Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances

Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances Acute care handbook for physical therapists (fourth edition) chapter 15 fluid and electrolyte imbalances

Fluid and Electrolyte Imbalances

CHAPTER

15

Jaime C Paz

CHAPTER OBJECTIVES

Provide a description of fluid and electrolyte imbalance including:

1 Clinical manifestations and diagnostic studies

2 Contributing health conditions

3 Medical management

4 Guidelines for physical therapy management

PREFERRED PRACTICE PATTERNS

Regulation of fluid and electrolyte imbalance is multifactorial and applies to many body systems For this reason, specific practice patterns are not delineated in this chapter

Please refer to Appendix A for a complete list of the preferred practice patterns in order to best delineate the most applicable practice pattern for a given patient with fluid and electrolyte imbalance

Maintaining homeostasis among intracellular fluid, extracellular fluid, and electrolytes

is necessary to allow proper cell function Proper homeostasis depends on the following factors:

• Concentration of intracellular and extracellular fluids

• Type and concentration of electrolytes

• Permeability of cell membranes

• Kidney function Many variables can alter a patient’s fluid and electrolyte balance These imbalances can further result in numerous clinical manifestations, which can subsequently affect a patient’s functional mobility and activity tolerance Recognizing the signs and symptoms of electrolyte imbalance is therefore an important aspect of physical therapy management In addition, the physical therapist must be aware of which patients are at risk for these imbalances, as well as the concurrent health conditions and medical management of these imbalances

Fluid Imbalance

The total amount of fluid in the body is distributed between the intracellular and extracellular compartments Intracellular fluid contains approximately two-thirds of the body’s fluid Extra-cellular fluid is further made up of interstitial fluid and intravascular fluid, which is the blood and plasma.1-3 Fluid imbalance occurs when there is a deficit or an excess primarily in extracel-lular fluid.1-6Table 15-1 provides an overview of fluid imbalances

Loss of Body Fluid

Loss of bodily fluid can occur from inadequate fluid intake, loss of blood (hemorrhage), loss

of plasma (burns), or loss of body water (vomiting, diarrhea) A fluid deficit can also result from a fluid shift into the interstitial spaces, such as ascites caused by liver failure or pleural effusion from heart failure Any of these situations can result in dehydration, hypovolemia (loss of circulating blood), or shock in extreme cases.1-8

CHAPTER OUTLINE

Fluid Imbalance

Loss of Body Fluid

Excessive Body Fluid

Electrolyte Imbalance

Physical Therapy Considerations

358 CHAPTER 15 Fluid and Electrolyte Imbalances

TABLE 15-1 Fluid Imbalances

Imbalance Definition Contributing Factors Clinical Manifestations Diagnostic Test Findings

Hypovolemia Decreased blood

volume Vomiting, diarrhea, fever, blood loss, uncontrolled

diabetes mellitus

Weak, rapid pulse;

decreased BP;

dizziness; thirst; cool, pale skin over extremities; confusion;

muscle cramps

Decreased hemoglobin and hematocrit with whole blood loss; increased hematocrit with plasma fluid shift from intravascular to interstitial spaces; increased BUN, serum sodium levels

Fluid volume deficit Decreased extracellular

fluid volume

Hypervolemia Increased blood

volume Renal failure, congestive heart failure, blood

transfusion, prolonged corticosteroid therapy

Shortness of breath;

increased BP;

bounding pulse;

presence of an S3 heart sound and cough

if heart is failing;

dependent edema

Decreased hematocrit, BUN; normal serum sodium levels with decreased potassium levels

Fluid volume excess Decreased extracellular

fluid volume

Hyponatremia Sodium deficiency

(serum sodium level <135 mEq/L)

SIADH (see Chapter 10);

diuretic therapy; renal disease; excessive sweating;

hyperglycemia; NPO status; congestive heart failure; side effects from anticonvulsants, glycemic agents, antineoplastics, antipsychotics, and sedatives

Lethargy, nausea, apathy, muscle cramps, muscular twitching, confusion (in severe states)

