Having a Colonoscopy

What is a colonoscopy?

A colonoscopy is a look into the large bowel. The large bowel is the last part of your digestive system. The diagram shows your large bowel (also called your colon).

The instrument used to do the examination is called a colonoscope. It is a long flexible tube with a bright light and a video camera at the tip. The camera transmits pictures of the inside of the bowel to a monitor allowing the endoscopist to examine the lining of the colon for any disease or abnormalities. It is inserted via the back passage and manoeuvred around the whole of the large bowel by the endoscopist.

The procedure usually takes 20-30 minutes, although you should expect to be in the hospital for about two to four hours.

Unfortunately, due to the nature of the investigations and individual needs of each patient, it is not always possible to run to time. The staff will try to keep you informed of any delays.

Why do I need a colonoscopy?

Your doctor has referred you for a colonoscopy to investigate the symptoms you have been having, for example, a change in bowel habit, rectal bleeding and/or anaemia. It may be a review of a chronic condition, such as colitis, or to check for a recurrence of polyps. Many examinations show a normal healthy bowel.

What are the benefits of having a colonoscopy?

A colonoscopy provides detailed information of the appearances of the lining of the bowel.

The information gained during your test may reveal a cause for your symptoms and assist your doctor in your further treatment.

What else may be done during the procedure?

During the colonoscopy a biopsy (a sample of the lining of the bowel for closer examination under a microscope) may be taken, using tiny biopsy forceps passed through the colonoscope. This is a painless procedure. It is also possible to remove polyps during a colonoscopy. Polyps are abnormal projections or growths of tissue from the lining of the bowel, rather like a wart, and certain types of bowel polyps may be at risk of developing into cancer if left. If polyps are found, the endoscopist may decide to remove them during the procedure; again this is painless.
Occasionally it may be necessary to return for a repeat colonoscopy in order to treat large or difficult to remove polyps.

What are the risks of having a colonoscopy?

Complications following colonoscopy are rare, but it is important that you are aware of them before the test begins.

• It is common to get some abdominal discomfort during the procedure due to the air put in to the bowel, but this usually settles quickly and will be helped by passing wind.
• A small amount of bleeding from the back passage is not unusual and should not cause alarm, especially following biopsy or removal of a polyp. Bleeding may occur up to several days after the procedure.
• Heavier bleeding may require further treatment in hospital. Please contact NHS 111 or attend the Emergency Department.
• Having a colonoscopy carries a small risk of making a hole in the bowel wall (a perforation). This is rare, occurring in one in 1,000 examinations. This will require a stay in hospital as perforations usually need to be repaired with an operation.
• Sedation medication can affect the breathing, but in order to minimise any risk, your dose is individually assessed and your oxygen level monitored throughout the procedure.
• If you are asthmatic, or have any breathing difficulties, please inform the nurse on your arrival and bring your inhalers with you.
• It is rare, but an allergic reaction to medications can occur and will need medical treatment.
• It cannot be guaranteed that we will spot everything that there is to be seen, although it is unlikely that we would miss anything significant.
• Your comfort and safety are our priority, and we will stop at any time if we cannot ensure this, or if there is a problem with equipment, which is rare. Alternative tests may be arranged.

Is there an alternative to a colonoscopy?

Yes. A CT colonogram may show the cause of your symptoms. However, a CT is not as accurate as a colonoscopy and it cannot treat any problems that might be found.

Remember; if you are unsure about this examination please seek more information from your referring doctor.

How do I prepare for my colonoscopy?

To allow a clear view, the colon must be clean and completely empty of waste material. If it is not, certain areas may be obscured and the test may have to be abandoned and repeated at a later date.

The bowel preparation that has been prescribed for you works as a powerful laxative and makes your bowel clean. Please read and follow the instruction sheet supplied with the bowel preparation carefully.

It is important to take all of the laxatives prescribed and considerably increase your intake of clear fluids on the day before the examination, which will help clean the bowel. Please also follow any dietary instructions for the few days preceding the test, as this will also help
to ensure the bowel is clean for the test.

