Chapter 10: Fluid & Electrolytes Vocabulary Study Guide

Vocabulary-style flashcards covering core concepts, laboratory normal ranges, fluid volume imbalances, electrolyte disorders, acid-base rules, and parenteral therapy from Chapter 10.

Diffusion

The movement of solutes from an area of higher concentration to an area of lower concentration.

Osmosis

The movement of water across a semipermeable membrane toward the side with the higher solute concentration.

Filtration

The movement of water and dissolved substances driven by hydrostatic pressure.

Active Transport

An energy-dependent movement of molecules across cell membranes, exemplified by the sodium-potassium pump.

Normal Serum Sodium Range

$$135-145\,\text{mEq/L}$$

Normal Serum Potassium Range

$$3.5-5.0\,\text{mEq/L}$$

Normal Total Calcium Range

$$\approx 8.6-10.2\,\text{mg/dL}$$

Normal Serum Magnesium Range

$$\approx 1.7-2.6\,\text{mg/dL}$$

Normal Serum Phosphorus Range

$$\approx 2.5-4.5\,\text{mg/dL}$$

Normal Serum Chloride Range

$$\approx 96-106\,\text{mEq/L}$$

Normal Arterial pH Range

$$7.35-7.45$$

Normal PaCO2 Range

$$35-45\,\text{mm Hg}$$

Normal HCO3- Range

$$22-26\,\text{mEq/L}$$

Fluid Volume Deficit (Hypovolemia)

A loss of extracellular fluid in excess of intake where water and sodium are lost together.

Fluid Volume Excess (Hypervolemia)

An expansion of extracellular fluid resulting from sodium and water retention.

Hyponatremia

A low serum sodium level ($<135\,\text{mEq/L}$), usually reflecting excess water relative to sodium and causing cellular swelling, especially in brain cells.

Hypernatremia

A high serum sodium level ($>145\,\text{mEq/L}$) caused by water deficit relative to sodium or excessive sodium gain, leading to cellular dehydration.

Hypokalemia

A potassium deficit ($<3.5\,\text{mEq/L}$) from true loss or shift into cells, altering membrane potential and leading to muscle weakness, GI ileus, and flattened T waves or U waves on ECG.

Hyperkalemia

An excess serum potassium level ($>5.0\,\text{mEq/L}$) that alters excitability and can cause tall peaked T waves, widened QRS, and lethal cardiac dysrhythmias.

Tolvaptan

An oral vasopressin-receptor antagonist used in selected euvolemic or hypervolemic hyponatremia that blocks vasopressin to promote free-water excretion.

Calcium Gluconate

An IV therapy used for severe hypocalcemia, severe hypermagnesemia, or to protect the myocardium by stabilizing cell membranes in severe hyperkalemia without lowering serum potassium.

Hypocalcemia

A low total or ionized calcium level that increases neuromuscular excitability, manifesting as numbness, tingling, tetany, hyperreflexia, and positive Chvostek or Trousseau signs.

Hypercalcemia

An elevated serum calcium level commonly linked to hyperparathyroidism or malignancy that decreases neuromuscular excitability, causing weakness, constipation, and confusion.

Hypomagnesemia

A low serum magnesium level that increases neuromuscular and cardiac excitability, manifesting as tremors, hyperreflexia, tetany, and potential ventricular dysrhythmias.

Hypermagnesemia

An elevated serum magnesium level that depresses neuromuscular transmission and cardiac conduction, causing hyporeflexia, hypotension, bradycardia, and respiratory depression.

Hypophosphatemia

An abnormally low serum phosphorus level that impairs ATP production, causing profound muscle weakness, respiratory failure, and neurologic changes.

Hyperphosphatemia

An elevated serum phosphorus level commonly associated with kidney dysfunction that often lowers ionized calcium and mimics hypocalcemic symptoms.

ROME Acronym

A memory tool for acid-base interpretation where Respiratory is Opposite (pH and PaCO2 move in opposite directions) and Metabolic is Equal (pH and HCO3- move in the same direction).

Isotonic IV Solutions

Solutions such as $0.9\%$ sodium chloride and Lactated Ringer's that expand extracellular fluid volume without causing major fluid shifts into or out of cells.

Hypotonic IV Solutions

Solutions such as $0.45\%$ sodium chloride that supply free water to move fluid into cells.

Hypertonic IV Solutions

Solutions such as $3\%$ sodium chloride that pull water out of cells and into the extracellular fluid compartment.