内視鏡検査 II: 大腸内視鏡検査

A colonoscopy visualizes the colon's inner lining to detect diverticula, ulceration, polyps, strictures, and colorectal cancer. The procedure allows healthcare providers to examine the entire colon and terminal ileum, making it valuable for cancer screening, investigating gastrointestinal symptoms, and evaluating patients with a strong family history of colorectal cancer.

The patient wears a gown and receives intravenous sedation combined with pain relief for comfort. They are positioned on their left side with legs flexed toward their chest on the examination table. An intravenous catheter is inserted before the procedure, and patients must stop blood thinners and follow pre-procedure diet and laxative instructions as advised by nursing staff.

The lubricated, flexible colonoscope with a camera is gently inserted into the rectum and advanced through the sigmoid, descending, transverse, and ascending colon. Air or carbon dioxide is insufflated to improve visibility. The colonoscope's tiny camera transmits real-time images to a monitor, allowing the healthcare provider to examine the colon lining and perform interventions like tissue sampling or polyp removal.

Nurses obtain informed consent, educate patients on pre-procedure requirements, and maintain privacy during the procedure while monitoring vital signs. After the procedure, they observe patients until sedation effects wear off and check for complications such as perforation, which may cause severe abdominal pain. They also provide post-procedure care instructions and monitor for delayed complications.

A colonoscopy typically takes 30 to 60 minutes, with initial sedation wearing off in about an hour. However, sedating effects can linger for up to a day, so patients must arrange a ride home and avoid driving, making important decisions, or working for the remainder of the day following the procedure.

Bloating, gas, and a small amount of blood during the first post-procedure bowel movement are normal as the colon clears. Walking helps ease discomfort. However, persistent blood passage, blood clots, severe abdominal pain, or fever should prompt immediate consultation with the healthcare provider, as these symptoms may indicate rare complications that can appear immediately or within one to two weeks.

Colonoscopy is both diagnostic and therapeutic, allowing direct visualization and real-time intervention. Unlike imaging studies such as gastrointestinal motility studies and virtual colonoscopy, which provide detailed images but limited intervention capability, colonoscopy enables tissue biopsy, polyp removal, and treatment during the same procedure.