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Chapter 14

Fluids and Electrolytes

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Electrolyte Imbalances

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HyponatremiaLower than normal sodium in the blood serum Can be actual deficiency of sodium or

increase in body water that dilutes the sodium excessively

AssessmentSymptoms: headache, muscle weakness,

fatigue, apathy, confusion, abdominal cramps, and orthostatic hypotension

Take blood pressures with the patient lying or sitting and then standing to determine if a significant drop

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HyponatremiaMedical treatment

The usual treatment is restriction of fluids while the kidneys excrete excess water

Diuretic: furosemide (Lasix) Sodium replacement therapy

Nursing careAdminister prescribed medications and IV

fluidsMeasure fluid intake and output and assess

mental status

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HypernatremiaHigher than normal concentration of

sodium in the bloodVery serious imbalance; can lead to death if

not correctedOccurs when excessive loss of water or

excessive retention of sodiumSigns and symptoms

Thirst, flushed skin, dry mucous membranes, low urine output, restlessness, increased heart rate, convulsions, and postural hypotension

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HypernatremiaMedical treatment

Oral or IV replacement of water to restore balance

A low-sodium diet often prescribed Nursing care

Encourage patients with hypernatremia to drink water

Closely monitor the infusion of IV fluidsTeach patient to track daily I&O and to

recognize the signs and symptoms of fluid retention or depletion

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HypokalemiaLow serum potassium

May result in gastrointestinal, renal, cardiovascular, and neurologic disturbances

Can cause abnormal, potentially fatal, heart rhythm

Signs and symptoms Anorexia, abdominal distention, vomiting,

diarrhea, muscle cramps, weakness, dysrhythmias (abnormal cardiac rhythms), postural hypotension, dyspnea, shallow respirations, confusion, depression, polyuria (excessive urination), and nocturia

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HypokalemiaMedical treatment

Potassium replacement by the IV or oral route Nursing care

Monitoring at-risk patients for decreased bowel sounds, a weak and irregular pulse, decreased reflexes, and decreased muscle tone

Cardiac monitors may be used to detect dysrhythmias

Administer oral or IV potassiumUrine output should be no less than 30 ml/hr

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HyperkalemiaHigh serum potassium

Patients at risk: decreased renal function, in metabolic acidosis, taking potassium supplements

A serious imbalance because of the potential for life-threatening dysrhythmias

Signs and symptoms Explosive diarrhea and vomiting; muscle cramps

and weakness, paresthesia, irritability, anxiety, abdominal cramps, and decreased urine output

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HyperkalemiaMedical treatment

Correct the underlying causeRestrict potassium intake Polystyrene sulfonate (Kayexalate)Intravenous calcium gluconate

Nursing carePatients with low urine output or those taking

potassium-sparing diuretics must be monitored carefully for signs and symptoms

Carefully monitor flow rate of IV fluids, which should not exceed 10 mEq/hr through peripheral veins

Screen the results of laboratory studies

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Chloride ImbalanceUsually bound to other electrolytes;

therefore, chloride imbalances accompany other electrolyte imbalancesHyperchloremia

Usually associated with metabolic acidosis Hypochloremia

Usually occurs when sodium is lost because chloride most frequently bound with sodium

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Calcium ImbalanceRegulated by the parathyroid glandsHypocalcemia results from diarrhea, inadequate

dietary intake of calcium or vitamin D, and multiple blood transfusions (banked blood contains citrates that bind to calcium), in addition to some diseases, including hypoparathyroidism

Hypercalcemia results from a high calcium or vitamin D intake, hyperparathyroidism, and immobility that causes stores of calcium in the bones to enter the bloodstream

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Magnesium ImbalanceHypomagnesemia: decreased

gastrointestinal absorption or excessive gastrointestinal loss, usually from vomiting and diarrhea, or increased urinary loss

Hypermagnesemia occurs most often with excessive use of magnesium-containing medications or intravenous solutions in patients with renal failure or preeclampsia of pregnancy

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Acid-Base Disturbances

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Respiratory AcidosisRespiratory system fails to eliminate the

appropriate amount of carbon dioxide to maintain the normal acid-base balance

Caused by pneumonia, drug overdose, head injury, chest wall injury, obesity, asphyxiation, drowning, or acute respiratory failure

Medical treatmentImprove ventilation, which restores partial

pressure of carbon dioxide in arterial blood (Paco2) to normal

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Respiratory AcidosisNursing care

Assess Paco2 levels in the arterial bloodObserve for signs of respiratory distress:

restlessness, anxiety, confusion, tachycardiaIntervention

Encourage fluid intake Position patients with head elevated 30

degrees

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Respiratory AlkalosisLow Paco2 with a resultant rise in pH

Most common cause of respiratory alkalosis is hyperventilation

Medical treatment Major goal of therapy: treat underlying cause of

condition; sedation may be ordered for the anxious patient

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Respiratory AlkalosisNursing care

Intervention In addition to giving sedatives as ordered,

reassure the patient to relieve anxiety Encourage patient to breathe slowly, which will

retain carbon dioxide in the body

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Metabolic AcidosisBody retains too many hydrogen ions or loses

too many bicarbonate ions; with too much acid and too little base, blood pH falls

Causes are starvation, dehydration, diarrhea, shock, renal failure, and diabetic ketoacidosis

Signs and symptoms: changing levels of consciousness, headache, vomiting and diarrhea, anorexia, muscle weakness, cardiac dysrhythmias

Medical treatment: treat the underlying disorder

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Metabolic AcidosisNursing care

Assessment of the patient in metabolic acidosis should focus on vital signs, mental status, and neurologic status

Emergency measures to restore acid-base balance. Administer drugs and intravenous fluids as prescribed. Reassure and orient confused patients

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Metabolic AlkalosisIncrease in bicarbonate levels or a loss of

hydrogen ions Loss of hydrogen ions may be from prolonged

nasogastric suctioning, excessive vomiting, diuretics, and electrolyte disturbances

Signs and symptoms: headache; irritability; lethargy; changes in level of consciousness; confusion; changes in heart rate; slow, shallow respirations with periods of apnea; nausea and vomiting; hyperactive reflexes; and numbness of the extremities

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Metabolic AlkalosisMedical treatment

Depends on the underlying cause and severity of the condition

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Metabolic AlkalosisNursing care

Assessment Take vital signs and daily weight; monitor heart

rate, respirations, and fluid gains and losses Keep accurate intake and output records,

including the amount of fluid removed by suction Assess motor function and sensation in the

extremities; monitor laboratory values, especially pH and serum bicarbonate levels

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Metabolic AlkalosisIntervention

To prevent metabolic alkalosis, use isotonic saline solutions rather than water for irrigating nasogastric tubes because the use of water for irrigation can result in a loss of electrolytes

Provide reassurance and comfort measures to promote safety and well-being