fluid and electrolytes WEEK 11

What are the two main fluid compartments?

Intracellular fluid (ICF) is inside cells; extracellular fluid (ECF) is outside cells.

What are the three main extracellular fluid spaces?

Interstitial fluid (between cells), intravascular fluid (plasma), and transcellular fluid (specialized spaces).

What is osmosis?

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

What is diffusion?

Movement of particles from an area of higher concentration to lower concentration.

What is an isotonic IV solution and its effect on cells?

Same effective tonicity as plasma; expands ECF without causing significant cell swelling or shrinking.

What are examples of isotonic IV solutions?

0.9% normal saline and lactated Ringer's; commonly used for extracellular fluid replacement.

What is a hypotonic IV solution and its effect on cells?

Lower effective tonicity than plasma; water moves into cells, causing swelling.

What is an example of a hypotonic IV solution?

0.45% normal saline; provides relatively more free water and can increase cellular hydration.

What is a hypertonic IV solution and its effect on cells?

Higher effective tonicity than plasma; draws water out of cells into ECF, causing cells to shrink.

What is an example and clinical use of hypertonic saline?

3% sodium chloride; may treat severe symptomatic hyponatremia or cerebral edema under close monitoring.

Why must hypertonic saline be administered cautiously?

It can cause fluid overload and dangerous sodium shifts; monitor neurological status, sodium, and respiratory status.

What is third spacing?

Fluid becomes trapped outside the circulation and is unavailable for normal physiological processes.

What causes edema?

Altered hydrostatic pressure, oncotic pressure, capillary permeability, or lymphatic drainage.

What is the difference between localized edema and anasarca?

Localized edema affects one area; anasarca is widespread edema associated with cardiac, renal, or liver failure.

What are common causes of fluid volume deficit (hypovolemia)?

Vomiting, diarrhea, hemorrhage, GI suctioning, decreased intake, and fluid shifts.

What are cardiovascular signs of hypovolemia?

Tachycardia, orthostatic hypotension, weak perfusion, and decreased capillary refill.

What are skin and neurological signs of hypovolemia?

Dry mucous membranes, decreased skin turgor, thirst, dizziness, restlessness, and confusion.

What urinary findings suggest hypovolemia?

Decreased urine output and concentrated urine with increased specific gravity.

What laboratory findings may occur with dehydration?

Increased hematocrit and BUN from hemoconcentration; sodium varies with the type of fluid loss.

What is the priority treatment for significant hypovolemia?

Replace fluid and electrolytes; isotonic IV crystalloids are commonly used when IV resuscitation is indicated.

What are common causes of hypervolemia?

Excessive IV fluids, renal dysfunction, heart failure, and abnormal sodium/water retention.

What are the cardiovascular signs of hypervolemia?

Increased BP, bounding pulse, jugular venous distention (JVD), and peripheral edema.

What respiratory findings suggest fluid volume excess?

Dyspnea, crackles, and pulmonary edema; assess oxygenation promptly.

What are common neurological and weight findings in hypervolemia?

Headache, confusion, lethargy, and weight gain.

What are the primary nursing interventions for hypervolemia?

Monitor I&O, daily weights, lung sounds, and electrolytes; administer prescribed diuretics and restrict fluids if ordered.

How should daily weights be obtained accurately?

Same time each day, same scale, and same or similar clothing.

What does a rapid 1 kg weight change usually represent?

Approximately 1 liter of fluid gained or lost, if the change is primarily fluid.

What assessments are essential for fluid balance?

Daily weights, intake/output, vital signs, lung sounds, edema, mucous membranes, and laboratory results.

What is the normal serum sodium range and primary function?

135–145 mEq/L; regulates extracellular fluid balance, blood volume, and nerve function.

What is hyponatremia and its major neurological danger?

Sodium below 135 mEq/L; severe cases can cause cerebral edema, seizures, and coma.

What are common manifestations of hyponatremia?

Headache, confusion, lethargy, weakness, nausea, and potentially seizures.

What nursing interventions are used for hyponatremia?

Monitor sodium and neurological status; fluid restriction or sodium replacement depends on cause and severity.

What is hypernatremia and its neurological manifestations?

Sodium above 145 mEq/L; may cause restlessness, irritability, confusion, seizures, and coma.

What assessment findings suggest hypernatremia?

Intense thirst, dry mucous membranes, restlessness, and altered mental status.

How is hypernatremia generally managed?

