Transcript Fluid - Wolters Kluwer Health

Chapter 15
Fluid and Electrolytes:
Balance and Disturbance
Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins
Fluid and Electrolyte Balance
• Necessary for life and homeostasis
• Nursing role is to help prevent and treat fluid
and electrolyte disturbances
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Fluid
• Approximately 60% of the typical adult is fluid
• Varies with age, body size, and sex
• Intracellular fluid
• Extracellular fluid (ECF)
– Intravascular
– Interstitial
– Transcellular
• “Third spacing”: loss of ECF into a space that
does not contribute to equilibrium
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Electrolytes
• Active chemicals that carry positive (cations) and
negative (anions) electrical charges
• Major cations:
• Major anions:
– Sodium
– Chloride
– Potassium
– Bicarbonate
– Calcium
– Phosphate
– Magnesium
– Sulfate
– Hydrogen ions
– Proteinate ions
• Electrolyte concentrations differ in the fluid
compartments
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Electrolytes cont’d
• Major cation in ECF
– Sodium
• Major cation in ICF
– Potassium
See Table 15-1
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Regulation of Fluid
• Movement of fluid through capillary walls depends
on:
– Hydrostatic pressure
 Pressure exerted on the walls of blood vessels
– Osmotic pressure
 Pressure exerted by the protein in the plasma
• The direction of fluid movement depends on the
differences of hydrostatic and osmotic pressures
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Regulation of Fluid cont’d
• Osmosis
• Diffusion
• Filtration
• Active transport
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Question
Which of the following is the major cation in extracellular
fluid?
a. Calcium
b. Sodium
c. Magnesium
d. Potassium
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Answer
b. Sodium
Rationale: Sodium is the most abundant electrolyte in the
ECF; its concentration normally ranges from 135 to 145
mmol/L.
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Fluid Balance
• Fluid gain
– Dietary intake of fluid and food or enteral feeding
– Parenteral fluids
• Fluid loss
– Kidney: urine output
– Skin loss: sensible and insensible losses
– Lungs
– GI tract
• Laboratory tests of fluid balance
• Homeostatic mechanisms
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Gerontologic Considerations
• Reduced homeostatic mechanisms: cardiac, renal,
and respiratory function
• Decreased body fluid percentage
• Medication use
• Presence of concomitant conditions
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Fluid Volume Imbalances
• Fluid volume deficit (FVD): hypovolemia
• Fluid volume excess (FVE): hypervolemia
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Fluid Volume Deficit
• Loss of extracellular fluid exceeds intake ratio of water,
and electrolytes are lost in the same proportion as they
exist in normal body fluids
• Dehydration refers to loss of water alone with increased
serum sodium level
• May occur in combination with other imbalances
• Causes: fluid loss from vomiting, diarrhea, GI suctioning,
sweating, decreased intake, and inability to gain access
to fluid
• Risk factors: diabetes insipidus, adrenal insufficiency,
osmotic diuresis, hemorrhage, coma, and third space
shifts
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Fluid Volume Deficit cont’d
• Manifestations: rapid weight loss, decreased skin turgor,
oliguria, concentrated urine, postural hypotension, rapid and
weak pulse, increased temperature, cool and clammy skin
caused by vasoconstriction, lassitude, thirst, nausea, muscle
weakness, and cramps
• Laboratory data: elevated BUN in relation to serum creatinine,
increased hematocrit, and possible serum electrolyte changes
• Medical management: provide fluids to meet body needs
– Oral fluids
– IV solutions: see Table 15-3
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Fluid Volume Deficit—Nursing Management
• Monitor intake and output (I&O) and volumetric
solution (VS)
• Monitor for symptoms: skin and tongue turgor,
mucosa, urinary output (UO), and mental status
• Initiate measures to minimize fluid loss
• Provide oral care
• Administer oral fluids
• Administer parenteral fluids
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Fluid Volume Excess
• Caused by fluid overload or diminished homeostatic
mechanisms
• Risk factors: heart failure, renal failure, and cirrhosis of the
liver
• Contributing factors: excessive dietary sodium or sodiumcontaining 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 is directed at the cause, restriction of
fluids and sodium, and the administration of diuretics
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Fluid Volume Excess—Nursing Management
• Take I&O and daily weights; assess for lung sounds,
edema, and other symptoms; monitor responses to
medications such as diuretics
• Promote adherence to fluid restrictions and patient
teaching related to sodium and fluid restrictions
• Monitor and avoid sources of excessive sodium; include
medications
• Promote rest
• Use semi-Fowler’s position for orthopnea
• Provide skin care and positioning or turning
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Electrolyte Imbalances
• Sodium: hyponatremia and hypernatremia
• Potassium: hypokalemia and hyperkalemia
• Calcium: hypocalcemia and hypercalcemia
