Preparation for colon surgery begins a few days prior to the procedure unless the surgery is being done on an emergency basis, such as for an injury or intestinal bleeding. Most patients have undergone a colonoscopy, sigmoidoscopy, or barium enema to diagnose the disease. These tests generally are not repeated. Prior to the operation, blood tests, a chest x-ray, an EKG, and an abdominal CT scan may be ordered.
The colon contains bacteria and waste products that can cause infection if they leak into the abdomen during surgery and precautions are taken to reduce this risk. Oral antibiotics are started several days before the operation is scheduled and the colon must be as empty as possible.
The procedure for colon cleansing depends on the physician, the patient's health and diagnosis, and the facility where the procedure is being performed. Generally, for 2 or 3 days prior to surgery, a soft or semi-liquid diet (i.e., foods that are quickly and easily digested) is ordered. For some patients, only clear liquids are permitted. These include fruit juice, sports drinks, clear broth, and gelatin. All patients must go on a clear liquid diet 24 hours prior to surgery. After midnight, the night before surgery, nothing may be taken by mouth.
Cleansing solutions and laxatives are used to cleanse the colon before surgery. Patients are given a laxative solution to drink that can cause severe diarrhea, so they may be admitted to the hospital the day before the surgery to receive intravenous fluids that prevent dehydration.
If the patient is unable to comply with this regimen, it is necessary to inform the physician as soon as possible. It may be unsafe to do the surgery as scheduled and it may have to be postponed.
During this period, it may not be possible to continue prescription medications. This must be discussed with the surgeon as soon as the decision to have the surgery is made. Blood "thinning" medications, including aspirin, must be discontinued one week before the operation to avoid excessive bleeding during the procedure.
The anesthesiologist (doctor who administers the anesthesia) speaks with the patient prior to surgery and performs a brief physical assessment. The anesthesiologist must be aware of medications that are being taken, any history of allergies, and prior adverse reactions to anesthesia. This information helps the anesthesiologist select the most suitable anesthetic agents and dosage and avoid possible complications.
An informed consent form must be signed acknowledging that the patient understands the procedure, the potential risks, and that they will receive certain medications.
The patient is then taken to a preoperative holding area and must remain in bed except to use the bathroom. An intravenous (IV) is started for fluids and medication, if one is not already in place. A sedative is given through the intravenous to induce drowsiness. Anesthesia is administered in the operating room.