VERY IMPORTANT – DO NOT EAT ANY SEEDED OR NUT PRODUCTS FOR FIVE DAYS PRIOR TO YOUR APPOINTMENT, EG SEEDED WHOLEMEAL BREAD.

This is very important as failure to follow the instructions will result in your colonoscopy being unsuccessful or cancelled.

Planning your care

If you are taking any of the following medications, or have any of the medical conditions listed here, please contact the Clinical Advice Line on 01305 253152 to help us plan appropriate care and management of your condition during your visit with us.

Do not take any other laxatives on the day before your procedure, except the medication provided for this test.

Please continue to take medication for Inflammatory Bowel Disease (IBD), (ulcerative colitis or Crohn’s disease) – if you are unsure please contact your IBD nurse for advice.

Contraceptive pill

Please note, if you are using the contraceptive pill, a loose bowel may make this ineffective. It is therefore recommended that other contraceptive measures, i.e. condoms are also used until your next menstrual period following the examination. Do not stop using the pill.

Please note: Individuals are unable to donate blood for four to six months after flexible endoscopy and until they have informed the transfusion service of the diagnosis.

Please bring with you

• A list of the medications that you take and also any medication you may require whilst you are in the department, such as insulin, inhalers, and GTN spray
• A dressing gown and slippers for your comfort and dignity.

What happens when I get to the Endoscopy Unit?

When you come to the Endoscopy Unit, please give your name to the receptionist.

A nurse will take you through to a private office. You will be asked some questions about the arrangements you have made to get home and about your health. The nurse will check your breathing, pulse and blood pressure. If you take Warfarin, your INR will be checked, and if you are diabetic, your blood sugars will be checked. Please tell the nurse if you are allergic to any medicines.

You can ask any questions that you have or tell the nurse of any worries. It is not unusual to feel anxious about having a colonoscopy. The nurses and endoscopists understand this and will do their best to reassure you. If you choose, a friend or relative can accompany you at this point but will not be able to accompany you into the endoscopy room during your procedure.

Once the nurse has finished taking your details, you will be asked to sit back in the waiting area. When the endoscopist is ready to see you, a nurse will come and take you through to get changed into a hospital gown and offer dignity shorts ready for the test.

You are advised not to bring expensive items of jewellery or clothing with you when you visit the Endoscopy Unit. You will be given a patient property bag to place your clothes in when changing for your procedure.

You will be asked to keep your property with you at all times.

The Endoscopy Unit and Dorset County Hospital NHS Foundation Trust cannot accept responsibility for the safeguarding of your property.

Signing the consent form

The endoscopist or a senior endoscopy nurse will meet and talk to you about the procedure. It is important before signing that you understand what is likely to happen. You will be given time to ask any questions that you may feel necessary to make up your mind.

What are the key things to remember?

It is your decision, and you can choose whether or not to consent to what is being proposed. Ask as many questions as you like and remember to tell the team about anything that concerns you or about any medication, allergies or past history which might affect your general health.

Your colonoscopy procedure

This test is usually carried out with inhaled analgesia called Entonox® or both a sedative injection (Midazolam) and opiate analgesia injection (Fentanyl).

Sedation: If you decide to have the sedative and opiate analgesia injection, you will need to have a responsible adult come into the Endoscopy Unit to collect you, drive you home and look after you for 24 hours. This is for your own safety, as the sedative injection can make you feel drowsy for up to 24 hours after the procedure.

If you have not made these arrangements we will not be able to proceed with the investigation.

Entonox® is a mixture of Nitrous Oxide Gas and Oxygen that is inhaled through a mouthpiece. It is an odourless, colourless gas which can provide excellent, short-term pain relief that works quickly and wears off almost as quickly. You will not need to be accompanied home and could drive yourself home afterwards.

Please tell the nurse if you:

• have recently used Entonox® for a procedure
• currently have, or have recently had, an ear infection or an operation on your ears
• have recently had eye surgery
• have recently had a head injury which required you to be in hospital
• have recently been scuba diving
• have recently suffered from a condition causing acute breathing problems (a chest injury, for example, or a collapsed lung)
• have emphysema, or chronic breathing problems, such as chronic bronchitis or moderate to severe asthma.

If you have any of the above conditions then Entonox® may not be suitable.

