Administration of liquids to a patient by any route to correct volume and electrolyte deficits. The deficit may be physiological, as when a ballplayer sweats excessively without rehydrating on a hot day. It may be pathological, as in traumatic or septic shock, acute respiratory distress syndrome, severe vomiting or diarrhea or both. It may be metabolic, as in diabetic ketosis or adrenal insufficiency. See: intravenous infusion
for illus; central venous catheter
; central line
; intravenous infusion
; oral rehydration therapy
The goal of fluid replacement is to correct electrolyte, fluid, and acid-base imbalances. The oral route of replacement is used if possible. The intravenous, intraperitoneal, or subcutaneous routes are also used, with the intravenous route being used most frequently. Fluids may be isotonic, hypotonic, or hypertonic; may contain certain crystalloids (e.g., sodium, potassium, chloride, or calcium); or may contain osmotically active substances (e.g., glucose, protein, starch, or a synthetic plasma volume expander such as dextran or hetastarch). The composition, rate of administration, and route depend on the clinical condition being treated.
A critically ill patient receiving fluid replacement should be monitored frequently to be certain that fluid overload is prevented and that the solution is flowing and not extravasating. This is esp. important in treating infants, small children, and the elderly.