If your patient develops end-stage renal disease, she may require hemodialysis or peritoneal dialysis to prolong her life. The physician probably won’t recommend dialysis until your patient’s serum creatinine level is about 6 mg/dl.

Hemodialysis

For hemodialysis, the surgeon creates an arteriovenous (AV) access site, usually in the patient’s arm, as shown. With each hemodialysis treatment, a needle is inserted into this AV access site. Blood is withdrawn through the arterial line and pumped through a semipermeable membrane in the hemodialysis machine. As the blood is pumped, dialysate moves through the membrane in the opposite direction, allowing body wastes to move by diffusion from an area of high concentration to an area of low concentration.

The pores in the membrane allow electrolytes, blood urea nitrogen, and creatinine to be filtered out, but they prevent larger particles such as blood cells and protein from passing through. The filtered blood is then returned to the patient through the venous line.

Hemodialysis can be performed in your patient’s home or in a medical facility. Treatments average 3 to 4 hours, three times each week.

Peritoneal Dialysis

In this closed-drainage procedure, a catheter is placed through an opening in the abdominal wall. At regular intervals, dialysate is instilled into the peritoneal cavity. Through osmosis and diffusion, fluid, electrolytes, and waste products are drawn from the blood, across the peritoneum, and into the dialysate. The peritoneum, which lines the peritoneal cavity, acts as a semipermeable membrane. The dialysate is drained regularly and replaced.

Most patients tolerate peritoneal dialysis better than hemodialysis. The patient’s blood pressure usually remains stable, and she experiences less cardiovascular stress and better control of her blood glucose levels. She’ll also have a decreased risk of retinal hemorrhage because she won’t need the higher doses of heparin that are used with hemodialysis. However, peritoneal dialysis places the patient at higher risk for developing an infection, such as peritonitis.