Supplementation and blood monitoring of bariatric surgery patients (G001)

This guideline will apply to obese individuals referred using Ayrshire and Arran’s Bariatric Referral Criteria (appendix 1). After a comprehensive assessment including a full nutritional assessment by the bariatric dietitian, referral to psychology, nutrition and behaviour change education at the PIPP course, weight loss targets achieved (appendix 4).

The following bariatric procedures are performed at University Hospital Ayr:

• intra gastric balloon
• adjustable gastric band
• Roux-en-y gastric bypass
• gastric sleeve
• one anastomosis gastric bypass.

This guideline focuses on ensuring appropriate nutritional supplementation and monitoring of bariatric surgical patients in Ayrshire and Arran. It is essential to determine any pre-existing nutritional deficiencies, develop appropriate dietary interventions for correction, and create a plan for postoperative dietary intake that will enhance the likelihood of success.

After surgery the risk of micronutrient deficiencies continues to be high, particularly after surgeries that affect the digestion and absorption of nutrients such as the Roux-en-Y gastric bypass which increases the risk of deficiency of vitamin B12 and other B vitamins in addition to iron and calcium. With other operations such as the adjustable gastric band, it was thought that deficiencies would not be present as it is a purely restrictive procedure, however poor eating behaviour and a restricted portion size can contribute to nutritional deficiencies. Routine metabolic and nutritional monitoring is recommended after all bariatric surgical procedures.

Patients GPs will be emailed a comprehensive letter following their patient having bariatric surgery (appendix 2).

Patients will be offered follow-up by the bariatric dietitian for a period of 2 years after bariatric surgery. The consultant endocrinologist will review patients if clinically required. Patients will be referred back to their GP after 2 years. This guideline provides all clinical staff in Ayrshire and Arran Hospitals including consultants, doctors, and trained nursing staff, allied health professionals and out-patient, Day Surgery and ward staff and will also apply to all primary care trained staff including GPs, practice nurses, health visitors and district nurses information on how to manage post bariatric surgical patients.

Bariatric surgery flowchart

C001: bloods to monitor pre and post bariatric surgery form.

• For the gastric bypass, one anastomosis gastric bypass, sleeve gastrectomy and gastric band the blood tests shown should be monitored:
  • at initial assessment appointment with bariatric nurse,
  • at pre-operative assessment clinic (limited range of bloods checked including Hba1c as per pre-operative assessment protocol),
  • at 6 months post operatively,
  • annually lifelong.
• If concerns at any other stage including at 3 months post-operative bloods should be monitored.
• For gastric balloon procedure blood should be monitored before insertion and on removal.

If any concerns regarding abnormal results to contact the bariatric dietitian or consultant endocrinologist.

Low vitamin D (<50nmol/l)

300,000iu IM ergocalciferol IM every month for 3 months then 300,000iu IM injection annually lifelong (during winter months).

Zinc, copper, magnesium or selenium deficiency or deficiencies

Initial treatment to take 2 complete multi-vitamins and mineral capsules daily (preferably Forceval as they have the correct ratio of trace elements) for 3 months and then repeat blood monitoring.

Other deficiencies

If patients experience prolonged vomiting suspect a thiamine deficiency could be possible. Immediately prescribe an additional thiamine supplement of 200-300mg/day and an urgently contact the Bariatric Surgical Service in Ayrshire or the patient should attend Accident and Emergency. If clinical suspicion of deficiency the patient will be admitted for IV thiamine without any delay. Oral or IV glucose must not be given as it can precipitate Wernicke’s encephalopathy (appendix 3).

If patients develop iron deficiency anaemia despite taking supplements they should be referred to the consultant endocrinologist for investigations and potentially intravenous iron infusions.

If the patient presents with oedema it could be related to protein malnutrition and could be related to poor dietary intake as well as malabsorption. The patient should be referred back to the Bariatric Surgical Service.

Patients will require to have their blood pressure monitored regularly at their GP surgery for the first 2 years post operatively (or until their weight has been stable for more than 3 months) and then annually when having bariatric bloods monitored.

