Fluid balance in elderly patients following acute stroke.

We studied the relationship between plasma osmolality, arginine vasopressin (AVP), and fluid input in patients during the acute phase of a first stroke. Fifteen consecutive patients were studied (median age 79) and their blood sampled on days 0, 1, 2, 3, 7 and 14. Plasma osmolality was related to fluid input over days 0-3 (p = 0.0013) and AVP over 14 days (p less than 0.001). Patients with a poor outcome had higher AVP concentrations (p = 0.02). Those on intravenous fluids received a higher volume (p less than 0.01) and had a lower plasma osmolality (p = 0.04). The results of this preliminary study indicate that a standard regime for fluid input is inappropriate.