CHECKING Your CPAP Machine Settings - Basic Information
For people with sleep apnea and for their healthcare professionals, peer coaching article #17, updated 1 December 2011
Part 1 of 2 on PAP Pressure
Tips for All PAP (Positive Airway Pressure) Users (CPAP, APAP, BiLevel)
Pressure Definition. Machine air pressure is measured in centimeters of water, cm/H2O or cwp, centimeters of water pressure. A pressure of 10 cm/H2O means that if you were drinking water from a 10 centimeter (3.9 inch) straw positioned at the top of the water to your mouth, the suction you create would be 10 centimeters of water pressure. Speech is measured at about 7 cm/H2O pressure past the vocal cords. The average pressure for treating sleep apnea is 10 cm/H2O. Typical pressures for treating obstructive sleep apnea are 6 to 15 cm/H2O. Some people require higher pressures. The air pressure acts as a pneumatic splint to keep the throat open. The pressure is less than a sneeze and rarely causes the ears to pop. Source: TS Johnson MD et al, Sleep Apnea – The Phantom of the Night, p. 92.
Titration is a scientific lab term, meaning to slowly add a little bit more of something until you reach a desired effect. During the sleep study, the sleep technician slowly increases the CPAP machine pressure one centimeter/water at a time until you stop having apneic events (apneas or stopped breathing and hypopneas or partial breaths). That and some more calculation lead to a titrated pressure setting. See Reasons Why Your Titrated Pressure May Be Wrong in the peer coaching article CPAP Machine Choices. Research article on the inaccuracies of a one-night titration: http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=14971878&dopt=Citation
Know your titrated pressure from the sleep study. Know the pressure your doctor prescribed. If you don’t know them, ask your doctor’s office for a copy of the sleep study report and doctor’s prescription. Some people start and continue CPAP treatment with the titrated pressure from their sleep study and have continuing good results with no problems. Others still feel tired, or feel tired again after a few months, and need to explore the correctness of their machine pressure setting and pressure prescription, as well as first solving other equipment problems.
Consequences of a wrong pressure setting
Don’t worry; unless you have other serious medical problems, your immediate life is probably not in danger! Long term effects are another matter if you give up on CPAP therapy. It’s important to know your titrated pressure from a sleep study (if you have been titrated) and pressure prescription, and know that your machine has been set up correctly by the Respiratory Therapist (RT). The prescribed pressure setting on your PAP machine is very important.
If the pressure is too low for you, it won’t eliminate all the apneas or hypopneas and may not clear out all the exhaled carbon dioxide from your mask. Pressure too low may be indicated by snoring, insomnia, feeling starved for air, subtle feelings of suffocation or claustrophobia while on PAP, an AHI (Apnea Hypopnea Index of events per hour) above the normal 5 or below events per hour, or still feeling tired or sleepy during the day. For example, some people find that a setting of 4 or 5 cm/H2O is not high enough to clear the exhaled carbon dioxide, and need a setting of 6, 7, or 8 cm/H2O or more as their lowest setting on an APAP.
Pressure that is too high for you may be indicated by uncomfortable therapy, large mask leaks, mouth breathing, dry mouth and throat even with heated humidification, aerophagia (swallowing air), an AHI above the normal 5 or below events per hour, and still feeling tired or sleepy during the day. Some people have concerns that too high a pressure setting may lead to pressure-induced central apneas (the brain not telling the body to breathe) unless the PAP machine algorithm (operating rules) prevent “runaways” of increased pressure. Pressure settings above 15 cm/H2O are considered high for some people; for others, 18, 19, 20 cm/H2O is high.
If your autopap machine is incorrectly left at the factory default setting of 4 to 20 cm/H2O, you may experience the problems of both too high and too low. In addition, the APAP machine may have difficulty responding quickly enough with this large range. With pressure too low, too high, or other wrong setting (CPAP or APAP mode, exhalation relief, ramp or settling), your AHI may not be as low as it should be, or you may be more uncomfortable, and you may think the therapy doesn’t work very well and be tempted to give it up. To know your AHI, you need a machine with a smart display or software. Your AHI should be 5 events per hour or less to be considered in the range of normal sleepers. Many people require an AHI of 2.5 or less to be truly rested and invigorated.
