Fluid and Electrolytes: Balance and Disturbance

1. Fluid and Electrolytes: Balance and Disturbance

2. Fluid and Electrolyte Balance • Necessary for life, homeostasis • Nursing role: help prevent, treat fluid, electrolyte disturbances

3. Fluid • Approximately 60% of typical adult is fluid • Varies with age, body size, gender • Intracellular fluid • Extracellular fluid • Intravascular • Interstitial • Transcellular • “Third spacing”: loss of ECF into space that does not contribute to equilibrium

4. Electrolytes • Active chemicals that carry positive (cations), negative (anions) electrical charges • Major cations: sodium, potassium, calcium, magnesium, hydrogen ions • Major anions: chloride, bicarbonate, phosphate, sulfate, and proteinate ions • Electrolyte concentrations differ in fluid compartments

5. Regulation of Fluid • Movement of fluid through capillary walls depends on • Hydrostatic pressure: exerted on walls of blood vessels • Osmotic pressure: exerted by protein in plasma • Direction of fluid movement depends on differences of hydrostatic, osmotic pressure

6. Regulation of Fluid • Osmosis: area of low solute concentration to area of high solute concentration • Diffusion: solutes move from area of higher concentration to one of lower concentration • Filtration: movement of water, solutes occurs from area of high hydrostatic pressure to area of low hydrostatic pressure • Active transport: physiologic pump that moves fluid from area of lower concentration of one of higher concentration

7. Active Transport • Physiologic pump that moves fluid from area of lower concentration to one of higher concentration • Movement against concentration gradient • Sodium-potassium pump: maintains higher concentration of extracellular sodium, intracellular potassium • Requires adenosine (ATP) for energy

8. Routes of Gains and Losses • Gain • Dietary intake of fluid, food or enteral feeding • Parenteral fluids

9. Routes of Gains and Losses (cont’d) • Loss • Kidney: urine output • Skin loss: sensible, insensible losses • Lungs • GI tract • Other

12. Gerontologic Considerations • Reduced homeostatic mechanisms: cardiac, renal, respiratory function • Decreased body fluid percentage • Medication use • Presence of concomitant conditions

13. Fluid Volume Imbalances • Fluid volume deficit (FVD): hypovolemia • Fluid volume excess (FVE): hypervolemia

14. Fluid Volume Deficit • Loss of extracellular fluid exceeds intake ratio of water • Electrolytes lost in same proportion as they exist in normal body fluids • Dehydration: loss of water along with increased serum sodium level • May occur in combination with other imbalances

15. Fluid Volume Deficit (cont’d) • Dehydration • Causes: fluid loss from vomiting, diarrhea, GI suctioning, sweating, decreased intake, inability to gain access to fluid • Risk factors: diabetes insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage, coma, third space shifts

16. Fluid Volume Deficit (cont’d) • Manifestations: rapid weight loss, decreased skin turgor, oliguria, concentrated urine, postural hypotension, rapid weak pulse, increased temperature, cool clammy skin due to vasoconstriction, lassitude, thirst, nausea, muscle weakness, cramps • Laboratory data: elevated BUN in relation to serum creatinine, increased hematocrit • Serum electrolyte changes may occur

17. Fluid Volume Deficit (cont’d) • Medical management: provide fluids to meet body needs • Oral fluids • IV solutions

18. Fluid Volume Deficit - Nursing Management • I&O, VS • Monitor for symptoms: skin and tongue turgor, mucosa, UO, mental status • Measures to minimize fluid loss • Oral care • Administration of oral fluids • Administration of parenteral fluids

19. Fluid Volume Excess • Due to fluid overload or diminished homeostatic mechanisms • Risk factors: heart failure, renal failure, cirrhosis of liver • Contributing factors: excessive dietary sodium or sodium-containing IV solutions • Manifestations: edema, distended neck veins, abnormal lung sounds (crackles), tachycardia, increased BP, pulse pressure and CVP, increased weight, increased UO, shortness of breath and wheezing • Medical management: directed at cause, restriction of fluids and sodium, administration of diuretics

20. Fluid Volume Excess - Nursing Management • I&O and daily weights; assess lung sounds, edema, other symptoms; monitor responses to medications- diuretics • Promote adherence to fluid restrictions, patient teaching related to sodium and fluid restrictions • Monitor, avoid sources of excessive sodium, including medications • Promote rest • Semi-Fowler’s position for orthopnea • Skin care, positioning/turning

