OSA

• OSA patients have narrow upper airways which can be due to fat deposition in the pharyngeal wall/tongue or abnormal skeletal features (such as posterior positioning of the mandible)
• The collapse of the upper airway can cause hypoxaemia and hypercapnia
• Risk factors:

  • Obesity
  • Craniofacial abnormalities such as posterior positioning of the mandible
  • Increased soft tissue volume such as adenotonsillar hypertrophy
  • Male sex
  • Down's syndrome
• Gold standard for diagnosis is polysomnography:

  • Electroencephalogram
  • Electromyogram
  • Pulse oximetry and airway capnography
• OSA is diagnosed if the apnoea-hypopnoea index (number of apnoeic/hypnoeic events per hour) is 15 or more per hour.
• Respiratory polygraphy - similar to polysomnography but usually only monitors respiratory activity so can be performed in a patients home
• Symptoms of OSA can be rated with the Epworth sleep scale
• Conservative management:

  • Weight loss regimens
  • Oral appliances to reduce upper airway collapsibility
  • Sleeping in the lateral position
• CPAP is the gold standard treatment for severe OSA with an apnoea-hypopnoea index of 30 or more
• Dopamine reuptake inhibitors can reduce sleepiness and drowsiness but are rarely used in OSA
• Surgical management:

  • Upper airway surgery e.g uvulopalatopharyngoplasty and tonsillectomy
  • Bariatric surgery
• Disease related complications:

  • Cardiovascular disease such as hypertension and myocardial infarction
  • Diabetes
  • Motor vehicle accidents