When kidney disease progresses to a certain level, it will damage most of the kidney tissues and kidney function will decline. When kidney function is only less than 10% of normal kidney function, kidney failure will occur. When less than 10% of kidney function is left, it is called residual kidney function. The less the residual kidney function, the more serious the uremia. Since the residual kidney function is too little to support the metabolic needs of life, dialysis is chosen to replace the duties of the original kidney – commonly known as artificial kidney. With dialysis treatment, patients say they are relieved, and the residual kidney function becomes dispensable and unnoticeable, so they let it disappear naturally. In recent years, it has been found that residual kidney function is very important in dialysis, and people are urged to pay attention to it and protect it. For all end-stage renal failure patients, residual renal function not only plays a role in maintaining the stability of body water balance (with residual renal function there will be a certain amount of urine), but also has an important supporting role in removing metabolites from the body. According to the observation of scholars, of the total creatinine (a uremic toxin) clearance of dialysis patients, the amount of creatinine coming out of the residual kidney accounts for 39% of the total, and even if the residual kidney function is only 2% of the original, it can still bear 1/3 of the total clearance of peritoneal dialysis. To maintain adequate dialysis, we must redouble our efforts to increase the number of dialysis sessions and extend the duration of dialysis, and also increase the dose of dialysis fluid. Therefore, in recent years, it is called to pay attention to the protection of residual kidney function even after dialysis. The common causes of decline in residual renal function are as follows: (1) Hypertension In addition to systemic hypertension, hypertension also causes high pressure in the glomerulus, which further aggravates the original renal lesion and promotes the deterioration of residual renal function. (2) Inflammation Some synthetic membranes in hemodialysis can promote the production of some substances that promote inflammation and cause damage to residual renal function. (3) Application of nephrotoxic drugs Thinking that with dialysis, give up the kidneys, inappropriate use of nephrotoxic drugs, such as gentamicin, kanamycin, tobramycin, etc., accelerates the decline of renal function. (4) The load of high osmotic pressure of dialysis fluid The fastest decline of residual renal function at the beginning of hemodialysis is probably twice as fast as that of peritoneal dialysis, which is estimated to be related to the osmotic effect of dialysis fluid and more ultrafiltration of water. (5) Etiology of renal disease Diseases that occur in the glomerulus at an early stage develop at an accelerated rate at a later stage, while diseases that occur in the interstitial tubules of the kidney occur at a slower rate of renal function impairment. For the above reasons, even if a patient receives dialysis treatment, it is still necessary to monitor blood pressure changes, actively treat hypertension, and avoid the use of nephrotoxic drugs as much as possible; although the patient has received dialysis treatment, some renal lesions continue to develop, and if treatment for these diseases is abandoned, residual renal function will be lost quickly. Therefore, it is also necessary to actively treat and develop a reasonable dialysis program to avoid the decline of kidney function due to excessive dialysis.