Dehydration (fluid volume deficit)
Fluid volume deficit occurs from the loss of body fluids. This occurs more rapidly when coupled with decreased fluid intake and can also occur after a prolonged period of inadequate intake. Dehydration or fluid volume deficit can be mild moderate or severe.
Cause: Causes of Dehydration include abnormal fluid losses such as those resulting from vomiting, diarrhea, GI suctioning, and sweating, decreased intake (because of nausea), or lack of access to fluids, third space shifts or fluids moving from the vascular system to other body spaces (edema with burns, acites with liver dysfunction) Diabetes insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage and coma can also cause fluid volume deficit.
Signs and Symptoms:
- Acute weight loss
- Decreased skin turgor
- Oliguria
- Concentrated urine
- Orthostatic hypotension (due to volume depletion)
- Weak, rapid heart rate.
- Flattened neck veins
- Increased temperature
- Thirst
- Delayed or decreased capillary refill
- Decreased CVP
- Cool, clammy pale skin (r/t peripheral vasoconstriction)
- Anorexia,
- Nausea
- Lassitude (listlessness, debility or weariness)
- Muscle weakness and cramps
Medical treatment: Correction of fluid loss. Oral route is preferred if deficit is not severe and patient can drink. An IV is required for moderate to severe fluid volume deficit. An isotonic solution (Lactated Ringers or 0.9% normal saline) can be used to treat a hypotensive patient to expand plasma volume. As soon as the patient becomes normotensive a hypotonic solution (0.45% sodium chloride) can be administered. Accurate assessments of I&O’s, weight and vital signs, LOC, breath sounds, skin color should be performed to determine when therapy should be slowed to avoid fluid volume overload. If the patient is oliguric the cause must be determined. It may be depressed renal function related to reduced renal blood flow or acute tubular necrosis from the prolonged volume deficit. To determine this, a fluid challenge is used. In this test specific volumes (100-200ml ) of fluid are administered at specific times and the patient’s hemodynamic response is monitored.
