Complications of Obesity


Obesity has multiple pathophysiological effects and leads to numerous multi-system complications



  • ↑Intra-abdominal pressure: abdominal compartment syndrome can cause renal, hepatic failure and visceral necrosis
  • ↓pH and increase gastric volume: GORD and aspiration risk


  • ↑Intracranial pressure: associated with raised intra-abdominal and pleural pressures


  • ↑Central venous pressure: increased by high intra-abdominal and pleural pressures
  • ↑blood volume and polcythaemia
  • ↑cardiac output and ventricular work


  • ↑upper airway soft tissues: difficult intubation and airway maintenance
  • ↑Pulmonary artery occlusion pressure: increased by high intra-abdominal and pleural pressures
  • ↑Pulmonary artery pressure: mild to moderate elevations may result from OSA alone
  • ↓Total lung capacity
  • ↓Vital capacity
  • ↓Functional residual capacity: atelectasis and reduced oxygen stores increase propensity for desaturation
  • ↑Pleural pressure: reflects chest wall compression
  • ↓Respiratory system compliance: stiffer respiratory system likely from lung and chest wall contribution
  • ↑Airway resistance: risk of asthma and airway closure
  • ↓Hypercapnic ventilatory response: contributes to obesity hypoventilation syndrome
  • ↑Upper airway resistance: contributes to difficult airway and sleep apnoea

Haematology/ Immunology

  • hypercoagulable, platelet hyperactivity: increased risk of VTE
  • obesity is a pro-inflammatory state


  • altered pharmacokinetics



  • Congestive heart failure
  • hypertension
  • myocardial infarction
  • dyslipidemia


  • Difficult airway
  • Hypoventilation (Pickwickian) syndrome
  • obstructive sleep apnea
  • asthma
  • respiratory failure


  • aspiration
  • gastroesophageal reflux (GERD)
  • nonalcoholic fatty liver disease (NAFLD) and steatohepatosis (NASH)
  • gastroparesis
  • gallstones and biliary tract disease
  • pancreatitis
  • hernias


  • Diabetes mellitus (type II)
  • metabolic syndrome / syndrome X
  • polycystic ovarian syndrome
  • hypothyroid
  • infertility


  • Stroke
  • depression
  • idiopathic intracranial hypertension
  • disordered eating


  • Deep vein thrombosis and pulmonary embolus (VTE)
  • hypercoagulable state
  • chronic venous stasis


  • Degenerative joint disease
  • chronic back pain

Immune system/infection

  • Pressure ulcers
  • skin-fold infections
  • poor wound healing
  • pro-inflammatory state

Increased cancer risk

  • Kidney
  • esophagus
  • pancreas
  • colon
  • breast
  • ovary
  • endometrial
  • prostate


  • difficult IV access
  • requires special monitoring
  • pressure area cares
  • more staff and equipment required to move
  • imaging difficulties (difficult to ultrasound, may not fit in CT or MRI scanners)

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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