Homeostasis: Fluid, Electrolyte, and Acid-Base Balance Flashcards

Comprehensive vocabulary flashcards covering fluid compartments, hormonal regulation, electrolyte imbalances, diuretic types, and acid-base interpretation based on the NUR1211 lecture.

Intracellular space (ICF)

The body fluid compartment consisting of fluid inside the cells.

Extracellular space

The body fluid compartment consisting of intravascular (serum) and interstitial fluid.

Sensible Losses

Measurable fluid losses such as urine ($1,200 \text{--} 1,500\,mL/day$), feces, vomit, perspiration, and wound or tube drainage.

Insensible Losses

Fluid losses that cannot be measured, specifically through respiration and skin evaporation.

Antidiuretic Hormone (ADH)

Hormone released by the posterior pituitary in response to dehydration, stress, or pain that promotes water reabsorption in the kidneys.

Aldosterone

Hormone released from the adrenal cortex in response to hypotension and $Na^+$ loss; it increases sodium and water reabsorption while increasing potassium excretion.

Renin-Angiotensin-Aldosterone System (RAAS)

System activated by decreased blood pressure or renal perfusion resulting in sodium and water retention and vasoconstricton.

Atrial/Brain Natriuretic Peptides (ANP/BNP)

Hormones released by the heart when stretched (due to Heart Failure or Fluid Volume Excess) that promote sodium and water excretion.

Fluid Volume Deficit

A condition characterized by weight loss ($1\,kg$ loss = $1\,L$ fluid loss), thirst, weak/thready pulses, and increased BUN, serum sodium, and hematocrit.

Fluid Volume Excess

A condition characterized by edema, bounding (3+) pulses, JVD, HTN, and pulmonary edema, often resulting in decreased BUN and hematocrit due to hemodilution.

Isotonic fluids

Fluids with a concentration of $270 \text{--} 300\,mOsm/L$ (e.g., $0.9\%\,NaCl$ or Lactated Ringers) where water does not move into or out of cells.

Hypertonic fluids

Fluids with a concentration of $>300\,mOsm/L$ (e.g., $3\%\,NaCl$ or $D10$) that cause water to move out of cells and into the bloodstream.

Hypotonic fluids

Fluids with a concentration of $<270\,mOsm/L$ (e.g., $0.45\%\,NaCl$) that cause water to move from the bloodstream into the cells.

Furosemide

A prototype loop diuretic, known as the strongest diuretic, used for fluid overload and electrolyte excess.

Spironolactone

A potassium-sparing (sodium-sparing) diuretic prototype used to block aldosterone receptors.

Mannitol

An osmotic diuretic prototype used primarily for increased intracranial pressure (ICP).

Hyponatremia

Serum sodium level $<135\,mEq/L$, which can cause brain swelling, headache, confusion, and seizures.

Hypernatremia

Serum sodium level $>145\,mEq/L$, which causes fluid to shift out of cells leading to brain cell shrinkage, restlessness, and agitation.

Hypokalemia

Serum potassium level $<3.5\,mEq/L$, manifesting as ECG changes (prolonged U-wave, flat T-wave), muscle weakness, and constipation.

Hyperkalemia

Serum potassium level $>5.0\,mEq/L$, manifesting as ECG changes (widened QRS, peaked T-wave), bradycardia, and muscle cramps.

Hypocalcemia

Serum calcium level $<8.5\,mEq/L$, associated with tetany, hyperreflexia, and Chvostek's or Trousseau's signs.

Hypercalcemia

Serum calcium level $>10.5\,mEq/L$, which can cause muscle weakness, kidney stones (flank pain), and bone pain.

Hypomagnesemia

Serum magnesium level $<1.5\,mEq/L$, leading to muscle cramps, tremors, and cardiac dysrhythmias.

Hypermagnesemia

Serum magnesium level $>2.5\,mEq/L$, which acts as a sedative causing bradycardia, hypotension, and respiratory depression.

pH

Measure of acidity or alkalinity of blood; normal adult range is $7.35 \text{--} 7.45$.

PaCO2

Pressure of carbon dioxide in the blood managed by the lungs; normal adult range is $35 \text{--} 45\,mmHg$.

HCO3

Bicarbonate level in the blood managed by the kidneys; normal adult range is $22 \text{--} 26\,mEq/L$.

ROME

An acronym for ABG interpretation: Respiratory Opposite (pH and $CO_2$ move in opposite directions) and Metabolic Equal (pH and $HCO_3$ move in the same direction).

Partially compensated (ABG)

An acid-base state where the body is attempting to correct the imbalance, but the blood pH remains abnormal; all three values (pH, $PaCO_2$, and $HCO_3$) are abnormal.

Respiratory Acidosis

Acid-base imbalance caused by hypoventilation ($CO_2$ retention), characterized by increased $PaCO_2$, restlessness, and mental status changes.

Metabolic Acidosis

Acid-base imbalance caused by acid gain or bicarbonate loss, characterized by decreased $HCO_3$, Kussmaul breathing, and hyperkalemia.