Pre-operative administration of fluids.
D000136:Acid-Base Equilibrium; D000368:Aged; D001794:Blood Pressure; D001803:Blood Transfusion; D006439:Hemodynamics; D006801:Humans; D007263:Infusions, Parenteral; D008875:Middle Aged; D011292:Premedication; D011300:Preoperative Care; D014554:Urination; D014690:Venous Pressure