Two measurements of Sleep Disordered Breathing (SDB)
Apnea. The Greek word “apnea” means “without breath.” You stop breathing during sleep for ten seconds or longer.
Hypopnea. There is airflow through your throat but at a much reduced level, which leads to not getting enough oxygen. It’s abnormally shallow breathing lasting at least ten seconds.
1. AHI, Apnea Hypopnea Index for sleep apnea:
Less than 5 events (apnea or hypopnea) per hour is considered normal.
5 or more events per hour is considered Mild sleep apnea
15+ considered Moderate
30+ considered Severe
(from T. S. Johnson MD, Sleep Apnea - The Phantom of the Night, page 211)
Flow limitation or Upper Airway Resistance Syndrome (UARS) is another important, subtle form of SBD. The airflow meets resistance in the nose or mouth, causing the brain to waken the sleeper. The American Academy of Sleep Medicine advocates counting apneas, hypopneas, and flow limitations/UARS for the Respiratory Disturbance Index, RDI.
2. RDI, Respiratory Disturbance Index for sleep apnea:
5 to 20 events per hour is Mild SDB
20 to 40 events is Moderate SDB
More than 40 events is Severe SDB
(from Barry Krakow, MD, Sound Sleep, Sound Mind, page 245)
Check the accuracy of your machine’s prescribed pressure setting. This is important.
Your doctor’s prescription was entered into the PAP machine by a Respiratory Therapist (RT) at a DME/home medical equipment company who could make a mistake. The DME company may not have procedures to detect setup errors, so if they made an error, you would never know, unless you had other means to check the settings. (Their follow-up phone call asking “how are you doing?” isn’t precise enough to detect set-up errors.) You are entitled to ask and observe to have the settings checked by a Respiratory Therapist other than the one who set it up, or by a lead respiratory therapist; or minimally, by a slow and careful walk-through demonstration by the same RT who programmed the machine originally. See the end of this article for a sample walk-through of machine set-up. The check could be done when you get the machine, or a few days later if you were overwhelmed by your diagnosis and too much information when you first picked up the machine.
If you run into resistance from the RT about checking your machine setting, is it because they are unwilling or unable? If unable because they are not competent in setting up the machine, there is a greater chance they made an error, and all the more reason to have it checked. If they are unwilling, it may be that, following company policy, they are unwilling to risk your learning how the machine is set so you don’t “tamper” with it. Nevertheless, you are entitled to see if it’s a correct prescription, just as you are entitled to see if the label on a bottled drug prescription for the right dosage pill. If you run into resistance, talk with the lead RT or branch manager, or if the DME insists, get a doctor’s prescription to let you observe the correct settings, or get a doctor’s prescription for the clinician’s manual from the DME and check it yourself. If you attend an AWAKE patient support meeting at a sleep lab and bring in your machine, the technicians there may calibrate your machine (do free pressure checks). AWAKE meetings are sponsored by the American Sleep Apnea Association.
Learn the patient-controlled settings. This is important.
Read the user’s manuals that come with your machine and heated humidifier to learn how to set the features you can control. For example, in an older, “classic tank” Respironics REMstar autopap, that would be heat/humidity level, C-Flex exhalation relief level, ramp or startup pressure and duration of ramp, mask-off alert/auto-off, and button lights. Learn to read the display screens. Use a flashlight and magnifying glass if necessary. If you have trouble pushing buttons, you may want to get someone to help you. Discussion thread on a ramp (settling) pressure setting that was too low: http://www.cpaptalk.com/viewtopic.php?p=134380#134380
Using a clinician’s set-up manual to check the accuracy of your prescribed pressure setting
Personal criteria for using a set-up manual
If you aren’t good with technology, you should probably rely on the respiratory therapist at your local DME to check the prescribed pressure settings; or rely on a family member, friend, nurse, or doctor. If you can’t program your DVR, cell phone, or use most of the features of a digital camera, seek help from others. If you can handle most basic consumer technology, it should be easy for you to use a set-up manual safely and well to check the accuracy of your machine settings. Checking the set-up menu is not much more difficult than changing the time on a digital clock and takes less than a minute, once you know what you are doing.
