(Peri-Op & Anaesthesia) (Respiratory)

Overview

• Sleep-related breathing disorder in which airflow significantly decreases or ceases due to an upper airway obstruction
  • Sleep → Decreased Muscle Tone → Upper Airway Collapse → Apnoea (Intermittent Hypoxia) → Arousal (Fragmented Sleep, Sleepiness and Cognitive Dysfunction) → Airway Reopens
• M>F, prevalence increases with age (classically an overweight middle aged man)
• May be mild (5-15 events/hr), moderate (15-30 events/hr) or severe (>30 events/hr)
• Aetiology → obesity, acromegaly (causes macroglossia), hypothyroidism (causes macroglossia), large tonsils, alcohol, smoking

Making Diagnosis

Clinical Features:

• Excessive Daytime Sleepiness → may be measured using Epworth Sleepiness Scale (14 = moderate sleepiness, 18 = severe sleepiness)
• Episodes of Apnoea & Gasping
• Restless Sleep
• Chronic, Loud Snoring
• Signs of Complications → impaired cognitive function, depression, decreased libido, hypertension with increased pulse pressure

Investigations:

• Polysomnography (PSG) → definitive test