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Consensus on When, Why and How to use HST and When is Auto Score Acceptable

 The LinkedIn Discussion Group, “SleepDisordersDentistry” has just completed an open discussion on the use of HST in Dental Sleep Medicine. Here is a consensus for all to ponder.

(John Viviano, Les Priemer, Bradley Eli, Kent Smith, Steve Lamberg, Steve Carstensen, Tim Mickiewicz, Tony Soileau, Shouresh Charkandeh, Scott Craig)

What was asked,

“ Why, when and how should a Sleep Disorders Dentist use HST and when is ‘Algorithm’ scored acceptable vs. ‘Human’ scored?”

What was said,

There are many controversial subjects in Dental Sleep Medicine; mostly due to an absence of good evidence based findings in the literature for us to refer to. Consequently, there is a tendency for groups of clinicians to develop “camps” based on “empirical and anecdotal evidence”. But this subject is different in that it also touches on both “political correctness”, and “scope of practice”, which varies with region. Although we will be touching on some of this regional variance, this article is not a comprehensive review of those differences, and a clinician considering using HST in their practice should conduct proper due diligence. This article will discuss use of HST for the following activities, Screening, Baseline Study, Appliance Calibration, Efficacy Study and Follow-up Study.

Screening and/or Baseline Sleep Study:

There is no support in the literature or in any published guidelines for a dentist to unilaterally use HST as a screening tool, or to conduct a Baseline Sleep Study. The AADSM guidelines require a face-to-face consultation with a physician before a HST is dispensed to an undiagnosed patient. The reason for this is that some patients require a full PSG (for a variety of reasons) and it is outside of a dentist’s scope of practice to make that determination.

 Appliance Calibration:

In this discussion, the use of HST seemed to be mostly limited to aiding in the calibration of an oral appliance. Typically, once an oral appliance is optimally calibrated as per subjective criteria, a HST would be performed to provide an objective assessment of improvement from the baseline sleep study (which may or may not have been conducted with an HST). The rational being that in a subset of patients, AHI persists even after the patient experiences subjective relief. By checking with HST, further adjustments could be made prior to referring the patient back to the referring physician to conduct their follow-up PSG (or HST). The use of HST in this way provides objective information regarding unresolved apnea and the positional nature of that apnea. This information aides in clinical decisions such as advancing further, altering vertical, placing elastics to help deal with supine apnea, and providing counseling on positional therapy once all the possible adjustment possibilities are exhausted.

The use of Algorithm vs. Technician scored studies was also discussed. This subject is usually more heated than what we witness in this discussion. When HST is used to aide in the calibration of an appliance, on occasion, it may be necessary to use the HST 2-4 times. Of course, this is the exception, however, it is impossible to determine upfront if that is the type of case one is dealing with. Consequently, some clinicians suggested using the Autoscore on a reliable device. Quite frankly, I can see how HST would be used much less to aide in calibration of an appliance if there was a 3rd party cost associated with each use. Some clinicians also suggested using the Autoscore initially, and once they had a study that they felt comfortable with they would review the RAW data on their computer rather than just accepting the autoscored conclusion. Of course, this requires extra training, which is not beyond the scope of a dentist. All this being said, a case was made regarding “Political Issues” associated with a dentist having their HST Technician scored; this simply looks TOO MUCH like what the referring physician is going to be doing when we send the patient back. Regionally, some dentists do not use HST to calibrate their appliances for fear of upsetting their referring physicians. Personally, I am a strong advocate of using HST for this purpose, however, I do not have them technician scored to avoid upsetting my referring physicians. I go out of my way to explain to the patient that my HST is different than the final Efficacy study they will have when I refer them back to their physician. So, I walk a fine line here, I want the objective information which helps me do a better job, but I don’t want to upset my referring physicians in the process. Some of the verbal skills I use are,

“I am using this automated home study to check how well we have done. It does not take the place of the in-lab sleep study your physician will need to determine how effective your appliance is, but it will give me more information than I can get from simply asking you questions”.

If they require further information, I explain the difference between “monitored vs. non-monitored”, “auto score vs. human scored” and “EEG verified sleep time vs. estimated sleep time”. I find that even the toughest patients get it then.

For those not wanting to worry about how a physician will interpret their use of a HST, Oximetry was mentioned to help calibrate appliances. Les Priemer explained his protocol,

“I use overnight pulse Oximetry once symptoms have resolved. The disposables are negligible, it’s simple to instruct the patient on its use, and just like you John I don’t want my referring physicians misinterpreting my intent. I can do this multiple times until the ODI is acceptable and then refer the patient back for an oral appliance titration polysomnogram which then hopefully won’t need many adjustments.” 

