Anaes · Perioperative medicine
Anaesthesia for obesity and bariatric surgery
Also known as Morbid obesity anaesthesia · Bariatric anaesthesia · SOBA guidelines obesity · STOP-Bang OSA perioperative
Exam-exhaustive obesity and bariatric anaesthesia: BMI classes, STOP-Bang OSA screening, ramping/HELP, IBW/LBW/TBW drug dosing, RSI and VL strategy, protective ventilation for laparoscopy, thromboprophylaxis, rhabdomyolysis risk, and HDU criteria for ANZCA Final and equivalents.
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Target exams
Red flags
- Dose most induction agents and opioids to lean body weight — TBW dosing causes prolonged apnoea and hypotension.
- Unrecognised severe OSA plus residual opioids = post-op respiratory arrest on the ward.
- Flat supine induction without ramp collapses FRC and laryngoscopy view.
- Long bariatric cases: rhabdomyolysis, pressure injury, VTE — plan padding, duration limits, prophylaxis.
- Day-case discharge criteria fail if OSA untreated and opioids heavy.
Meet the patient
A 48-year-old woman for a laparoscopic sleeve gastrectomy weighs 140 kg, with a body mass index of 52. She snores loudly, wakes unrefreshed, and uses her continuous positive airway pressure machine three nights a week at best. Her STOP-Bang score is 6. The airway looks ordinary on inspection, but the neck is thick and the mouth opening is limited.[1][2]
The two questions that decide her whole perioperative course are the two that decide every obese anaesthetic: which weight scalar do I draw the drug to? and where does she spend the first night? Get the dosing wrong and she stops breathing on the ward; get the destination wrong and she may not be found in time.[1]
References3ShowHide
- [1]Nightingale CE, Margarson MP, Shearer E, et al. Peri-operative management of the obese surgical patient 2015: Association of Anaesthetists of Great Britain and Ireland Society for Obesity and Bariatric Anaesthesia Anaesthesia, 2015.PMID 25950621
- [2]Chung F, Subramanyam R, Liao P, et al. High STOP-Bang score indicates a high probability of obstructive sleep apnoea Br J Anaesth, 2012.PMID 22401881
- [3]Ingrande J, Lemmens HJM Dose adjustment of anaesthetics in the morbidly obese Br J Anaesth, 2010.PMID 21148651