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Sufficient body water and electrolyte homeostasis are essential for healthy physiolog ic functioning. Nurses are key to preventing detecting early, and treating fluid and electrolyte imbalances. Dehydration significantly alters both physical and psychological functioning and older adults are at increased risk. Identifying fluid disorders early can prevent complications and reduce hospital stays. Understanding the mechanisms of fluid homeostasis enables nurses to assess, prevent, and collaborate in managing isotonic, hypertonic, and hypotonic dehydration.
Optimal physiologic function depends on a balance of body water and electrolytes. In periods of health, the volume, concentration, and composition of body fluids are regulated by a combination of renal, metabolic, and neurologic functions. Changes in osmotic gradients, such as a gain or loss of sodium, affect water balance (Sansevero, 1997). Sodium imbalance occurs in response to alterations in water volume. Dehydration develops when water loss exceeds water intake, resulting in a negative balance. A water loss of 1% to 2% impairs cognitive and physical performance, and a loss of 7% can lead to body collapse (Armstrong & Epstein, 1999; Sansevero, 1997). Water and sodium imbalances can be classified as either isotonic, hypertonic, or hypotonic dehydration.
While all adults are at risk for developing dehydration, elders are more vulnerable. Metabolic changes that occur with aging impede homeostatic mechanisms. Further, symptoms of dehydration can be insidious and easily overlooked in postoperative patients or patients receiving enteral nutrition. Chronic physical or mental illness, medications that enhance fluid loss, or selfimposed fluid restriction to manage incontinence all can contribute to dehydration. The classic early signs and symptoms of dehydration may be missing in older adults until the problem is well advanced (Weinberg, Minaker, and Council on Scientific Affairs, 1995). When living in the community, older adults, and especially those who are frail, are at an even higher risk for dehydration because they may go unmonitored by family and professional caregivers for long periods of time.
Since dehydration is a preventable problem, promoting fluid balance, identifying patients at risk, and providing information are effective ways to reduce morbidity and mortality (Sansevero, 1997). Nurses play a key role in the prevention, early detection, and treatment of water and electrolyte imbalances. To improve patients' health, nurses must understand the distribution, composition, and regulation of water and electrolytes;...