Decreased urine and serum sodium levels; elevated hematocrit and plasma protein levels

Hypernatremia Sodium excess (serum

sodium level

>145 mEq/L)

Water deficit; diabetes insipidus (see Chapter 10); diarrhea;

hyperventilation;

excessive administration

of corticosteroid, sodium bicarbonate, or sodium chloride

Elevated body temperature; lethargy

or restlessness; thirst;

dry, flushed skin;

weakness; irritability;

hyperreflexia; ataxia;

tremors; tachycardia;

hypertension or hypotension; oliguria;

pulmonary edema

Increased serum sodium and decreased urine sodium levels

Hypokalemia Potassium deficiency

(serum potassium level <3.5 mEq/L)

Inadequate potassium intake, diarrhea, vomiting, chronic renal disease, gastric suction, polyuria, corticosteroid therapy, digoxin therapy

Fatigue; muscle weakness;

slow, weak pulse;

ventricular fibrillation;

paresthesias; leg cramps; constipation;

decreased BP

ST depression or prolonged

PR interval on ECG, increased arterial pH and bicarbonate levels, slightly elevated glucose levels Hyperkalemia Potassium excess

(serum potassium level >5 mEq/L)

Excessive potassium intake, renal failure, Addison’s disease, burns, use of potassium-conserving diuretics, ACE inhibitors, NSAIDs, chronic heparin therapy

Vague muscle weakness, nausea, initial tachycardia followed

by bradycardia, dysrhythmia, flaccid paralysis, paresthesia, irritability, anxiety

ST depression; tall, tented

T waves; or absent P waves on ECG; decreased arterial pH level

Hypocalcemia Calcium deficiency

(serum calcium level <8.5 mg/dl)

Inadequate intake or absorption, bone or soft- tissue deposition, blood transfusions, decreased PTH and vitamin D

Confusion, paresthesias, muscle spasms, hyperreflexia

Prolonged QT segment on ECG, hyperactive bowel sounds

Hypercalcemia Calcium excess

(serum calcium

>12 mg/dl)

Hyperparathyroidism, bone metastases, sarcoidosis, excess vitamin D

Fatigue, weakness, lethargy, anorexia, nausea, constipation

Shortened QT segment or depressed and widened

T waves on ECG

CHAPTER 15 Fluid and Electrolyte Imbalances 359

Imbalance Definition Contributing Factors Clinical Manifestations Diagnostic Test Findings

Hypophosphatemia Phosphate deficiency

(serum phosphate level <2 mg/dl)

Intestinal malabsorption, increased renal excretion Thrombocytopenia, muscle weakness,

irritability, confusion, numbness

Decreased heart rate, hypoxia

Hyperphosphatemia Phosphate excess

(serum phosphate

>4.5 mg/dl)

Chemotherapy, laxatives, hypoparathyroidism Confusion, paresthesias, muscle spasms,

hyperreflexia

Prolonged QT segment on ECG, hyperactive bowel sounds Hypomagnesemia Magnesium deficiency

(serum magnesium

<1.5 mEq/L)

Malnutrition, intestinal malabsorption, alcoholism, renal dysfunction, use of loop and thiazide diuretic agents

Depression, confusion, irritability, hyperreflexia, muscle weakness, ataxia, nystagmus, tetanus, convulsions

Tachyarrhythmias

Hypermagnesemia Magnesium excess

(serum magnesium

>2.5 mEq/L)

Renal failure, excessive antacid intake Nausea, vomiting, muscle weakness Bradycardia, decreased BP

ACE, Angiotensin-converting enzyme; BP, blood pressure; BUN, blood urea nitrogen; ECG, electrocardiogram; NPO, nothing by mouth; SIADH, syndrome of

inappropriate antidiuretic hormone secretion; ACE, angiotensin-converting enzyme; NSAIDs, nonsteroidal antiinflammatory drugs; PTH, parathyroid hormone.