Les has a good working rapport with the sleep lab and they are accustomed to further appliance titrating during the sleep study when required. So clearly, there are other ways to obtain objective information without the use of HST. There is also less that can go wrong with Oximetry, resulting in fewer failed tests. However, HST provides much more information than Oximetry, such as, Central vs. Obstructive Apnea, Upper Airway Resistance Syndrome, AHI, Bruxism, Positional Information and Snoring Severity.

Kent Smith elaborated on the concern of upsetting the referring physicians. In fact, in some regions, HST is quickly replacing PSG in the physicians hands, making distinguishing “the dentists use of HST to calibrate” suspiciously similar to “the physicians use of HST to establish Efficacy”. Kent also provides some insights about when he uses HST vs. Oximetry,

“I always look at the baseline PSG (which is morphing into HSAT) to see what the data showed before making a decision on calibration efficacy. For example, if they spent 30% of the night under 90% with an AHI of 8, I would never consider HSAT, and would move to pulse Oximetry (also less expensive and easier for the patient to wear). If on the other hand, we see only 2 minutes under 90% and the AHI was 28, I would lean towards HSAT.”

Steve Lamberg does much the same as above but tweaks the protocol a bit and actually includes the physician in the process as follows,

“Once I am pleased with benefits of treatment (subjectively) I usually give them a pulse Ox to evaluate desats and if that looks good I have them take home a Watch PAT. In my area the docs like the Watch PAT study. They are only too happy to receive it from me along with a letter for them to please read and evaluate….which they can submit to their insurance without having to administer the test themselves. Of course I always suggest that the docs evaluate the need for a follow-up PSG to validate the HSAT at their discretion. (Always recommended for severe, rarely for mild, and the moderates will get a follow-up based on comorbidities).”

Steve Carstensen contributed another tip when using Oximetry alone, he suggests watching for Heart Rate Variability (HRV) on the Nonin in addition to the degree and frequency of desaturation. Off label and on RARE occasions, Steve uses HST on undiagnosed patients as a tool to “push a high-risk but stubborn” patient into the diagnostic pathway.

Tim Mickiewicz suggested that this discussion might be moot in the near future with a simple urine test that will be on the market soon, making inexpensive screening of the masses possible. This would certainly change things up, no wonder there are fewer and fewer Physicians being Board Certified in Sleep.

Tony Soileau explained his harmonious relationship with a local physician. Working with “Dedicated Sleep” Tony hired a local Sleep Physician/ENT as his medical director. Thus Tony is able to bill in network for medical insurance through the Sleep Physician’s tax id number. He is also contracted with him to score all his HST studies and provides a medical RX for sleep appliances when appropriate. This relationship not only facilitates cross referral with this ENT but it has also helped him establish relationships with other physicians that know this particular Sleep Specialist as well. He has become part of “da club!”.

Shouresh Charkandeh shared his protocols with us; he practices in Alberta, Canada where HST is the Standard,

“We use HST for screening/diagnosis, in conjunction with a full medical and sleep history questionnaires and a consultation with a local sleep physician (Diagnosis is ALWAYS made by a Sleep Physician, of course). In patients with multiple co-morbidities and complicated medical history, we always recommend a PSG and a consultation with the Sleep Physician.

Then HST is frequently used throughout the treatment, as a titration/calibration tool. Although, since we use MATRx/Titration Test, our use for HST as a titration tool is getting reduced. However, I find it extremely important (if not mandatory) to use “objective” data for titration. Otherwise I feel like we’re titrating based on bunch of non-objective measures. With 50% of OSA patients being asymptomatic to start with, titration based on symptoms alone doesn’t seem very effective. Also, as studies suggest, even when patients feel like their symptoms are improved and they fell better, 37-40% of them still require further titration to achieve “objective” improvement in their OSA (i.e. reduction in AHI to “acceptable” level. e.g. 50% reduction & below 10). And snoring; although it could be used as a tool, I don’t find it very reliable, since it can be affected by “lifestyle” very easily. Keeping this in mind and the importance of “As Little Advancement As Possible/Necessary” to minimize the possible side-effects, use of Level 3 monitors are very important.”

