Jamie,
I agree with the previous poster, shaking is not a good sign. When my dad suddenly had the chills, we took him straight to ER. They could never find the source of infection even after numerous blood draws. They tried several IVATB but dad eventually succumbed on 01/04/08. His postassium levels fluctuated quite a bit as well, necessitating bags and bags of IV K+ infusions. He also became anemic and needed 3 units of whole blood transfusions.
I suggest you get the oncologist involved immediately. Get your parent admitted right away.
Geri