From Colin Adams, Surgical Nurse:

In the hospital where I work, the following observations are carried out during the transfusion of blood and blood products:

 the temperature, pulse and blood pressure are taken and recorded both before and following the transfusion and at the commencement of each new unit of blood  fifteen minutes into the transfusion the pulse and temperature are taken and recorded  further clinical recordings are taken only if it is felt that signs of an adverse reaction are emerging  subjective observations continue throughout.

We shall look forward to hearing about the outcome of your research.