title: Obstructive sleep apnoea and non-restorative sleep induced by the interface.
abstract: BACKGROUND
  There are only few data about the influence of interfaces on restorative sleep and required CPAP/APAP levels in patients with obstructive sleep apnoea (OSA). Observations of obstructive apnoeas when using oro-nasal masks with normalisation of respiratory disturbance index (RDI) under nasal masks and of non-restorative sleep under oro-nasal masks in spite of normal RDI led to a registration of patients with such findings.
  
  
  METHODS
  This study is a cohort analysis (June 1, 2006 to April 30, 2014) of patients with OSA using an oro-nasal mask and normalisation of the RDI after changing to a nasal mask and of patients complaining about a non-restorative sleep under an oro-nasal mask despite normal RDI.
  
  
  RESULTS
  Sixty-five patients (BMI 32.2 ± 8.1 kg/m(2); 64.4 ± 12.8 years) with OSA (n = 54) and non-restorative sleep with normal RDI (n = 11) under oro-nasal masks were included. In the group of patients with pathologic RDI under oro-nasal masks (n = 54), switching the interface to a nasal mask normalised RDI (31.8 ± 16.3 to 6.0 ± 3.6/h [p < 0.001]) and arousal index (p < 0.001); slow-wave and REM sleep increased (p < 0.05). In the patient group with a pathological RDI under CPAP/APAP therapy (n = 45), the pressure decreased from 9.5 ± 2.2 to 7.3 ± 2.0 cm hPa (p < 0.001), and in the group with normal RDI (n = 11) from 10.1 ± 2.4 to 6.8 ± 1.2 hPa (p < 0.01).
  
  
  CONCLUSIONS
  The usage of an oro-nasal mask can result in a paradoxical induction of obstructive hypopnoeas or apnoeas. Clinicians should be aware of this phenomenon. When adapting patients to a PAP therapy, a nasal mask should be preferred even if patients report mouth breathing.
authors: Department of Pneumology, Intensive Care and Sleep Medicine, Hemer Lung Clinic, Theo-Funccius-Str. 1, 58675, Hemer, Germany. woelkewesthoff@aol.com.
authors: Michael
authors: M
authors: Westhoff
authors: Department of Pneumology, Intensive Care and Sleep Medicine, Hemer Lung Clinic, Theo-Funccius-Str. 1, 58675, Hemer, Germany. patric.litterst@lkhemer.de.
authors: Patric
authors: P
authors: Litterst
mesh_terms: D000368:Aged; D015331:Cohort Studies; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects* / Q000295:instrumentation*; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D016896:Treatment Outcome
keywords: CPAP therapy; Full-face mask; Nasal mask; Non-restorative sleep; Obstructive sleep apnoea; Oro-nasal mask