How to get a clinician’s set-up manual
The clinician’s set-up manual is boxed with the new machine, along with the user’s manual. The local DME/HME (Durable Medical Equipment or Home Medical Equipment) company should give you the patient/user’s manual but, fearing liability, will probably withhold the clinician’s manual unless you have a doctor’s prescription for it. When you ask your doctor for a prescription for the manual (before or after you get your machine), tell him/her that without it you can’t check the correctness of your machine settings made by the DME. Discuss your ability to scroll through a menu with your doctor, show him/her the sample dialog at the end of this article if he/she isn’t familiar with a machine’s setup, and show him/her the user’s manual if you already have one. The clinician’s manual isn’t much different; if you can follow the user’s manual, you can follow the clinician’s manual.
If you buy your machine online at www.cpap.com, all manuals will be included. Some people buy clinician’s manuals online, but be sure that you get the one for your machine, not another model. Some people ask other experienced users for the simple directions on how to use the buttons to access the set-up menu in the display; you really don’t need the hardcopy set-up manual. For example, see
http://www.cpaptalk.com/viewtopic/t15421/How-to-change-settings-on-RemStar-Plus.html and http://www.cpaptalk.com/viewtopic.php?t=11376 and http://www.cpaptalk.com/viewtopic.php?t=10055 . Don’t expect support from your local DME in using a set-up manual or machine software.
You do not need machine software to use a set-up manual or instructions to check whether the DME RT set your machine correctly. As you scroll through the settings, write them down for later reference. If you find that the DME set up the machine wrong, not following your doctor’s prescription, inform your doctor and take the machine into your DME for correction by the lead RT or correct it yourself. Report the error to the local DME supervisor/lead respiratory therapist or branch or regional manager, and consider reporting it to the DME branch or regional manager and filing a complaint with The Joint Commission of Accreditation of Healthcare Organizations, so other patients won’t be harmed.http://jcwebnoc.jcaho.org/QMSInternet/IncidentEntry.aspx The DME needs feedback to improve their quality of service to other patients.
Tips for All PAP (Positive Airway Pressure) Users (CPAP, APAP, BiLevel)
Pressure Definition. Machine air pressure is measured in centimeters of water, cm/H2O or cwp, centimeters of water pressure. A pressure of 10 cm/H2O means that if you were drinking water from a 10 centimeter (3.9 inch) straw positioned at the top of the water to your mouth, the suction you create would be 10 centimeters of water pressure. Speech is measured at about 7 cm/H2O pressure past the vocal cords. The average pressure for treating sleep apnea is 10 cm/H2O. Typical pressures for treating obstructive sleep apnea are 6 to 15 cm/H2O. Some people require higher pressures. The air pressure acts as a pneumatic splint to keep the throat open. The pressure is less than a sneeze and rarely causes the ears to pop. Source: TS Johnson MD et al, Sleep Apnea – The Phantom of the Night, p. 92.
Titration is a scientific lab term, meaning to slowly add a little bit more of something until you reach a desired effect. During the sleep study, the sleep technician slowly increases the CPAP machine pressure one centimeter/water at a time until you stop having apneic events (apneas or stopped breathing and hypopneas or partial breaths). That and some more calculation lead to a titrated pressure setting. See Reasons Why Your Titrated Pressure May Be Wrong in the peer coaching article CPAP Machine Choices. Research article on the inaccuracies of a one-night titration: http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=14971878&dopt=Citation
Know your titrated pressure from the sleep study. Know the pressure your doctor prescribed. If you don’t know them, ask your doctor’s office for a copy of the sleep study report and doctor’s prescription. Some people start and continue CPAP treatment with the titrated pressure from their sleep study and have continuing good results with no problems. Others still feel tired, or feel tired again after a few months, and need to explore the correctness of their machine pressure setting and pressure prescription, as well as first solving other equipment problems.
Consequences of a wrong pressure setting
Don’t worry; unless you have other serious medical problems, your immediate life is probably not in danger! Long term effects are another matter if you give up on CPAP therapy. It’s important to know your titrated pressure from a sleep study (if you have been titrated) and pressure prescription, and know that your machine has been set up correctly by the Respiratory Therapist (RT). The prescribed pressure setting on your PAP machine is very important.
