In peritoneal dialysis, waste removal occurs primarily through which mechanisms across the peritoneal membrane?

In peritoneal dialysis, waste removal occurs primarily through which mechanisms across the peritoneal membrane?

• A. Diffusion and osmosis
• B. Active transport
• C. Filtration by hydrostatic pressure
• D. Hemofiltration

Answer: (A)

Waste removal in peritoneal dialysis relies on two passive processes across the peritoneal membrane: diffusion of small solutes and osmosis-driven ultrafiltration of water. The peritoneal membrane acts as a semipermeable barrier between blood in the capillaries and the dialysate inside the abdomen. Small waste molecules such as urea, creatinine, and electrolytes diffuse from higher concentration in the blood to lower concentration in the dialysate, moving along their concentration gradients. At the same time, the dialysate often contains glucose, creating an osmotic gradient. Water moves from the blood across the membrane into the dialysate to balance this gradient, producing ultrafiltration and removing excess fluid. No energy-dependent transport is involved, and this mechanism is distinct from active transport or convection-based processes seen in other dialysis modalities. Filtration by hydrostatic pressure plays a role, but diffusion and osmosis are the primary drivers in peritoneal dialysis.

Waste removal in peritoneal dialysis relies on two passive processes across the peritoneal membrane: diffusion of small solutes and osmosis-driven ultrafiltration of water. The peritoneal membrane acts as a semipermeable barrier between blood in the capillaries and the dialysate inside the abdomen. Small waste molecules such as urea, creatinine, and electrolytes diffuse from higher concentration in the blood to lower concentration in the dialysate, moving along their concentration gradients. At the same time, the dialysate often contains glucose, creating an osmotic gradient. Water moves from the blood across the membrane into the dialysate to balance this gradient, producing ultrafiltration and removing excess fluid. No energy-dependent transport is involved, and this mechanism is distinct from active transport or convection-based processes seen in other dialysis modalities. Filtration by hydrostatic pressure plays a role, but diffusion and osmosis are the primary drivers in peritoneal dialysis.