In a 68-year-old hypertensive man with known colorectal polyps presenting with bright red rectal bleeding, pallor, blood pressure 160/90 mmHg and heart rate 110 bpm, should the initial management be urgent colonoscopy or immediate intravenous crystalloid resuscitation and packed red blood cell transfusion?

Management of Acute Lower Gastrointestinal Bleeding with Hemodynamic Compromise

The most appropriate initial management is B – IV fluid and blood transfusion, NOT urgent colonoscopy. This patient presents with hemodynamic instability (shock index = 110/160 = 0.69, though tachycardia and pallor suggest significant blood loss) requiring immediate resuscitation before any diagnostic procedure.

Immediate Resuscitation Protocol

Resuscitation must take place concurrently with initial evaluation and always precedes diagnostic procedures. 1

• Establish two large-bore IV lines immediately and begin aggressive crystalloid resuscitation (normal saline or Ringer's lactate) to normalize blood pressure and heart rate. 1

• Transfuse packed red blood cells when hemoglobin is <100 g/L (10 g/dL) in acute bleeding, as changes in cardiac output occur at this threshold and mortality relates to severity of anemia in critically ill patients. 1

• Use restrictive transfusion thresholds once stabilized: maintain hemoglobin >70 g/L (7 g/dL) for patients without cardiovascular disease, but given this patient's hypertension (a cardiovascular risk factor), target hemoglobin >80 g/L (8 g/dL) with a goal of 100 g/L after transfusion. 1, 2

• Correct coagulopathy immediately: transfuse fresh frozen plasma if INR >1.5 and platelets if platelet count <50,000/µL. 1

Why Colonoscopy is Contraindicated Initially

Colonoscopy should only be performed after adequate resuscitation is achieved. 1

• This patient requires 4-6 liters of polyethylene glycol over 3-4 hours for adequate bowel preparation – this is not feasible in an actively bleeding, hemodynamically compromised patient. 1, 2

• Urgent colonoscopy within 24 hours does NOT improve rebleeding rates, mortality, or length of stay compared to elective timing after stabilization. 1, 2

• Colonoscopy is explicitly contraindicated when shock index >1 or the patient remains unstable after initial resuscitation. 1, 2

Diagnostic Approach After Stabilization

Calculate Shock Index

• Shock index = heart rate ÷ systolic BP = 110/160 = 0.69. While technically <1, the presence of tachycardia (HR 110), pallor, and bright red blood per rectum in a 68-year-old indicates significant ongoing blood loss. 1, 2

If Patient Remains Unstable After Resuscitation

• Perform CT angiography immediately as the first diagnostic test – it provides the fastest, least invasive means to localize bleeding with 94% sensitivity and can detect bleeding rates as low as 0.3 mL/min. 1, 2

• Following positive CTA, proceed to catheter angiography with embolization within 60 minutes to achieve immediate hemostasis (successful in 40-100% of cases). 1, 2

If Patient Stabilizes After Resuscitation

• Perform colonoscopy on the next available inpatient list after adequate bowel preparation with 4-6 L polyethylene glycol over 3-4 hours. 1, 2

• Given his known colorectal polyps, colonoscopy will be essential for both diagnosis and potential therapeutic intervention (clipping, cautery, or band ligation of bleeding polyp sites). 1

Critical Pitfalls to Avoid

• Never proceed to colonoscopy before achieving hemodynamic stability – endoscopy must only be done when resuscitation has been achieved, ideally with stable blood pressure and central venous pressure. 1

• Do not assume bright red blood always indicates lower GI bleeding – approximately 10-15% of patients with severe hematochezia have an upper GI source, especially with hemodynamic instability. If CTA is negative for lower GI source, perform upper endoscopy before considering surgery. 1, 2

• Avoid blind surgical intervention – surgery without prior localization carries rebleeding rates up to 33% and mortality 33-57%, compared to ~10% when bleeding is first localized radiologically. 1, 2

• Monitor for ongoing bleeding during resuscitation – if patient requires >6 units of packed red blood cells or remains unstable despite aggressive resuscitation, proceed to angiography or surgery rather than colonoscopy. 1

Management of Hypertension During Active Bleeding

• The elevated blood pressure (160/90) should NOT be aggressively treated during active hemorrhage – some degree of hypertension may be compensatory to maintain perfusion. Focus on volume resuscitation first. 1

• Avoid vasopressors if possible – use only to prevent fluid overload and abdominal compartment syndrome, as they can worsen mesenteric perfusion. 1