Unoptimised OSA, super morbid obesity, for minor gynae procedure

PIG Meeting: 8th July 2021

26yo female with grade 1 endometrial cancer for repeat hysteroscopy, D+C and mirena exchange


  • Endometrial cancer – being treated with mirena/curettes. If cancer persists will require hysterectomy.
  • 197kg, 15kg weight gain in 9 months.
  • Nulliparous woman, keen to have children, may do so via surrogate with egg donation if hysterectomy proceeds.
  • 2 x previous same procedure – one under GA igel 5, one under sedation with THRIVE. Both nil issues
  • OSA – overnight oximetry with ODI 48/hr and witnessed apnoeas. Did not attend for respiratory physician review despite repeated appointments.


  • Unoptimised OSA and future surgeries planned (ideally lap hysterectomy but high risk of conversion to open given body habitus)
  • Possible OHS
  • Severe obesity, weight gain despite dietician review.
  • Metabolic syndrome


  • Anaesthetic technique for similar super-morbidly obese patients having short gynae procedures
    • Increasingly common
    • Some consultants utilising a technique of conscious sedation using ketamine and THRIVE with good results.
    • Individual clinicians should only practice within their comfort zone
    • ANZCA PS15 suggests that patients with high BMI with confirmed or suspected OSA should have minimal post-operative opioid requirement and ideally discharge analgesia should not include opioids to be considered suitable for day case surgery.
    • Safe, agreed, discharge plan required for these patients, and it may be suitable to keep them in hospital overnight for observation.​
    • Combined CME (with O&G) required to discuss these increasingly common cases. 
    • suggestion to have a regular list dedicated to similar patients in order to increase efficiency/safety. 


  • Given minor surgery, ok to proceed without OSA optimisation.
  • Resp physician will review patient while in hospital due to previous issues with attendance. They have requested an ABG (if arterial line used due to body habitus intraop) to check awake PaCO2. If elevated this would guide BiPAP initiation (for obesity hypoventilation syndrome/mixed picture) rather than CPAP (for OSA alone)
  • Medicare-funded bariatric surgery with certain criteria is available in Sydney. Blacktown Hospital Metabolic & Weight Loss Clinic – WSLHD (​ Information provided to the patient’s GP for consideration.