In patients on nasal CPAP, can Mandibular Advancement Devices (MADs) be a satisfactory substitute in the short term?

Use of nasal CPAP for OSA can be very restricting on lifestyle. We were interested to see if MADs could satisfactorily treat OSA for the equivalent of a weekend, a week, or a month, whilst off nasal CPAP. Patients were eligible for this trial if they used nasal CPAP on average for >4hrs/night, their original Epworth Sleepiness score (ESS) was >12, their original >4%SaO2 dip rate was >15/hr, and they had sound teeth. Fixed MADs were made with estimated 75% maximum protrusion of the mandible. Patients were studied at home with a portable monitor (RM50) whilst using, and after 3 days off, nasal CPAP. In addition they were studied on the 3rd night of wearing their MAD, and potentially on their 7th and 28th nights if their OSA remained controlled. The return of the >4%SaO2 dip rate to >20/hr, or an ESS rise to >10, or an absolute rise of >4 points above their baseline ESS, defined arbitrarily the failure of the MAD to control their OSA. So far 41 patients, out of an intended 50, have completed the protocol. 25 patients did not wish to continue using their MAD for a variety of reasons, usually jaw/gum discomfort, excessive salivation, or due to concerns that the MAD was not working. Of the remaining 16, OSA was controlled satisfactorily in 14 of them at night 3, in 9 at night 7, and in 8 at night 28. Thus 20% of patients on nasal CPAP may be able to use a MAD as a substitute for up to 1 month, 22% up to a week, and 34% for a week end, without return of their OSA by our criteria.