In a 68-year-old hypertensive man with colorectal polyps presenting with bright red hematochezia, pallor, tachycardia and hypertension, what is the most appropriate immediate management: urgent colonoscopy, intravenous fluid and blood transfusion, or CT angiography?

Management of Acute Lower GI Bleeding with Hemodynamic Compromise

The most appropriate immediate management is B: IV fluid and blood transfusion to achieve hemodynamic stabilization before any diagnostic procedure. 1, 2

Immediate Resuscitation Protocol

This 68-year-old patient presents with signs of significant hemorrhage (pallor, tachycardia at 110 bpm) despite a relatively preserved blood pressure of 160/90 mmHg. The tachycardia and pallor indicate compensated shock requiring urgent resuscitation.

First-Line Actions

• Establish two large-bore peripheral IV lines immediately in the antecubital fossae to enable rapid fluid administration 3, 1
• Infuse 1-2 liters of isotonic crystalloid solution (normal saline or balanced crystalloids) rapidly to restore intravascular volume 3, 1, 2
• Transfuse packed red blood cells to maintain hemoglobin >10 g/dL given this patient's age (68 years) and cardiovascular risk factor (hypertension) 3, 1, 2
• Insert a urinary catheter and target urine output ≥30 mL/hour as a marker of adequate tissue perfusion 3, 1

Hemodynamic Targets Before Diagnostic Procedures

Resuscitation must achieve ALL of the following before proceeding to colonoscopy or CT angiography: 1

• Heart rate <100 beats/min
• Systolic blood pressure >100 mmHg
• Mean arterial pressure (MAP) >65 mmHg
• Hemoglobin ≥10 g/dL (in elderly patients with cardiovascular comorbidities)

Why Not Urgent Colonoscopy or CT Angiography First?

Colonoscopy Timing

• Endoscopy must be deferred until hemodynamic stability is achieved; performing colonoscopy in an unstable patient markedly increases the risk of aspiration, cardiovascular events, and mortality 3, 1, 2
• Once stabilized, colonoscopy should be performed within 24 hours after adequate bowel preparation, which is the gold-standard diagnostic modality 3, 1, 4
• The patient should remain fasted until stable 3

CT Angiography Limitations

• CT angiography requires hemodynamic stability and should only be performed after resuscitation targets are met 1
• CT angiography can only localize active bleeding when the rate exceeds approximately 0.5 mL/min 3, 1
• It is most useful as a secondary diagnostic tool in hemodynamically stable patients with ongoing bleeding after initial resuscitation when endoscopy is nondiagnostic 3, 1

Critical Pitfalls to Avoid

• Never delay resuscitation to perform diagnostic procedures – stabilization always takes priority over diagnosis 1, 2
• Avoid fluid overload during resuscitation, which can exacerbate bleeding 1, 2
• Do not assume a lower GI source – approximately 10-15% of patients with bright red rectal bleeding have an upper GI source, so upper endoscopy should be considered if colonoscopy is nondiagnostic 1, 4

Special Consideration for This Patient

Given the history of colorectal polyps, the bleeding source is likely colonic. However, the immediate priority remains hemodynamic stabilization through aggressive IV fluid resuscitation and blood transfusion before any attempt at source localization 3, 1, 2.