Complications of Colonoscopy

Introduction

Colonoscopy remains the gold standard for colonic investigation. It is a sensitive diagnostic tool and provides a nonsurgical approach for the removal of colonic and rectal polyps. However, colonoscopy is invasive. It can be a challenging procedure to perform and is associated with infrequent but potentially serious complications. Most of these complications occur after therapeutic procedures have been performed. Potential complications are listed in Box 86-1 .

Adverse events can occur before, during, or after a procedure. Postprocedure complications can occur immediately, within days, or sometimes years after the procedure (e.g., a stricture related to previous endoscopic mucosal resection). Knowledge of the potential complications together with early recognition and appropriate management of the situation will help improve patient outcomes.

Risk Management

Perhaps the most important aspect of colonoscopy is minimizing risk for the patient, which starts with a targeted history that includes cardiac and respiratory risk factors, history of renal impairment, the presence of diabetes or bleeding disorders, drug history (particularly antiplatelet and anticoagulant agents), and a history of allergies. The patient’s comorbidities are balanced against the possible benefits of colonoscopy to determine whether the procedure should be performed at all. Comorbidities also influence choice of bowel preparation (renal function status) and the depth and duration of conscious sedation (respiratory function).

Although the skill and experience of each colonoscopist varies, every colonoscopy should be performed or supervised by an endoscopist with adequate training as defined by the various supervising societies. The complication rate is highest for inexperienced colonoscopists who have performed a low volume of procedures. The risk of complications can be up to three times higher after a polypectomy performed by a “low-volume” colonoscopist (i.e., an endoscopist who has experience with 1 to 141 colonoscopies) when compared with a “high-volume” colonoscopist (i.e., an endoscopist who has experience with 379 to 1225 colonoscopies). Inherent in the better outcome of experienced endoscopists is experience and knowledge of the equipment, including the electrocautery generator and the various adjuncts. A poorly functioning scope and lack of familiarity with equipment will place the patient at an unnecessary risk. It is also important that colonoscopists be aware of their own limitations because overambition may lead to adverse events. As the complexity of polypectomy increases, the risk of complications also increases. Using lower risk procedures when appropriate, or referring patients to “high-volume” endoscopists, can reduce the risk of perforation and gastrointestinal bleeding.

In this chapter we will concentrate on the management of two potentially life-threatening and surgically important complications of colonoscopy: perforation and hemorrhage.

Hemorrhage

Hemorrhage is a rare complication of diagnostic colonoscopy because clinically significant bleeding from mucosal biopsy sites is uncommon. However, hemorrhage is the most common complication associated with endoscopic polypectomy. Hemorrhage can be defined as acute blood loss after a polypectomy that is severe enough to mandate admission to the hospital.