If you have vp shunt do you pee out the fluid?

Sort of : The shunt transfers excess cerebrospinal fluid from the ventricle to the peritoneum where it is absorbed into the body fluids. Eventually excess liquid does become urine, but the vp product has already been intermixed with the rest of your body's production.

Not directly: The fluid is absorbed back into the bloodstream through the peritoneum after a ventriculo-peritoneal shunt. Of course, urine is generated by the blood flow through the kidney.