Situation: A nurse on the pediatric cardiology and surgical ward cares for infants with congenital anomalies. A 10-month-old had cardiac catheterization through the right femoral artery for device closure of a ventricular septal defect 4 hours ago. The nurse finds: Heart rate: 132/min; blood pressure: 90/56 mmHg Insertion site: dressing dry, no swelling Right foot: cool and pale, weak pedal pulse, capillary refill 4 seconds Left foot: warm and pink, strong pedal pulse What is the MOST likely problem?

Changes limited to the catheterized limb — coolness, pallor, a weak pulse, and slow capillary refill — while the other foot is normal point to arterial obstruction, such as thrombosis or spasm, at the insertion site. Heart rate and blood pressure are normal for the age and the site is dry, so the problem is local; the nurse reports it at once.

Clinical situation The findings are confined to the right lower extremity: the foot is cool and pale, the pedal pulse is weak, and capillary refill is prolonged at 4 seconds. The left foot remains warm and pink with a strong pulse. This asymmetry is the key clue. A systemic problem such as hypovolemic shock or hypothermia would affect both legs, not one. The dressing is dry and there is no swelling at the insertion site, so visible bleeding is not the immediate concern. The heart rate of 132/min and blood pressure of 90/56 mmHg are within acceptable limits for a 10-month-old infant, which further argues against a systemic perfusion problem. The unilateral cool, pale extremity with weak pulse and delayed capillary refill indicates reduced arterial inflow to the right leg, most likely from thrombus or spasm at the femoral artery access site.

Why the right leg loses arterial flow after catheterization During transfemoral cardiac catheterization, the catheter passes through the femoral artery. The vessel wall can be injured by the puncture, the catheter, or the closure device. This injury triggers platelet activation and local thrombus formation, or it can provoke arterial spasm. Either mechanism narrows or occludes the vessel lumen. The result is acute limb ischemia—a sudden drop in arterial perfusion distal to the obstruction. In infants, the femoral artery is small in diameter, so even a modest thrombus can significantly reduce flow. The classic findings of acute arterial occlusion are the “six Ps,” but in an infant the most observable signs are coolness, pallor, weak or absent pulse, and delayed capillary refill. Pain and paresthesia are harder to assess in a 10-month-old, so the nurse relies on objective perfusion signs.

How the evidence supports a local arterial problem The case report by El Hanbali and colleagues describes a 13-month-old child who developed acute ischemia of the right lower limb after inadvertent femoral arterial injury during a vascular access procedure ^[1]. The presentation mirrors this scenario: a unilateral cool, pale limb with poor perfusion following femoral artery instrumentation. The mechanism is iatrogenic arterial trauma leading to thrombosis. Flanigan and colleagues prospectively studied children before and after cardiac catheterization and found that 24% sustained vascular injuries, with transfemoral cardiac catheterization being a major cause . This underscores that arterial complications after femoral access are not rare in pediatric patients and must be actively assessed. Katsouras and colleagues reported acute lower limb ischemia after use of a vascular closure device, with an incidence of 0.7% in their series . Although the incidence is lower with modern devices, the complication is serious and requires prompt recognition.

Assessment finding	Supports local arterial obstruction	Does not support systemic problem
Right foot cool and pale	Yes—reduced arterial inflow to that limb	No—systemic hypoperfusion would affect both feet
Weak right pedal pulse	Yes—diminished flow distal to femoral obstruction	No—left pedal pulse is strong
Capillary refill 4 seconds	Yes—delayed distal perfusion in the affected limb	No—left foot refill is normal
Heart rate 132/min, BP 90/56 mmHg	Neutral—not the primary indicator	Yes—age-appropriate, argues against shock
Dressing dry, no swelling	Neutral—does not rule out arterial thrombus	Yes—no visible bleeding or expanding hematoma

Distinguishing arterial obstruction from other options Watch out! Hypovolemic shock from hidden bleeding would present with tachycardia, hypotension, prolonged capillary refill in all extremities, and often a change in mental status. This infant has a normal heart rate and blood pressure for age, and the left foot is well perfused. Watch out! Hypothermia would also cause symmetric coolness and vasoconstriction in both feet, not a one-sided change. Key point! Unilateral limb changes after femoral artery catheterization are never “expected” and always require immediate reporting. Vasoconstriction limited to one catheterized limb is a sign of arterial compromise until proven otherwise.

Nursing priority The nurse should immediately notify the provider and the pediatric cardiology team. While waiting for further orders, the nurse keeps the infant calm, maintains the leg in a neutral position, avoids flexion at the hip that could kink the femoral artery, and continues to monitor perfusion of the right foot. The unaffected left foot serves as the child’s own control. Serial assessment of color, temperature, pulse, and capillary refill in the affected limb is essential because progression from weak pulse to absent pulse signals worsening ischemia and the need for urgent intervention.