Hypoxaemia post Cardiac Surgery


  • this is an unexpected situation post routine cardiac surgery but not uncommon.
  • management approach would be based on a systematic assessment of the patient using history, examination and review of investigations with regard to the following possible causes.


  • inadequate O2 delivery
  • endotracheal tube malposition or not patent
  • patient: acute lung pathology (atelectasis, collapse, pneumothorax, haemothorax, APO, ALI)
  • patient: chronic lung pathology (smoker, COPD, emphysema)
  • inadequate cardiac output
  • measurement problem


  • review notes
  • duration and degree of smoking related lung disease (pack years, symptoms, pre-operative spirometry, CXR, ABG)
  • intraoperative events (difficulties with ventilation, oxygenation, intubation, aspiration, analphylaxis)
  • post operative chest CXR findings
  • secretion burden
  • haemodynamic trends


  • ETT position and patency
  • tracheal position
  • chest expansion, percussion, AE (collapse, consolidation, pneumothorax, haemothorax, bronchospasm)
  • cardiac examination: cardiac output, peripheral perfusion, signs of tamponade


  • CXR: ETT position, lung fields
  • PV Loops: airflow obstruction, compliance
  • ABG: PaCO2, pH
  • ETCO2: slope
  • CT chest: rarely indicated but may be of use in a few days


  • dependent on findings


  1. improve oxygenation
  2. prevent lung damage (baro, volu, atelect-trauma)
  3. treat the underlying cause
  • exclude equipment failure and malposition of tube
  • drain pneumothorax or pleural fluid
  • atelectasis/collapse: recruit, increase PEEP, bronchoscopy
  • pulmonary oedema: diuresis, inotropy, PEEP
  • optimise cardiac output
  • bronchodilators
  • lung protective ventilation
  • consider antibiotics if indicated

References and Links


CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a 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 three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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