11/24/2009
Fluid & Electrolytes
The Basics
Fluid Balance
Sodium 135‐145 meq/L
• Imbalances typically associated with parallel changes in osmolality • Plays a major role in – ECF volume and concentttiration – Generation and transmission of nerve impulses – Acid–base balance
1 11/24/2009
Hypernatremia
• Elevated serum sodium occurring with water loss or sodium gain • Causes hyperosmolality leading to cellular dehydration • Primary protection is thirst from hypothalamus
Differential Assessment of ECF Volume
Hypernatremia
• Manifestations – Thirst, lethargy, agitation, seizures, and coma • Impaired LOC • Produced by clinical states – Central or nephrogenic diabetes insipidus – Serum sodium levels must be reduced gradually to avoid cerebral edema
2 11/24/2009
Nursing Management Nursing Diagnoses • Potential complication: seizures and coma leading to irreversible brain damage • Management • Treat undliderlying cause • If oral fluids cannot be ingested, IV solution of 5% dextrose in water or hypotonic saline • Diuretics
Hyponatremia
• Results from loss of sodium‐containing fluids or from water excess • Manifestations – CfiConfusion, nausea, vomiting, seizures, and coma
Nursing Management Nursing Diagnoses • Risk for injury • Potential complication: severe neurologic changes • Management • Abnormal fluid loss – Fluid replacement with sodium‐containing solution • Caused by water excess – Fluid restriction is needed • Severe symptoms (seizures) – Give small amount of IV hypertonic saline solution (3% NaCl)
3 11/24/2009
Potassium 3.5‐5.5 meq/L
• Major ICF cation • Necessary for – Transmission and conduction of nerve and muscle impulses – Maintenance of cardiac rhythms – Acid–base balance • Sources – Fruits and vegetables (bananas and oranges) – Salt substitutes – Potassium medications (PO, IV) – Stored blood
Hyperkalemia
• High serum potassium caused by – Massive intake – Impaired renal excretion – Shift from ICF to ECF • Common in massive cell destruction – Burn, crush injury, or tumor lysis • Manifestations – Weak or paralyzed skeletal muscles – Ventricular fibrillation or cardiac standstill – Abdominal cramping or diarrhea
Nursing Management Nursing Diagnoses • Risk for injury • Potential complication: dysrhythmias • Management • Eliminate oral and parenteral K intake • Increase elimination of K (diuretics, dialysis, Kayexalate) • Force K from ECF to ICF by IV insulin or sodium bicarbonate
4 11/24/2009
Hypokalemia
• Low serum potassium caused by – Abnormal losses of K+ via the kidneys or gastrointestinal tract – Magnesium deficiency – Metablibolic alka los is • Manifestations – Most serious are cardiac – Skeletal muscle weakness – Weakness of respiratory muscles – Decreased gastrointestinal motility
Nursing Management Nursing Diagnoses • Risk for injury • Potential complication: dysrhythmias • KCl supplements orally or IV • Should not exceed 10 to 20 mEq/hr – To prevent hyperkalemia and cardiac arrest
Calcium 4‐5 meq/L
• Obtained from ingested foods • More than 99% combined with phosphorus and concentrated in skeletal system • Inverse relationship with phosphorus
5 11/24/2009
Calcium
• Bones are readily available store • Blocks sodium transport and stabilizes cell membrane
• Functions – Transmission of nerve impulses – Myocardial contractions – Blood clotting – Formation of teeth and bone – Muscle contractions
Calcium • Balance controlled by – Parathyroid hormone – Calcitonin – Vitamin D • High serum calcium levels caused by – Hyperparathyroidism – Malignancy – Vitamin D overdose – Prolonged immobilization
Hypercalcemia
• Manifestations – Decreased memory – Confusion – Disorientation – Fatigue – Constipation
6 11/24/2009
Nursing Management Nursing Diagnoses • Risk for injury • Potential complication: dysrhythmias • Management: • Excretion of Ca with loop diuretic • Hydration with isotonic saline infusion • Synthetic calcitonin • Mobilization