Replace water carefully, treat the cause, monitor sodium and neurological status, and avoid overly rapid correction.

What is the normal potassium range and its main function?

3.5–5.0 mEq/L; essential for cardiac conduction and skeletal/smooth muscle contraction.

What are common causes of hypokalemia?

Vomiting, diarrhea, potassium-wasting diuretics such as furosemide, and inadequate intake.

What ECG changes suggest hypokalemia?

Flattened or inverted T waves, ST depression, and prominent U waves.

What clinical manifestations occur with hypokalemia?

Muscle weakness, decreased bowel sounds, constipation, dysrhythmias, and possible respiratory weakness.

What is the priority nursing concern with hypokalemia?

Cardiac dysrhythmias; monitor ECG, serum potassium, and response to replacement.

What are important potassium replacement safety rules?

Never give IV push; use a pump and prescribed rate, monitor IV site, renal function, and urine output.

What dietary foods are high in potassium?

Bananas, oranges, potatoes, tomatoes, spinach, and beans.

What are common causes of hyperkalemia?

Renal failure, potassium-sparing medications, potassium supplements, and tissue breakdown.

What ECG changes are associated with hyperkalemia?

Tall peaked T waves, widening QRS, and potentially life-threatening dysrhythmias.

What clinical manifestations occur with hyperkalemia?

Muscle weakness, paresthesias, diarrhea, and cardiac conduction abnormalities.

What is the priority intervention for severe hyperkalemia?

Cardiac monitoring and urgent prescribed treatment; IV calcium stabilizes the heart, while insulin/glucose shifts K into cells.

What is the normal total calcium range and its main functions?

9–11 mg/dL in the lecture; supports bones, blood clotting, muscle contraction, and nerve function.

What are hallmark manifestations of hypocalcemia?

Tetany, muscle spasms, tingling, hyperactive reflexes, seizures, and possible laryngospasm.

What is Trousseau's sign?

Carpal spasm induced by inflating a blood pressure cuff; suggests hypocalcemia.

What is Chvostek's sign?

Facial twitching when tapping over the facial nerve; may indicate hypocalcemia.

What nursing interventions are important for hypocalcemia?

Seizure precautions, airway assessment, cardiac monitoring when indicated, and prescribed calcium replacement.

What are hallmark manifestations of hypercalcemia?

Muscle weakness, decreased reflexes, constipation, lethargy, nausea, and possible dysrhythmias.

What are common nursing interventions for hypercalcemia?

Monitor cardiac/neurological status, encourage or administer fluids when appropriate, and give prescribed treatment.

What is the normal magnesium range and its main function?

1.5–2.5 mEq/L in the lecture; regulates neuromuscular excitability and supports cardiac function.

What manifestations indicate hypomagnesemia?

Hyperactive DTRs, tremors, muscle twitching, tetany, seizures, and dysrhythmias.

What nursing interventions are used for hypomagnesemia?

Seizure precautions, cardiac monitoring when indicated, and prescribed oral or IV magnesium replacement.

What manifestations indicate hypermagnesemia?

Decreased or absent DTRs, lethargy, hypotension, bradycardia, and respiratory depression.

What is the priority nursing intervention for severe hypermagnesemia?

Support airway and breathing, stop magnesium sources, and administer prescribed IV calcium as an antidote.

What is the normal phosphate range and its main function?

2.4–4.2 mg/dL in the lecture; supports bones, teeth, energy metabolism, and muscle function.

What manifestations indicate hypophosphatemia?

Muscle weakness, respiratory muscle weakness, confusion, reduced cardiac output, and impaired bone mineralization.

What manifestations indicate hyperphosphatemia?

Often hypocalcemia-like symptoms: tetany, muscle spasms, and positive Trousseau's or Chvostek's signs.

What nursing interventions are used for phosphate imbalances?

Monitor phosphate and calcium; provide prescribed replacement for low levels or phosphate restriction/binders for high levels.

What is the relationship between calcium and phosphate?

They often change inversely; elevated phosphate can lower ionized calcium.

What electrolyte should be monitored closely with furosemide?

Potassium; furosemide increases urinary potassium loss and may cause hypokalemia.

What should a nurse teach a patient taking potassium supplements?

Take with food and water as directed, avoid extra potassium unless prescribed, and report weakness or palpitations.

What are the most urgent complications of fluid and electrolyte imbalances?

Life-threatening dysrhythmias, seizures, respiratory failure, pulmonary edema, and impaired tissue perfusion.