• Magnesium: hypomagnesemia and
hypermagnesemia
• Phosphorus: hypophosphatemia and
hyperphosphatemia
• Chloride: hypochloremia and hyperchloremia
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Hyponatremia
• Serum sodium less than 135 mEq/L
• Causes: adrenal insufficiency, water intoxication,
SIADH, and losses by vomiting, diarrhea,
sweating, and diuretics
• Manifestations: poor skin turgor, dry mucosa,
headache, decreased salivation, decreased BP,
nausea, abdominal cramping, and neurologic
changes
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Hyponatremia cont’d
• Medical management: water restriction and
sodium replacement
• Nursing management: assessment and
prevention, monitoring of dietary sodium and
fluid intake, identification and monitoring of atrisk patients and the effects of medications
(diuretics and lithium)
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Hypernatremia
• Serum sodium greater than 145 mEq/L
• Causes: excess water loss, excess sodium
administration, diabetes insipidus, heat stroke, and
hypertonic IV solutions
• Manifestations: thirst; elevated temperature; dry,
swollen tongue; sticky mucosa; neurologic symptoms;
restlessness; and weakness
– Thirst may be impaired in the elderly or ill
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Hypernatremia cont’d
• Medical management: hypotonic electrolyte
solution or D5W
• Nursing management: assessment and
prevention, assess for over-the-counter (OTC)
sources of sodium, offer and encourage fluids
to meet patient needs, and provide sufficient
water with tube feedings
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Question
Which of the following is a contributing factor of
hyponatremia?
a. Heat stroke
b. Impaired renal function
c. SIADH
d. Diabetes insipidus
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Answer
c. SIADH
Rationale: Potential contributing factors of hyponatremia
include disease states associated with SIADH such as
head trauma and oat-cell lung tumour, use of diuretics,
renal disease, and adrenal insufficiency.
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Hypokalemia
• Below-normal serum potassium (<3.5 mmol/L) may
occur with normal potassium levels in alkalosis owing
to shift of serum potassium into cells
• Causes: GI losses, medications, alterations of acid–
base balance, hyperaldosteronism, and poor dietary
intake
• Manifestations: fatigue, anorexia, nausea, vomiting,
dysrhythmias, muscle weakness, cramps, paresthesias,
glucose intolerance, decreased muscle strength, and
deep tendon reflexes (DTRs)
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Hypokalemia cont’d
• Medical management: increased dietary
potassium, potassium replacement, and IV for
severe deficit
• Nursing management: assessment (severe
hypokalemia is life-threatening), monitoring of
electrocardiogram (ECG), arterial blood gases
(ABGs), and dietary potassium, and providing
nursing care related to IV potassium
administration
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Hyperkalemia
• Serum potassium greater than 5.0 mmol/L
• Causes: usually treatment-related, impaired
renal function, hypoaldosteronism, tissue
trauma, and acidosis
• Manifestations: cardiac changes and
dysrhythmias, muscle weakness with potential
respiratory impairment, paresthesias, anxiety,
and GI manifestations
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Hyperkalemia cont’d
• Medical management: monitor ECG, cation
exchange resin (Kayexalate), IV sodium
bicarbonate, IV calcium gluconate, regular insulin
and hypertonic dextrose IV, and -2 agonists; limit
dietary potassium; and perform dialysis
• Nursing management: assess serum potassium
levels, mix well IVs containing K+, monitor
medication effects, and initiate dietary potassium
restriction and dietary teaching for patients at risk
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Effect of Potassium on ECG
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Hyperkalemia
• Hemolysis of blood specimen or drawing of blood
above IV site may result in false laboratory result
• Salt substitutes and medications may contain
potassium
• Potassium-sparing diuretics may cause elevation
of potassium and should not be used in patients
with renal dysfunction
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Hypocalcemia
• 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, and
anxiety
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Hypocalcemia cont’d
• Medical management: IV of calcium gluconate,
calcium and vitamin D supplements, diet
• Nursing management: assessment as 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
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Trousseau’s Sign
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Hypercalcemia
• 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, and dysrhythmias
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Hypercalcemia cont’d
• Medical management: treat underlying cause,
administer fluids, furosemide, phosphates, calcitonin,
and bisphosphonates
• Nursing management: assessment as hypercalcemic
crisis has high mortality, encourage ambulation, fluids
of 3 to 4 L/d, provide fluids containing sodium unless
contraindicated and fibre for constipation, and ensure
safety
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Question
Of which electrolyte is the following true: 98% of it is
found intracellularly?
