What is the recommended bowel preparation for a patient with a diverticular bleed?

Rapid Bowel Preparation for Diverticular Bleeding

For patients with acute diverticular bleeding requiring urgent colonoscopy, perform rapid bowel preparation using 4-6 liters of polyethylene glycol electrolyte-based solution administered over 3-4 hours, which can be delivered via nasogastric tube if needed. 1

Bowel Preparation Protocol

Standard Rapid Purge Approach

• Administer polyethylene glycol (PEG) electrolyte-based solutions in volumes of 4-6 liters over 3-4 hours for patients requiring urgent colonoscopy without a known bleeding point 1
• Nasogastric tube delivery is acceptable and may be necessary for patients who cannot tolerate oral intake 1
• This rapid purge protocol allows colonoscopy to be performed within 12-48 hours of presentation after adequate preparation 2

Alternative Low-Volume Preparation

• A novel 1-liter polyethylene glycol ascorbate solution may demonstrate similar efficacy to traditional higher-volume preparations and substantially reduces preparation time, though evidence is limited to case reports 3
• This low-volume option can be considered when colonoscopy must be rapidly planned in critically ill patients 3

When Bowel Preparation Can Be Modified or Avoided

Distal Bleeding Sources

• If the bleeding point is known to be in the distal colorectum (such as post-polypectomy bleeding or source identified on CT angiography), an enema and copious washing may suffice instead of full bowel preparation 1
• This approach is supported by small retrospective proof-of-concept studies, though evidence is limited 1

Blood as Natural Laxative

• Blood itself acts as a potent laxative, which may facilitate adequate visualization in some cases of active bleeding 1

Safety Considerations During Preparation

Common Complications

• The most frequently reported complications of bowel preparation in lower GI bleeding are hypotension and vomiting 1
• Importantly, aspiration pneumonia and volume overload have not been reported in retrospective reviews 1

Monitoring Requirements

• Monitor hemodynamic status closely during rapid purge administration
• Ensure adequate IV access and resuscitation measures are in place before initiating bowel preparation
• Consider ICU-level monitoring for patients with severe bleeding or significant comorbidities 2

Clinical Context and Timing

When to Proceed with Colonoscopy

• For hemodynamically unstable patients (shock index >1), CT angiography should be performed first rather than proceeding directly to colonoscopy, as it can localize bleeding sources throughout the GI tract without requiring bowel preparation 1
• Colonoscopy should be performed within 12-48 hours of presentation after rapid bowel preparation in stable patients 2
• Urgent colonoscopy (<12 hours) has not shown advantage over elective colonoscopy (36-60 hours) in randomized trials for diagnostic yield, therapeutic yield, length of stay, or transfusion requirements 1

Endoscopic Therapy Options After Preparation

• Once adequate preparation is achieved, endoscopic options for diverticular bleeding include epinephrine injection, endoscopic clipping (through-the-scope and over-the-scope), thermal therapies (bipolar coagulation, argon plasma coagulation), endoscopic band ligation, endoloops, and hemostatic powders 1
• Use CO2 insufflation rather than air to reduce gas explosion risk in poorly prepared colons when using diathermy or argon plasma coagulation 1

Common Pitfalls to Avoid

• Do not delay resuscitation to perform bowel preparation in hemodynamically unstable patients—proceed to CT angiography first 1
• Do not assume full bowel preparation is always necessary; tailor the approach based on suspected bleeding location 1
• Do not use air insufflation in poorly prepared colons when thermal therapy is planned due to explosion risk 1
• Recognize that most diverticular bleeding (approximately 80%) stops spontaneously, so aggressive preparation may not always be necessary 2