Tunneled catheters serve as a temporary vascular access for haemodialysis. There is a subcutaneous tunnel under the skin before leading to the large veins. Complications, in particular infection is high with catheters. They should not be used as substitutes for permanent haemodialysis access except for patients who have no sizeable veins or are medically unfit for arteriovenous fistula or graft creation. For the best catheter blood flow, the catheter tip should be placed at the mid-right atrium level.