It is also important to monitor and record the patient’s weight at every appointment that a patient attends to highlight weight trajectory and if necessary refer patient to bariatric dietitian (in first 2 years after surgery) or GP aligned dietitian (if 2 years or more after surgery). This also encourages patients to manage their weight longer term.

Employees are reminded that they may have patients/carers who require communication in an alternative format e.g. other languages or signing. Additionally, some patients/carers may have difficulties with written material. At all times, communication and material should be in the patient’s/carer’s preferred format. This may also apply to patients with learning difficulties.

In some circumstances there may be religious and/or cultural issues which may impact on clinical guidelines e.g. choice of gender of health care professional. Consideration should be given to these issues when treating/examining patients.

Some patients may have a physical disability or impairment that makes it difficult for them to be treated/examined as set out for a particular procedure requiring adaptations to be made.

Patients’ sexual orientation may or may not be relevant to the implementation of this guideline, however, non-sexuality specific language should be used when asking patients about their sexual history. Where sexual orientation may be relevant, tailored advice and information may be given.

This guideline has been impact assessed using the NHS Ayrshire and Arran Equality Impact Assessment Tool Kit. No additional equality & diversity issues were identified.

1. Mechanick JI et al. American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and non surgical support of the bariatric surgical patient. Endocrine Practice Vol 14 (Suppl 1) July/ August 2008.
2. Aills L et al. ASMBS Guidelines, allied health nutritional guidelines for the surgical weight loss patient. Surgery for Obesity and Related Diseases 4 (2008) S73-S1018.
3.O’Kane M et al. BOMSS guidelines on peri-operative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery. Adopted by BOMSS Council September 2014.
4. O’Kane M et al. British Obesity and Metabolic Surgery Society guidelines on
peri operative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric, surgery—2020 update.

All referrals made for assessment for bariatric surgery must be made on the Bariatric Surgery Referral Proforma. These referrals will then be triaged by the team which includes a surgeon, anaesthetist, endocrinologist, specialist dietitian, specialist nurse and psychologist. Any referrals not accepted at triage stage will be returned to the referring GP or consultant with an explanation of the reasons for unsuitability.

Pre-operative Assessment

Patients will be assessed pre-operatively by hospital specialists. Medical, dietetic and psychology history / current treatment will be determined. The decision to proceed to surgery will be based on this. Patients must also demonstrate further and ongoing weight loss as a measure of motivation and commitment to surgery. Their treatment plan will also be discussed pre-operatively.

Letter to GP following gastric sleeve or gastric bypass surgery

Severe thiamine deficiency resulting in Wernicke’s encephalopathy (WE) is not uncommon in patients who have had bariatric surgery. Incidence in the bariatric surgical population is estimated at 18%. The biological half-life is 9-14 days. Deficiency may manifest within 18 days.

It can occur as a result of malabsorption, malnutrition, increased requirements due to acute weight loss or from a secondary bacterial overgrowth.

Postoperative patients who present to accident and emergency with:

• anorexia, loss of appetite
• nausea and persistent vomiting (4-90 days)
• non-compliance with vitamin and mineral supplementation
• ascending peripheral neuropathy; tingling sensation or pins and needles in arms and legs
• muscle weakness
• blurred or impaired visual acuity; nystagmus and gaze palsy
• slurred speech
• behavioural changes; forgetfulness and or confusion
• gait ataxia
• seizures
• coma.

Diagnosis

MRI diagnosis of WE is accurate in 47% of cases. CT scans are not. Blood biochemical analysis i.e. transkeltolase activity or specific thiamine ester do not allow for immediate diagnosis.

Treatment in patient

• Pabrinex IVI without glucose
  • Dose: 2 vials every 8 hours (500mg thiamine) 3 times per day (total 1500mg thiamine)
  • Duration: 5 days followed by oral administration on discharge.
• Discharge home/prescription:
  • Oral thiamine: 50-100mg tid (300mg/day indefinitely)

Clinical outcomes: Reversible if treatment is given in the early stages of the disease.

Treatment should never be delayed where thiamine deficiency is a possibility.

Clinical care pathway for patients requiring bariatric surgery

Patient is encouraged to attend monthly patient support group meeting.