TABLE 15-1 Fluid Imbalances—cont’d

Data from Huether SE: The cellular environment: fluids and electrolytes, acids and bases In McCance KL, Huether SE, Brashers VL et al, editors: Pathophysiology, the biologic basis for disease in adults and children, ed 6, St Louis, 2010, Mosby, pp 96-125; The body fluid compartments: extracellular and intracellular fluids; edema In Hall JE, editor: Guyton and Hall textbook of medical physiology, ed 12, Philadelphia, 2011, Saunders, pp 285-301; Porth CM: Alterations in fluids and electrolytes In Porth CM, editor: Pathophysiology, concepts of altered health states, ed 6, Philadelphia, 2002, Lippincott, pp 693-734; Gorelick MH, Shaw KN, Murphy KO: Validity and reliability of clinical signs in the diagnosis of dehydration in children, Pediatrics 99(5):E6, 1997; Mulvey M: Fluid and electrolytes: balance and disorders In Smeltzer SC, Bare BG, editors: Brunner and Suddarth’s textbook of medical-surgical nursing, ed 8, Philadelphia, 1996, Lippincott; Goodman CC, Kelly Snyder TE: Problems affecting multiple systems In Goodman CC, Boissonnault WG, editors: Pathology: implications for the physical therapist, Philadelphia,

1998, Saunders; Fall PJ: Hyponatremia and hypernatremia: a systematic approach to causes and their correction, Postgrad Med 107(5):75-82, 2000; Marieb EN editor: Human anatomy and physiology, ed 2, Redwood City, CA, 1992, Benjamin Cummings, p 911.

Clinical manifestations may include decreased blood

pres-sure, increased heart rate, changes in mental status, thirst,

dizziness, hypernatremia, increased core body temperature,

weakness, poor skin turgor, altered respirations, and

ortho-static hypotension.1-8 Clinical manifestations in children also

include poor capillary refill, absent tears, and dry mucous

membranes.8

Electrolyte Imbalance

Fluid imbalances are often accompanied by changes in electro-lytes Loss or gain of body water is usually accompanied by a loss or gain of electrolytes Similarly, a change in electrolyte balance often affects fluid balance Cellular functions that are reliant on proper electrolyte balance include neuromuscular excitability, secretory activity, and membrane permeability.9 Clinical manifestations will vary depending on the severity of the imbalance and can include those noted in the Fluid Imbal-ance section In extreme cases, muscle tetany and coma can also occur Common electrolyte imbalances are further summarized

in Table 15-1 Alterations in arterial blood gas (ABG) levels are also considered electrolyte imbalances.10

Electrolyte levels are generally represented schematically in the medical record in a sawhorse figure, as shown in Figure 15-1 Electrolytes that are out of reference range are either highlighted with a circle or annotated with an arrow (↑ or ↓)

to denote their relationship to the reference value

Medical management includes identification of causative factors and ongoing monitoring of electrolyte imbalances with laboratory testing of blood and urine These tests include

CLINICAL TIP

During casual conversation among physicians and nurses,

patients who are hypovolemic are often referred to as being

dry, whereas patients who are hypervolemic are referred to as

being wet.

Excessive Body Fluid

Excessive bodily fluid can occur when there is excessive sodium

or fluid intake, or sodium or fluid retention Acute or chronic

kidney failure can also result in a fluid volume excess A shift

of water from the intravascular space to the intracellular

com-partments can also occur as a result of excessive pressure in the

vasculature (ventricular failure), loss of serum albumin (liver

failure), or fluid overload (excessive rehydration during

surgery).1-6,8

Clinical manifestations of fluid overload include weight gain,

pulmonary edema, peripheral edema, and bounding pulse

Clin-ical manifestations of this fluid shift may also resemble those of

dehydration (e.g., tachycardia and hypotension), as there is a

resultant decrease in the intravascular fluid volume.1-6,8

CLINICAL TIP

Patients with interstitial edema may often be referred to as

third-spacing, which refers to the shift of fluid volume from

intravascular to extravascular spaces

360 CHAPTER 15 Fluid and Electrolyte Imbalances

• Patients who have a fluid volume deficit are at risk for ortho-static hypotension; therefore monitor vital signs carefully and proceed with upright activities very gradually

