Advice please, I am scared for my Pogo

[Cdeleon0401]

My 14 yr old chihuahua Pogo was diagnosed with CHF 3 years ago.  He was in bad shape when we got him to a specialist. He was put on a cocktail Vetmedin, sildenifil, furosimide and benzipril. Almost 3 years to the day with absolutely no episodes he had a seizure. Took him in to get checked out and we find out he now has kidney disease.  His BUN was maybe 40 or so, the vet choose to treat the heart rather than the kidney by upping the dosage of the first 3 meds mentioned above from 1x a day to 2x a day. 3 weeks later BUN 140's . Now we are being told no more furosimite and no more benzapril. Vetmedin 3x a day and sildenifil 2x a day.  We are starting subcontanious fluids 300 cc for 3 days then checking labs again. I'm scared. He seemed to respond well to the first session today. He drank water and ate with enthusiasm.  I just Don't know what to expect. We changed his diet as soon as we heard kidney disease.  He is on a home cooked diet low phos. Any advice on the subcontanious fluids therapy?