Is it normal for iv fluids to cause severe bruising and swelling?

No, unless they're running too much heparin..... which would be a problem and hence abnormal. Generally, IV fluids will only cause this if they are not truly IV... meaning that for what ever reason the fluid is NOT going into the vein but is going to the tissues surrounding the vein. As an RN, it would be time for a new IV site if this were to happen.