- Study methods: intervention and comparison - Results: Weight of the oliguria group was well controlled during CVVH process as well as the non-oliguria group (normal), there were 5 groups of patients with hyponatremia, hypernatremia, hypokalemia, hyperkalemia and acidemia with 13.5%, 36.5%, 38.5%, 17.3% and 34.6% consecutively) before CVVH processing but later all were corrected by CVVH.