Contraindications Absolute contraindications Untrained or inexperienced ultrasound operator Unsuitable axillary / subclavian vein, thrombosed (uncompressible) or inaccessible as seen by ultrasound Fracture of the clavicle or proximal ribs Local infection at the insertion site Antibiotic-impregnated catheter in allergic patient Relative contraindications Unilateral lung disease: Cannulate ipsilaterally.