How it happens
Loss of body fluids causes an increase in blood solute concentration (increased osmolality), and serum sodium level rise. In an attempt to regain fluid balance between intracellular fluid and extracellular spaces, water molecule shift out of cells into more concentrated blood. This process, combines with increase water intake and increased water retention in the kidneys, usually restores the body’s fluid volume.
Who
is at risk?
Failure to respond adequately to the thirst stimulus increases the risk for dehydration. Confused, comatose, and bedridden patients are particularly vulnerable, as are infants, who cannot drink fluid on their own and who have immature kidneys that cannot concentrate urine efficiently. Older patients are also prone to dehydration because they have lower body-water content, diminished kidney function, and a reduced ability to sense thirst, so they cannot correct fluid-volume deficits as easily as younger adults. A patient may also become dehydrated if he or she is receiving highly concentrated tube feeding without enough supplemental water.
What
to look for?
As dehydration progresses, watch for changes in mental status. The patient may complain of dizziness, weakness or extreme thirst. He may have a fever (because less fluid is available for perspiration, which lowers body temperature), dry skin, or dry mucous membranes. Skin turgor may be poor. It is because an older patient’s skin may lack elasticity, checking skin turgor may be an unreliable indicator for dehydration.
The
patient’s heart rate may go up, and his or her blood pressure may fall. In
severe cases, seizures and coma may result. Also, urine output may fall because
less fluid is circulating in the body. The patient’s urine will be more
concentrated unless he or she has diabetes insipidus, in which case the urine
will probably be pale and produced in large volume.
How
it is treated?
Treatment for dehydration aims to replace missing fluids. Because a dehydrated patient’s blood is concentrated, avoid hypertonic solutions. If the patient can handle oral fluids, encourage them. However, because the serum sodium level is elevated, make sure the fluids given are salt-free.
A
severely dehydrated patient should receive Intravenous Fluids to replace lost
fluids. Most patients receive hypotonic, low-sodium fluids such as dextrose 5%
in water (D5W). Remember, if you give hypotonic solution too quickly, the fluid
moves from the veins into the cells, causing them to become edematous. Swelling
of cells in the brain can create cerebral edema. To avoid such potentially
devastating problems, give fluids gradually, over a period about 48 hours.
How
you intervene?
Monitor at-risk person closely to detect impending dehydration. If a patient becomes dehydrated, here are some steps you will want to take:
1. Monitor symptoms and vital signs closely so you can intervene quickly.
2. Accurately record the intake and output, including urine and stool
3. Provide a safe environment for any patient who is confused, dizzy, or at risk for a seizure, and teach his family to do the same.
4. Obtain daily weights (same scale, same time of day) to evaluate treatment progress.
5. Provide skin and mouth care to maintain the integrity of the skin surface and oral mucous membranes.
Teaching
Points
When teaching a person with dehydration, be sure to cover the following topics and then evaluate your patient’s learning:
1. Explanation of dehydration and its treatment
2. Warning signs and symptoms
3. Prescribed medications
4. Importance of complying with therapy.