a. Calcium
b. Potassium
c. Sodium
d. Magnesium
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Answer
b. Potassium
Rationale: Potassium is the major intracellular electrolyte.
98% of the body’s potassium is inside the cells.
Potassium influences both skeletal and cardiac muscle
activity.
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Hypomagnesemia
• Causes: alcoholism, GI losses, enteral or parenteral
feeding deficient in magnesium, medications, rapid
administration of citrated blood; contributing causes
include diabetic ketoacidosis, sepsis, burns, and
hypothermia
• Manifestations: neuromuscular irritability, muscle
weakness, tremors, athetoid movements, ECG
changes and dysrhythmias, and alterations in mood
and level of consciousness
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Hypomagnesemia cont’d
• Medical management: diet, oral magnesium, and magnesium
sulfate IV
• Nursing management: assessment, ensure safety, patient
teaching related to diet, medications, alcohol use, and
nursing care related to IV magnesium sulfate
• Hypomagnesemia is often accompanied by hypocalcemia
– Monitor and treat potential hypocalcemia
– Dysphagia is common in magnesium-depleted patients;
assess ability to swallow with water before administering
food or medications
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Hypermagnesemia
• Causes: renal failure, diabetic ketoacidosis, and
excessive administration of magnesium
• Manifestations: flushing, lowered BP, nausea, vomiting,
hypoactive reflexes, drowsiness, muscle weakness,
depressed respirations, ECG changes, and dysrhythmias
• Medical management: IV calcium gluconate, loop
diuretics, IV NS or RL, hemodialysis
• Nursing management: assessment, avoid administering
medications containing magnesium, and provide patient
teaching regarding magnesium-containing OTC
medications
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Hypophosphatemia
• 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, and diuretic and antacid use
• Manifestations: neurologic symptoms, confusion, muscle
weakness, tissue hypoxia, muscle and bone pain, and
increased susceptibility to infection
• Medical management: oral or IV phosphorus replacement
• Nursing management: assessment, encourage foods high
in phosphorus, and gradually introduce calories for
malnourished patients receiving parenteral nutrition
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Hyperphosphatemia
• Causes: renal failure, excess phosphorus, excess vitamin D,
acidosis, hypoparathyroidism, and chemotherapy
• Manifestations: few symptoms, soft-tissue calcifications,
symptoms occur owing to associated hypocalcemia
• Medical management: treat underlying disorder; use vitamin D
preparations, calcium-binding antacids, phosphate-binding gels
or antacids, loop diuretics, NS IV, and dialysis
• Nursing management: assessment, avoid high-phosphorus
foods, and provide patient teaching related to diet, phosphatecontaining substances, and signs of hypocalcemia
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Hypochloremia
• Causes: Addison’s disease, reduced chloride intake,
GI loss, diabetic ketoacidosis, excessive sweating,
fever, burns, medications, and metabolic alkalosis
• Loss of chloride occurs with loss of other
electrolytes, potassium, and sodium
• Manifestations: agitation, irritability, weakness,
hyperexcitability of muscles, dysrhythmias, seizures,
and coma
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Hypochloremia cont’d
• Medical management: replace chloride—IV NS or 0.45% NS
• Nursing management: assessment, avoid free water,
encourage high-chloride foods, and provide patient
teaching related to high-chloride foods
• Causes: excess sodium chloride infusions with water loss,
head injury, hypernatremia, dehydration, severe diarrhea,
respiratory alkalosis, metabolic acidosis,
hyperparathyroidism, and medications
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Hyperchloremia
• Manifestations: tachypnea, lethargy, weakness,
