CPAP Setup, Sleep Therapy Data Analysis, and Sleep Consultation/Compliance Service

By Anne – Registered Polysomnographic Technologist

If you are new to CPAP therapy or do not have a sleep clinic that is following your therapy, you may want to consider enrolling in our Therapeutic Services program. 

We can assess how well your CPAP is treating your apneas and can often make changes to your therapy remotely to make it easier and more comfortable for you to use your machine regularly. 

We can also provide compliance downloads to you if you need to show consistent usage to the Department of Transportation or when preparing for surgery. 

We have Respiratory Therapists and Polysomnographic Technologists on staff who are happy to assist you with any of the problems you may be facing with your machine.

There are several reports that we can download for you to see how effectively the machine is treating your apneas. Here is my favorite report: The Sleep Trend Report. We will break it down section by section and discuss what we are seeing.

Here we are looking at a 30-day compliance download. Compliance just refers to how much you are using the machine. 

Typically, a patient is considered to be “compliant with therapy” if they are using the machine for more than four hours a night on 80% of nights. 

We can see that during this time, the patient used the machine for 23 of the 30 days and did not use it at all on 7 of the days. This gives us a percentage of days used as 76.7%. 

We would hope that the patient would be using the machine every day, and not infrequently. But there could be several reasons why the patient may have taken a few days off the machine, including:

• hospitalization
• vacation
• using a different machine
• a nasal infection
• just plain forgetting to use it. 

Many insurance companies will require 80% compliance when you are doing a rental through them. If you have purchased your machine outright, there is no compliance requirement to keep your equipment. It is yours to use or not use as you wish. 

That said, we do encourage patients to use their equipment any time they sleep as that is the only way to prevent apneas.

Moving down this section, we can see that our patient has used the machine on average for 9 hours and 32 minutes each night on the days the machine was used. 

Again, anything over 4 hours is good when trying to maintain that compliance level. But more importantly, if the patient is sleeping for most of that usage, that is a great amount of sleep each night.

This patient uses an automatically adjusting CPAP machine or APAP. In this section, we can see the therapeutic pressure – the pressure required to treat this patient’s apneas. 

With automatically adjusting CPAP machines, the pressure will fluctuate throughout a pre-set range to provide optimal treatment through the night. 

For this patient, the 90th percentile pressure – the pressure at which the machine is at or below 90% of the night – is 10.5cmH2O. The therapist will usually look at this pressure when considering making changes to therapy to ensure that the patient will remain fully treated. 

We also look at the average time spent in large leaks – this can sometimes be quite elevated if there is a poor mask seal or if the patient removes the mask at night.

Here we also see the number one thing most patients, doctors, and therapists want to know – the Average AHI. AHI stands for Apnea Hypopnea Index. This is the number of times per hour that the patient is having apneas or hypopneas. 

Apneas are gaps in breath longer than 10 seconds. Hypopnea is restricted airflow so significant that it is basically an apnea, also longer than 10 seconds. 

The best analogy I have heard to explain the difference between the two is to imagine you are drinking through a straw. Regular breathing is like drinking water. Everything goes up and down the straw without any issues. 

Hypopneas are like drinking an excessively thick milkshake. You suck on the straw, and there is a little movement, but not enough. The top of the straw collapses, and the milkshake slowly makes its way up the straw as your eyes start to bug out from the pressure. 

An apnea is like putting your hand on the end of a straw. Nothing is coming up; nothing is going down. It is completely blocked. Both apneas and hypopneas have a similar effect on our health and our sleep and are therefore counted together for the purposes of the AHI score. 

You probably also heard about your AHI when you took your diagnostic sleep study. It is often referred to as the number of times you stopped breathing throughout the night. 

Here, we can see that the patient is treated down to 1.6 apneas per hour, or AHI 1.6. Anything less than 5 is considered to be “normal and non-dangerous levels.” If the AHI is still elevated above 5 events per hour, we would want to consider changing the pressure settings to try to bring it down. 

It is important to remember that this number is the number of apneas that the patient has while using the machine. If they stop using the CPAP machine, the AHI will go back up to where it was prior to treatment. CPAP is a treatment, not a cure.

Here we have the patient’s device settings. We can see that their automatically adjusting CPAP is set at 6-13cmH2O. We saw earlier that their 90th percentile pressure was 10.5cmH2O, so this range seems appropriate. 

