Peripheral Vascular Assessment

A patient's foot is cool, pale, and pulseless after a cardiac catheterization — but the cardiac monitor looks fine. The problem isn't the heart. It's downstream. Knowing how to assess peripheral vasculature catches what cardiac assessment misses.

Peripheral vascular assessment evaluates arterial inflow and venous return in the extremities. You systematically assess the 6 P's of arterial compromise: Pain, Pallor, Pulselessness, Paresthesia, Paralysis, and Poikilothermia (coolness). Palpate pulses bilaterally — dorsalis pedis, posterior tibial, popliteal, femoral, radial, and ulnar — grading them 0 (absent) through 3+ (bounding). An absent or diminished pulse demands immediate follow-up. Capillary refill should be under 3 seconds; longer suggests impaired arterial perfusion. The ankle-brachial index (ABI) compares ankle systolic pressure to brachial systolic pressure: normal is 1.0–1.2, below 0.9 indicates peripheral arterial disease (PAD), and below 0.5 signals severe ischemia. For venous assessment, inspect for edema, varicosities, skin discoloration (hemosiderin staining), and measure calf circumference bilaterally — a difference greater than 2 cm raises concern for deep vein thrombosis. Homan's sign is unreliable and no longer recommended as a screening tool. Arterial insufficiency presents with shiny, hairless skin, thickened nails, and pain that worsens with elevation (dependent rubor relieved by dangling). Venous insufficiency shows brown discoloration, stasis dermatitis, and edema that worsens with dependency.

Key Distinctions

Don't confuse arterial ulcers (distal, deep, well-defined borders, painful) with venous ulcers (medial malleolus, shallow, irregular, less painful). Students mix up positioning: elevate for venous insufficiency, keep dependent for arterial. A bounding pulse (3+) is not the same as a normal pulse (2+) — bounding can indicate fluid overload or aortic regurgitation, not just 'good circulation.'

Clinical Pearl

Arterial = pale, painful, pulseless, elevated makes it worse. Venous = brown, brawny, edematous, dangling makes it worse. Think 'Arteries Act up when you go UP.'