Upper airway mucosa temperature in obstructive sleep apnoea/ hypopnoea syndrome, nonapnoeic snorers and nonsnorers

Abstract

Upper airway (UA) inflammation (oedema and hyperaemia) is frequently observed in snorers and patients with sleep apnoea/hypopnoea patients. The temperature of different UA regions measured in 11 male nonsnorers, 13 non-apnoeic snorers and 10 untreated sleep apnoea/hypopnoea syndrome (SAHS) patients using infra-red video recording. Measurements were taken with the mouth open during tidal volume mouth breathing, and at the beginning and end of a 10 s end-inspiratory voluntary apnoea which followed either mouth or nasal breathing. Three measurements were obtained from the uvula and from each side of the posterior pharyngeal wall and two from each side of the soft palate, The different UA regions were characterized by their inspiratory temperature, the expiratory rewarming and the changes in UA temperature during apnoea. The temperature of the uvula was significantly lower than that of the other UA regions. For each anatomical region, there were no differences in inspiratory temperature between normals, snorers and SAHS, In normals, the expiratory rewarming was significantly higher in the uvula than in the velum and the posterior pharyngeal wall, whereas these regional differences were not observed in snorers and SAHS, The velum and posterior pharyngeal rewarming was significantly less in normals than in snorers and SAHS. During apnoea, the UA rewarming was similar to that observed during expiration. In conclusion, tissue temperature varies between the different upper airway regions and during tidal breathing and the intensity of the regional expiratory rewarming differs between normals, snorers and patients with sleep apnoea/hypopnoea syndrome.