21. Electrolyte Imbalances • Sodium: hyponatremia, hypernatremia • Potassium: hypokalemia, hyperkalemia • Calcium: hypocalcemia, hypercalcemia • Magnesium: hypomagnesemia, hypermagnesemia • Phosphorus: hypophosphatemia, hyperphosphatemia • Chloride: hypochloremia, hyperchloremia

22. Hyponatremia • Serum sodium less than 135 mEq/L • Causes: adrenal insufficiency, water intoxication, SIADH or losses by vomiting, diarrhea, sweating, diuretics • Manifestations: poor skin turgor, dry mucosa, headache, decreased salivation, decreased BP, nausea, abdominal cramping, neurologic changes • Medical management: water restriction, sodium replacement • Nursing management: assessment and prevention, dietary sodium and fluid intake, identify and monitor at-risk patients, effects of medications (diuretics, lithium)

23. Hypernatremia • Serum sodium greater than 145mEq/L • Causes: excess water loss, excess sodium administration, diabetes insipidus, heat stroke, hypertonic IV solutions • Manifestations: thirst; elevated temperature; dry, swollen tongue; sticky mucosa; neurologic symptoms; restlessness; weakness • Note: thirst may be impaired in elderly or the ill • Medical management: hypotonic electrolyte solution or D5W • Nursing management: assessment and prevention, assess for OTC sources of sodium, offer and encourage fluids to meet patient needs, provide sufficient water with tube feedings

24. Hypokalemia • Below-normal serum potassium (<3.5 mEq/L), may occur with normal potassium levels with alkalosis due to shift of serum potassium into cells • Causes: GI losses, medications, alterations of acid-base balance, hyperaldosterism, poor dietary intake • Manifestations: fatigue, anorexia, nausea, vomiting, dysrhythmias, muscle weakness and cramps, paresthesias, glucose intolerance, decreased muscle strength, DTRs • Medical management: increased dietary potassium, potassium replacement, IV for severe deficit • Nursing management: assessment, severe hypokalemia is life-threatening, monitor ECG and ABGs, dietary potassium, nursing care related to IV potassium administration

25. Hyperkalemia • Serum potassium greater than 5.0 mEq/L • Causes: usually treatment related, impaired renal function, hypoaldosteronism, tissue trauma, acidosis • Manifestations: cardiac changes and dysrhythmias, muscle weakness with potential respiratory impairment, paresthesias, anxiety, GI manifestations • Medical management: monitor ECG, limitation of dietary potassium, cation-exchange resin (Kayexalate), IV sodium bicarbonate , IV calcium gluconate, regular insulin and hypertonic dextrose IV, -2 agonists, dialysis

26. Hyperkalemia (cont’d) • Nursing management: assessment of serum potassium levels, mix IVs containing K+ well, monitor medication affects, dietary potassium restriction/dietary teaching for patients at risk • Hemolysis of blood specimen or drawing of blood above IV site may result in false laboratory result • Salt substitutes, medications may contain potassium • Potassium-sparing diuretics may cause elevation of potassium • Should not be used in patients with renal dysfunction

27. Hypocalcemia • Serum level less than 8.5 mg/dL, must be considered in conjunction with serum albumin level • Causes: hypoparathyroidism, malabsorption, pancreatitis, alkalosis, massive transfusion of citrated blood, renal failure, medications, other • Manifestations: tetany, circumoral numbness, paresthesias, hyperactive DTRs, Trousseau’s sign, Chovstek's sign, seizures, respiratory symptoms of dyspnea and laryngospasm, abnormal clotting, anxiety

28. Hypocalcemia (cont’d) • Medical management: IV of calcium gluconate, calcium and vitamin D supplements; diet • Nursing management: assessment, severe hypocalcemia is life-threatening, weight-bearing exercises to decrease bone calcium loss, patient teaching related to diet and medications, and nursing care related to IV calcium administration

29. Trousseau’s Sign

30. Hypercalcemia • Serum level above 10.5 mg/dL • Causes: malignancy and hyperparathyroidism, bone loss related to immobility • Manifestations: muscle weakness, incoordination, anorexia, constipation, nausea and vomiting, abdominal and bone pain, polyuria, thirst, ECG changes, dysrhythmias • Medical management: treat underlying cause, fluids, furosemide, phosphates, calcitonin, biphosphonates • Nursing management: assessment, hypercalcemic crisis has high mortality, encourage ambulation, fluids of 3 to 4 L/d, provide fluids containing sodium unless contraindicated, fiber for constipation, ensure safety

