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Efficacy of
Positive Airways Pressure and Oral Appliance in
Mild to Moderate Obstructive Sleep Apnea.
Maree Barnes, R. Douglas McEvoy,
Siobhan Banks, Natalie Tarquinio,
Christopher G Murray, Norman Vowles, and Robert J Pierce
Am. J. Respir. Crit. Care Med. published 16 June 2004, online.
http://www.ajrccm.org/cgi/content/abstract/200311-1571OCv1?etoc
Abstract:
The efficacy of currently – recommended
treatments is uncertain in patients with mild to moderate
obstructive sleep apnea (apnea – hypopnea index 5-30). A group of
114 sleep clinic patients with apnea- hypopnea index 5-30 have
participated in a randomized controlled crossover trial of 3 months
treatment with each of nasal continuous positive airways pressure,
a mandibular advancement splint and a placebo tablet. Outcomes were
sleep fragmentation and hypoxemia, daytime sleepiness, quality of
life, neurobehavioral function and blood pressure.
Both active treatments improved sleep outcomes, but positive
pressure had a greater effect.
Quality of life, symptoms and subjective but not objective
sleepiness improved to a similar degree with both treatments,
however many of the improvements seen in the neuropsychological
function and mood were no better then the placebo effect.
Some aspects of nocturnal blood pressure were improved with the
splint but not with continuous positive airway pressure.
This study has shown that although both continuous positive
airways pressure and mandibular advancement splint effectively
treated sleep-disorder breathing and sleepiness, the expected
response in neurobehavioral function was incomplete. This may be
due to the splint having a lesser therapeutic effect, and the
continuous positive airways pressure being poorly tolerated and
therefore used less in this patient group.
(Products used; CPAP Resmed Australia.
Oral Appliance MDSA® supplied by RJ & VK Bird Pty
Ltd)
What the paper specifically
states about the MDSA®
Patient
Selection:
…patients were excluded if they did not have at least 2 teeth in
the upper and lower jaws on both left and right sides to enable
adequate retention of the MDSA®
…only 5 patients out of 99 could not be fitted with an MDSA®
Patient
Fitting:
…The goal of the MDSA® advancement was maximum comfortable
protrusion.
At the initial fitting, the MDSA®was advanced maximally as
tolerated by the subject. Subjects were reviewed weekly and the
MDSA® advanced further. (wash in period for the MDSA® was 1-3
weeks). When no further advancement was possible, the screw was,
sealed, advancement measured, and 3 month treatment period
commenced.
.. no subjects required an extra dental
visit.
Patient
Advancement:
…Mandibular advancement with the MDSA® was 10..3 ± 0.3mm. And
ranged between 1-13mm. Seventy five percent of subjects required
at least 75% of maximum possible protrusion.
Patient
Acceptance:
…only one subject was unable to tolerate CPAP and two were
unable to use the MDSA®
Effectiveness of
the MDSA® design:
...There has been concern that vertical
dimension opening of an oral appliance may result in posterior
movement of the tongue and soft palate with consequent reduction of
the posterior airway space and worsening of sleep disordered
breathing. The AHI increase in uncontrolled oral appliance trials
has attributed to a problem with the design of the oral
appliance,
...however we found that significantly fewer
subjects had an AHI increase with MDSA® than with
placebo.
Treatment
adherence:
CPAP - MDSA®
Nights per week: 4.2 ± 0.3 5.3 ± 0.3
Hours per night: 3.6 ± 0.3 5.5 ± 0.3
…It has been proposed that effective CPAP treatment of OSA requires
usage for at least 4hours per night on at least 70% nights. 43% of
subjects treated with CPAP received adequate treatment, 71% with
MDSA®
….. suggesting that the CPAP response extends to low usage
levels.
Response to
MDSA®:
...In addition to the primary analysis, we measured the improvement
in sleep disordered breathing with the MDSA® using response
definitions that have been used in similar studies. A complete
response is defined as a reduction in the AHI to below 10, and
partial response is a fall of at least 50% in the AHI but not below
10, with an improvement in symptoms; the remainder of subjects are
classified as treatment failures. By this criteria 49.1% subjects
had a complete response to the MDSA®, and a further 6.1% had a
partial response.
(55.2% in total)
Quality of
life:
...Both treatments (CPAP-MDSA®) were more effective than placebo in
improving quality of life symptoms and subjective not objective
sleepiness, with neither treatment being better than the
other.
Blood
Pressure:
...There was no response in blood pressure to CPAP, however
MDSA® improved the nocturnal diastolic blood pressure and
significantly increased the proportion of subjects with a normal
night time dip in blood pressure.
...The blood pressure response to MDSA® was greater than that to
CPAP, and raises the possibility that some aspects of CPAP
treatment may mitigate against a lowering of blood pressure in the
mild OSA severity range. To our knowledge, there have been no other
published controlled trials of the effect on blood pressure of
treating OSA subjects with CPAP,and none with an oral
appliance.
Reported Side
Effects.
Subjective
Effectiveness
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