Sleep Dynamic Therapy

Archive for the ‘Sleep Apnea’ Category

This study on changes in depression following CPAP use is very important, because it looks at the longer term impact of treating SDB. In some other recent studies, the time frame was too short to learn much about what PAP therapy does to depression. Remember, most depression builds in patients over many months time, if not longer. To reverse depression or at least reduce it, we would expect a sleep-oriented treatment to take several weeks or months to have a meaningful impact. That’s what these researchers found.

Today, at my talk at Sandia National Laboratories, the audience was interested in my opinion on the recent article on sleep duration in relationship to premature death from heart disease. As I’ve pointed out previously, these studies are incomplete works because they are looking at a sleep quantity model. Yet, the real insight is mostly likely explained by underlying physiological sleep disorders that causes one group to sleep too long (for example, classic sleep apnea patients with hypersomnia) and one group to sleep too short (for example, sleep breathing patients with a co-occurring problem of insomnia). Both types of patients have an underlying physical sleep disorder, but they look very different due to their pronounced differences in sleep duration. So, is sleep duration the important risk, or is it really the underlying physical sleep disorder? Parsimony suggests that sleep breathing problems provide the best reason to explain premature death rates.

This report from the European Respiratory Society highlights two important problems in the way the media and bariatric researchers are framing the discussion about post-operative sleep breathing changes following significant weight loss. First and foremost, they only report the AHI, the apnea-hypopnea index, and not the RDI, the Respiratory Disturbance Index. Thus, it is safe to assume that the researchers did not use advanced respiratory technology to measure UARS events (a.k.a. flow limitation events), the subtle breathing patterns that also provoke sleep fragmentation and subsequent daytime impairment in ways quite similar to classic sleep apnea. The second issue is the comment that the surgical intervention reduced or eliminated snoring in some patients, as if to suggest that snoring is a reliable marker of sleep breathing problems.

In sum, we are faced with the dilemma that both the media and the bariatric researchers are accepting outdated metrics for assessing sleep-disordered breathing (SDB). In the first instance, the assumption is that the AHI tells the whole story. It’s wonderful news to hear that AHI drops post-weight loss, but by not defining and measuring the RDI, it is safe to assume that many of these patients still suffer from SDB that likely needs treatment. The commentary on snoring represents another outdated metric in that we know many patients don’t snore and have SDB, and there are some who do snore and don’t have SDB. Bottom line is that snoring doesn’t tell us a lot about someone’s SDB condition. Again, it’s wonderful news that snoring decreases or disappears with post-op weight loss, and it likely signals that SDB severity has decreased, but it doesn’t tell us whether or not the patient still suffers from SDB, and that is the most important issue in question about the patient’s sleep health.

Imagine if the heart surgeon told a patient, “Looks like we’ve cut down your coronary blockages by 50%.” No intelligent heart patient would be satisfied with such a claim. “Okay, but how much coronary blockage do I still have left?” Same goes for SDB, “how much SDB do these patients still suffer from?” is the question at hand.

In this Washington Post article covering recent research on longevity in patients undergoing weight loss surgery, the emphasis seems to favor bariatric procedures. That is, it appears that those who undergo weight loss surgery and lose weight increase their lifespan. I’ve not read the research articles yet, but the question raised would be why would these patients live longer. Obesity is a risk for many diseases, but the one least likely to get a mention would be obstructive sleep apnea. I’d bet the research articles mention SDB as one explanation for why patients might live longer, even though the Post didn’t make a comment on it. However, I doubt the research conducted pre and post weight loss sleep tests to find out what happened to the severity of SDB in these cases. That information might prove quite illuminating.

In this short video on WebMD, the explicit discussion revolves around one man’s desire for a better night’s sleep, which will somehow be achieved by eliminating his snoring. The treatment he receives is polyester implants into the soft palate for the expressed purpose of stopping the vibrations of these tissues to reduce snoring. What’s the problem here? Actually a very serious one. At no point in the video do we learn whether the patient has been tested with an overnight sleep study (polysomnography) before the surgery or after to evaluate its effects. What would the sleep study show? In all likelihood, the patient has something far more medically significant than snoring; namely, sleep-disordered breathing (SDB), for example, obstructive sleep apnea or upper airway resistance syndrome. The standard of care in the field of sleep medicine requires the patient to undergo a sleep test before and after such treatments to determine to what extent the procedure has improved his condition. Many of these site-specific snoring surgeries provide scant relief of SDB. Some actually worsen SDB. We do not know the patient involved in this video and cannot comment on what he may or may not be suffering from. However, we can state categorically that patients who share some of his features, apparently a long history of snoring, a thick neck, dark circles under his eyes, and most importantly a recessed chin (often covered up by a beard or goatee) frequently test positive on a polysomnogram for obstructive sleep apnea or upper airway resistance syndrome. Was this patient informed of the need for testing before and after surgery? Did the patient receive a full explanation of the risks snoring carries for an SDB diagnosis. Was the patient evaluated by a sleep specialist for a possible SDB diagnosis? If not, then the standard of care established by the field of sleep disorders medicine was not met prior to the surgical intervention.