1272 Control of Sleep-Associated Respiratory Distress with a Mandibular Advancement Oral Appliance in an Unusual Case of a Patient with a Mild Rather Persistent Nocturnal Baseline Hypoventilation/Hypoxia

Abstract

Abstract Introduction Normal respiratory function is crucial for adequate sleep. Sleep Related Breathing Disorders, namely Obstructive Sleep Apnea (OSA) are frequent conditions among a large spectrum of obstructive events in the upper airway which are often linked to significant sleep related oxyhemoglobin dessaturation levels compared to those observed in baseline PSG-oximetry recorded. On the other hand, low baseline oxygen saturation (LBOS) is commonly linked to symptomatic cardiorespiratory disturbances which may adversely impact respiratory outcomes either awake or during sleep. Therefore it is relevant to be aware of the baseline ventilatory status in order to optimize the therapeutic care. Report of Case We present an unusual case of a patient with moderate OSA which was successfully controlled with a Mandibular Advancement Oral Appliance (OAm). Despite the control with the OAm, the patient still maintained a nocturnal pattern of hypoventilation/hypoxia. The 53 yo female patient with normal weight/height ratio (BMI=25,2) complaining of non restorative sleep, tiredness, impaired memory, excessive diurnal sleepiness (Epworth Sleepiness Scale - ESS=10 and bruxism with a PSG diagnosis of moderate OSA (BaselineO2Sat=94%; IAH=17,4 ev/h; ODI=32,9 ev/h; T90=34,7% of TST) was referred for treatment with a OAm. A PM Type 1 positioner was inserted and titrated until 12 mm of advancement (80% of maximal measured protrusion). Within 6 months follow up and after clinical titration, there was a clear symptomatic and objective improvement with resolution of all major complaints including sleepiness (ESS=5). Titration PSG showed a normalization in all parameters (IAH=1,4 ev/h;ODI=4 ev/h;T90=0,1% of TST). Baseline O2 Sat however remained low (93%) in the titration PSG even though no symptoms or signs of a disorder existed even after discounting for Ph related metabolic changes (normal levels of HCO3) Conclusion This is an interesting case of an unusual patient who presented with a LBOS level in the diagnostic PSG. Despite the therapeutic success of the OAm in controlling the sleep related respiratory condition, measured by all otherwise normalized PSG based sleep and respiratory parameters, maintained a LBOS in the titration PSG without any signs or symptoms of disease.