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Introduction
The human body relies on being adequately hydrated to facilitate the effective functioning of organs and to maintain homeostasis. Problems with hydration occur when the body's compensating mechanisms are unable to maintain physiologic homeostasis. Most people are unaware of the adjustments the body makes to maintain these balances. However, when these adjustments fail, a person may experience unpleasant sensations, the severity of which depends on the seriousness of the imbalance.
An older adult's ability to maintain adequate hydration differs to that of a younger adult or child. Many factors contribute to poor hydration and these are discussed in this paper. The paper also outlines risk factors for dehydration; nursing assessments to identify dehydration; and management strategies for an older adult who is dehydrated. In this paper, an older adult is defined as a person aged 70 years and over.
Dehydration
Dehydration is not specific to ageing, but it is more prevalent among people who are older.1
In healthy adults, total body water is approximately 60% of total body weight, but this figure changes as we age.2
A reduction in muscle mass and an increase in fat storage means the total body water percentage is lower in an older adult, putting them at higher risk of becoming dehydrated.
A simple definition of dehydration (supported by the literature) is: 'a decrease in fluid intake and/or an increase in fluid loss'.3 Weinberg and Minaker define dehydration as 'the rapid water loss of greater than 3% of body weight'.4
Dehydration is an appropriate term to describe a water deficit, but dehydration is also commonly used to indicate both sodium and water loss.
Individuals who are diagnosed as dehydrated should have the cause identified as isotonic, hypotonie or hypertonic in origin. Isotonic occurs when there is a balanced loss of sodium and water. Hypotonie relates to a greater loss of sodium than water causing a decrease of in serum sodium levels to below 135mmol/l_. Hypertonic, often termed hypernatraemia, is the excessive loss of water and a resultant serum sodium level above 145mmol/L.
AssRSsmp
To accurately identify a dehydrated older adult, a comprehensive nursing history must be undertaken; clinical data should be gathered; a physical assessment performed; and a review of laboratory results to evaluate fluid and electrolyte levels.
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