If the pressure is too low for you, it won’t eliminate all the apneas or hypopneas and may not clear out all the exhaled carbon dioxide from your mask. Pressure too low may be indicated by snoring, insomnia, feeling starved for air, subtle feelings of suffocation or claustrophobia while on PAP, an AHI (Apnea Hypopnea Index of events per hour) above the normal 5 or below events per hour, or still feeling tired or sleepy during the day. For example, some people find that a setting of 4 or 5 cm/H2O is not high enough to clear the exhaled carbon dioxide, and need a setting of 6, 7, or 8 cm/H2O or more as their lowest setting on an APAP.
Pressure that is too high for you may be indicated by uncomfortable therapy, large mask leaks, mouth breathing, dry mouth and throat even with heated humidification, aerophagia (swallowing air), an AHI above the normal 5 or below events per hour, and still feeling tired or sleepy during the day. Some people have concerns that too high a pressure setting may lead to pressure-induced central apneas (the brain not telling the body to breathe) unless the PAP machine algorithm (operating rules) prevent “runaways” of increased pressure. Pressure settings above 15 cm/H2O are considered high for some people; for others, 18, 19, 20 cm/H2O is high.
If your autopap machine is incorrectly left at the factory default setting of 4 to 20 cm/H2O, you may experience the problems of both too high and too low. In addition, the APAP machine may have difficulty responding quickly enough with this large range. With pressure too low, too high, or other wrong setting (CPAP or APAP mode, exhalation relief, ramp or settling), your AHI may not be as low as it should be, or you may be more uncomfortable, and you may think the therapy doesn’t work very well and be tempted to give it up. To know your AHI, you need a machine with a smart display or software. Your AHI should be 5 events per hour or less to be considered in the range of normal sleepers. Many people require an AHI of 2.5 or less to be truly rested and invigorated.
Two measurements of Sleep Disordered Breathing (SDB)
Apnea. The Greek word “apnea” means “without breath.” You stop breathing during sleep for ten seconds or longer.
Hypopnea. There is airflow through your throat but at a much reduced level, which leads to not getting enough oxygen. It’s abnormally shallow breathing lasting at least ten seconds.
1. AHI, Apnea Hypopnea Index for sleep apnea:
Less than 5 events (apnea or hypopnea) per hour is considered normal.
5 or more events per hour is considered Mild sleep apnea
15+ considered Moderate
30+ considered Severe
(from T. S. Johnson MD, Sleep Apnea - The Phantom of the Night, page 211)
Flow limitation or Upper Airway Resistance Syndrome (UARS) is another important, subtle form of SBD. The airflow meets resistance in the nose or mouth, causing the brain to waken the sleeper. The American Academy of Sleep Medicine advocates counting apneas, hypopneas, and flow limitations/UARS for the Respiratory Disturbance Index, RDI.
2. RDI, Respiratory Disturbance Index for sleep apnea:
5 to 20 events per hour is Mild SDB
20 to 40 events is Moderate SDB
More than 40 events is Severe SDB
(from Barry Krakow, MD, Sound Sleep, Sound Mind, page 245)
Check the accuracy of your machine’s prescribed pressure setting. This is important.
Your doctor’s prescription was entered into the PAP machine by a Respiratory Therapist (RT) at a DME/home medical equipment company who could make a mistake. The DME company may not have procedures to detect setup errors, so if they made an error, you would never know, unless you had other means to check the settings. (Their follow-up phone call asking “how are you doing?” isn’t precise enough to detect set-up errors.) You are entitled to ask and observe to have the settings checked by a Respiratory Therapist other than the one who set it up, or by a lead respiratory therapist; or minimally, by a slow and careful walk-through demonstration by the same RT who programmed the machine originally. See the end of this article for a sample walk-through of machine set-up. The check could be done when you get the machine, or a few days later if you were overwhelmed by your diagnosis and too much information when you first picked up the machine.
If you run into resistance from the RT about checking your machine setting, is it because they are unwilling or unable? If unable because they are not competent in setting up the machine, there is a greater chance they made an error, and all the more reason to have it checked. If they are unwilling, it may be that, following company policy, they are unwilling to risk your learning how the machine is set so you don’t “tamper” with it. Nevertheless, you are entitled to see if it’s a correct prescription, just as you are entitled to see if the label on a bottled drug prescription for the right dosage pill. If you run into resistance, talk with the lead RT or branch manager, or if the DME insists, get a doctor’s prescription to let you observe the correct settings, or get a doctor’s prescription for the clinician’s manual from the DME and check it yourself. If you attend an AWAKE patient support meeting at a sleep lab and bring in your machine, the technicians there may calibrate your machine (do free pressure checks). AWAKE meetings are sponsored by the American Sleep Apnea Association.
