An 82-year-old woman was brought to the emergency department by her granddaughter.She is a widow and lives alone,although her granddaughter checks on her daily.She has been vomiting for 2 days and has not been able to eat or drink anything during this time.She has not urinated for 12 hours.Physical examination reveals the following: T = 99.6°F (37.6°C) orally; P = 110 beats/min,weak and thready; BP = 80/52 mm Hg.Her skin and mucous membranes are dry,and there is decreased skin turgor.The patient states that she feels very weak.The following are her laboratory results:
Sodium 138mEq/L
Potassium 3.7 mEQ/L
Calcium 9.2mg/dL
Magnesium 1.8 mg/dL,
Chloride 99mEq/L
BUN 29 mg/dL
The nurse recognizes that the patient is displaying symptoms associated with which of the following?

A) Hypovolemia
B) Hypervolemia
C) Hypernatremia
D) Hyponatremia

Hypovolemia may occur as a result of insufficient intake of fluid; bleeding; excessive loss through urine,skin,or the gastrointestinal tract; insensible losses; or loss of fluid into a third space.The first symptom of hypovolemia is thirst.Other symptoms are a rapid,weak pulse,a low blood pressure (although initially the blood pressure may rise),dry skin and mucous membranes,decreased skin turgor,and decreased urine output.Temperature increases because the body is less able to cool itself through perspiration.The person with fluid volume deficit usually has elevated BUN (blood urea nitrogen)and hematocrit levels.Hypervolemia involves excessive retention of sodium and water in the extracellular fluid,and the vital sign changes are opposite those of a patient with hypovolemia.Hypernatremia and hyponatremia are not applicable because the patient's sodium level is within normal range.