CHAPTER 16 Fluid and Electrolyte Abnormalities

Betty L. Kuiper, MSN, ARNP-CNS, CEN

MAJOR TOPICS

General Strategy

Assessment

Analysis: Differential Nursing Diagnoses/Collaborative Problems

Planning and Implementation/Interventions

Evaluation and Ongoing Monitoring

Documentation of Interventions and Patient Response

Age-Related Considerations

Specific Fluid Emergencies

Dehydration

Specific Electrolyte Emergencies

Sodium

Hyponatremia

Hypernatremia

Potassium

Hypokalemia

Hyperkalemia

Calcium

Hypocalcemia

Hypercalcemia

Magnesium

Hypomagnesemia

Hypermagnesemia

I. GENERAL STRATEGY

A. Assessment

1. Primary and secondary assessment/resuscitation (see Chapter 1)

a. Subjective data collection

1) History of present illness/chief complaint

a) Pain: PQRST (see Chapter 9)

b) Injury: mechanism (see Chapter 30) and time

c) Fatigue, malaise

d) Nausea, vomiting

e) Altered mental status or decreased level of consciousness

f) Fever

g) Dyspnea

h) Urticaria

i) Edema: location and type

j) Weakness

k) Rash

l) Cough

m) Sore throat

n) Other symptoms: anorexia, pruritus, diarrhea

o) Efforts to relieve symptoms

(1) Home remedies

(2) Alternative therapies

(3) Medications

(a) Prescription

(b) Over-the-counter

2) Past medical history

a) Current or preexisting diseases/illness

(1) Vascular disease

(2) Diabetes

(3) Alcoholism

(4) Sickle cell anemia

(5) Hemophilia

(6) Renal disease

(a) Acute renal failure

(b) Dialysis

(c) Adrenal disease

(7) Exposure to illness

(8) Splenectomy: alters immune system

(9) Infection: viral, bacterial, fungal, rickettsial, or parasitic

(10) Vitamin deficiency

(11) Malabsorption syndromes

b) Recent major injury

c) Previous similar episodes

d) Inadequately treated disease process

e) Last normal menstrual period: female patients of childbearing age

f) Smoking history

g) Substance and/or alcohol use/abuse

h) Current medications

(1) Prescription

(a) Anticoagulants

(b) Insulin or oral hypoglycemic

(c) Phenothiazines

(d) Angiotensin-converting enzyme (ACE) inhibitors

(e) Beta-blockers

(f) Potassium-sparing diuretics

(g) Angiotensin II receptor antagonists (or blockers) (ARBs)

(h) Calcium channel blockers

(i) Digitalis

(2) Over-the-counter/herbal

(a) Decongestants

(b) Acetaminophen or aspirin

i) Allergies

j) Immunization status

3) Psychological/social/environmental factors

a) Age: illness more severe in very young and elderly

b) Family history

c) Gender: some disorders are gender linked

d) Race: may determine increased incidence

e) Possible/actual assault, abuse, or intimate partner violence situations (see Chapter 3)

f) Lifestyle

(1) Sedentary lifestyle

(2) Nutritional status: obesity and dietary excess or deficit

g) Stressors: surgery, trauma, illness, psychosocial factors

h) Climate or environment

i) Immobilization

b. Objective data collection

1) General appearance

a) Level of consciousness, behavior, affect

b) Vital signs, including orthostasis

c) Odors

d) Gait

e) Hygiene

f) Weight

g) Level of distress/discomfort

2) Inspection

a) Neck veins

b) Skin color, rash or urticaria

c) Mucous membranes

d) Evidence of trauma

e) Areas of erythema

3) Auscultation

a) Breath sounds: clear, wheezes, crackles

b) Bowel sounds: normal, hyperactive, hypoactive, absent

c) Heart sounds: S₁ and S₂, other sounds (e.g., murmurs) dysrhythmias

4) Palpation/percussion

a) Skin moisture, turgor

b) Areas of tenderness

c) Areas of edema

d) Areas of hyperthermia

e) Arteries: equality of peripheral pulses

f) Veins: venous filling and varicosities

g) Capillary refill

h) Lymph nodes

i) Muscle tone, strength

j) Deep tendon reflexes

3. Diagnostic procedures

a. Laboratory studies

1) Complete blood count (CBC) with differential

2) Serum chemistries including glucose, blood urea nitrogen (BUN), and creatinine

