Some interactions between gastrointestinal function and fluid and electrolyte homeostasis.

Purpose Of Review: The gastrointestinal tract plays an important role in the maintenance of fluid and electrolyte balance, and its diseases cause disturbances in that balance. Conversely, fluid and electrolyte disorders may disturb gastrointestinal function. The purpose of this review is to highlight some recent literature describing these interactions against a background of fluid and electrolyte physiology in normal and disease states.

Recent Findings: Gastrointestinal disease is the most common cause of fluid and electrolyte disturbance, and this can usually be corrected by the oral route, although parenteral replacement is sometimes required. The use of self-administered subcutaneous fluid and electrolyte administration at home is described. Reduced microcirculatory perfusion as a result of hypovolaemia or a rise in blood viscosity after packed cell transfusion may precipitate gut necrosis, particularly during enteral feeding. Positive salt and water balance postoperatively of as little as 3 l impairs gastrointestinal function and increases complications. Other states of salt and water retention may have similar effects, although further research is needed to define this.

Summary: The role of the gastrointestinal tract in controlling fluid and electrolyte balance is underestimated. Conversely, the effect of fluid and electrolyte imbalance on gastrointestinal function is apparent, but requires more research.