Hypocalcemia
• Low serum Ca levels caused by – Decreased production of PTH – Acute pancreatitis – Multiple blood transfusions – Alkalosis – Decreased intake • Manifestations – Positive Trousseau’s or Chvostek’s sign – Laryngeal stridor – Dysphagia – Tingling around the mouth or in the extremities
Nursing Management Nursing Diagnoses • Risk for injury • Potential complication: fracture or respiratory arrest • Management • Treat cause • Oral or IV calcium supplements • Treat pain and anxiety to prevent hyperventilation‐induced respiratory alkalosis
7 11/24/2009
Phosphate 3‐4.5
• Primary anion in ICF • Essential to function of muscle, red blood cells, and nervous system • Deposited with calcium for bone and tooth structure • Involved in acid–base buffering system, ATP production, and cellular uptake of glucose • Maintenance requires adequate renal functioning
Hyperphosphatemia
3 • High serum PO4 caused by – Acute or chronic renal failure – Chemotherapy – Excessive ingestion of phosphate or vitamin D
Hyperphosphatemia
• Manifestations – Calcified deposition in soft tissue such as joints, arteries, skin, kidneys, and corneas – Neuromuscular irritability and tetany • Management – Identify and treat underlying cause 3 – Restrict foods and fluids containing PO4 – Adequate hydration and correction of hypocalcemic conditions
8 11/24/2009
Hypophosphatemia
3 • Low serum PO4 caused by – Malnourishment/malabsorption – Alcohol withdrawal – Use of phosphate‐binding antacids – During parenteral nutrition with inadequate replacement
Hypophosphatemia
• Manifestations – CNS depression – Confusion – Muscle weakness and pain – Dysrhythmias – Cardiomyopathy • Management – Oral supplementation 3 – Ingestion of foods high in PO4 – IV administration of sodium or potassium phosphate
Magnesium 1.5‐2.5 meq/L
• 50% to 60% contained in bone • Coenzyme in metabolism of protein and carbohydrates • Factors that regulate calilcium blbalance appear to influence magnesium balance
• Acts directly on myoneural junction • Important for normal cardiac function
9 11/24/2009
Hypermagnesemia
• High serum Mg caused by – Increased intake or ingestion of products containing magnesium when renal insufficiency or failure is present
Hypermagnesemia
• Manifestations – Lethargy or drowsiness – Nausea/vomiting – Impaired reflexes – Respiratory and cardiac arrest • Management – Prevention – Emergency treatment • IV CaCl or calcium gluconate – Fluids to promote urinary excretion
Hypomagnesemia
• Low serum Mg caused by – Prolonged fasting or starvation – Chronic alcoholism – Fluid loss from gastrointestinal tract – Prolonged parenteral nutrition without supplementation – Diuretics
10 11/24/2009
Hypomagnesemia
• Manifestations – Confusion – Hyperactive deep tendon reflexes – Tremors – Seizures – Cardiac dysrhythmias • Management – Oral supplements – Increase dietary intake – Parenteral IV or IM magnesium when severe
Electrolyte Disorders Signs and Symptoms
Electrolyte Excess Deficit Sodium (Na) Hypernatremia Hyponatremia Thirst CNS deterioration CNS deterioration Increased interstitial fluid
Potassium (K) Hyperkalemia Hypokalemia Ventricular fibrillation Bradycardia ECG changes ECG changes CNS changes CNS changes
Electrolyte Disorders Signs and Symptoms Electrolyte Excess Deficit Calcium (Ca) Hypercalcemia Hypocalcemia Thirst Tetany CNS deterioration Chvostek’sChvostek’s,, Trousseau’s Increased interstitial fluid signs Muscle twitching CNS changes ECG changes Magnesium (Mg) Hypermagnesemia Hypomagnesemia Loss of deep tendon reflexes Hyperactive DTRs (DTRs) CNS changes Depression of CNS Depression of neuromuscular function
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