Information for patients undergoing Colonoscopy
Your physician has asked that the inside of your colon (large intestine)
be inspected by using a long flexible tube (colonoscope) so that he can
know what disease,if any, is present.
Proper preparation is extremely important for this examination. The large
intestine must be clean and empty for the doctor to make an adequate exam-ination.
The preparation requires the use of a clear liquid diet for one day before the
examination. This is achieved by using a laxative, often “Golytely”; it is usual
to use up to 4 litres to clean out the colon before the procedure; other
preparations may be used by your doctor. Because many patients are apprehensive,
Dormicum® and Pethidine® are often given intravenously at the time of the
examination to relax the patient; once again, your doctor may use a different
drug or combinations. Ask him/her about this.These drugs will not put you to
sleep but may cause some lightheadedness.(See “Conscious Sedation: What you need
to know”) If you have had any unfavourable reaction to any of these drugs, you
should tell the examiner before the injection is given.
The examination is carried out with the patient lying on his left side on the
examining table.A lubricant is applied around the anus and the colonoscope
ispassed into the rectum.It is necessary for the doctor to use some air to aid
him in the examination. This may cause you to feel distended and full.If you
havethe urge to pass this air by rectum, it is permissible to do so unless the
doctor requests otherwise.The large intestine may be twisted and tortuous. As
the instrument passes around some of these turns, it may cause a cramping or
tugging sensation.This is usually relieved as the instrument is passed around
abend and straightened. The examination may take anything from 15 – 60
minutes.If polyps are to be removed, it may take longer.(Polyps are benign
growthswhich have the potential to be malignant.) A nurse is present to help the
doctor and to assist in monitoring the patient’s condition. After the
examination iscompleted, you will be asked to rest for an hour or two in an
adjoining room until the effects of the medications have subsided and until you
have passedmuchof the air which was introduced during the examination.
Polyps are removed by first locating them with the colonoscope and then placing
a wire loop around the base of the polyp. An electric current is used to cut the
polyp off at its stalk or base. You will not feel this current.The polyp
specimen is usually retrieved by applying suction to the instrument and catching
the polyp on the tip of the instrument.Polyp and instrument are then both
withdrawn. If there is more than one polyp it is necessary to re-insert the
instrument to remove the additional polyp.
There are certain risks to this procedure: