Should obtain focused history, physical exam, and labs at presentation to assess severity, location, and etiology of bleeding while initiating hemodynamic resuscitation.

Hematochezia + hemodynamic instability may suggest UGIB → should perform upper endoscopy. NG aspirate/lavage may be used if moderate suspicion.

Risk assessment and stratification should be done to distinguish low and high risk patients and assists with triage (timing of procedures, level of care).

If hemodynamic instability and/or suspected ongoing bleeding, should give IVF resuscitation → goal is to normalize BP/HR before endoscopy.

Should transfuse pRBCs to keep Hgb >7 g/dL; if massive bleeding, significant comorbid illness (especially CV ischemia), or possible delay in intervention, should consider Hgb >9 g/dL.

May consider endoscopic hemostasis if INR 1.5-2.5 before or concomitant with reversal; should consider reversal before endoscopy if INR >2.5.

Should consider platelet transfusion to maintain platelets >50 x 10⁹/L if severe bleeding and requiring endoscopic hemostasis.

Should consider platelet and plasma transfusions in patients requiring massive pRBC transfusions.

To balance risk of thromboembolic events and ongoing bleeding in patients on AC, should use multidisciplinary approach (e.g. hematology, cardiology, neurology, GI) when deciding to discontinue or reverse the agent.

Colonoscopy should be the initial diagnostic procedure in almost all acute LGIBs.

Should carefully inspect thoroughly cleansed colonic mucosa on both insertion and withdrawal; should aggressively attempt to wash residual blood/stool to identify bleeding; should intubate terminal ileum to rule out potential small bowel bleeding.

In high-risk patients with suspected ongoing bleeding, perform colonoscopy within 24 h (after hemodynamic resuscitation followed by rapid bowel purge) to potentially improve diagnostic and therapeutic yield.

In patients without high-risk clinical features or serious comorbid diseases or in patients with high-risk clinical features without signs or symptoms of ongoing bleeding, should perform colonoscopy after bowel purge at next available.

Once the patient is hemodynamically stable, colonoscopy should be performed after adequate colon cleansing. 4-6 L of a PEG-based solution or equivalent should be administered over 3–4 h until rectal effluent is clear of blood and stool. Unprepped colonoscopy/sigmoidoscopy is not recommended.

A nasogastric tube can be considered to facilitate colon prep in high-risk patients with ongoing bleeding who are intolerant to oral intake and are at low risk of aspiration.

Should endoscopically treat high-risk stigmata of bleeding: active bleeding; non-bleeding visible vessel; adherent clot.

For diverticular bleeds, through-the-scope clips are recommended (may be safer than thermal therapy and are generally easier than band ligation, especially for right-sided colon lesions).

For angioectasia bleeds, non-contact thermal therapy (i.e., APC) is recommended.

For post-polypectomy bleeds, clips or contact thermal therapy +/- dilute epinephrine is recommended.

Epinephrine injection (1:10,000 or 1:20,000 in saline) can be used for initial control of active bleeding and improved visualization; should be used with a second modality (mechanical or thermal therapy) for definitive hemostasis.

If evidence for recurrent LGIB, should consider repeat colonoscopy for control of bleeding.

Should consult surgery for patients with high-risk clinical features and ongoing bleeding, particularly if other therapies have failed; should consider prior bleeding control measures, bleeding severity/source, and comorbidities. Important to very carefully localize source of bleeding to target resection and avoid missed lesions.

Should consider angiography if ongoing bleeding and high-risk clinical features if upper endoscopy is negative and not adequately responsive to resuscitation (i.e., unlikely to tolerate bowel prep and urgent colonoscopy).

If diagnostic test desired to localize bleeding before angiography, should consider CTA for localization of bleeding site before angiography.

Should avoid non-ASA NSAIDS in patients with history of acute LGIB, especially if due to diverticulosis or angioectasias.

Should not discontinue ASA for secondary prevention if known high-risk CV disease and history of LGIB; should avoid ASA for primary prevention in most patients with LGIB.

In patients on DAPT or monotherapy with non-ASA antiplatelet agents (thienopyridine), should resume antiplatelet agent ASAP (within ≤7 d) based on multidisciplinary assessment of CV and GI risk and adequacy of endoscopic therapy (should not discontinue ASA). Should not discontinue DAPT if ACS within past 90 d or coronary stenting within past 30 d.