Med Surg Electrolyte Imbalance Exam
Brunner and Suddarth Review 2025
ECPI University
Med Surg Electrolyte Imbalance Exam – Brunner and
Suddarth Review 2025 | Sodium, Potassium, Calcium, and
Fluid Volume Disorders | ECPI University
, Med surg Brunner and Suddarth – Electrolytes
Hypovolemia
Also known as fluid volume deficit (FVD) entails ECF loss greater than intake of fluid.
Electrolytes and water are losses in the same proportion, ratios are unchanged. Hypovolemia is
not dehydration (loss of water with increased sodium concentration).
Hypovolemia causes
Vomiting, diarrhea, GI suctioning, sweating, decreased intake, or third-space fluid shift. Diabetes
insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage, and coma are also causes.
Body composition
60% of adult weight is fluid; age, gender, and body fat effect fluid %; skeleton least amount of
fluid, muscle and skin the most.
Body compartments - fluid
Intracellular (inside cell) and extracellular (outside cell); extracellular sub divided into
intravascular (inside blood vessels), interstitial (matrix outside cell), transcellular (space just
outside the cell membrane); loss of fluid can disrupt equilibrium between compartments (fluid
shift). Neurologic and circulatory symptoms, physical examination, and lab test can differentiate
what compartment is experiencing fluid loss.
Intracellular fluid
2/3 of body fluid, mostly found in skeletal muscle, high in potassium, magnesium, phosphate and
sulfate, and proteinate (small protein molecules which carry charges)
Extracellular fluid
1/3 of the body, high in sodium, calcium, chloride, bicarbonate, and organic acids, 6L of plasma
and blood cells (RBC, WBC), 12L of interstitial (includes lymph), 1L of trancellular fluids
(cerebrospinal, pericardial, synovial, intraoccular).
Third space fluid shift
Loss of ECF into spaces that do not contribute to ICF ECF equilibrium; signs of shift include:
decrease urine output, increased heart rate, decreased BP, edema, increased weight, I&O
imbalance. Shift takes place with hypocalcemia, decreased iron, liver disease, alcoholism,
hypothyroidism, malabsorption, immobility, burns, and cancer.
Electrolytes
Brunner and Suddarth Review 2025
ECPI University
Med Surg Electrolyte Imbalance Exam – Brunner and
Suddarth Review 2025 | Sodium, Potassium, Calcium, and
Fluid Volume Disorders | ECPI University
, Med surg Brunner and Suddarth – Electrolytes
Hypovolemia
Also known as fluid volume deficit (FVD) entails ECF loss greater than intake of fluid.
Electrolytes and water are losses in the same proportion, ratios are unchanged. Hypovolemia is
not dehydration (loss of water with increased sodium concentration).
Hypovolemia causes
Vomiting, diarrhea, GI suctioning, sweating, decreased intake, or third-space fluid shift. Diabetes
insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage, and coma are also causes.
Body composition
60% of adult weight is fluid; age, gender, and body fat effect fluid %; skeleton least amount of
fluid, muscle and skin the most.
Body compartments - fluid
Intracellular (inside cell) and extracellular (outside cell); extracellular sub divided into
intravascular (inside blood vessels), interstitial (matrix outside cell), transcellular (space just
outside the cell membrane); loss of fluid can disrupt equilibrium between compartments (fluid
shift). Neurologic and circulatory symptoms, physical examination, and lab test can differentiate
what compartment is experiencing fluid loss.
Intracellular fluid
2/3 of body fluid, mostly found in skeletal muscle, high in potassium, magnesium, phosphate and
sulfate, and proteinate (small protein molecules which carry charges)
Extracellular fluid
1/3 of the body, high in sodium, calcium, chloride, bicarbonate, and organic acids, 6L of plasma
and blood cells (RBC, WBC), 12L of interstitial (includes lymph), 1L of trancellular fluids
(cerebrospinal, pericardial, synovial, intraoccular).
Third space fluid shift
Loss of ECF into spaces that do not contribute to ICF ECF equilibrium; signs of shift include:
decrease urine output, increased heart rate, decreased BP, edema, increased weight, I&O
imbalance. Shift takes place with hypocalcemia, decreased iron, liver disease, alcoholism,
hypothyroidism, malabsorption, immobility, burns, and cancer.
Electrolytes