Their machine is set to turn on and off automatically and has a 30-minute ramp time should the patient opt to use it. We have a bunch of standard settings here, as well, that can be modified remotely should the patient experiences difficulties, such as with the heated hose or humidifier temperature settings. 

We also have a lovely graph that shows the patient’s hours of usage each night. We saw above that the patient had only used the machine for 23 of the 30 days in the 30-day period. 

Now, we can see that it is because they are new to this machine and were not using it prior to the 23 days. We now can understand that their use is 100% compliance, not 76.7%, as the report indicated. As this patient’s use reaches 30 days, we will see that statistic correct itself. 

We can also pull a report showing just the 23 days of use if we needed to show a more representative look at their sleep, but for the purposes of this article, doing so is unnecessary.

Now we are moving into the visual representation of the month. Here we can see the pressure settings for the patient. We can see that there was a settings change made on the last day to both the minimum and maximum CPAP pressures.

The EZ-Start is also turned on. We can see how the 90th percentile pressure changes throughout the month based on the patient’s requirements. 

This is one of the major advantages of an automatic machine over a fixed-pressure machine. It will allow for lower pressures for treatment overall because of its ability to adapt.

These next few graphs show us the types of respiratory events the patient experiences. We can see that they had no instances of periodic breathing – which, if seen, could be indicative of Cheyne-Stokes respiration – recorded during the month. 

We can see that their AHI of 1.6 is broken down a bit further here to help the therapist understand how to adjust to the pressures. This patient’s AHI is 0.1 central or clear airway apneas per hour; 0.4 obstructive apneas per hour; and 1.1 hypopneas per hour. 

This is how the total of AHI 1.6 is found. They also note a RERA index of 1.0/hour. RERAs are the Respiratory Effort Related Arousals. These can not truly be measured without polysomnography but can be estimated based on the air movement sensed by the CPAP machine.

In the last graph, we also see the flow limitations index and the vibratory snore indexes. While not factored into the AHI, these can have a significant impact on sleep as well as on bed partners and may factor into the therapist’s decision to adjust the pressure settings.

Next, we have the detailed report. This looks at just a single night. We can see how the pressure moved throughout the night as well as the types of events experienced at each point during the night. 

We can see that on this night in particular, our patient had a 90th percentile pressure of 11.2cmH2O and an average pressure overall of 9.3cmH2O. We can see that the events experienced by the patient were primarily obstructive apneas and hypopneas. 

We can also see a few flow limitations and vibratory snores. In the last graph, we can see that there was minimal mask leak. Some mask leak is intentional to allow for the carbon dioxide in the exhale to be flushed out so that the patient can inhale clean oxygenated air.

But there was one spike in the middle of the night of a large leak for about 2 minutes. Generally, when this is seen, we can assume that the patient either pulled their mask off and then put it back on when the air loss woke them up, or they went to the washroom and returned to bed without turning the machine off while they were gone.

So, that is a lot of information, but what does it mean for you as an end user? It means that we can give you personalized feedback to help you optimize your treatment and address any concerns or issues you may have. 

You can reach out to us at any time and let us know what you are experiencing, and we can troubleshoot the machine and your experience backed by all the information your machine has gathered. 

For instance, if you reach out to me and say that you are feeling like you can’t get a breath in when you start therapy, I would be able to remotely adjust your pressure to give you more pressure at the beginning of the night. 

If you then say you tend to wake up with a dry mouth and throat, I would be able to adjust your humidity settings to enhance your comfort. 

If you also need a compliance report sent to the Department of Transportation, I would be able to generate your compliance report and send that off to both the DOT and you so you both have copies. If you’re curious about your detailed sleep data and want to see your compliance report, that’s no problem. I can email one to you right away.  

Q: Which CPAP units are DOT-compliant? Which machines keep hours used so I can download hours and days used for DOT compliance?

A: In theory, any machine that tracks usage hours and AHI is DOT-compliant and most CPAP machines available on the market in 2023 records usage hours and AHI. Nearly all of them store data in an external storage device such as an SD card. This data can then be downloaded via a software designed by the machine’s manufacturer or a third-party. Premium machines offer extra features such as remote data access via a mobile app and/or remote data transmission to your provider. In short, when shopping for a CPAP, make sure you know all the ways you can access your sleep data on the machine.

The best bet for a CPAP machine that is DOT-compliant is the AirSense line by ResMed. These machines are a frontrunner in the industry and come with the ability to store data in an SD card and transmit data remotely (cellular modem models only), giving you more than one option to access your compliance data.