Acute Peripheral Vascular Emergencies [ALI, Ruptured AAA vs. Dissection, Phlegmasia]

Triage & Hemodynamic Assessment: Place patient on continuous cardiac monitor, pulse oximetry, and cycle NIBP. Insert two large-bore (16G–18G) peripheral IV lines. Perform immediate vascular exam (palpate pulses, check motor/sensory function, use handheld 8 MHz continuous-wave Doppler) [1,2,3].

Systemic Anticoagulation (ALI / Phlegmasia): Unfractionated Heparin (UFH) load 80 units/kg (6,400 units for 80 kg) IV bolus, followed immediately by continuous infusion at 18 units/kg/hr (1,440 units/hr = 14.4 mL/hr of 100 units/mL bag) [2,4].

Prevents propagation of thrombus into distal microvascular beds and preserves collateral patency in Acute Limb Ischemia (ALI) or massive iliofemoral deep venous thrombosis (Phlegmasia Cerulea Dolens) [2,4].

Point-of-Care Diagnostics & Ruptured AAA Override:
• ALI / Phlegmasia: Check handheld Doppler at ankle/foot (dorsalis pedis, posterior tibial) and measure Ankle-Brachial Index (ABI) [2,4].
• Suspected Ruptured AAA: Perform Bedside POCUS of the Abdominal Aorta (Transverse & Longitudinal views from xiphoid to iliac bifurcation, outer-to-outer wall) [1,5].

Permissive Hypotension / Fluid Restraint in Ruptured AAA: DO NOT aggressively fluid load. Target a permissive SBP of 70–90 mmHg (or mean arterial pressure MAP ≥ 50–60 mmHg) only sufficient to maintain cerebration/verbal responsiveness [1,5,6].

Avoids dislodging the retroperitoneal periaortic tamponade clot ("blowing the clot"); excessive crystalloids increase Laplace wall tension, dilute clotting factors, and accelerate lethal hemorrhage [1,5,6].

Invasive Arterial Line & Resuscitation Labs: Insert a radial 20G arterial line for beat-to-beat blood pressure monitoring. Draw urgent baseline labs: CBC, Type and Cross-Match (6 units packed RBCs, 6 FFP, 1 apheresis platelets), Coagulation profile, Lactate, Creatine Kinase (CK), and Electrolytes [2,5,6].

Vasoactive & Hemostatic Support in Ruptured AAA Shock: If SBP drops below 70 mmHg with altered sensorium, transfuse 1:1:1 balanced blood products and start Norepinephrine 0.05–0.2 mcg/kg/min IV (3.75–15 mL/hr of 64 mcg/mL solution) [5,6].

Maintains minimum coronary and cerebral perfusion pressure while preventing dilutional coagulopathy and hypothermia during preparation for aortic clamping or endovascular occlusion [1,5,6].

Emergency Vascular Surgery Activation & Diagnostic Imaging:
• Ruptured AAA (Unstable) or Rutherford IIb ALI: Bypass CT scanner or expedite directly to the Operating Room / Hybrid Vascular Suite [2,5,6].
• Stable AAA / Rutherford I–IIa ALI: Perform urgent CTA Aorta / Lower Extremity Runoff [2,5,7].

Analgesia & Anti-Impulse Differentiation (AAA vs. Dissection): Administer Fentanyl 1–2 mcg/kg IV PRN severe pain [2,5]. If POCUS/CTA shows Aortic Dissection with malperfusion rather than ruptured AAA: initiate Esmolol 500 mcg/kg load + 50–200 mcg/kg/min IV [7].

Distinguishes free/retroperitoneal AAA rupture (requires permissive hypotension + EVAR/Open repair) from Stanford Type B dissection with iliac malperfusion (requires anti-impulse therapy + TEVAR) [5,7].

Ischemia-Reperfusion Prophylaxis & Compartment Syndrome Monitoring: Position ALI limb dependent (slightly below heart level) and Phlegmasia limb elevated (above heart level). Prepare for post-revascularization washout [2,4].

Hyperkalemia & Myoglobinuric ATN Protection: Infuse Isotonic Sodium Bicarbonate (150 mEq NaHCO₃ in 1,000 mL D5W) at 150–250 mL/hr + Calcium Gluconate 10% 30 mL (3 g) IV + Regular Insulin 10 units + D50W 50 mL IV if K⁺ > 5.5 mEq/L [2].

Alkalinizes urine (target urine pH > 6.5) to prevent Tamm-Horsfall protein/myoglobin cast precipitation in renal tubules, and stabilizes myocardial membranes against reperfusion hyperkalemia [2].