31. Hypomagnesemia • Serum level less than 1.8 mg/dL, evaluate in conjunction with serum albumin • Causes: alcoholism, GI losses, enteral or parenteral feeding deficient in magnesium, medications, rapid administration of citrated blood; contributing causes include diabetic ketoacidosis, sepsis, burns, hypothermia • Manifestations: neuromuscular irritability, muscle weakness, tremors, athetoid movements, ECG changes and dysrhythmias, alterations in mood and level of consciousness • Medical management: diet, oral magnesium, magnesium sulfate IV

32. Hypomagnesemia (cont’d) • Nursing management: assessment, ensure safety, patient teaching related to diet, medications, alcohol use, and nursing care related to IV magnesium sulfate • Hypomagnesemia often accompanied by hypocalcemia • Need to monitor, treat potential hypocalcemia • Dysphasia common in magnesium-depleted patients • Assess ability to swallow with water before administering food or medications

33. Hypermagnesemia • Serum level more than 2.7 mg/dL • Causes: renal failure, diabetic ketoacidosis, excessive administration of magnesium • Manifestations: flushing, lowered BP, nausea, vomiting, hypoactive reflexes, drowsiness, muscle weakness, depressed respirations, ECG changes, dysrhythmias • Medical management: IV calcium gluconate, loop diuretics, IV NS of RL, hemodialysis • Nursing management: assessment, do not administer medications containing magnesium, patient teaching regarding magnesium containing OTC medications

34. Hypophosphatemia • Serum level below 2.5 mg/DL • Causes: alcoholism, refeeding of patients after starvation, pain, heat stroke, respiratory alkalosis, hyperventilation, diabetic ketoacidosis, hepatic encephalopathy, major burns, hyperparathyroidism, low magnesium, low potassium, diarrhea, vitamin D deficiency, use of diuretic and antacids • Manifestations: neurologic symptoms, confusion, muscle weakness, tissue hypoxia, muscle and bone pain, increased susceptibility to infection • Medical management: oral or IV phosphorus replacement • Nursing management: assessment, encourage foods high in phosphorus, gradually introduce calories for malnourished patients receiving parenteral nutrition

35. Hyperphosphatemia • Serum level above 4.5 mg/DL • Causes: renal failure, excess phosphorus, excess vitamin D, acidosis, hypoparathyroidism, chemotherapy • Manifestations: few symptoms; soft-tissue calcifications, symptoms occur due to associated hypocalcemia • Medical management: treat underlying disorder, vitamin-D preparations, calcium-binding antacids, phosphate-binding gels or antacids, loop diuretics, NS IV, dialysis • Nursing management: assessment, avoid high-phosphorus foods; patient teaching related to diet, phosphate-containing substances, signs of hypocalcemia

36. Hypochloremia • Serum level less than 96 mEq/L • Causes: Addison’s disease, reduced chloride intake, GI loss, diabetic ketoacidosis, excessive sweating, fever, burns, medications, metabolic alkalosis • Loss of chloride occurs with loss of other electrolytes, potassium, sodium • Manifestations: agitation, irritability, weakness, hyperexcitability of muscles, dysrhythmias, seizures, coma • Medical management: replace chloride-IV NS or 0.45% NS • Nursing management: assessment, avoid free water, encourage high-chloride foods, patient teaching related to high-chloride foods

37. Hyperchloremia • Serum level more than 108 mEq/L • Causes: excess sodium chloride infusions with water loss, head injury, hypernatremia, dehydration, severe diarrhea, respiratory alkalosis, metabolic acidosis, hyperparathyroidism, medications • Manifestations: tachypnea, lethargy, weakness, rapid, deep respirations, hypertension, cognitive changes • Normal serum anion gap • Medical management: restore electrolyte and fluid balance, LR, sodium bicarbonate, diuretics • Nursing management: assessment, patient teaching related to diet and hydration

38. Maintaining Acid-Base Balance • Normal plasma pH 7-35-7.45: hydrogen ion concentration • Major extracellular fluid buffer system;bicarbonate-carbonic acid buffer system • Kidneys regulate bicarbonate in ECF • Lungs under control of medulla regulate CO2, carbonic acid in ECF