3) Arterial blood gases (ABGs)

4) Serum and urine toxicology: therapeutic level and toxic ingestion

5) Clotting profile: partial thromboplastin time (PTT), prothrombin time (PT)

6) Type and crossmatch

7) Serum ammonia level

8) Carboxyhemoglobin level

9) Serum uric acid

10) Liver enzymes

11) Sickle cell screen

12) Hepatitis screen

13) Serum ketone levels

14) Cerebrospinal fluid (CSF): cell count, glucose, and protein count, culture

15) Brain natriuretic peptide (BNP)

16) Urinalysis; pregnancy test in female patients of childbearing age

b. Imaging studies

1) Chest radiograph

2) Computed tomography (CT) scan

3) Magnetic resonance imaging (MRI) scan

c. Other

1) 12- to 15-lead electrocardiogram (ECG)

2) Electroencephalogram (EEG)

3) Lumbar puncture

B. Analysis: Differential Nursing Diagnoses/Collaborative Problems

1. Ineffective airway clearance

2. Impaired gas exchange

3. Decreased cardiac output

4. Deficient/excess fluid volume

5. Ineffective tissue perfusion

6. Anxiety/fear

7. Fatigue

8. Impaired skin integrity

9. Deficient knowledge

10. Pain

11. Risk for infection

12. Risk for injury

C. Planning and Implementation/Interventions

1. Determine priorities of care

a. Maintain airway, breathing, and circulation (seeChapter 1)

b. Provide supplemental oxygen as indicated

c. Establish intravenous (IV) access for administration of crystalloid fluid/blood products/medications

d. Obtain and set up equipment and supplies

e. Prepare for/assist with medical interventions

f. Administer pharmacologic therapy as ordered

2. Relieve anxiety/apprehension

3. Allow significant others to remain with patient if supportive

4. Educate patient and significant others

D. Evaluation and Ongoing Monitoring (see Appendix B)

1. Continuously monitor and treat as indicated

2. Monitor patient response/outcomes, and modify nursing care plan as appropriate

3. If positive patient outcomes are not demonstrated, reevaluate assessment and/or plan of care

E. Documentation of Interventions and Patient Response

F. Age-Related Considerations

1. Pediatrics

a. Growth or development related

1) Children have a faster metabolic rate and greater oxygen demand per kilogram of body weight

2) Neonates have higher sodium and chloride levels but lower potassium, magnesium, and phosphate levels than older children

3) The fluid exchange rate is greater in neonates than in older children

4) Dehydration can occur rapidly because of a larger body surface area, faster metabolic rate, and smaller extracellular fluid volume

b. “Pearls”

1) Dehydration in a previously healthy child is frequently the result of gastrointestinal (GI) losses from vomiting and diarrhea

2) The most common type of dehydration is isotonic

3) Normal urinary output in well-hydrated children is 1 mL/kg/hour and in newborns is 2 mL/kg/hour

4) Neonates are prone to developing acidosis when under stress

5) Neonates have limited fluid volume reserve

2. Geriatrics

a. Aging related

1) Decreased nutritional intake can occur because of mouth dryness, decreased appetite, poor fitting dentures, or lack of interest in eating

2) Total body water (TBW) decreases with age

3) A decreased sense of “thirst” can lead to dehydration

b. “Pearls”

1) Chronic dehydration is more common in older adults

2) Anorexia can be caused by hypercalcemia

3) Hyponatremia is a common cause of delirium in the older adult

4) Use of nutritional supplements (e.g., Ensure) can lead to hyponatremia

II. SPECIFIC FLUID EMERGENCIES

A. Dehydration

Fluid volume deficit is a TBW deficit that is associated with a loss of sodium accompanied by water. Iso-osmolar fluid volume deficit occurs when sodium and water are lost in equal amounts. Hyperosmolar fluid volume deficit occurs when more fluid is lost than sodium, a condition resulting in higher serum osmolality than normal. Hypo-osmolar fluid deficits occur from sodium deficiencies or free water excess, resulting in a lower than normal serum osmolality. Fluid deficit leads to conditions known as dehydration and hypovolemia. Dehydration is a disorder of water loss with or without loss of sodium and is frequently observed in critically ill patients. There are three types of dehydration: (1) isotonic, (2) hypotonic, and (3) hypertonic.

