Comments on the Series about UARS and Its Cascade Preference Potential

One reader sent us extensive notes on his experience, which are listed below and the followed by additional commentary:

“I have known I have sleep apnea for about 25 years. I tried PAP machines several times but never saw any benefit for my symptoms so used it relatively little. I tried again about 16 months ago with a new sleep test. Showed the usual AHI of about 30 and arousal rate of about 60. It took about 3 months to get an AutoPAP. It was obvious to me after a couple of weeks it wasnt going to work with AHI of about 20 and Cheyne-Stokes breathing up to 80% of the night. It took 5 months to get another sleep test and another 2 months to upgrade to a BPAP. This did a better job, but still AHI of about 15 with mostly central apneas. I finally got an ASV and that does great getting the AHI to about 2, but through the approximately 9 months there was no improvement in symptoms even with the low AHI. In looking at the data from the ASV, I noticed the graph of flow limitations (UARS) was terrible through each night. Dr. Krakows information seems to indicate that this issue can cause the same problems as a high AHI. Now I have to convince the doctor of these residual breathing events. Its going to be difficult since I dont think their software even shows the flow limitations. The machines give a lot more information now than 20 years ago, and I think I can see why I was never helped before with CPAP. Hopefully getting rid of the UARS will help with the symptoms.”

After we asked the reader for permission to use his story anonymously, he added some additional insights: 

“Some of the figures quoted are from memory and may not be real accurate, but the general idea is correct. I used Sleepyhead software for analysis and while not approved for clinical use, it seems to be very consistent. I have changed to another sleep doctor between the BPAP and the ASV. I lost confidence in the original one when the doc changed devices from APAP to BPAP but continued to deny I was suffering from central apneas. That suggested to me no one was really looking at the data. Yet, during the five months I used that machine, it showed a minimum of 30% of the night to a maximum of about 80% with central apnea problems.”

“I assume the solution to the flow limitations is a higher pressure which presents a problem if true as now I am getting pressures in the morning of up to 23 cm and mask leak is a real problem. The setting of the ASV is EPAP of 8.0 with Min PS of 3 and a Max of 15 and set on rate of AUTO. Over the 9 months of using the 3 machines I have not seen any improvement in symptoms, and in fact, probably the opposite. My hope is that solving the sleep disorder will give significant improvement. If not, then I'll have to assume other causes are in play.” 

Let me start by thanking you for describing the journey you have been on in trying to treat your UARS. You are not alone. Regrettably, tens of thousands of patients just like you travel along these windy paths full of bends and potholes. As a sleep specialist who was mentored by Dr. Guilleminault, the pioneer who discovered UARS, it remains astonishing so many sleep specialists choose or refuse to acknowledge the importance of UARS.

The reader highlights a critical way in which these data are literally ignored—if no one looks at the data downloads carefully enough to use the information on flow limitation. The irony here cannot go unspoken. In the past, it would have been the sleep specialists clamoring for more data to better treat their patients. Instead, the PAP manufacturers, most notably ResMed and Respironics, are engineering devices to track flow limitation; and, yet apparently, many sleep doctors completely disregard what is often invaluable data on many of their patients. Thus, we have the business end of sleep medicine leading the field, but the sleep specialists apparently have not gotten the message.

Even when data are more obvious, as with central apneas, it too was apparently ignored in this case. Now, it is true that some central apneas registered on data downloads are actually artefacts, but that observation is usually a rarity when the number of centrals are so proportionally high compared to other breathing events as they were in the reader’s story. And, even when the central apnea index is lower, it has been our experience more often than not to find still more central apneas when the patient returns for a retitration study.

The last point I want to drive home is to not rely on setting pressure calibrations based on guesstimates. Many in the field of sleep medicine think that ASV and ABPAP devices only need to run on auto-mode. Some may look at your data and then attempt to tweak the settings using their clinical judgment. Occasionally, such approaches work, but nothing compares to returning the patient to the sleep center for a retitration with ASV or ABPAP where the sleep technologist manually titrates these devices while they remain in auto-mode.

What seems to not be widely known is that these devices on their own do not meet the requirements of the American Academy of Sleep Medicine standards for successful titrations. However, when a patient undergoes a titration with ASV and ABPAP, again with manual adjustments to the various pressure settings, then this fine-tuning process will yield a much better response and achieve these standards. Indeed, we have treated many such patients who were placed on ASV by another sleep center, and the settings were either the default program or a doctor’s guesstimate. After completing the titration in our sleep lab where the sleep tech manually titrates the ASV or ABPAP device, the vast majority of such patients recognized clear-cut improvements in their responses despite the previous lack of or mediocre responses while using the machine on the “wrong” settings. It is perplexing that more sleep centers do not conduct these manual titrations of auto-adjusting devices.

It is true, as the reader ponders, that other causes may induce feelings of daytime fatigue and sleepiness, but it is a sad commentary on the field of sleep medicine that more attention to precision targeting of the UARS condition is not carried out by the majority of sleep labs. Doing so would most certainly help a great many UARS patients to achieve better results and that would be a good thing for all parties concerned. 

Finally, we had one more quote from the individual who operates the Sleepyhead software that was described in the story above:

“Great series, Dr. Krakow! I’m not only a sleep educator/RPSGT, but someone who has UARS. I absolutely appreciate the attention you’ve placed on why this is a condition that struggles to be validated even after scientific evidence is robust. Ill be following your blog!”

Thanks for your support. Spreading the word on UARS is perhaps the only consistent way in which to influence patients and sleep doctors to take this condition seriously. Rarely do we find UARS even mentioned at the annual sleep conference. One day that might change, but for now it is valuable to hear the stories from frustrated patients, which may be the only ammunition we possess to attack the problem head-on. Eventually, we would hope a preference cascade will form and bring the UARS problem into mainstream sleep medicine.

Barry Krakow MD


Dr Krakow’s 27 years of sleep research have focused on the complex relationship between physiological and psychological sleep disorders. Dr Krakow currently operates private sleep medical center, Maimonides Sleep Arts & Sciences, Ltd., and serves as Classic SleepCare’s paid Medical Director.

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