Obstructive Sleep Apnoea Syndrome
What is Sleep Apnoea ? • Apnoea : a period of no airflow at the nose or mouth for atleast 10 s. • Apnoea index (AI) : the number of periods of apnoea per hour • Hypopnea : 50% or greater reduction in normal tidal volume • Sleep apnoea syndrome : > 30 apnoeic episodes in 7 h of sleep or if the AI > 5. Mild SAS – AI 5 – 20 Modeate - AI 20-40 Severe - AI > 40
Types of Sleep Apnoea 3 types : 1. Obstructive – complete airway obstruction but patient makes effort to overcome this, peripheral causes 2. Central - respiratory effort and airflow ceases for a time being, CNS causes 3. Mixed
Consequences of Sleep Apnoea • Hypoxia – cardiac arrhythmias, pulmonary & systemic hypertension, cor pulmonale • Increased negative intra thoracic pressure Increased cardiovascular strain • Poor sleep quality • Increased risk of mortality due to cardiovascular disease
Clinical features of OSAS • In adults OSA more common in increasing age, obese, alcohol • In children – most common around 5 • Excessive day time somnolence, morning headaches, personality change, intellectual deterioration, impotence, increased risk of RTA • Find out any excerbating factors (drugs, endocrine disorders, anatomical) • Identify the site and level of obstruction
Investigations 1. Body mass index (BMI) : kg /m2, calculates degree of obesity Normal BMI = 19-25 Overweight =26-30 Obese =31-40 Very obese= >40 2. General investigations : FBC, TFT, CXR, ECG 3. To identify sleep apnoea : polysomnography – gold standard, EEG, EMG,ECG,airflow,abd & chest movements,O2 saturation,body position monitor,recording of snoring 4. Site of obstruction : palatal / tongue base / multiple. Lateral cephalometry, sleep nasoendoscopy, manometry,cine CT,somnoflueroscopy
Treatment • Multifactorial condition – so no single Rx • General : Reassurance, weight loss, abstain from alcohol, sedatives • Treat nasal obstruction : Rhinitis, DNS, hyp turbinates,polyps, • Oropharyngeal obstruction : UPPP (uvulopalatopharyngoplasty) LAUP (laser assisted uvuloplasty) Somnoplasty Adeonotonsillectomy – treatment of choice in children
Rx of OSAS • Tongue base /multisegmental : Nasal CPAP (continuous positive airway pressure) gold standard treatment. Air under pressure is given via tight fitting nasal mask. • Maxillofacial : Mandibular Positioning Devices Hyoid Suspension Techniques • Tracheostomy : 100% effective. Should be performed only when other measures fail