Can mandibular advancement devices be a satisfactory substitute for short term use in patients on nasal continuous positive airway pressure?
Smith DM., Stradling JR.
BACKGROUND: Mandibular advancement devices (MADs) can successfully control both snoring and obstructive sleep apnoea (OSA). Many patients on nasal continuous positive airway pressure (NCPAP) for OSA would like a more portable alternative, even if only temporarily. This study assesses what proportion of patients with OSA already on NCPAP can successfully use a MAD for short periods (up to 1 month) as a temporary alternative to NCPAP. METHODS: Fifty patients with OSA, already on NCPAP for at least 3 months, were recruited by invitation. They were provided with a simple fixed MAD estimated to provide 75% of maximum mandibular protrusion. Sleep studies using a portable home recorder were performed on and after three nights without NCPAP to provide control data. Following acclimatisation to the MAD, sleep studies were also planned after 3, 7, and 28 days while using the MAD. If their overnight >4% SaO(2) dips per hour deteriorated to >20 or the Epworth sleepiness score (ESS) rose to >9 (or increased by >4 over baseline) on nights 3 or 7, they were then deemed to have failed the trial and were withdrawn. RESULTS: Of the 50 patients entered, one had inadequate teeth for a MAD and 31 gave up trying to use the device during the acclimatisation period because of side effects. Of the 18 prepared to use the device, two patients failed at night 3, five at night 7, and two at night 28. Thus, nine patients remained controlled by our criteria at night 28. On average, sleep study indices while using the MAD were poor compared with the night on NCPAP. CONCLUSIONS: Simple MADs are poorly tolerated by patients with OSA already on NCPAP. OSA was adequately controlled by our criteria in 32% of those recruited for the equivalent of a weekend, in 22% for 1 week, and in 18% for up to 1 month. Better tolerated devices would be likely to improve on these figures.