COLONOSCOPY

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A colonoscopy is a medical procedure that allows a doctor, usually a gastroenterologist, to examine the inner lining of the large intestine (rectum and colon). They use a thin, flexible tube called a colonoscope to view the colon. This device has a small camera attached to its end, which transmits images to a monitor for the doctor to review.

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It may be performed for either diagnostic or therapeutic purposes.

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A grounding pad may need to be placed for cautery excision.

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Here are the key steps in the procedure:

1. Preparation: Before the procedure, patients need to clean out your colon (colon prep) to give the doctor a clear view. This usually involves a liquid diet for 1 to 3 days before the procedure and taking a strong laxative or over-the-counter enema kit.

2. Sedation: Before the colonoscopy starts, patients receive a sedative to help them relax and reduce discomfort.

3. Procedure: The doctor will slowly insert the colonoscope into the rectum and guide it into the colon. Air or carbon dioxide will be introduced to expand the colon for a better view.

4. Polyp Removal & Biopsy: If the doctor finds polyps (abnormal growths), they can remove them during the procedure using tiny tools passed through the scope. Similarly, if other abnormal tissues are found, they can be sampled (biopsy) for further testing.

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Colonoscopies are often used to diagnose gastrointestinal symptoms, screen for colon cancer, and follow up on a positive stool test. The American Cancer Society recommends that people at average risk of colon cancer begin regular screenings at age 45,

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                                                                Anesthetic Implications for Colonoscopy

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Anesthesia type:  TIVA, sedation

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Airway: Oral airway, nasal ariway 

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Preoperative:

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• Patients receive a bowel prep and present with dehydration and hypovolemia

• Oxygen is administered via nasal cannula or simple face mask

• CO2 monitoring is a helpful adjunct

• Airway equipment and emergency medications must be available

• Risk of aspiration for patients with obstruction

• Patients with colon cancer are likely to be anemic

• Metastatic colon cancer maybe associated with concomitant organ dysfunction (liver and lungs)

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Intraoperative:

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• Vagal effect and bradycardia may occur from colon insufflation

• Position: left lateral position, with knees pulled up and legs bent

• The doctor may ask to press on abdomen (stimulating)

• Insufflation of the colon can decrease functional residual capacity (FRC)

• Duration 15-60 minutes

• EBL none to minimal. Unless associated with underlying GI bleed or coagulopathy

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Postoperative:

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• Recovery period

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Complications:

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• Bleeding

• Colonic perforation

• Airway obstruction

• Desaturation

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Sources:

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Macksey, L. F. (2011). Surgical procedures and anesthetic implications: A handbook for nurse anesthesia practice. 

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Jaffe, R. A. (2020). Anesthesiologist's Manual of Surgical Procedures (6th ed.). 

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Singh-Radcliff, N. (2013). 5-Minute Anesthesia Consult.

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