Protocol for managing type 1 diabetes or ketone prone type 2 diabetes after gastric bypass
and sleeve gastrectomy (but not gastric banding)
Preop diabetes medications: □Metformin □Other (all to be stopped) □Insulin, units___
Preop eGFR (from ICE): _______
date: ________
Initial sliding scale:
First 20-24 hours after operation: standard Imperial College intravenous sliding scale
Subsequent insulin sliding scale selection:
Sliding scale 1
For patients requiring only oral hypoglycaemics
Sliding scale 2
For patients requiring insulin, but less than a total of 40 U per day
Sliding scale 3
For patients requiring more than 40 U of insulin per day
Bariatric 4 Hourly s.c. Sliding Scale Prescription
Check BM 4 hourly. Give Actrapid 4 hourly s.c.
BM Stix Range
< 4.0
4.1 - 8.0
8.1 - 11.0
11.1 - 14.0
14.1 - 17.0
17.1 - 20.0
Call Doctor
Perfect
Call Doctor and ask to consider changing scales
Call Doctor, a senior review is needed.
Sub.Cut Actrapid Dose
1
2
0 Units
0 Units
0 Units
2 Units
2 Units
4 Units
4 Units
6 Units
6 Units
8 Units
8 Units
10 Units
Signature of Doctor
Bleep Number
Date Signed ___/____/___
Date (dd/mm)
Admission
Time (hh:mm)
Blood Glucose
Actrapid Dose
___/____/___
Signed
3
0 Units
4 Units
6 Units
8 Units
10 Units
12 Units
___/____/___
Initialled
All diabetic patients to have latest eGFR (with date) documented in notes on admission
Day of surgery/
drugs
Start intravenous sliding scale immediately pre-op and stop all oral hypoglycaemic
Inform diabetes team
Diabetes team to manage fluid and insulin in consultation with surgical team
Continue same dose of Glargine or Detemir that patient took pre surgery
Postop. day 1
Diabetes team to review and to switch patient to sub cut sliding scale
Continue same dose of Glargine or Detemir that patient took pre surgery
Two hourly glucose measurements
Check blood ketones if glucose >14mmol/L
Call diabetes team if glucose <4 or >10 mmol/L
Postop. day 2
Diabetes team to review
Continue same dose of Glargine or Detemir that patient took pre surgery
Give short acting insulin with meals as 1 Unit for every 15g of protein
Prescribe Metformin at the same dose as on admission (which in most cases should
be 1g twice daily unless poor tolerability) starting the evening 2 days after surgery,
unless the latest eGFR is <60mL/min. For these patients, contact obesity physician
Discharge
1. No patient to be discharged if last BM >10 mmol/L
2 All diabetic patients to text “Blood glucose mobile phone” (07970719453) with
fasting glucose value for 10 days immediately after surgery. If patient does not text
before 12:00, the team will contact them
Metformin dosage selection:
1. All patients will be restarted on their usual metformin dose (usually metformin 1g twice daily) starting 2
days following surgery, provided that eGFR>60mL/min. Metformin will be started on the second
postoperative evening (eg if operation on Tuesday then start metformin on Thursday evening). Patients who
can’t tolerate metformin should be reviewed by clinician/nurse specialist.
2. Metformin doses if eGFR <60 ml/min:
a. eGFR 45-60 ml/min: All patients will be prescribed metformin 850mg twice daily starting 2 days after
surgery. Metformin will be started on the second postoperative evening (eg if operation on Tuesday then start
metformin on Thursday evening).
b. eGFR 30-45 ml/min: All patients will be prescribed metformin 500mg twice daily starting 4 days after
surgery. Metformin will be started on the fourth postoperative evening (eg if operation on Tuesday then start
metformin on Saturday evening).
c. eGFR < 30ml/min: no metformin to be given.
3. If patients can’t tolerate metformin then continue with insulin therapies alone.
After discharge:
Daily insulin requirement will be adjusted by 2 to 4 units to achieve a fasting blood glucose of 5.6-7mmol/l.
1. At Day 10 post op clinic review
a. Metformin dose at discharge will be continued.
b. If FPG is >7mmol/l, increase short acting insulin doses to 1 unit for every 10g of carbohydrate
2. At 3 months, all diabetic patients will be reviewed and hypoglycaemic medication adjusted
3. At 6 months, all diabetic patients will be reviewed by phone and those with HbA1c >7% will be brought
back to the diabetes clinic for review of hypoglycaemic medication.