When the kidneys can no longer clear waste and fluid, hemodialysis does part of that work. It is not a cure and it is not a full replacement — but it keeps people alive, often for many years, and many of them work, travel, and live well.
When it starts
Usually when the eGFR is somewhere between 5 and 10, and when symptoms appear: nausea, fatigue that does not lift, swelling, breathlessness, confusion. The number alone does not decide it. How you feel does.
We do not wait for a crisis. The patients who do worst are the ones who arrive at an emergency room in fluid overload and start dialysis through a catheter placed in the neck that afternoon.
How it works
Blood is drawn from your body through a vascular access, pumped through a filter, and returned. The filter removes urea, potassium, phosphate, and excess fluid.
Most patients come to a center three times a week for about four hours. Some do shorter, more frequent treatments at home, which are gentler on the heart and generally leave people feeling better between sessions.
Your access, and why it matters so much
This is the part that determines how well your years on dialysis go, and it is the part patients hear about too late.
An arteriovenous fistula — an artery joined to a vein in your arm — is the best access there is. It lasts longest, clots least, and infects least. It also takes three to six months to mature before it can be used.
A graft is a synthetic tube between artery and vein. Usable sooner. Fails sooner.
A catheter in a large central vein works immediately and is the worst option by a wide margin. Infection rates are high. Clotting is common. Every month on a catheter carries risk that a fistula would not.
The entire argument for planning ahead comes down to this: a fistula placed six months before you need it means you never require a catheter.
What dialysis does not replace
The kidney is not only a filter. It makes erythropoietin, activates vitamin D, and regulates blood pressure and acid balance. Dialysis does none of that.
So you will still need treatment for anemia, for bone and mineral disease, for blood pressure. Diet still matters — potassium, phosphorus, and fluid all require attention. This is why dialysis is managed by a nephrologist and not simply administered by a machine.
Transplant
For most patients who are candidates, a transplant offers more years and better ones. You can be evaluated and listed before dialysis ever begins.
Starting dialysis does not close that door. But time on dialysis is itself a risk factor for how a graft performs afterward, which is a reason to have the conversation early rather than late.