Open a PDF version to print this topic

HealthInfo West Coast-Te Tai Poutini

Colonoscopy & sigmoidoscopy if you have diabetes

This information is to help you manage your diabetes before your procedure. Read it with the booklet about preparing your bowel for your colonoscopy or sigmoidoscopy, which you have received from the General Surgery Department.

FDP blood sugarMost people can manage their diabetes by following this advice. However, if you have recently been admitted to hospital because of poorly controlled diabetes, or if you are having major problems with low blood sugar (hypoglycaemia) make sure you talk to your GP or diabetes nurse. Some people may need to go to hospital to prepare for their colonoscopy or sigmoidoscopy.

Managing your diabetes will probably be easier if you have a morning appointment early in the day. If you don't have a morning appointment, please phone the number on your booking letter to see if your procedure can be rescheduled to an earlier time.

Carefully read the information about food and clear fluids on the leaflet you have been given on bowel preparation. On the day before the procedure you should only have clear fluids and nothing else from 9 am. So if your appointment is on a Tuesday, you must have only clear fluids from 9 am on Monday.

Don't worry if your blood glucose level is not as well controlled as usual, as long as it is above 5 mmol/L but below 15 mmol/L.

Bring your blood glucose monitor, insulin and injecting equipment with you to the appointment. Also bring some dextrose tablets or whatever you would normally use to manage a hypo.

How to prepare

If you take tablets for diabetes

If you are using insulin

The anaesthetist will work out how much insulin you need to take, and when, based on the answers you have given in your patient questionnaire. When you go to your pre-admission appointment the nurse will tell you what you need to do.

If you are taking tablets and insulin

The anaesthetist will work out what you need to do, based on the answers you have given in your patient questionnaire. When you go to your pre-admission appointment the nurse will tell you what you need to do.

You can restart your tablets once you are able to eat a regular meal.

Carbohydrates in clear fluids

FDP bubbles in glassThese clear fluids have a similar amount of carbohydrate to one medium slice of bread (15g of carbohydrate)

You will digest carbohydrates in clear fluids more quickly than other carbohydrates, so you should spread the fluids through the day. Have some at lunchtime, some mid-afternoon, some at dinnertime, some after dinner and at midnight, depending on your blood glucose readings. You can also have some of these carbohydrate-containing fluids up until four hours before your procedure. If you have to have any after that time because your blood sugar is low, let the staff know when you arrive for your procedure.

Important

You should not drive while you are fasting.

Information provided by the Canterbury DHB. Adapted by the West Coast DHB. Last reviewed June 2016.

Page reference: 271205

Review key: HIDIE-96281