fluid, electrolyte, and acid base

What are electrolytes?

Minerals in the body that conduct electricity.

Where are electrolytes found?

Urine, blood, tissues, and other body fluids.

Examples of electrolytes

Potassium (K+), Sodium (Na+), Calcium (Ca2+), Magnesium (Mg2+).

Electrolytes can also be obtained from

Food, drinks, and supplements.

What do electrolytes help regulate?

Water balance, pH, nutrient transport, waste removal, and muscle, heart, nerve, and brain function.

What is dehydration?

A loss of body water when fluid intake does not replace fluid loss.

What stimulates thirst?

Nerve centers in the brain when the body needs water.

What hormone conserves water?

Vasopressin (ADH).

What does ADH do?

Signals the kidneys to excrete less urine to conserve water.

Common causes of electrolyte imbalance

Dehydration, overhydration, medications, heart disease, kidney disease, liver disease, incorrect IV fluids/feedings.

Normal potassium level

3.5–5.1 mEq/L.

Normal sodium level

135–145 mEq/L.

Normal calcium level

8.5–10.5 mg/dL.

Normal magnesium level

1.8–2.2 mg/dL.

Main function of potassium

Supports nerve function, muscle function, and heart muscle activity.

Low potassium

Hypokalemia.

High potassium

Hyperkalemia.

Main function of sodium

Supports nerves, muscles, blood pressure, and fluid balance.

Low sodium

Hyponatremia.

High sodium

Hypernatremia.

Main function of calcium

Strengthens bones and teeth, supports muscles, nerves, and blood vessels.

Low calcium

Hypocalcemia.

High calcium

Hypercalcemia.

Common cause of hypocalcemia

Hypoparathyroidism.

Common cause of hypercalcemia

Hyperparathyroidism.

Main function of magnesium

Regulates nerve and muscle function, blood pressure, blood sugar, bone, protein, and DNA production.

Low magnesium

Hypomagnesemia.

High magnesium

Hypermagnesemia.

What is hypovolemia?

A decrease in blood volume due to fluid or blood loss.

Common causes of hypovolemia

Excessive sweating, burns, diuretics, inadequate fluid intake, increased urination.

Early signs of hypovolemia

Dry mucous membranes, decreased skin elasticity, decreased urine output.

How does the body compensate for hypovolemia?

Increases heart rate and constricts blood vessels.

Untreated hypovolemia signs

Blue lips/nails, altered consciousness, chest pain, palpitations, no urine output, tachycardia, tachypnea, hypotension, weak pulse.

What is hypovolemic shock?

Loss of about 20% of blood or body fluid causing inadequate circulation.

How is hypovolemic shock diagnosed?

X-ray, FAST ultrasound, CT scan, labs, ECG, echocardiogram.

Treatment for hypovolemic shock

Give oxygen, control blood loss, replace blood and fluids.

What is hypervolemia?

Fluid overload caused by too much water in the body.

Common causes of hypervolemia

Heart failure, kidney disease, cirrhosis, hepatitis, diabetes.

Treatment for hypervolemia

Diuretics, low-salt diet, fluid restriction, dialysis, paracentesis.

What are crystalloid IV solutions?

Solutions that easily move from the bloodstream into cells and tissues.

Hypotonic IV solutions

Move water from the extracellular space into cells.

Hypertonic IV solutions

Move water out of cells.

Isotonic IV solutions

No net movement of water between intracellular and extracellular spaces.

Purpose of packed red blood cells

Restore oxygen-carrying capacity without greatly increasing blood volume.

What is whole blood?

Contains plasma, red cells, white cells, and platelets.

When is whole blood commonly used?

Trauma or surgery with significant blood loss.

Function of plasma

Liquid portion that carries blood cells and platelets.

Function of platelets

Help stop or prevent bleeding.

When are platelets commonly given?

Organ transplants, cancer treatment, and surgery.

What is intake?

Everything a client receives by mouth, IV, or feeding tube.

What is output?

Urine, bowel movements, and vomiting.

How often should intake and output be recorded?

At least every 8 hours or according to facility policy.

What is acid-base balance?

The balance of acids and bases in the blood.

What is acidosis?

Too much acid in the blood.

What is alkalosis?

Too much base (alkaline) in the blood.

Common causes of metabolic acidosis

Kidney disease, lactic acidosis, diabetic ketoacidosis, severe dehydration, severe diarrhea.

Common causes of metabolic alkalosis

Diuretic overuse, vomiting, antacids, potassium or sodium loss, bicarbonate ingestion, alcohol abuse, laxatives, heart/kidney/liver failure.

What causes respiratory alkalosis?

Hyperventilation causing low carbon dioxide levels.

What causes respiratory acidosis?

Inability to remove enough carbon dioxide.

Common causes of respiratory acidosis

COPD, asthma, chest disorders, lung disease, narcotics, obesity, obstructive sleep apnea.

Normal arterial blood pH

7.35–7.45.

Normal PaCO₂

35–45 mmHg.

Normal HCO₃⁻

22–26 mEq/L.

ROME mnemonic

Respiratory Opposite, Metabolic Equal.

Respiratory disorders (ROME)

pH and PaCO₂ move in opposite directions.

Metabolic disorders (ROME)

pH and HCO₃⁻ move in the same direction.

What is compensation in acid-base balance?

The body's attempt to restore normal pH by adjusting the respiratory or metabolic system.