Isotonic dehydration, also termed isotonic fluid volume depletion, is a balanced depletion of water and sodium causing extracellular fluid loss. Causes include vomiting, diarrhea, and osmotic diuresis from elevated glucose levels. Total circulating volume is affected in isotonic dehydration as a result of overall fluid volume depletion.

Hypotonic dehydration, also termed extracellular fluid volume depletion, is a reduction in both sodium and water, with greater losses of sodium than water, that results in extracellular fluid loss. Causes include overuse of diuretics, chronic salt wasting, renal disease, and decreased intake of both salt and water. Circulation is affected in hypotonic dehydration because fluid moves intracellularly and decreases plasma volume.

Hypertonic dehydration, also known as intracellular or hypernatremic dehydration, is depletion in TBW content consequent to pathologic fluid losses, diminished water intake, or a combination of both. It results in hypernatremia (greater than 145 mEq/L) in the extracellular fluid compartment, thereby drawing water from the intracellular fluids. The water loss is shared by all body fluid compartments, and relatively little reduction in extracellular fluids occurs. Thus, overall circulation is not compromised unless the loss is very large.

1. Assessment

a. Subjective data collection

1) History of present illness/chief complaint

a) Nausea, vomiting, diarrhea

b) Decreased intake

c) Bleeding from any source

d) Weight loss

e) Polyuria, polydipsia

f) Lassitude, fatigability, muscle cramps

g) Postural dizziness and syncope

h) Seizures, coma, confusion, syncope

i) Unusual salt craving

j) Trauma: blunt or penetrating forces

k) Abdominal or chest pain (i.e., attributable to pancreatitis and decreased organ perfusion)

l) Alcohol ingestion

m) Fever

2) Past medical history

a) Current or preexisting diseases/illness

(1) Diabetes

b) Previous similar episodes

c) Substance abuse

d) Medications

e) Allergies

b. Objective data collection

1) Physical examination

a) General appearance

(1) Level of consciousness, behavior, affect: confusion, lethargy, coma

(2) Tachycardia, hypotension, orthostasis

(3) Possible elevated temperature

(4) Moderate to severe distress/discomfort

b) Inspection

(1) Lacerations, abrasions, ecchymosis, rashes, asymmetry, or edema

(2) Petechiae

(3) Bony deformities or angulation

(4) Flattened external jugular veins

(5) Sunken eyes

(6) Pupils, including size, shape, equality, reactivity to light

(7) Dry mucous membranes

(8) Drainage or external bleeding

(9) Respiratory rate, depth, work of breathing, use of accessory muscles, abdominal muscles, paradoxical chest wall movement

(10) Abdominal distention

(11) Venous access devices, feeding tubes or buttons

(12) Weight loss

c) Palpation/percussion

(1) Skin temperature, moisture and turgor

(a) Poor skin turgor: sternum or inner thigh in the elderly

(2) Diminished peripheral pulses

(3) Sunken fontanelle

(4) Skeletal muscle weakness

2) Diagnostic procedures

a) Serum osmolality: increased or decreased

b) CBC with differential: hematocrit elevated or decreased

c) Serum chemistries including glucose, BUN, and creatinine

(1) Sodium increased or decreased

d) ABG analysis: metabolic alkalosis or metabolic acidosis

e) Blood, urine, or CSF fluid cultures as appropriate

f) Urinalysis; pregnancy test in female patients of childbearing age

g) Radiograph studies as determined by history to rule out infection or trauma

h) ECG

2. Analysis: differential nursing diagnoses/collaborative problems

a. Deficient fluid volume

b. Decreased cardiac output

c. Ineffective tissue perfusion

d. Deficient knowledge

3. Planning and implementation/interventions

a. Maintain airway, breathing, and circulation (seeChapter 1)

b. Provide supplemental oxygen

c. Establish IV access for administration of crystalloid fluids/medications

1) Rapidly infuse 1 to 2 L of normal saline solution in adults who have no cardiovascular disease

2) Administer normal saline solution fluid challenge in older adults and monitor closely for fluid overload

