Final answer:
Continuous venovenous hemodialysis (CVVHD) is a form of dialysis used to remove waste products and excess water from the blood by adding dialysate. It works by allowing waste products like urea to pass through a semi-permeable membrane while retaining larger molecules, with ultrafiltration removing excess water. CVVHD is essential for patients with severe kidney dysfunction, either as a temporary solution or a life-long necessity.
Step-by-step explanation:
Continuous Venovenous Hemodialysis (CVVHD):Continuous venovenous hemodialysis is used to remove plasma water and solutes by adding dialysate. This medical procedure is essential for patients with kidney failure, where the kidneys can no longer filter waste products effectively. In CVVHD, the patient’s blood flows through tubes made of a semi-permeable membrane, such as cellophane. This membrane allows waste products like urea to pass through while retaining larger molecules like proteins and blood cells. The dialysate in the system has a composition that encourages diffusion of wastes from the blood into the dialysate, thus purifying the blood before it is returned to the body.
Dialysis machines feature a compartment separation where the blood and the dialysate are on opposite sides of the semi-permeable membrane. The concentration of solutes is lower in the fresh dialysate, promoting diffusion of waste products from the blood into the dialysate. The semi-permeable membrane is permeable to small waste molecules such as urea and impermeable to larger molecules such as red blood cells. The process of dialysis also includes ultrafiltration, which removes excess water from the blood.For patients with severe kidney dysfunction, CVVHD is a vital and life-supporting procedure. It may be used as an interim solution while the patient is waiting for a kidney transplant or as a lifelong therapy in cases where transplantation is not an option.