Hemodialysis: What the Treatment Involves
How hemodialysis works, the schedule, vascular access, and the dietary considerations that go with it.
Last updated: 2026-09-24
Hemodialysis uses a machine and a filter (dialyser) to clean the blood. Blood is drawn from the body, passed through the filter where waste and excess fluid are removed, and returned. A typical session lasts about four hours.
Schedule and frequency
Most patients receive hemodialysis three times per week. Some centres offer longer or more frequent sessions, which can provide gentler fluid removal and better clearance for selected patients.
Vascular access
Reliable access to the circulation is essential. The preferred access is a fistula, created surgically by joining an artery to a vein in the arm, because it lasts longer and carries a lower infection risk than a catheter.
Diet and fluids
- Limit salt and fluid to control blood pressure and swelling
- Watch potassium and phosphorus intake
- Maintain adequate protein as advised by a renal dietitian
Frequently asked questions
Why does blood pressure fall during dialysis?
Removing too much fluid too quickly can lower blood pressure. The team adjusts the target dry weight over time to avoid this.
What should I avoid before a session?
Heavy meals and exceeding your fluid allowance. Bring your medicines and a list of questions for the team.