Obstructive Sleep Apnoea

OVERVIEW

Obstructive sleep apnea (OSA) syndrome is defined by the following features:

  • cessation of airflow from nose/mouth for >10s
  • resulting in intermittent respiratory arrests with hypoxaemia
  • interruption of REM sleep
  • >5 episodes/h

PATHOPHYSIOLOGY

  • patency of the oropharyngeal airway is due to activity of paired sets of upper airway muscles
  • during normal respiratory activity muscles (e.g. soft palate, pharyngeal walls, tongue) prevent otherwise floppy structures from being sucked into the airway
  • obstruction during sleep may be due to a combination of factors:
  1. reduced airway size
    • enlarged tonsils/adenoids, macroglossia, myxoedema, acromegaly, malignancy, structurally small airway
  2. decreased neuromuscular tone
    • reduced tone occurs in REM sleep, particularly in postural muscles of the pharynx and palate
  3. neuromuscular incoordination
    • the normal coordination of increased upper airway tone with inspiration is lost

RISK FACTORS

Children

  • tonsillar hypertrophy
  • congenital syndromes
  • hypotonia

Adults

  • smoking
  • ETOH
  • CORD
  • airway pathology
  • CVA
  • acromegaly
  • DM
  • CHF
  • cushings
  • polio

HISTORY (STOPBANG)

  • Snoring (ask the patient’s partner!)
  • Tired
  • Obstruction (apnoea)
  • Pressure (HTN)
  • BMI (increased)
  • Age (middle aged)
  • Neck circumference
  • Gender (males > females)

Symptoms of pulmonary hypertension and right heart failure

  • e.g SOBOE, ankle swelling, chest pain, tightness

PMH

OSA is a multi-system disease

  • CNS: decreased cognition, decreased mood, CVA, accidents, headaches, somnolence, glaucoma
  • CVS: HT, IHD, PHT, right heart failure, AF
  • RESP: hypoxaemia, hypercapnia, cor pulmonale, decreased FRC
  • ENDO: DM, impotence
  • HAEM: polycythaemia

Meds:

  • inhalers, medications for above problems

SH:

  • occupation – sedentary occupation
  • diet – high energy consumption
  • exercise – regular exercise

EXAMINATION

BMI >30

Airway

  • large tongue
  • full pharyngeal, palate, and tonsillar fat pads
  • stridor on breathing while conscious and upright (collapsing of pharyngeal tissue)
  • Mallampati 3-4
  • neck circumference >40cm
  • limited atlanto-occipital movement
  • large amount of breast tissue

Breathing

  • decreased SpO2 on RA
  • increased RR
  • cyanosis

Circulation

  • hypertension, tachycardia
  • signs of heart failure: elevated JVP, right ventricular heave, apex displaced, murmurs, ankle swelling, enlarged liver

INVESTIGATIONS

  • FBC: polycythaemia
  • U+E: renal impairment
  • ECG: right heart strain
  • ABG: PO2 on RA
  • ECHO: PHT, right heart function
  • Sleep study/Polysomnograph
    — SpO2, nasal airflow, EEG, EMG, respiratory and abdominal muscle movement, ECG
    — apnoea index = <5/hr mild, >30/hr severe

MANAGEMENT

  • CPAP (bring in from home while an inpatient)
  • continue normal respiratory medications
  • RHF treatment
  • life style modification (weight loss, stop smoking, decrease ET-OH)
  • surgical options
    — weight reduction
    — adenoidectomy, ect
  • avoid premedication (sedation)
  • plan for difficult mask ventilation +/- intubation

References and Links

  • Park JG, Ramar K, Olson EJ. Updates on definition, consequences, andmanagement of obstructive sleep apnea. Mayo Clin Proc. 2011 Jun;86(6):549-54;quiz 554-5. PMC3104914.
  • Patil SP, Schneider H, Schwartz AR, Smith PL. Adult obstructive sleep apnea:pathophysiology and diagnosis. Chest. 2007 Jul;132(1):325-37. PMC2813513.

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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