Fluid/Electrolyte and Acid-Base Imbalances (Video Notes)

A set of vocabulary-style flashcards covering key concepts from the lecture notes on fluid/electrolyte balance and acid-base balance, including compartments, transport mechanisms, common imbalances, their causes, signs, and nursing interventions.

Fluid and Electrolyte Balance

Maintenance of body fluid compartments, electrolyte concentrations, osmolality, and pH within normal ranges to support all body systems.

Intracellular Fluid (ICF)

Two-thirds of total body water located inside cells.

Extracellular Fluid (ECF)

One-third of total body water located outside cells; divided into intravascular, interstitial, and transcellular compartments.

Intravascular Fluid

Fluid within blood vessels (plasma).

Interstitial Fluid

Fluid surrounding cells in the interstitial spaces.

Transcellular Fluid

Specialized fluids such as cerebrospinal, synovial, and pleural fluids.

Osmosis

Movement of water across a semipermeable membrane from lower to higher solute concentration.

Diffusion

Passive movement of solutes from higher to lower concentration.

Filtration

Movement of fluid and solutes across membranes due to pressure differences.

Na+/K+ Pump

Active transport mechanism moving Na+ out and K+ into cells to maintain gradients.

Thirst

Primary regulator of fluid intake.

Minimum Urine Output

400–600 mL per 24 hours to excrete waste products.

Hypovolemia (Dehydration)

Fluid volume deficit from insufficient intake or excessive loss; can be isotonic or real dehydration.

Hypervolemia (Overhydration)

Fluid volume excess from too much fluid intake or impaired excretion.

Hypovolemic Shock

Life-threatening decreased tissue perfusion due to significant fluid loss.

Pulmonary Edema

Fluid overload in the lungs, often from hypervolemia.

Hyponatremia

Serum Na+ < 135 mEq/L; often from water excess or Na+ loss.

Hypernatremia

Serum Na+ > 145 mEq/L; often from water deficit or Na+ gain.

Sodium Imbalance Mnemonic SALT LOSS

Sodium deficit signs: Stupor/coma, Anorexia/nausea, Lethargy, Tendon reflexes decreased, Limp muscles, Orthostatic hypotension, Seizures/headache, Stomach cramping.

Hypernatremia Signs Mnemonic FRIED SALT

F flushed skin; R restlessness; I irritability; E edema; D dehydration; S thirst; A agitation; L low-grade fever; T trouble concentrating.

Sodium Imbalance Treatment (Hyponatremia/Hypernatremia)

Hyponatremia: address fluid status; IV hypertonic fluids cautiously if indicated; restrict fluids; diuretics for hypervolemia. Hypernatremia: restrict Na+, provide hypotonic fluids to dilute Na+, treat underlying cause.

Potassium (K+) Normal Range

3.5–5.0 mEq/L.

Hypokalemia

Potassium < 3.5 mEq/L. Causes include diuretic use, GI losses, diuresis, kidney disease; signs include the 6 L’s: Lethargy, Leg cramps, Limp muscles, Low shallow respirations, Lethal dysrhythmias, Lots of urine.

Hyperkalemia

Potassium > 5.0 mEq/L. Causes include kidney failure, rapid K+ replacement, tissue damage; signs include MURDER: Muscle cramps/weakness, Urine (oliguria/anuria), Respiratory distress, Decreased cardiac contractility, EKG changes, Reflexes decreased.

Potassium Administration Precautions

Potassium must be diluted and never given IV push; monitor ECG; use potassium-wasting diuretics or insulin with glucose to shift K+ intracellularly.

Calcium (Ca2+) Normal Range

9.0–10.5 mg/dL.

Hypocalcemia

Ca2+ < 9.0 mg/dL. Signs mnemonic CATS GO NUMB: Convulsions, Arrhythmias, Tetany, Stridor/spasms, Numbness; Positive Chvostek’s and Trousseau’s signs.

Hypercalcemia

Ca2+ > 11.0 mg/dL. Signs mnemonic BACKME: Bone pain, Arrhythmias, Cardiac arrest, Kidney stones, Muscle weakness, Excessive urination.

Magnesium (Mg2+) Normal Range

1.5–2.5 mg/dL.

Hypomagnesemia

Mg2+ < 1.5 mg/dL. Causes include malnutrition, GI losses, diuretics, alcoholism; signs: irritability, tremors, confusion, tetany, seizures; positive Trousseau’s/Chvostek’s signs.

Hypermagnesemia

Mg2+ > 2.5 mg/dL. Signs: drowsiness, hypotension, bradycardia, hyporeflexia, shallow respirations; treatment includes diuretics, calcium gluconate, dialysis.

Acid-Base Balance

Regulation of body pH within 7.35–7.45 by buffers, lungs, and kidneys.

Acid and Base (Definitions)

Acid: substance that releases H+. Base: substance that binds H+. Buffers: systems that prevent large pH changes.

Cellular Buffers

Immediate buffers (proteins, hemoglobin, bicarbonate, phosphates) that neutralize acids/bases.

Lungs as Buffer (Respiratory)

Second line of defense; regulate CO2; hyperventilate to blow off CO2 or hypoventilate to retain CO2.

Kidneys as Buffer (Renal)

Slowest to respond (24–48 h) but provide long-term pH regulation by bicarbonate handling and acid/base excretion.

ABG Interpretation Rule (ROME)

R: Respiratory changes move pH and CO2 in opposite directions; O: opposite. M: Metabolic changes move pH and HCO3- in the same direction; E: Equal.

Respiratory Acidosis ABG Pattern

pH < 7.35, PaCO2 > 45 mmHg; HCO3- normal or compensated; cause: hypoventilation.

Respiratory Alkalosis ABG Pattern

pH > 7.45, PaCO2 < 35 mmHg; HCO3- normal or compensated; cause: hyperventilation.

Metabolic Acidosis ABG Pattern

pH < 7.35, HCO3- < 22 mEq/L; PaCO2 normal or compensated; causes include DKA, kidney failure, severe diarrhea.

Metabolic Alkalosis ABG Pattern

pH > 7.45, HCO3- > 26 mEq/L; PaCO2 normal or compensated; causes include vomiting, diuretic use, antacid excess.

Dehydration Labs (Hypovolemia)

Increased hematocrit and BUN; urine specific gravity >1.030; serum Na+ >145; osmolality >295 mOsm/kg.

Overhydration Labs (Hypervolemia)

Decreased Hgb/Hct, BUN, osmolality; urine specific gravity <1.003; possible weight gain and edema.

Fluid Gain/Loss Assessment Basics

Monitor vital signs, I&O, daily weights, mental status, and edema; assess for orthostatic changes and skin turgor.

Nursing Interventions: Dehydration

Provide oral/IV rehydration, monitor I&O and VS, gradual position changes, safety precautions, and oxygen if needed.

Nursing Interventions: Fluid Overload

Fluid/sodium restriction, high-Fowler or semi-Fowler position, diuretics, oxygen therapy, monitor for edema and respiratory status.

Common Signs of Fluid Imbalance (General)

Altered mental status, dizziness, tachycardia or bradycardia, hypotension or hypertension, edema or dry mucous membranes depending on deficit or excess.

Sodium-Potassium Relationship

Sodium and water balance are closely linked; sodium losses or gains influence water movement and osmolality.

Advisable ABG Management Actions

For acidosis/alkalosis, monitor ABGs, support airway, administer appropriate medications (e.g., bicarbonate for metabolic acidosis, bronchodilators for respiratory acidosis), and correct underlying cause.