Thanks for the query.
1) Patients on dialysis
do not pass adequate volume of urine. Therefore the excess fluids are removed or as you call "drained" on dialysis. Thus it is an essential part of dialysis; anywhere from 500ml to 4L of fluid may be removed as per the nephrologists' discretion.
2) Espogen is used to increase hemoglobin
. Once Hgb is >10gm/dl the dose may be reduced or stopped altogether.
Hope this helps.