When I asked Shouresh about the Auto score vs. Technician score issue, he responded,

“I look at the summary page (i.e. Auto Scoring) first to get a general idea and then I go through the whole night data as well. I find you learn a lot more about it that way. It’s like looking at a radiograph/pan/CT: General look, making sure the quality is satisfactory and the “big picture” looks good. Then start looking at details (e.g. Teeth, Condyle,…. / Flow, O2 Sat,…). I don’t rely on the algorithm for my decision.”

Efficacy and Follow-up Studies:

Just as with Screening and Baseline Studies, there is no support in the literature or in any published guidelines for a dentist to unilaterally use HST to establish official Efficacy, or to conduct a Follow-up Sleep Study. No one described the use of HST for these purposes.

To sum up, dentists that are utilizing HST are mostly restricting its use to aiding in appliance calibration. Exceptions to this included working directly with a physician. Although the AADSM does not include Auto Scored HST in the protocols they recommend to calibrate an oral appliance, they do recommend the use of objective measurements to aide in this process. “Love and Kuna JDSM 2015 Vol. 2 No. 2, 2015” states,

“HST, however, is often used in tandem with clinical evaluations to determine if an OA is effectively titrated. A patient’s subjective symptoms and the objective data provided from an auto-scored PM are both used to guide advancement of device.” … “The use of HST in addition to assessment of subjective symptoms may be reasonable for the use of titration of OA to ensure an adequate adjustment of the device.”

 Scott Craig suggested that a dentist implementing HST into their dental sleep medicine program consider the legal, political, economic and liability issues associated with implementing a HST program. He suggested that you should clear it with your state dental board and also your malpractice carrier. One should also consider the economic and political reality of implementing a HST program as well as the clinical reality along with the AASM’s OCST accreditation guidelines. Additionally, dentists will need to carefully consider issues regarding;

  1. Defacto diagnosis
    2. Whether all calibration tests should be interpreted by a physician
    3. Determining an appropriate endpoint in calibration
    4. Insurance reimbursement and payer policies (Medicare and HMO’s are probably out)
    5. Who is Medically Managing the patient
    6. Apposing guidelines from the AASM
    7. Economic practicality of managing a HST program based on the size of your practice and the reimbursement model
    8. Understanding contraindications for HST

    All very valid points, however, the reality is that clinicians on this blog seem to be utilizing HST simply to aide in appliance calibration, unless they are working with a physician. The AADSM has not taken a position against this application of HST. In my case, I always send the HST report to the referring physician to review when I send my reporting letter. Once again, dentists are trying their best for patients in a system that continues to tie one hand behind their back! Yeah, I said it!

Steve Carstensen shed some light on the realities we face. In a study club he just held, one attendee lives in the biggest town in her small state and it takes a year to get a slot in the sleep clinic. Another attendee lives in a town of 60,000 with just one sleep physician! Yet 85% of the problem remains undiagnosed! Steve also pointed out that this 85% number has remained unchanged in the last 20 years and that fewer physicians are becoming Board Certified in Sleep!

 “As long as boarded sleep docs are the gatekeepers, we won’t have the impact on this public health problem that we need … Enter HST facilitated by many more parts of the health care team, including dentists. There are ways to use this without abandoning proper medical management. Dentists may be the ones to push this forward.”

However, from the posts in this discussion, as dentists, we remain politely concerned about stepping on the physician’s toes and being compliant with guidelines and following the rules, which is the way it should be. But unfortunately, while we are busy doing all that, the patient’s needs remain unmet, and the severity and magnitude of this problem persists! Change is clearly needed!

Nox T3 by Carefusion, mebibyte,wabtchpat, HSTOnce again, I would like to thank all those clinicians that took the time to participate in this discussion, this consensus article is intended to provide guidance for those that are new to this area of practice and also to provide valuable insights for those of us that have been at this a while. I look forward to your participation in future SleepDisordersDentistry LinkedIn discussions.

John Viviano B.Sc. DDS Diplomate ABDSM

John Viviano B.Sc. DDS Diplomate ABDSM

John Viviano B.Sc. DDS Diplomate ABDSM; from Mississauga ON Canada,obtained his credentials from U of T in 1983, he provides conservative therapy for snoring and sleep apnea and Sleep Bruxism in his clinic, Limited to the Management of Breathing Related Sleep Disorders. A member of various sleep organizations, he is a Credentialed Diplomate of the American Board of Dental Sleep Medicine, and has lectured internationally regarding management of Sleep-Disordered Breathing and the use of Acoustic Reflection. Dr Viviano has also conducted original research, authored articles and established protocols on the use of Acoustic Reflection for assessing the Upper Airway and its Normalization. For more info or to contact Dr Viviano click: Website
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