In resuming our dialogue, bear in mind many individuals respond well to the instructions described above in Part II. Their use of imagery distraction to prevent the “control of breathing” behavior often resolves any discomfort with pressurized air. However, no system works for every patient, especially for those already suffering from anxiety, which then is aggravated by the PAP experience. In particular, severe anxiety patients like those with severe PTSD may attempt these instructions yet fail to resolve this problem. Worse, some will report greater intensity of anxiety, which can trigger something close to a panic attack or feelings of claustrophobia. In the setting of a pre-sleep desensitization, one way to ward off these side-effects is to step back from the behavioral approach and return to an educational approach on the general topic of hyperventilation and changes in carbon dioxide (CO2), which often are major factors among patients whose anxiety worsens when trying to use pressurized airflow.
ST: So, if the imagery distraction is not working here, you’ll have plenty of time to practice it at home under circumstances that might prove more amenable to your efforts. Right now, as we proceed with the desensitization, we want to work on another idea that also might prevent or reduce some of the anxiety you are feeling about the pressure sensations.
PT: I’m sorry I’m such a difficult patient.
ST: Believe me you are not alone in suffering this discomfort. Lots of patients go through this exact experience before they adjust to the device. Even Dr. Krakow told us it took him awhile to recognize that imagery distraction was required for his own efforts to use PAP. And, it took him several years of different attempts at PAP before he regularly embraced it in 2002.
PT: So, the cobbler didn’t even have shoes for himself! OK, I’m in…what’s next?
ST: Do you know the term hyperventilation?
PT: Breathing too fast, right?
ST: Yes, now why would someone breathe too fast?
PT: Obviously while running…
ST: Good. Can you think of a way you might breathe more rapidly but you are standing still, that is, not exercising?
PT: Maybe getting worked up about something…I notice sometimes when I’m nervous I have trouble catching my breath and I want to breathe harder.
ST: Excellent, that’s the example we’re looking for, and we would generally call it anxiety. Anything that causes pain, discomfort, or worry is likely to cause some degree of anxiety…
PT: …wait, you are saying the PAP machine or the mask or the air pressure by causing me discomfort could trigger anxiety…it’s not just that I’m already anxious about trying the machine?
ST: Yes, both aspects are in play here. Most people start out with some anxiety about PAP, but others with greater vulnerabilities to distress develop huge bursts of anxiety as soon as they try out the mask or pressurized air.
PT: And with this anxiety comes more rapid breathing…
ST: …hyperventilation, yes…which is its own problem because at higher breathing rates, there is no way for the computer chip inside the PAP device to keep up with the fast pace. With fast breathing we get the opposite problem from what we described at the outset…now the machine can no longer harmonize with your breathing, and the machine will start creating erratic air pressure delivery, which in turn of course drives a patient crazy if the patient is also trying to control his or her own breathing pattern.
PT: Is that what happened to me earlier when I could not take my mind off the pressure? I noticed I was breathing harder at one point and felt some tingling sensations in my fingers.
ST: Exactly. That’s a classic hyperventilation problem, which may include tingling in the hands, numbness around the lips, chest pain, dizziness, lightheadedness, and above all a sense of breathing difficulty. So, now, I’m going to pull out this piece of paper and explain something to you in a bit more detail, so you can understand hyperventilation in a more technical way. With this information, you may discover two things: 1) a big part of the problem might be the type of PAP device you tried to use; 2) another, more advanced PAP device may solve the problem.
If you breathe too fast (hyperventilation), you blow off more carbon dioxide in the air you are breathing out. In fact, most people do not realize carbon dioxide is the main stimulus for your brain to keep breathing as it continuously works to reduce this gas in your blood. In contrast, most people think you breathe to receive oxygen, which is of course true, but the brain responds to different chemical molecules or gases in the body through what are called “respiratory drives.” The drive to breathe to reduce CO2 (carbon dioxide) is stronger than the drive to capture oxygen, which means CO2 has a very important impact in the hyperventilation side-effect.
If you’ve never tried this experiment before, it’s quite revealing. While sitting, breathe very rapidly for about 5 or 10 seconds and just focus on breathing out. Don’t worry about breathing in, just focus rapidly on pushing out as much air as you can. If you suffer from heart or lung problems or some other medical condition that might make you nervous about trying this step, then do the exercise in the presence of your doctor or a nurse. To be clear, you only need to do this exercise for as little as 5 seconds. Now, here’s the remarkable teaching point: as soon as you stop breathing rapidly after the 5 or 10 seconds, a very odd sensation emerges—you no longer possess any desire to breathe. And, it will take at least 5 and usually 10 to 15 seconds before you naturally feel the sensation to want to breathe again. Can you tell me why this would be so?
PT: Based on what you said, it sounds like I blew off too much carbon dioxide when I was breathing rapidly, so my brain no longer wants to breathe.
ST: Exactly, so during the next 5 to 15 seconds carbon dioxide must build up again in the brain, and then breathing resumes to start blowing it off again. If you were to hyperventilate and stop breathing while wearing the PAP mask, did you know there is a special name for this breathing event?
PT: Well, if you stop breathing, like I did on my diagnostic sleep study, you told me it was called an apnea…
ST: Correct, but that apnea was caused by obstruction in your airway. Notice in this hyperventilation example, your breathing airway was not obstructed; you were breathing fine just very fast. Then, suddenly when you stopped breathing, you did not immediately resume breathing for several seconds. In other words the brain not the airway caused the change.
PT: Right, no obstruction. Just the brain’s response to no longer needing to blow off CO2?
ST: Very good, so it is still an apnea; however, because the brain caused it, the more technical term is “central apnea,” as central refers to the central nervous system or brain.
PT: And, this central apnea can occur if I start hyperventilating from my anxiety about the pressure…or even the mask while I am trying to use the device, I guess?
ST: Dude, go to the head of the class!
PT: Thanks, but how am I supposed to stop myself from hyperventilating?
ST: Through the wonders of technology. If central apneas recur again and again, then you will qualify for a diagnosis known as “complex sleep apnea,” which really just means you started out with regular or obstructive apneas, but then developed central apneas as a side-effect caused by the pressurized air triggering anxiety and then hyperventilation and finally rapid blow-off of CO2. As you can see, taken together the diagnosis of complex sleep apnea is the name for a side-effect for a patient who cannot tolerate a standard PAP device such as CPAP or BPAP. Once you meet the criteria for this diagnosis that we call for short, CompSA, your sleep doctor can arrange to switch you to another device with a new technology known as adaptive servo-ventilation or ASV, and which specifically solves the problem of central apneas that might be caused by your anxiety.
In the fourth and final part of this series of posts, I will explain to you how ASV works and one key to rapidly adapting to the device.