Haemodialysis requires the surgical construction of an arterio-venous fistula that is usually sited in the non-dominant forearm using the cephalic vein and either the radial or brachial artery. After six to eight weeks the fistula has usually thickened sufficiently to allow it to be cannulated with two large-bore needles that take blood to and from the dialysis machine. Blood is pumped through a semi-permeable membrane filter in the dialysis machine allowing removal of excess solutes and fluid. Haemodialysis is repeated every two to three days with the time on dialysis dependent on the patient's body size and residual renal function. If a patient has no permanent access and requires emergency dialysis this can be done through a temporary neckline or a semipermanent catheter in a central vein (14).
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