What is the most appropriate initial management for an unstable patient with lower gastrointestinal bleeding, hypotension, and evidence of ongoing bleeding?

Management of Unstable Lower GI Bleeding with Hypotension

For this unstable patient with lower GI bleeding and persistent hypotension (BP 70/50) despite blood transfusion, CT angiography should be performed immediately, followed by catheter angiography with embolization if positive—laparotomy is reserved only for patients who fail angiographic intervention or continue to deteriorate despite all localization attempts. 1, 2

Immediate Assessment and Resuscitation

• Confirm hemodynamic instability using shock index (heart rate/systolic BP), with a shock index >1 indicating instability requiring urgent intervention rather than colonoscopy 1, 3
• Continue aggressive fluid resuscitation with crystalloids and blood products using restrictive transfusion thresholds (Hb trigger 70 g/L, target 70-90 g/L), or higher threshold (Hb trigger 80 g/L, target ≥100 g/L) if cardiovascular disease is present 1, 2, 4
• Correct coagulopathy immediately if present by transfusing fresh frozen plasma for INR >1.5 and platelets for platelets <50,000/µL 1

Diagnostic and Therapeutic Algorithm for Unstable Patients

First-Line: CT Angiography

• Perform CT angiography immediately as it provides the fastest and least invasive means to localize bleeding in hemodynamically unstable patients 1, 2, 4
• CTA should be done before any endoscopic or surgical intervention in patients with shock index >1 or ongoing bleeding 1, 4

Second-Line: Catheter Angiography with Embolization

• Following positive CTA, proceed to catheter angiography with embolization within 60 minutes in centers with 24/7 interventional radiology to maximize success rates 1, 2, 3
• This approach allows both localization and therapeutic intervention simultaneously 1

Why NOT Colonoscopy in This Patient

• Colonoscopy is explicitly contraindicated as the initial approach when patients have shock index >1 or remain unstable after resuscitation 1
• Urgent colonoscopy should be reserved for stable patients or after successful localization and stabilization via angiography 1, 4
• There is no high quality evidence that early colonoscopy influences patient outcomes in major acute lower GI bleeding 4

Why NOT Immediate Laparotomy

• Laparotomy should be avoided unless every effort has been made to localize bleeding through radiological and endoscopic modalities 1
• Diagnostic laparotomy is mandatory only in unstable patients who are non-responders to aggressive resuscitation AND after failure of other localization methods 5, 1
• Blind segmental resection and emergency subtotal colectomy are associated with substantial rates of rebleeding (as high as 33%) and mortality (33-57%) 5
• Overall operative mortality rate for emergency surgery for lower GI bleeding is 10%, with higher rates in elderly patients 5

Critical Considerations

Upper GI Source Must Be Excluded

• Always consider an upper GI source in patients with hemodynamic instability, even with apparent lower GI bleeding, as failure to do so can lead to delayed diagnosis and treatment 1, 2, 3
• If no lower GI source is identified on CTA, upper endoscopy should be performed 1

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
• The patient's unstable status despite blood transfusion places her in this high-risk category 1

Surgical Indications (Last Resort)

• Surgery is indicated only when: hemodynamic instability persists despite aggressive resuscitation, blood transfusion requirement exceeds 6 units, angiographic intervention fails, or the patient continues to deteriorate despite all attempts at localization and intervention 5, 1
• If surgery becomes necessary, accurate preoperative localization of the bleeding site is essential to permit segmental rather than subtotal colectomy 5