Electrolytes
Chemicals that carry a positive or negative charge
Cations carry a positive charge
Anions carry a negative charge
Impact the electrical impulses in nerves and muscles
Imbalance is present whenever there is an excess (hyper) or deficit (hypo) in the serum
Chemicals to remember
sodium (Na+)
potassium (K+)
chloride (Cl-)
calcium (Ca2+)
magnesium (Mg2+)
bicarbonate (HCO3-)
phosphate (PO42-)
sulfate (SO42-)
Plasma values expressed as
Milliequivalents per liter (mEq/L).
Expressed as mEq/L because this is a measure of chemical activity rather than weight.
May be expressed as milligrams per deciliter (mg/dL).
Values reported as mEq/L can be converted to mg/dL by multiplying by 1.2
Sodium Na
Primary cation in the extracellular fluid.
Diffusion of Na+ occurs between the vascular and interstitial fluids.
Na+ transport across the cell membrane is controlled by the sodium-potassium pump or active transport.
Sodium loss occurs with perspiration, u
Potassium K
A major intracellular cation.
Ingested in food and excreted primarily in the urine.
Levels are influenced by the acid-base balance.
Assists in the regulation of intracellular fluid volume and has a role in many metabolic processes.
Important in nerve cond
Calcium Ca
An important extracellular cation.
Ingested in food, Stored in bone, Excreted in urine and feces, Controlled by the parathyroid hormone and calcitonin and influenced by vitamin D and phosphate , Calcium and phosphate have a reciprocal relationship in the
Magnesium Mg
Intracellular ion, About 50% of total body magnesium is stored in bone, Serum levels are linked to potassium and calcium levels, Found in green vegetables, Important in many enzyme reactions, Important in protein and DNA synthesis.
Normal serum magnesium
Phosphate
Phosphate ions are located primarily in the bone, but circulate in the intracellular and extracellular fluids, Important in bone and tooth mineralization
Utilized in many metabolic processes, particular cellular energy and ATP, Important as a buffer syste
Chloride
The major extracellular anion. Tends to follow sodium because of the electrical charge on the ions. Chloride and bicarbonate ions can exchange places as the blood circulates through the body - this helps maintain acid-base balance. Normal serum chloride l
Hyponatremia
Serum sodium concentration below 135 mEq/L. May result in impaired nerve conductions and fluid imbalances in the compartments.
Decreased osmotic pressure in the extracellular compartment may cause a fluid shift into cells
Brain cells may swell.
Hyponatremia Etiology
Direct loss of sodium from the body.
Excess of water in the extracellular compartment resulting in dilution of sodium. Excessive sweating, vomiting, or diarrhea. Use of diuretic drugs. Low salt diets. Hormonal imbalances - insufficient aldosterone, adrena
Hyponatremia Clinical Manifestations
Impaired nerve conductions. Fatigue, Muscle cramps, Fluid imbalances in the compartments, Abdominal discomfort or cramps, Nausea and vomiting, Decreased osmotic pressure in the extracellular compartment may cause a fluid shift into the cells. Hypovolemia,
Hyponatremia Diagnostic Testing
Serum sodium level Normal = 135-145 mEq/L
Hyponatremia Nursing Assessment
Complete history of risk factors and presenting manifestations . Complete information on diet and medications. Monitor body weight. Intake and output. Peripheral vein filling time. Vital signs.
Monitor lab values.
Hypernatremia
an excessive sodium level in the blood and extracellular fluids - above 145 mEq/L.
Fluid shifts out of the cells due to the increased osmotic pressure of interstitial or extracellular fluid.
Hypernatremia Etiology
Ingestion of large amount of sodium without proportionate water intake.
Loss of water from the body that is faster than the loss of sodium.
Insufficient ADH can result in a large volume of dilute urine.
Loss of thirst mechanism, Watery diarrhea, Prolonged
Hypernatremia Clinical Manifestations
Weakness, Agitation, Firm subcutaneous tissues,
Increased thirst, Dry mouth, Rough mucous membranes. Decreased urine output or possibly increased urine output if the etiology is hypernatremia due to lack of ADH.
Hypernatremia Nursing Assessment
Assess for clinical manifestations.
Obtain a thorough diet and medication history
Assess vital signs, peripheral vein filling time.
Intake and output, Monitor body weight.
Assess oral membranes, skin condition
Assess for changes in LOC or behavior. Monito
Hypokalemia
serum potassium level below 3.5 mEq/L.
