Bariatric Surgery: Selection & Pre-Operative Workup

  • Criteria for selection of appropriate candidates for bariatric surgery have been established to minimise surgical complications and to maximise the benefit of these important and limited procedures.
  • The pre-operative workup should evaluate a patient’s medical, nutritional, mental and functional health status.
  • There should be a balance between comprehensive evaluation and preparation pre-surgery, and the potential harms from mandating participation in compulsory fixed-duration “lifestyle programmes” or setting weight-change targets, which may delay surgery and reinforce obesity stigma.
  • Special attention should be given to the care of patients living with type 2 diabetes mellitus (T2DM) who are considering bariatric surgery, to minimise complications from out-of-target glycaemia in the perioperative period.
  • The prevalence of obstructive sleep apnoea (OSA) in patients attending an Irish bariatric clinic was 93%. As undiagnosed OSA is a risk factor for adverse perioperative outcomes, all patients should have assessment and treatment of OSA before bariatric surgery.
  • Because of the risks of post-operative complications associated with nicotine use, cessation of smoking prior to bariatric surgery is mandatory and should be maintained lifelong.
  • In patients living with severe obesity, bariatric surgery, in combination with behavioural interventions, is an effective option for long-term obesity and obesityrelated chronic disease management, such as T2DM, hypertension, OSA and dyslipidaemia, as well as other conditions associated with increased adiposity.
  1. We suggest a comprehensive medical, nutritional, psychological, and functional evaluation be completed, and nutrient deficiencies corrected, in candidates for bariatric surgery (Level 4, Grade D)1,2.
  2. Pre-operative smoking cessation can minimise postoperative complications (Level 2a, Grade B)3,4.
  3. We suggest screening for and treatment of obstructive sleep apnoea in people seeking bariatric surgery (Level 4, Grade D)5,6.
  • Bariatric surgery is the beginning of a new treatment in your lifelong obesity management. You should be aware of, and understand, the necessary changes required to optimise your long-term outcomes for a healthier life. Peer support groups such as the Irish Coalition for People Living with Obesity can help during this time of adjustment.
  • Before surgery you will be asked to perform several investigations, such as blood tests and cardiac or breathing testing, to ensure that you are ready and safe for surgery.
  • You may be asked to have a sleep study to determine if you have significant obstructive sleep apnoea, which may require treatment before surgery.
  • A current or recent history of smoking or nicotine consumption puts you at risk of complications after bariatric surgery. Smoking cessation is required before surgery and must be maintained for life.
  • You may be given a low-calorie diet two to three weeks before surgery, which may help to shrink your liver size and make your surgery easier.
  • If you are living with type 2 diabetes mellitus, you may be asked to monitor blood glucose closely, and obtain instructions on how to adjust your diabetes medications while on the low-calorie diet prior to bariatric surgery.
  • Because changes in the absorption of some medications may occur with certain bariatric surgical procedures, you may be asked to change either the type or preparation of medications you are currently taking.

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