steve says:

   August 26, 2010 at 10:58 am

   I am a bit confused. A sleep study is done to diagnose obstructive sleep apnea(OSA). It will also show central sleep apnea(CSA). CPAP is the treatment for OSA. If you don’t have OSA you should not be on CPAP. I will assume you had a sleep study, were diagnosed with OSA, and while on CPAP you had no apnea.
   You may have developed CSA while on CPAP. This can also be treated with a more sophisticated machine called BiPAP autoSV. You should call your sleep lab and discuss this with them. Or you can ask your equipment provider.
   Hope this helps you.
3. Intus says:

   August 26, 2010 at 11:57 am

   Your question lacks crucial information to give a meaningful answer but hopefully this helps you in that direction.

   A sleep study generally is done in one of three ways.

   A limited study often just uses a finger pulse oximeter and measures blood oxygen saturation as well as heart rate. This can only rule in OSA but not rule it out. Oxygen dips of 4% or more are looked for as they tend to correspond with an apnea or hypopnea event. Great care must be taken that the sleep technician understands sampling rates and software extrapolation algorithms to correctly ‘score’ the sleep study. This type of study is no good for detecting Central Sleep Apnea (CSA). It’s often done in-home.

   A multi-channel study can be done in home or at the sleep lab. This also measures blood oxygen levels and heart rate but adds airflow through a nasal cannula, and often chest effort and body position. With the extra data channels recorded, this can distinguish obstructive events from central sleep apnoea. Hypopnea’s are better detected too.

   Lastly, a polysomnogram (PSG) is a full blown sleep study including all the above plus wires to measure brainwaves and so on. It’s the most comprehensive and always done in the lab.

   If you are overweight, you snore and feel tired in the day and the pulse oximetry study came out negative, they should do a multi-channel or PSG with you. If it was already such a more comprehensive test and OSA was ruled out, did they comment on CSA at all?

   If you are still tired in the day and CPAP doesn’t work, it can be any of a number of other sleep disorders, such as periodic limb movement etc. Or not a sleep disorder at all but for example problems with thyroid function.

   So if you have reasons to suspect OSA, witnessed apnea events, snoring etc. ask to go up a level in sleep diagnostics with a more in-depth study. This may be able to confirm CSA or a different sleep disorder altogether after which the correct therapy can be prescribed. indeed BiLevel may be more appropriate or in case of PLMS, some form of medication can work very well.