Tayside Diabetes MCN Handbook - Perioperative Management of Patients with Diabetes

There are three aspects to the peri-operative management of diabetic patients:

General Assessment: It is important to check for the presence of cardiac, renal and neurological sequelae of diabetes as the presence of these may complicate the peri-operative management and increase patient risk.
Please take this opportunity to ensure that patients have had their eyes screened for retinopathy within the last year (either retinal photo or attendance at an Ophthalmology Clinic). If eye screening has not been done, please contact the Retinal Screening team directly (tel. 01382 740068 or ext. 40068) to arrange an appointment.
Please also ensure that no other diabetes-related problems need to be attended to. If further advice is required, please contact the Diabetes team.
Assessment of Glycaemic Control: HbA1c is an indicator of recent control i.e. over the previous three months. If the HbA1c is above 9 %, control is poor and the Diabetes team should be involved. If above 12 %, consideration should be given to improving control before elective surgery is undertaken.
Careful Peri-operative Control of Blood Glucose: The benefit of intensive glucose management in the acute setting is being increasingly recognised. The following are intended as guidelines because individual patients and individual circumstances may vary

Management of patients on diet alone or oral hypoglycaemic agents

Minor Operations (Body surface or endoscopic procedures)

Omit oral hypoglycaemic therapy on the day of operation and avoid glucose infusions.
Check finger prick blood glucose on the morning of the operation and regularly thereafter as clinical circumstances dictate
The management of these patients is easier if they are operated on early in the morning. For afternoon cases, patients taking oral hypoglycaemic drugs should omit these in the early am and have clear fluids only thereafter.
There is no need to stop Metformin any sooner than on the day of surgery
Oral medication should be restarted as normally prescribed with the first meal. The only exception to this is for patients taking Metformin
NB be aware of the potential association between Metformin and lactic acidosis. This is more likely if there is renal impairment present and so Metformin should not be restarted post operatively unless the renal function is known to be satisfactory
Metformin should not be used if eGFR <30 and doses not higher than 500mg BD are advised for patients with eGFR 30-49
If Metformin is contraindicated, then additional hypoglycaemic therapy may be required. If in doubt, contact the Diabetes team for advice.

Major Operations

Patients undergoing major operations will require intravenous insulin (see Appendices 1 & 2). There is no advantage in starting intravenous insulin therapy until the patient is fasted as otherwise the glucose control will escape during eating
Patients on oral therapy who are inadequately controlled (i.e. random venous blood glucose >15.0 mmol/l or HbA1c >9%) should be stabilized on insulin pre-operatively and managed in the same way as insulin-treated patients (see below)

Pre operatively

All patients on insulin should be adequately controlled pre-operatively and they should ideally be stabilised over 48 hours.
For patients using twice daily insulin, this may be possible with their usual regime but it may involve switching them to a multiple injection regimen. For further information on multiple injection regimens, see Appendix 3. If in doubt contact the Diabetes team for advice
For people with type 1 diabetes on multiple daily insulin regimens, it is advisable to continue their ‘usual’ daily long acting analogue insulin (Lantus or Levemir). This will reduce the risk of diabetic ketoacidosis if IV insulin is interrupted, and it will facilitate a smooth transition to subcutaneous insulin at a suitable mealtime post operatively.
Remember that some patients with type 2 diabetes may be treated with both insulin and Metformin – see guidance above regarding monitoring of renal function post-operatively before re-starting Metformin.
On the day prior to operation, check random venous blood glucose and urea and electrolytes

On the morning of the operation

Check the blood glucose and commence an intravenous infusion of glucose and insulin – use a GKI infusion unless specifically requested to do otherwise by the anaesthetist.
Ensure that the patient does not receive any subcutaneous rapid acting or pre-mixed insulin on the day of surgery. The last dose of either type of insulin should have been given on the previous evening
Continue to check the blood glucose hourly, pre- and post-operatively

Post-operatively

Change to subcutaneous insulin post-operatively when eating normally.
It is important to continue the IV insulin infusion for 60 minutes after the first subcutaneous insulin injection has been given
If the patient has been previously poorly controlled (HbA1c >9%) please refer to the Diabetes team for further advice before discharge

Aim for “first on list”
For those on a multiple injection regimen, continue the usual basal (long acting) insulin on the evening prior to procedure
For patients on twice daily insulin, continue the usual evening insulin prior to the procedure
Fast from midnight and omit the morning insulin
Check a finger prick blood glucose before and after the procedure
Resume the usual insulin and diet after the procedure. If a BD insulin regimen is restarted at lunchtime it is recommended that half of the normal ‘breakfast’ insulin dose should be prescribed with lunch after procedure
The above applies if rapid recovery is expected i.e. the patient is expected to be eating within 2 hours of the procedure.
If the patient is unable to tolerate diet or the blood glucose is >14 mmol/L, then a GKI infusion or alternative (see below) will be required