1. Chapter 14 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. Question Tell whether the following statement is true or false:
Osmosis is the movement of a substance from an area of higher concentration to one of lower concentration.

9. Answer
False.
Rationale: Diffusion is the movement of a substance from an area of higher concentration to one of lower concentration. The concentration of dissolved substances draws fluid in that direction. Osmosis is the movement of fluid, through a semipermeable membrane, from an area of low solute concentration to an area of high solute concentration until the solutions are of equal concentration.

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

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

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

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

16. 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

17. 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

18. 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

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

20. 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

21. Question What is a major indicator of extracellular FVD?
Full and bounding pulse
Drop in postural blood pressure
Elevated temperature
Pitting edema of lower extremities

22. Question What is a major indicator of extracellular FVD?
Full and bounding pulse
Drop in postural blood pressure
Elevated temperature
Pitting edema of lower extremities

23. Answer B. Drop in postural blood pressure
Rationale: FVD signs and symptoms include acute weight loss; decreased skin turgor; oliguria; concentrated urine; orthostatic hypotension due to volume depletion; a weak, rapid heart rate; flattened neck veins; increased temperature; thirst; decreased or delayed capillary refill; decreased central venous pressure; cool, clammy, pale skin related to peripheral vasoconstriction; anorexia; nausea; lassitude; muscle weakness; and cramps. Clinical manifestations of FVE result from expansion of the ECF and include edema, distended neck veins, and crackles (abnormal lung sounds).

24. 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

25. 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

26. 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)

27. 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

28. 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 (why?), 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

29. 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

30. 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

31. Question Tell whether the following statement is true or false:
The ECG change that is specific to hyperkalemia is a peaked T wave. (Money in the bank!)

32. Answer
True.
Rationale: The ECG changes that are specific to hyperkalemia are peaked T wave; wide, flat P wave; and wide QRS complex. The ECG changes that are specific to hypokalemia are flatted T wave and the appearance of a U wave.

33. 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

34. 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

35. Trousseau’s Sign

36. 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 (why?)
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

37. 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

38. 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 (and hypokalemia)
Need to monitor, treat potential hypocalcemia
Dysphasia common in magnesium-depleted patients
Assess ability to swallow with water before administering food or medications

39. 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

40. 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

41. 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

42. 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

43. 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

44. *Maintaining Acid-Base Balance
Normal plasma pH : 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

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

46. Question What is the most common buffer system in the body?
Plasma protein
Hemoglobin
Phosphate
Bicarbonate-carbonic acid

47. Answer D. Bicarbonate-carbonic acid
Rationale: The body’s major extracellular buffer system is the bicarbonate–carbonic acid buffer system, which is assessed when arterial blood gases are measured.

48. 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. Why?

49. *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

50. Metabolic Alkalosis High pH >7.45 High bicarbonate >26 mEq/L
Most commonly due to vomiting or gastric suction (why?)
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

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

52. 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

53. Respiratory Acidosis (cont’d)
Potential increased intracranial pressure (WHY???)
Treatment aimed at improving ventilation??

54. 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

55. Arterial Blood Gases pH 7.35 - (7.4) - 7.45 PaCO2 35 - (40) - 45 mm Hg
HCO3ˉ 22 - (24) - 26 mEq/L
Assumed average values for ABG interpretation
PaO2 80 to 100 mm Hg (lower indicates hypoxemia)
SaO2 (Oxygen saturation) >94% (too low indicates hypoxia)
Base excess/deficit ±2 mEq/L

56. IV Site Selection

57. Complications of IV Therapy
Fluid overload
Air embolism
Septicemia, other infections
Infiltration, extravasation
Phlebitis
Thrombophlebitis
Hematoma
Clotting, obstruction