How does automated peritoneal dialysis really work?

Automated by 2 ways: Some machines put liquid in the abdomen and pull it out by gravity i.e. The machine is located below the level of the bed on which the patient lies. The other does not use gravity but creates gentle negative pressure to suck the fluid back. You know the rest, the liquid that remained sometime inside the belly comes out with waste removed from the capillary circulation of the peritoneum by osmosis.

Fluid exchange: A catheter is placed through the skin, into the peritoneum (space in the belly) and fluid is put into the belly, through this catheter. The fluid causes the electrolytes and other substances in the blood to diffuse into the fluid. Then, through the same catheter, the fluid is removed. This is cycled over and over, and can be done while you sleep.

Automatic overnight!: I wonder if you are asking about continuous automatic cycling: the kind that is done overnight while you sleep. This is truly amazing, because the machine moves from one bag of dialysis solution to the next - all while you are sleeping. Once it is set up, the whole process is automatic. Of all of the varieties of home dialysis, this is probably the easiest - and least intrusive. LGromkoMD