The Absorption Rate of Subcutaneous Infused Fluid

Patients will twice receive a subcutaneous infusion of 250 ml isotonic sodium chloride (NaCl) with 30 MBq Tc-99m pertechnetate mixed in. The patients will receive the first infusion during admission to our geriatric ward (when they are acutely ill) and the second infusion approximately 8 weeks after discharge when they are no longer acutely ill. The subcutaneous access will be placed on the abdomen in the lower left or right quadrant.