3) Infuse 20 mL/kg normal saline solution bolus in children; may repeat once

d. Prepare for/assist with medical interventions

1) Institute cardiac and pulse oximetry monitoring

2) Provide oral fluid challenges

3) Catheter placement and monitoring of central venous pressure (CVP) (see Chapter 7)

4) Insert gastric tube and attach to suction as indicated

5) Insert indwelling urinary catheter as indicated

6) Assist with possible hospital admission

e. Administer pharmacologic therapy as ordered

1) Oral or IV sodium replacement

2) IV sodium bicarbonate if pH less than 7.1

3) Antiemetics

4) Antidiarrheals

f. Educate patient and significant others

1) Administer small, frequent amounts of oral fluids for 12 to 24 hours after vomiting stops, then advance diet as tolerated

2) Continue feeding normally even when diarrhea is present

3) Signs and symptoms that indicate need to return to emergency care setting

a) Continued vomiting

b) Continued diarrhea

c) Elevated temperature

d) Dry mucous membranes and skin

e) Decreased urine output

f) Sunken fontanelle and sunken eyes

g) Crying without tears (i.e., after 2 to 3 months old)

h) Lethargy

i) Postural dizziness

4. Evaluation and ongoing monitoring (see Appendix B)

a. Level of consciousness

b. Hemodynamic status including orthostasis

c. Breath sounds and pulse oximetry

d. Cardiac rate and rhythm

e. Intake and output

III. SPECIFIC ELECTROLYE EMERGENCIES

Electrolytes are divided into positively and negatively charged groups of cations (+) and anions (−). Electrolytes are found in intracellular and extracellular fluid and are critical for normal cellular metabolism and function. Sodium, the major extracellular cation, is responsible for maintaining plasma osmolarity, propagation and transmission of action potentials, maintaining acid-base balance, and maintaining electroneutrality. Potassium, the major intracellular cation, is responsible for electrical membrane excitability, maintaining acid-base balance, and regulating intracellular osmolarity. Calcium has several major roles; it is an essential component in the contractile processes (i.e., cardiac, skeletal, and smooth muscle), provides strength and density of teeth and bones, stabilizes excitable membranes, and is a cofactor in the clotting cascade.

Direct measurement of intracellular electrolytes is not possible in the clinical setting, so the values are determined indirectly. Electrolyte abnormalities may be caused by dietary excesses or deficits, prescribed medications, excess or lack of water ingestion, vomiting, and diarrhea.

A. Sodium

Sodium is responsible for normal water balance and impulse conduction. Active transport by adenosine triphosphate (ATP) is necessary to keep sodium in the extracellular space. Sodium is regulated by the renin-angiotension-aldosterone system, sympathetic nervous system (SNS), and in a less well-defined system, mediated by atrial natriuretic factor (ANF). Baroreceptor stimulation of the SNS leads to vasoconstriction, decreased glomerular filtration rate, and retention of sodium and water. Release of ANF by the atria leads to excessive sodium excretion and diuresis. The normal sodium level is 135 to 145 mEq/L.

Hyponatremia

Hyponatremia may result from either actual sodium deficits or dilutional causes. Sodium deficits resulting from dilutional effects can be caused by excess water intake, freshwater drowning, inappropriate antidiuretic hormone secretion, and psychogenic polydipsia or true sodium loss from hyperglycemia, heart failure, or burns. Causes of actual sodium deficits resulting from increased sodium excretion include diaphoresis, diuretic use, wound drainage, decreased secretion of aldosterone, hyperlipidemia, and renal disease. Causes of actual sodium deficits resulting from inadequate sodium intake include nothing by mouth (NPO) restrictions and a low-sodium diet. Symptoms related to hyponatremia usually do not occur unless the sodium level is less than 120 to 125 mEq/L.

1. Assessment

a. Subjective data collection

1) History of present illness/chief complaint

a) Anorexia, nausea, vomiting, diarrhea

b) Altered oral intake: immobility or inability to obtain oral fluids

c) Altered dietary intake of sodium

d) Excessive water consumption

e) Trauma, burns, or neurologic injury or surgery

f) Lethargy and apathy

g) Thirst

h) Confusion, personality changes

i) Seizures and coma

j) Weight change

k) Fatigue and muscle cramps

l) Dizziness

m) Headache

n) Poor peripheral pulses

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