Abnormal levels can adversely affect cardiac and skeletal muscle leading to weakness, fatigue, and cardiac dysrhythmias.
Alkalosis (high blood pH) causes hydrogen ions to diffuse out of the cell and potassium to diff
Hypokalemia Etiology
Excessive loss due to diarrhea, Diuresis associated with diuretics , Excessive aldosterone or glucocorticoids, Decreased dietary intake, Treatment of diabetic ketoacidosis with insulin.
Extra notes
Extracellular fluid hypokalemia can develop without losses of total body potassium. Potassium shifts into the cell during states of respiratory or metabolic alkalosis or after administration of insulin. K shifts into the cell in exchange for H+.
If sodium
Hypokalemia Clinical Manifestations
Cardiac dysrhythmias. Fatigue and muscle weakness. Paresthesias. Anorexia and nausea
Shallow respirations. In severe cases, impaired renal function and polyuria.
Hypokalemia Diagnostic Testing
Serum K level
Normal = 3.5 to 5 mEq/L
Hypokalemia Nursing Assessment
Obtain history , focus on dietary intake, conditions promoting potassium loss, and use of diuretics.
Assess potassium levels, Especially in pre-op patients because general anesthesia promotes potassium loss - patients with low pre-op potassium levels may
Hyperkalemia
serum potassium level above 5 mEq/L.
Abnormal levels can adversely affect cardiac and skeletal muscle leading to weakness, fatigue, and cardiac dysrhythmias.
Acidosis (low blood pH) promotes hydrogen ion excretion by the kidneys which leads to retention o
Hyperkalemia Etiology
Renal failure, Aldosterone deficit, Use of potassium-sparing diuretics, Leakage of intracellular potassium into the extracellular fluids in cases of severe tissue injury.
Displacement of potassium from cells due to acidosis.
Hyperkalemia Clinical Manifestations
Cardiac dysrhythmias. Muscle weakness progressing to paralysis. Fatigue, Nausea, Paresthesias.
Hyperkalemia Nursing Assessment
Assess for risk factors through history-taking and a thorough physical exam.
Monitor vital signs, including apical pulse.
Assess hourly with severe hyperkalemia.
ECG monitoring, Assess bowel function, Monitor urine output, Assess lung sounds, Monitor for
Hypocalcemia
serum calcium level below 8.5 mg/dL. Vitamin D promotes calcium movement from bone and intestines into the blood. Low blood calcium levels stimulate the secretion of PTH (parathyroid hormone), which increases calcium absorption from the digestive tract an
Hypocalcemia Etiology
Hypoparathyroidism, Malabsorption, Deficient serum albumin, Increased serum pH, In cases of renal failure, results from retention of phosphate.
Hypocalcemia Clinical Manifestations
Excitability of skeletal muscle: Carpopedal spasm,
Chvostek's sign, Trousseau's sign, Tetany, Laryngospasm, Paresthesias, Abdominal cramps.
Weak heart contractions and arrhythmias
Hypocalcemia Diagnostic Testing
Serum calcium levels
Normal = 8.5 to 10.5 mg/dL
Hypocalcemia Nursing Assessment
Thorough history of current and chronic illness, diet intake of calcium, and medications.
Assess for Trousseau's and Chvostek's signs
Assess for paresthesias, Monitor ECG, Monitor vital signs
Hypercalcemia
serum calcium level above 10.5 mg/dL.
Vitamin D promotes calcium movement from bone and intestines into the blood.
Any condition that causes calcium to be released, such as certain neoplasms or immobility, can cause hypercalcemia.
High calcium levels inte
Hypercalcemia Etiology
Malignant bones tumors that destroy bone tissue or secrete PTH.
Hyperparathyroidism, Immobility, which leads to demineralization, Increased intake of calcium,
Milk-alkali syndrome - increased milk and antacid intake.
Hypercalcemia Clinical Manifestations
Muscle weakness, Lack of muscle tone, Lethargy and stupor, Personality changes, Anorexia and nausea, Polyuria . In severe cases, decreased blood volume, decreased renal function, increased nitrogen waste and cardiac arrest.
Hypercalcemia Nursing Assessment
Calcium levels are not routinely checked - Assess for high-risk clients.
Thorough history including diet, medications, and over-the-counter supplements.
Monitor vital signs, including apical pulse. Monitor ECG, Monitor I & O, Monitor renal function
Monito