26 May 2019

How to overcome Central Apnea using Bilevel?

“Don’t be discouraged. It’s often the last key in the bunch that opens the lock.”
- Author Unknown 

All patients being treated with CPAP therapy by a sleep medical specialist would have gone for a Sleep Study. Should few or no Central Sleep Apnea (CSA) have come up in the Study, it is likely the CPAP machine and the settings being used that are causing CSA to appear after starting sleep apnea therapy. This post will show how I overcome central sleep apnea caused by CPAP by using a Bilevel or BiPAP auto adjusting pressure machine. 
CSA is where you have no obstruction in your upper airway, however you stop breathing. CSA occurs because your brain doesn't send proper signals to the muscles that control your breathing. 

Medical Research has shown that CPAP may actually cause CSA in certain patients including male sex and history of cardiac disease. The presence of CSA may limit the effectiveness of CPAP therapy. Known as Treatment-Emergent Central Sleep Apnea. 

Lehman S; Antic NA; Thompson C; Catcheside PG; Mercer J; McEvoy RD. Central sleep apnea on commencement of continuous positive airway pressure in patients with a primary diagnosis of obstructive sleep apnea-hypopnea. J Clin Sleep Med 2007; 3(5):462-466. 
Read more at the following link: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1978327/

A major weakness of the CPAP and auto-adjusting CPAP Machines is that the machines are limited to Pressure Support of 3 cmH2O. In addition, these machines do not have settings for Trigger and Cycle and TI Max and TI Min like the machine that I use, which is ResMed S9 VPAP Auto. This is a bilevel auto adjusting pressure machine (bilevel). This machine is now known as ResMed AirCurve 10 VAuto bilevel machine.  

Note that you will also see the bilevel machines known as BiPAP machines. BiPAP stands for Bilevel Positive Airway Pressure. BiPAP is a Registered Trademark owned by Philips Respironics. This company’s machine is known as Philips Respironics DreamStation Auto BiPAP. 

Previously when using the CPAP machine, my breathing would stop or pause when transitioning between Inhales to Exhale and Exhale to Inhale leading to CSA occurring each night. The Trigger and Cycle settings on the bilevel machine overcame these pauses in my breathing reducing CSA to nil or minimal each night. The TI Max setting assists in ensuring that your breathing on inhale goes no longer than is optimal for you. For example, I use 1.2 seconds. 

From the sleep apnea forums (listed right hand side), I note that a number of patients when they use Pressure Support or increase Pressure Support especially above 3 cmH2O, have CSA appearing. The Trigger and Cycle setting is a fantastic feature which has overcome the CSA issue for me. Note that I was only diagnosed with Obstructive Sleep Apnea in my Sleep Study. 

On a CPAP machine, I was seeing usually half or more of my apneas as CSA. This was due to the machine having an estimated “medium” Trigger and Cycle setting. Further, I was being subject to much higher median pressure each night causing many issues when compared to a bilevel machine. You can see the extensive list of issues that arose from using the sleep apnea machine at the blog page Stop CPAP Side Effects and Issues.

Should you have a CPAP machine, I suggest reducing EPR pressure support to 1 cmH2O or completely turning pressure support off to assist in reducing CSA. Clearly, this will require you to not have issues such as a feeling of having too much pressure on the machine. In this situation, whilst not ideal, consider reducing your CPAP pressure. 

By using a bilevel machine and changing the Trigger and Cycle settings to high/ very high from the default setting of Medium and increasing the Pressure Support to at least 5 cmH2O, I have taken over some of the control of the machine. I have made the machine work how I would like it to work. That is, you are setting the machine so that the settings are optimized for you! 

For the Trigger and Cycle settings, I am using: 

Trigger (from exhale to inhale)               High 
Cycle (from inhale to exhale)                 High/ Very High 

You can see the various settings that I am using on the bilevel machine on the blog page Different Bilevel Settings Example.
From my personal experience, it is much easier to breathe using a bilevel machine than using a CPAP or an Auto Adjusting CPAP machine. The bilevel auto adjusting pressure machine is very smooth and it is a natural feeling when breathing. Your breathing can be in sync with the machine. From my experience, the bilevel machine offers better comfort, compliance, therapy and sleep quality. 

By using the Trigger and Cycle settings and TI Max of 1.2 seconds, I have minimized or completely removed CSA occurring each night. These settings are critical to me when using pressure support of between 5.0 to 5.6 cmH2O every night and to having successful sleep apnea therapy. 

You can read more about the bilevel or BiPAP machine and CSA at:

From a practical point of view, the various sleep apnea machines can be likened to televisions. 

The CPAP fixed pressure machine is like the old black and white television.  
The auto adjusting CPAP machine is like the old colour television.
The Bilevel or BiPAP auto adjusting machine is like a high definition colour television. 

Which machine would you prefer to sleep with each night especially since you may be sleeping with this machine for the next 40 to 50 years? 

There is a comparison of the CPAP and Bilevel Machines using my SleepyHead data on the blog page CPAP Vs Bilevel Settings Example.
An update to this blog post using BiPAP and Bilevel ST machines to overcome Central Apnea is at:

Since originally writing this blog post, in early 2021 I began using a very high starting IPAP of 18.2 cmH2O and EPAP of 13.0 cmH2O (inhale and exhale pressure) which may cause central sleep apnea. This was essential to stop hypoxia (oxygen desaturation) and sleep disordered breathing causing the symptoms of Dementia. More details are on the blog post:
Should you be having side effects and issues with your sleep apnea therapy; CHANGE what you are doing so that you can wake up feeling refreshed and energized each day. 

“Have courage. Be adventurous and Go for it! Overcome your fear.”
- Mrhelpful