The colonoscopy

You will be taken to a treatment room for the procedure and introduced to the staff. You will be asked to lie on your left side on a trolley. You will be covered with a blanket. The endoscopist or nurse will insert a flexible plastic tube called a cannula into your arm or hand .Your pulse, breathing and blood pressure will also be monitored throughout the procedure.

If you have chosen Entonox®, the nurse will show you how to breathe through the mouth piece. It will make you feel relaxed, but can give you a dry mouth.

If you have chosen the sedation and pain relief, they will be administered through the cannula in your arm. These two drugs together make most people feel drowsy and relaxed.

Some extra oxygen will be given to you through a small tube placed in your nose.

It may also be necessary to administer Buscopan which is a medication that reduces bowel spasms during the procedure.

You should not feel pain during the test although you may have brief periods of discomfort, particularly when the endoscope is first inserted and when the scope passes around bends in the bowel. Occasionally the nurse will press gently on your stomach or your position may be altered to aid the passage of the scope.

Your bowel will be inflated with a little air so that good views are seen. This can sometimes be uncomfortable. Please tell the nurse if you have any discomfort.

You can watch the procedure on the screen if you feel awake enough and wish to do so.

How do I get the results?

When the procedure is over, you will be taken back to the recovery area on a trolley to recover. During this time the nursing staff will continue to monitor your pulse and blood pressure.

It is not unusual to have some ‘windy’ discomfort in your abdomen but this should soon start to disperse. You may feel a bit light-headed. The nurses in the recovery area will be making regular checks on you to see that all is well. It doesn’t take long before you feel more awake and are ready for a drink.

Once you are ready for discharge, the nurse will take you to a private room and will talk to you (and the responsible adult collecting you, if you have had sedation) about any results.

You will also be given the opportunity to ask any questions. Biopsies need time to be processed and the result will be made available to the referring doctor/GP, along with a copy of the report. If biopsies are taken, you will be advised to visit or phone your GP after two to three weeks for the result, unless advised otherwise at the time of the procedure.

Are there any restrictions afterwards?

A nurse will prepare your discharge information to take home with you. This information includes instructions on how you need to take care of yourself until the sedation has worn off. If needed, you will be given a leaflet that will explain any specific findings in more detail.

Going home following sedation

Please remember: If you have chosen the sedative injection, you must have someone come into the Endoscopy Unit to collect you, drive you home and look after you for 24 hours. Travelling on public transport (train or bus) is inappropriate. You can travel by taxi, but must have a responsible adult with you.

For the first 24 hours after the procedure you must not:

• Drink any alcohol
• Drive a car
• Operate machinery
• Sign any legally binding documents
• Be responsible for small children
• Lock the bathroom door.

You can go back to your normal eating. We do advise, however, to start with something light.

It may take a few days for your bowels to get back to normal.

Please note: individuals are unable to donate blood for four to six months after flexible endoscopy and until they have informed the blood service of the diagnosis.

We are privileged to be a training hospital

There may be a trainee endoscopist observing or performing your procedure. If this is the case, there will also be a consultant present, and you will be informed during your admission.

Contact numbers

Endoscopy Unit main reception: 01305 255225
Appointment enquiries: 01305 255701
Medical enquiries: 01305 253152

If you call the Clinical Advice Line and your call goes to answer phone, please leave a message with the following details:

• Your name and telephone number
• The procedure you are having
• Date and time of your appointment
• Your reference number (hospital number) or our reference number (NHS number)
• Your query.

Someone will return your call as soon as possible to discuss your telephone message with you.

If you are using hospital transport and your appointment is after 2pm, please contact the appointments line to rearrange an earlier appointment.

Useful videos

A number of useful videos are available on the Our Dorset Health Video Library. Visit https://healthvideos.ourdorset.org.uk/endoscopy?videoId=4493

About this leaflet

Author: Tracey Marsh
Written: April 2020
Approved: November 2020
Review date: November 2023
Edition: 1v7

If you have feedback regarding the accuracy of the information contained in this leaflet, or if you would like a list of references used to develop this leaflet, please email patientinformation.leaflets@dchft.nhs.uk