• Furthermore, patients who have a sodium deficit may also have fluid restrictions to minimize risk of hyponatremia

• Slight potassium imbalances can have significant effects on cardiac rhythms; therefore carefully monitor the patient’s cardiac rhythm before, during, and after physical therapy intervention If the patient is not on a cardiac monitor, then consult with the nurse or physician regarding the appropri-ateness of physical therapy intervention with a patient who has potassium imbalance

• Patients who are taking antihypertensive medications are at risk for electrolyte imbalances These medications include thiazide, loop, and potassium-sparing diuretics; β-blockers; angiotensin-converting enzyme (ACE) inhibitors; and angio-tensin receptor blockers (ARBs).11

• Refer to Chapter 3 for more information on cardiac arrhythmias

• Refer to Chapter 4 for more information on ABGs

• Refer to Chapter 9 for more information on fluid and elec-trolyte imbalances caused by renal dysfunction

• Refer to Chapter 10 for more information on fluid and elec-trolyte imbalances caused by endocrine dysfunction

• Refer to Chapter 19 for more information on antihyperten-sive medications

measuring levels of sodium, potassium, chloride, and calcium

in blood and urine; arterial blood gases; and serum and urine

osmolality Treatment involves managing the primary cause of

the imbalance(s), along with providing supportive care with

intravenous or oral fluids, electrolyte supplementation, and diet

modifications

Physical Therapy Considerations

• Review the medical record closely for any fluid restrictions

that may be ordered for a patient with fluid volume excess

These restrictions may also be posted at the patient’s bedside

• Conversely, ensure proper fluid intake before, during, and

after physical therapy intervention with patients who have a

fluid volume deficiency

FIGURE 15-1

Schematic representation of electrolyte levels BUN, Blood urea nitrogen;

BS, blood sugar; Cl, chloride; Cr, creatinine; HCO 3 , bicarbonate; K,

potas-sium; Na, sodium

Na

K

Cl

HCO3

BUN

BS Cr

References

6 Kokko J, Tannen R, editors: Fluids and electrolytes, ed 2, Philadelphia, 1990, Saunders.

7 McGee S, Abernethy WB 3rd, Simel DL: Is this patient hypovolemic? JAMA 281(11):1022-1029, 1999.

8 Springhouse: Portable fluids & electrolytes, Philadelphia, 2008, Lippincott William & Wilkins.

9 Marieb EN, editor: Human anatomy and physiology, ed 2, Redwood City, CA, 1992, Benjamin Cummings, p 911.

10 Fukagawa M, Kurokawa K, Papadakis MA: Fluid & electrolyte disorders In Tierney LM, McPhee SJ, Papadakis MA, editors: Current medical diagnosis & treatment, New York, 2007, McGraw-Hill.

11 Liamis G, Milionis H, Elisaf M: Blood pressure drug therapy and electrolyte disturbances, Int J Clin Pract 62(10):1572-1580, 2008.

1 Huether SE: The cellular environment: fluids and electrolytes,

acids and bases In McCance KL, Huether SE, Brashers VL et al,

editors: Pathophysiology, the biologic basis for disease in adults

and children, ed 6, St Louis, 2010, Mosby, pp 96-125.

2 The body fluid compartments: extracellular and intracellular

fluids; edema In Hall JE, editor: Guyton and Hall textbook of

medical physiology, ed 12, Philadelphia, 2011, Saunders,

pp 285-301.

3 Porth CM: Alterations in fluids and electrolytes In Porth CM,

editor: Pathophysiology, concepts of altered health states, ed 6,

Philadelphia, 2002, Lippincott, pp 693-734.

4 Rose BD, editor: Clinical physiology of acid-base and electrolyte

disorders, ed 2, New York, 1984, McGraw-Hill.

5 Cotran RS, Kumar V, Robbins S et al, editors: Robbins

pathologic basis of disease, Philadelphia, 1994, Saunders.