(09-12-2016, 09:38 PM)elbie Wrote: The PA that is monitoring my CPAP treatment says that I am too number oriented and that the machine is not all that accurate with these AHI numbers. He says that if I want to know if the treatment is successful or not I should go back in and have another sleep study session.
My questions are: Is the ResMed machine that inaccurate that I can't get a fairly good indication of the successfulness of my treatment? Is it possible for the AHI numbers to change so dramatically by just changing the mask (I did reset the machine for the change in mask)?
First, about the accuracy of a sleep study. It is a snapshot in time under challenging circumstances and does not represent your medical condition with any degree of repeatable precision. Therefore, it is a starting point to develop an informed diagnosis and some initial titration guidelines.
Second, about the accuracy of your machine -- or any machine for that matter -- they are not precision measurement devices and use only a few parameters from sensors to algorithmically compute the scores you are seeing displayed. It is the trend over time that really matters, not the day-to-day readings unless they are repetitively poor.
Third, about the mask. Leak rates do directly affect the sensors and can alter results dramatically. You find the mask that appears to produce the best results and one that is not uncomfortable to use. It takes experimentation and some tweaking. I have not met anyone that did not spend time, effort, and money on trying to find a better mask setup.
Fourth, about you personally. Some of us, myself included, are analytical and wish for a precision machine that yields accurate numbers. Since we do not live in a sleep lab, this is a matter of approximation not precision. My medical mentor in the old days cautioned me to treat the patient, not the machine. And that chasing numbers was often futile over the short-term. It is like watching a patient with PEA (Pulseless Electrical Activity) that appears to have a somewhat normal EKG, but their heart is not pumping blood and they are dying.
Fifth, and lastly, whether or not your therapy is working is subjective. How do you feel? Are you symptom free? Has your quality of life improved? AND DO THE NUMBERS LOOK REASONABLE OVER A SUFFICIENT PERIOD OF TIME?
I suggest you do what I do. Track the numbers, take screen snapshots of some of the anomalies, and when you have questions based on accumulated data, make an appointment with your sleep doctor (not the DME's respiratory therapist and not a physician's assistant -- unless they are a nurse practitioner skilled in sleep disorders) to discuss your findings, conclusions, and a course for the future.
Best of luck.
"The object in life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." -- Marcus Aurelius