Darknights

Hi, We frequently have extremely elderly patients with heart failure and multiple co-morbidities who require blood transfusions. The physician wants the 350ml Packed Cells administered over an hour and doesn't provide an order for frusemide. Is this volume enough to overload an already compromised patient? IF so, what is your standard over in the U.S for duration of transfusion of Packed Cells for such patients. And, I'd be extremely grateful if someone could tell me why vaccines, heparin, Enoxaparin etc are given via DEEP subcutaneous injection. I can't find the rationale for it to be deep, less pain receptors in the deep tissue????