Learn the patient-controlled settings. This is important.
Read the user’s manuals that come with your machine and heated humidifier to learn how to set the features you can control. For example, in an older, “classic tank” Respironics REMstar autopap, that would be heat/humidity level, C-Flex exhalation relief level, ramp or startup pressure and duration of ramp, mask-off alert/auto-off, and button lights. Learn to read the display screens. Use a flashlight and magnifying glass if necessary. If you have trouble pushing buttons, you may want to get someone to help you. Discussion thread on a ramp (settling) pressure setting that was too low: http://www.cpaptalk.com/viewtopic.php?p=134380#134380
Using a clinician’s set-up manual to check the accuracy of your prescribed pressure setting
Personal criteria for using a set-up manual
If you aren’t good with technology, you should probably rely on the respiratory therapist at your local DME to check the prescribed pressure settings; or rely on a family member, friend, nurse, or doctor. If you can’t program your DVR, cell phone, or use most of the features of a digital camera, seek help from others. If you can handle most basic consumer technology, it should be easy for you to use a set-up manual safely and well to check the accuracy of your machine settings. Checking the set-up menu is not much more difficult than changing the time on a digital clock and takes less than a minute, once you know what you are doing.
How to get a clinician’s set-up manual
The clinician’s set-up manual is boxed with the new machine, along with the user’s manual. The local DME/HME (Durable Medical Equipment or Home Medical Equipment) company should give you the patient/user’s manual but, fearing liability, will probably withhold the clinician’s manual unless you have a doctor’s prescription for it. When you ask your doctor for a prescription for the manual (before or after you get your machine), tell him/her that without it you can’t check the correctness of your machine settings made by the DME. Discuss your ability to scroll through a menu with your doctor, show him/her the sample dialog at the end of this article if he/she isn’t familiar with a machine’s setup, and show him/her the user’s manual if you already have one. The clinician’s manual isn’t much different; if you can follow the user’s manual, you can follow the clinician’s manual.
If you buy your machine online at www.cpap.com, all manuals will be included. Some people buy clinician’s manuals online, but be sure that you get the one for your machine, not another model. Some people ask other experienced users for the simple directions on how to use the buttons to access the set-up menu in the display; you really don’t need the hardcopy set-up manual. For example, see
http://www.cpaptalk.com/viewtopic/t15421/How-to-change-settings-on-RemStar-Plus.html and http://www.cpaptalk.com/viewtopic.php?t=11376 and http://www.cpaptalk.com/viewtopic.php?t=10055 . Don’t expect support from your local DME in using a set-up manual or machine software.
You do not need machine software to use a set-up manual or instructions to check whether the DME RT set your machine correctly. As you scroll through the settings, write them down for later reference. If you find that the DME set up the machine wrong, not following your doctor’s prescription, inform your doctor and take the machine into your DME for correction by the lead RT or correct it yourself. Report the error to the local DME supervisor/lead respiratory therapist or branch or regional manager, and consider reporting it to the DME branch or regional manager and filing a complaint with The Joint Commission of Accreditation of Healthcare Organizations, so other patients won’t be harmed.http://jcwebnoc.jcaho.org/QMSInternet/IncidentEntry.aspx The DME needs feedback to improve their quality of service to other patients.
With a clinician’s manual, you will be able to change the pressure settings beyond the original prescription, but it is inadvisable to do that unless you have supervision from your doctor and software to give you feedback on the results of changes.
To get the machine pressure changed by your doctor and DME, you need to get an appointment or phone your doctor, explain why you think a change is needed, make sure that a prescription was sent to the DME and received, make sure that the DME processed the prescription internally so your local office can make the change, make an appointment at the DME, drive to the local office, wait, have the respiratory therapist make the change, which literally takes about 30 seconds, and drive home. Before you leave, request that another RT check the accuracy of the setting, or get a careful walk-though demonstration from your machine showing correct settings.
An alternative is to team with your doctor to correct or adjust the pressure settings yourself, if you are a suitable candidate for this team effort. See the next article on Changing Your CPAP Pressure Setting.