rapid, deep respirations, hypertension, and
cognitive changes
• Normal serum anion gap
• Medical management: restore electrolyte and fluid
balance, LR, sodium bicarbonate, and diuretics
• Nursing management: assessment, provide
patient teaching related to diet and hydration
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Maintaining Acid–Base Balance
• Normal plasma pH is 7.35 to 7.45: hydrogen ion
concentration
• Major extracellular fluid buffer system; bicarbonatecarbonic acid buffer system
• Kidneys regulate bicarbonate in ECF
• Lungs under the control of the medulla regulate CO2 and,
therefore, carbonic acid in ECF
• Other buffer systems
– ECF: inorganic phosphates and plasma proteins
– ICF: proteins, organic and inorganic phosphates
– Hemoglobin
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Metabolic Acidosis
• Low pH <7.35
• Low bicarbonate <22 mEq/L
• Most commonly caused by 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 the underlying problem and correct the imbalance;
bicarbonate may be administered
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Metabolic Acidosis cont’d
• With acidosis, hyperkalemia may occur as
potassium shifts out of the cell
• As acidosis is corrected, potassium shifts back
into the cell and potassium levels decrease
• Monitor potassium levels
• Serum calcium levels may be low with chronic
metabolic acidosis and must be corrected before
treating the acidosis
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Metabolic Alkalosis
• High pH >7.45
• High bicarbonate >26 mEq/L
• Most commonly caused by vomiting or gastric suction;
may also be caused by medications, especially long-term
diuretic use
• Hypokalemia will produce alkalosis
• Manifestations: symptoms related to decreased calcium,
respiratory depression, tachycardia, and symptoms of
hypokalemia
• Correct underlying disorder, supply chloride to allow
excretion of excess bicarbonate, and restore fluid volume
with sodium chloride solutions
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Respiratory Acidosis
• Low pH <7.35
• PaCO2 >42 mm Hg
• Always caused by a respiratory problem with inadequate
excretion of CO2
• With chronic respiratory acidosis, the body may
compensate and may be asymptomatic; symptoms may
include a suddenly increased pulse, respiratory rate, and
BP; mental changes; feeling of fullness in the head
• Potential increased intracranial pressure
• Treatment is aimed at improving ventilation
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Respiratory Alkalosis
• High pH >7.45
• PaCO2 <35 mm Hg
• Always caused by hyperventilation
• Manifestations: lightheadedness, inability to
concentrate, numbness and tingling, and
sometimes loss of consciousness
• Correct cause of hyperventilation
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Arterial Blood Gases
• pH—7.35 to 7.45
• PaCO2—35 to 45 mm Hg
• HCO3ˉ—22 to 26 mmol/L
• PaO2—80 to 100 mm Hg
• Oxygen saturation >94%
• Base excess/deficit ±2 mmol/L
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Question
Which of the following clinical manifestations is most
characteristic of hypocalcemia and hypomagnesemia?
a. Tetany
b. Constipation
c. Facial flushing
d. Diplopia
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Answer
a. Tetany
Rationale: Tetany is the most characteristic manifestation
of hypocalcemia and hypomagnesemia. Tetany refers to
the entire symptom complex induced by increased
neural excitability.
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Parenteral Fluid Therapy
• Solutions are classified as isotonic, hypotonic, or
hypertonic
• Nursing management
• Venipuncture devices
• Performing venipuncture—see Chart 15-3
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IV Site Selection
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Complications of IV Therapy
• Fluid overload
• Air embolism
• Septicemia and other infections
• Infiltration and extravasation
• Phlebitis
• Thrombophlebitis
• Hematoma
• Clotting and obstruction
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