|
|
|
|
|
newly diagnosed - what do all of these numbers mean?
I have gone through past forums but can't seem to find a general explanation of all of the numbers from my sleep study results. Can someone please tell me what they mean? I was basically just told that I have severe OSA and need a CPAP machine (I'll be getting it in the next 2-3 days), but I would like to know where my numbers "fall" in some ranges.
Here are my results:
Recording time of 311 minutes,
total sleep time
-157 minutes longest apnea
- 32 seconds longest hypopnea
- 22 seconds (what is the difference between these 2 things?)
Apnea plus hypopnea index - 46.2
Sleep efficiency - 50%
oxygen saturation low (in non-REM sleep) 74%
Heart rate variations were noted WITH CPAP of 12
- oxyten saturation of 93% or greater
Any answers would be greatly appreciated (or directions to a previous forum). I'm new at all of this so would like any advice or encouragement! Thanks!Follow-up
1. Recording time of 311 minutes, total sleep time-157 minutesYou tried to sleep for 311 minutes in the sleep lab but managed to sleep only 157 minutes. Getting sleep in a sleep lab is tough for lots of people. It was for me.
2. longest apnea - 32 secondsAn Apnea is total blockage of air flow. Usually the threshold for an apnea is no flow for at least 10 seconds. An apnea can last a minute or more. The longer they last, the worse off you are. 32 seconds means you ceased breathing for 32 seconds. This was indicated as your longest apnea.
3. longest hypopnea - 22 seconds (what is the difference between these 2 things?)A hypopnea is a reduced air flow. 50% reduction is the usual threshold. 22 seconds means you had a reduction of 50% or more (but not 100%) for 22 seconds. Hypopneas are usually accompanies by snores. This was indicated as your longest hypopnea.
4. Apnea plus hypopnea index - 46.2Apnea index (AI) is defined as the number of apneic episodes/hour sleep, and apnea-hypopnea index (AHI) is the total apneas plus hypopneas during total time asleep, divided by the number of hours asleep. The respiratory distress index (RDI) is the same as AHI. An RDI of 0 to 5 in normal; 5 to 20 is mild; 20 to 40 is moderate; over 40 is considered severe.
You also want to know how the AHI is divided between apneas and hypopneas, as the apneas probably have more effect regarding sleep arousals and oxygen levels than the hypopneas.
5. Sleep efficiency - 50%157 divided by 311. percentage of time monitored that you actually slept.
6. oxygen saturation low (in non-REM sleep) 74%
OSA causes a drop in one's blood oxygen saturation (SaO2) and an increase in the blood's carbon dioxide (CO2). When the SaO2 drops the heart will start pumping more blood with each beat. If the SaO2 continues to drop the heart will start beating faster and faster. Asthe CO2 increases the brain will try to drive the person to breathe. The effort and action of the abdomen and chest will increase. Eventually that action can become severe enough to cause an arousal, clearing the upper airway blockage, allowing the person to breathe. Then you go back to sleep and it happens all over again.
Anything below 90% is considered problematic, though the amount of time spent below 90% also indicates the extent of the problem.
7. Heart rate variations were noted
See 6. Also, OSA can induce heart arrhythmias. I had PVCs for years that were just shrugged off as being harmless.
8. WITH CPAP of 12 - oxygen saturation of 93% or greaterThe 12 is a pressure value with units of centimeters of H2O, often written as cmh2o or CMH2O. 12CMH2O is a moderate to moderate-high pressure. More importantly, what is the AHI/RDI value for you at 12CMH2O. Poor oxygen levels negatively affect the body, particularly the brain and heart. However, the contant sleep arousals induced by the sleep/apnea/wakeup/breath cycle (which in your case happens 46 times or less per hour) ultimately creates havoc with daytime brain function, causing memory and cognitive processes to be disrupted. Subjective descriptions of these disruptions describe failing memory, mental fuzziness, and inability to concentrate or focus. Extreme daytime fatigue is another symptom of the nefarious impacts of sleep apnea.
Regarding advice, educate yourself! Read every post on the last few forums. I also encourage you to read "Phantom of the Night", which can be purchased if necessary at http://www.newtechpub.com/ Essentially you need to learn enough to form a treatment partnership with your doctor. Also, CPAP can be a royal pain in the ass to get to work properly, but many people describe the results as a miracle. Some people get relief in one night. Many others feel better in a week or two. Working through all of the trials and tribulations of CPAP can be a real challenge. It often requires perseverance, disipline, and most of all, a positive and inventive attitude.
Copyright ©1995-2000 Sleepnet.com., All rights reserved