F+E: Fluid Volume Deficit or Hypovolemia

FVD, or hypovolemia, occurs when

loss of ECF volume exceeds the intake of fluid.

What causes fluid volume deficit (FVD), and when does it occur more rapidly?

results from loss of body fluids and occurs more rapidly when coupled with decreased fluid intake.

Causes of FVD include:

abnormal fluid losses, such as those resulting from vomiting, diarrhea, GI suctioning, and sweating; decreased intake (as in nausea or lack of access to fluids) and third-space fluid shifts, or the movement of fluid from the vascular system to other body spaces

Additional causes include diabetes insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage, and coma

How quickly can fluid volume deficit (FVD) develop, and what determines its severity?

FVD can develop rapidly, and its severity depends on the degree of fluid loss.

Signs/Symptoms of FVD

Acute weight loss, ↓ skin turgor, oliguria, concentrated urine, capillary filling time prolonged, low CVP, ↓ BP, flattened neck veins, dizziness, weakness, thirst and confusion, ↑ pulse, muscle cramps, sunken eyes, nausea, increased temperature; cool, clammy, pale skin

Laboratory Findings of FVD

↑ hemoglobin and hematocrit, ↑ serum and urine osmolality and specific gravity, ↓ urine sodium, ↑ BUN and creatinine, ↑ urine specific gravity and osmolality

What is oliguria, and is it always present in hypovolemia?

Oliguria is the excretion of less than 400 mL of urine per day in adults, and it may or may not be present in hypovolemia.

How does urine specific gravity change during fluid volume deficit?

It changes in relation to the kidneys’ attempt to conserve water.

What happens to urine and urine specific gravity if the kidneys do not reabsorb water?

Urine contains more water, and urine specific gravity is low.

What happens to urine and urine specific gravity if the kidneys reabsorb water?

Urine becomes concentrated, and urine specific gravity increases.

How does diabetes insipidus affect urine water content and urine specific gravity?

Due to lack of ADH, urine water content increases, which decreases urine specific gravity.

What role does aldosterone play when fluid volume is low?

It causes reabsorption of sodium and chloride, resulting in decreased urinary sodium and chloride.

When is the oral route preferred for fluid replacement?

If the fluid deficit is not severe and the patient is able to drink

When is the IV route required for fluid replacement?

When fluid losses are acute or severe.

What type of fluid is often first-line for treating a hypotensive patient with fluid volume deficit (FVD), and why?

Isotonic electrolyte crystalloid solutions (e.g., lactated Ringer’s or 0.9% sodium chloride) because they expand plasma volume.

Nursing management for FVD?

I&O’s, check labs (electrolytes, CBC, urine specific gravity), assess for hypotension and weak pulses, assess respiratory system and tissue perfusion, check orientation, vision, hearing, reflexes, and muscle strength, monitor weight, check for skin breakdown 

How does body weight change relate to fluid loss or gain?

An acute loss of 0.5 kg (1.1 lb) represents ~500 mL of fluid loss. One liter of fluid weighs ~1 kg (2.2 lb), so a daily weight change of 1–2 lb is mainly due to water loss or gain.

What does a urine specific gravity greater than 1.020 indicate in a volume-depleted patient?

It indicates healthy renal conservation of fluid.

What does dark amber-colored urine indicate?

It indicates that the urine is highly concentrated.

What does clear yellow urine indicate?

It indicates that the urine is dilute.

How can a nurse help prevent fluid volume deficit (FVD)?

By identifying patients at risk and taking measures to minimize fluid losses.

Why are oral fluids given to correct FVD, and what should be considered?

They are given to help correct FVD, with consideration of the patient’s likes and dislikes.

What oral rehydration solutions may be offered to a patient, and why?

Small volumes of solutions like Rehydralyte, Elete, or Cytomax, because they provide fluid, glucose, and electrolytes in concentrations that are easily absorbed.