What is the next step in managing a patient with lower gastrointestinal (GI) bleeding and hypotension despite initial resuscitation efforts?

Management of Hemodynamically Unstable Lower GI Bleeding

For a patient with lower GI bleeding who remains hemodynamically unstable (BP 80/60 mmHg) despite initial resuscitation with fluids and blood, the most appropriate next step is angiography (option b) with immediate catheter embolization. 1

Immediate Diagnostic Approach

CT angiography (CTA) should be performed immediately as the first diagnostic step in this hemodynamically unstable patient (shock index >1) to rapidly localize the bleeding source before any therapeutic intervention. 1, 2, 3 The ACR Appropriateness Criteria specifically designate CTA or transcatheter arteriography/embolization as equivalent and appropriate first-line options for hemodynamically unstable patients with active lower GI bleeding. 1

• CTA provides the fastest and least invasive means to localize bleeding in unstable patients, allowing for immediate treatment planning. 1, 2
• Following positive CTA findings, catheter angiography with embolization should be performed within 60 minutes in centers with 24/7 interventional radiology services to maximize success rates. 1, 3

Why Other Options Are Inappropriate

Fresh frozen plasma (FFP) alone (option a) is insufficient as the primary intervention in this scenario. While coagulopathy correction is important if INR >1.5, 2 FFP administration does not address the fundamental problem of ongoing hemorrhage requiring source control. 1

Emergency colonoscopy (option d) is contraindicated in hemodynamically unstable patients. 1 The British Society of Gastroenterology explicitly recommends against colonoscopy as the initial approach when patients have shock index >1 or remain unstable after resuscitation. 1 Colonoscopy is reserved for stable patients or after successful localization and stabilization via angiography. 1

Laparotomy (option c) should be avoided unless every effort has been made to localize bleeding through radiological and endoscopic modalities. 1 The British Society of Gastroenterology provides a strong recommendation that "no patient should proceed to emergency laparotomy unless every effort has been made to localise bleeding by radiological and/or endoscopic modalities, except under exceptional circumstances." 1 Similarly, the World Society of Emergency Surgery states that diagnostic laparotomy is mandatory only in unstable patients not responding to aggressive resuscitation AND after failure of other localization methods. 1

Critical Management Algorithm

1. Confirm hemodynamic instability using shock index (HR/systolic BP >1). 1, 2, 3

2. Continue aggressive resuscitation with restrictive transfusion thresholds (Hb trigger 70 g/L for patients without cardiovascular disease, 80 g/L for those with cardiovascular disease). 1, 2, 3

3. Perform immediate CTA to localize the bleeding source. 1, 2

4. Proceed directly to catheter angiography with embolization if CTA is positive, ideally within 60 minutes. 1, 3

5. Consider upper endoscopy if no lower GI source is identified, as hemodynamic instability may indicate an upper GI source. 1

6. Reserve surgery only for patients who fail angiographic intervention or continue to deteriorate despite all attempts at localization and intervention. 1

Common Pitfalls to Avoid

Delaying angiography in favor of colonoscopy is a critical error in unstable patients, as colonoscopy requires bowel preparation and hemodynamic stability for safe performance. 1

Proceeding to blind laparotomy without localization carries high rates of recurrent bleeding and poor outcomes, with mortality rates of 27-57% when perforation occurs. 1 Surgery without localization, such as total colectomy, has particularly poor outcomes. 1

Failure to consider upper GI sources in hemodynamically unstable patients can lead to delayed diagnosis, as significant hypotension may indicate brisk upper GI bleeding presenting with hematochezia. 1, 3

Mortality Context

Mortality in lower GI bleeding is generally related to comorbidity rather than exsanguination, with overall in-hospital mortality of 3.4%, but this rises to 20% in patients requiring ≥4 units of red cells. 1, 2, 3, 4 This underscores the importance of rapid source localization and definitive intervention in unstable patients to prevent ongoing transfusion requirements and complications.