After you have mastered hose, mask, leaks, comfort, humidity, ramp/settling, exhalation relief, and been stable on PAP for a few weeks or months, borrow an overnight recording pulse oximeter from your doctor or RT, or buy one online. Use it to check your blood oxygen saturation levels at night as another indicator that your PAP and pressure settings are working well.
Even better, get a machine with a smart display or software to more precisely show how well your therapy is working each night.
Appendix I
Check the machine accuracy with a manometer
New users, don’t let this scare you. This is rare but important: http://www.cpaptalk.com/viewtopic/t15002/cpap-machine-gone-crazy.html
Rarely, the pressure reading on the machine’s LCD display and actual pressure may be different. You may want to check the actual pressure every six months or annually. An instrument called a manometer will give an accurate reading. A free manometer check may easily be done by your local DME, perhaps before and after AWAKE support group meetings at a sleep lab, or you can make or buy a manometer online if you are technically inclined. See http://www.cpap.com/ and search. If the pressure is off, some machines have an internal reset feature. If there is no reset, you can change the machine’s pressure setting to match the actual pressure. For example, if you are seeking a prescribed pressure of 9 cm H2O but 9 on your machine isn’t really a pressure of 9, you can bump it up to 10 to get an actual pressure of 9. If you don’t have a manometer and the pressure is off, what really matters is how you feel and your AHI at the actual pressure you do have.
Appendix II
Sample walk-through to check settings on an older Respironics REMstar Auto with C-Flex CPAP (the “classic tank” model)
It takes less than a minute to scroll through the menu, using the buttons on the machine. The respiratory therapist should demonstrate competence and confidence in working with the machine settings. This is a sample dialog that you should hear from the respiratory therapist to confirm correct settings. The dialog for your machine will be different, but the RT should explain each screen.
“Screen 1. Nights at more than 4 hours means the number of nights you used the machine for more than 4 hours. Stop me and ask if you have questions about any of these settings.
Screen 2. AFLE means that the therapy mode is set to Auto CPAP with C-Flex pressure relief, what your doctor prescribed.
Screen 3. Min 9.0 means that your lower pressure is set to 9.0 cm H2O pressure, what your doctor prescribed.
Screen 4. Max. 11.5 means that your higher pressure is set to 11.5 cm H2O. Your machine will automatically adjust up and down between 9 and 11.5 cm H2O, what your doctor prescribed.
Screen 5. C Flex 3 means that your exhalation relief is set to 3, the highest setting offering the most relief. You can change this setting on your own, following the instructions in the user’s manual.
Screen 6. 0:00 ramp means that your ramp (startup) time is set to 0. This means there is no ramp in the APAP mode. Your machine will start at your lowest setting, 9 cm H2O, and adjust upward to 11.5 as you need it. For older REMstar auto machines, the ramp time must be set to zero in the auto mode. If the ramp is set to anything other than 0:00, the machine is set for a split night sleep test, remaining at the lowest pressure for the set number of hours, so you are not getting a full night of therapy. (If your doctor had prescribed CPAP mode instead of APAP, ramp time from 5 to 45 minutes would be available on this older machine. Respironics newer M series autopaps can use ramp while operating in auto mode.)
Screen 7. Alert 1 means that your mask-off alarm beep is turned on. If your hose disconnects or your mask comes off, the machine will beep. It also means that the machine auto-off feature is turned on. You can change this setting on your own.
Screen 8. LED 0 means that the button lights are turned off while the machine is on. You can change this setting on your own.
Screen 1 again means that this is where we came in; we’ve gone through the whole menu and it’s correct.”
Sources: Based on personal experience with obstructive sleep apnea and gleaned from the collective wisdom of cpaptalk.com contributors.
Want more? See the peer coaching articles at http://smart-sleep-apnea.blogspot.com , http://www.cpap.com FAQ Learning Center, or search http://www.cpaptalk.com or post a message there.
Not written by healthcare professionals. The information and opinions offered are not intended or recommended as a substitute for professional medical advice.
© Mile High Sleeper, August 2006 - 2011. All rights reserved. You may make copies of this message and distribute in any media for free educational purposes, as long as you credit the author and include this copyright notice and the web address smart-sleep-apnea dot blogspot dot com
Labels: CPAP pressure too high, CPAP pressure too low, titration
posted by Mile High Sleeper Gal | 7:02 PM
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