126

Part II Nutrition Assessment, Consequences, and Implications

10 to 20 beats/min above baseline with a change in position.

The dilemma with using either the CMS criteria or the AMDA guidelines is that by the time these nonspecific signs and symptoms appear, an older person is already dehydrated. Because older adults develop dehydration readily and are slow to respond to therapy, it is vital to not wait for signs and symptoms to appear but to act as soon as conditions associated with increased fluid need or loss are recognized.

Signs and Symptoms of Dehydration When systems are disturbed due to fluid loss, there are several common symptoms shared by most bodies, but there may also be unusual or unexpected responses, depending on the person. The health care professional must remember that symptoms of dehydration will differ from person to person because the body is a complex network of systems and everyone’s body is different. At 5% total fluid loss, the body may exhibit the following symptoms:

● ● ● ● ● ●

increased heartbeat increased respiration decreased sweating decreased urination

increased body temperature extreme fatigue ● muscle cramps headaches nausea

● ● ● tingling of the limbs

At 10% total fluid loss, the symptoms become even more critical:

● muscle spasms vomiting

● ● ●

racing pulse shriveled skin

● dim vision ●

● ● ●

painful urination confusion

difficulty breathing seizures

● chest and abdominal pain unconsciousness

●

Be aware that these are not the only symptoms of severe dehydration that may manifest; these are simply

the most common, and in some older adults, there may be no symptoms at all.

The body can compensate by shifting water from cells into the blood vessels if intravascular water is lost; yet this is a very short-term solution. Dehydration will occur quickly if the water is not replenished. Age plays a part in the manifestation of symptoms. Signs of dehydration in a child will not be the same as those experienced by an active adult or by the older adult. It is important to use critical thinking when examining the clinical picture of the older adult.

Water, Body Weight, and

Electrolyte Balances Most total body weight is from water. Water makes up approximately 60% of the male body mass but only 50% of the female body mass. Water makes up 75% of muscle mass, but only 25% of fat mass; therefore, the higher a person’s body fat percentage is, the lower their water percentage will be (39). “A loss of body water equivalent to about 1% of body weight is normally compensated within 24 hours. Thirst stimulates drink- ing, so intake is increased.” There may also be a reduc- tion in water loss by the kidneys. If losses are greater than 1% of body weight, “reductions in physical and cognitive performance may occur, and there may be some impairment of thermoregulation and cardiovascu- lar function” (20).

Assessment of Electrolyte Levels Most of the water in the body is found within the cells (intracellular space). The rest is found in the extracellu- lar space, which consists of the blood vessels (intravas- cular space) and the spaces between the cells (interstitial space). As noted earlier, extracellular fluid travels easily between the two spaces, regulated by blood pressure and colloid osmotic pressure. “Sodium, the major extracellular ion, is the primary [osmotic par- ticle] maintaining total-body water volume and the ratio between extracellular and intracellular fluid volume” (26). Water balance is judged by the clinical assessment of extracellular fluid volume, which is much more sub- jective than the measure of serum sodium concentra- tion (6). Laboratory evaluation is the clinical gold standard for both diagnosing dehydration and monitor- ing hydration (15). If dehydration is suspected, the AMDA guidelines suggest that, at minimum, BUN, serum bicarbonate, creatinine (Cr), glucose, and sodium should be obtained (2).

The health care professional must be cautious when using the BUN:Cr ratio to assess hydration since this ratio is less useful in older adults due to the high