Contraindications to Femoral Artery Cannulation, US-Guided Absolute contraindications Untrained or inexperienced ultrasound operator Unsuitable artery, thrombosed, heavily atherosclerotic, or inaccessible as seen by ultrasound An artery that is neither palpable nor detectable by ultrasound (ie, an arterial site should never be cannulated if no artery is evident) Inadequate circulation (eg, Raynaud syndrome, Buerger disease) Full-thickness burns Local infection at the insertion site Antibiotic-impregnated catheter in allergic patient Relative contraindications Coagulopathy, including therapeutic anticoagulation * Local anatomic distortion, traumatic or congenital, or gross obesity History of prior surgery or catheterization of the intended site† Atherosclerosis Inadequate collateral flow Uncooperative patient: Such patients should be sedated if necessary.