39. Maintaining Acid-Base Balance (cont’d) • Other buffer systems • ECF: inorganic phosphates, plasma proteins • ICF: proteins, organic, inorganic phosphates • Hemoglobin

40. ACID–BASE DISTURBANCES • Plasma pH is an indicator of hydrogen ion (H+) concentration. • Normal range pH (7.35–7.45). • Buffer systems • Kidneys • Lungs • The H+ concentration is extremely important: • Increased concentration H+ • Increased acidity • Lower the pH. • Deceased H+ concentration • Increased alkalinity • Higher the pH. • pH range compatible with life (6.8–7.8)

41. BUFFER SYSTEMS • Buffer systems prevent major changes in the pH of body fluids • Both intracellular and extracellular buffers. • Major extracellular buffer system is Bicarbonate-carbonic acid • Assessed when arterial blood gases are measured. • Normally, there are 20 parts of bicarbonate (HCO3−) to one part of carbonic acid (H2CO3). • If this ratio is altered, the pH will change. • The ratio which maintains pH, not absolute values. • Carbon dioxide (CO2) is a potential acid; when dissolved in water, it becomes carbonic acid (CO2 + H2O = H2CO3). • Thus, when CO2 is increased, the carbonic acid is also increased • Changes in and H2CO3 concentration results in acid–base imbalances. • Intracellular buffers are proteins, organic and inorganic phosphates • Hemoglobin.

42. KIDNEYS • Regulate the bicarbonate level in the ECF • Can regenerate and reabsorb HCO3− • In respiratory acidosis and most cases of metabolic acidosis • Kidneys excrete H+ and conserve HCO3− • In respiratory and metabolic alkalosis • Kidneys retain H+ and excrete HCO3− • Kidneys cannot compensate for the metabolic acidosis created by RF • Renal compensation is relatively slow (a matter of hours or days).

43. LUNGS • Control PaCO2 and thus the H2CO3 of ECF. • A rise PaCO2 is a powerful stimulant to respiration. • PaO2 also influences respiration, But PaCO2 is stronger • In metabolic acidosis • Respiratory rate increases to eliminate CO2 (to reduce acid). • In metabolic alkalosis • Respiratory rate decreases to retain CO2 (to increase acid).

44. Metabolic Acidosis • Low pH <7.35 • Low bicarbonate <22 mEq/L • Most commonly due to renal failure • Manifestations: headache, confusion, drowsiness, increased respiratory rate and depth, decreased blood pressure, decreased cardiac output, dysrhythmias, shock; if decrease is slow, patient may be asymptomatic until bicarbonate is 15 mEq/L or less • Correct underlying problem, correct imbalance • Bicarbonate may be administered

45. Metabolic Acidosis (cont’d) • With acidosis, hyperkalemia may occur as potassium shifts out of cell • As acidosis is corrected, potassium shifts back into cell, potassium levels decrease • Monitor potassium levels • Serum calcium levels may be low with chronic metabolic acidosis • Must be corrected before treating acidosis

46. Metabolic Alkalosis • High pH >7.45 • High bicarbonate >26 mEq/L • Most commonly due to vomiting or gastric suction • May also be due to medications, especially long-term diuretic use • Hypokalemia will produce alkalosis • Manifestations: symptoms related to decreased calcium, respiratory depression, tachycardia, symptoms of hypokalemia

47. Metabolic Alkalosis (cont’d) • Correct underlying disorder, supply chloride to allow excretion of excess bicarbonate, restore fluid volume with sodium chloride solutions

48. Respiratory Acidosis • Low pH <7.35 • PaCO2 >42 mm Hg • Always due to respiratory problem with inadequate excretion of CO2 • With chronic respiratory acidosis, body may compensate, may be asymptomatic • Symptoms may be suddenly increased pulse, respiratory rate and BP, mental changes, feeling of fullness in head

49. Respiratory Acidosis (cont’d) • Potential increased intracranial pressure • Treatment aimed at improving ventilation

50. Respiratory Alkalosis • High pH >7.45 • PaCO2 <35 mm Hg • Always due to hyperventilation • Manifestations: lightheadedness, inability to concentrate, numbness and tingling, sometimes loss of consciousness • Correct cause of hyperventilation