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

CHAPTER 15 Fluid and Electrolyte Imbalances Jaime C Paz CHAPTER OUTLINE CHAPTER OBJECTIVES Fluid Imbalance Loss of Body Fluid Excessive Body Fluid Electrolyte Imbalance Physical Therapy Considerations Provide a description of fluid and electrolyte imbalance including: Clinical manifestations and diagnostic studies Contributing health conditions Medical management 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 Extracellular 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 extracellular fluid.1-6 Table 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.1-8 357 358 CHAPTER 15    Fluid and Electrolyte Imbalances TABLE 15-1  Fluid Imbalances Imbalance Definition Contributing Factors Clinical Manifestations Diagnostic Test Findings Hypovolemia Decreased blood volume Decreased extracellular fluid volume Vomiting, diarrhea, fever, blood loss, uncontrolled diabetes mellitus Weak, rapid pulse; decreased BP; dizziness; thirst; cool, pale skin over extremities; confusion; muscle cramps Increased blood volume Decreased extracellular fluid volume Renal failure, congestive heart failure, blood transfusion, prolonged corticosteroid therapy Hyponatremia Sodium deficiency (serum sodium level 145 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 Water deficit; diabetes insipidus (see Chapter 10); diarrhea; hyperventilation; excessive administration of corticosteroid, sodium bicarbonate, or sodium chloride Shortness of breath; increased BP; bounding pulse; presence of an S3 heart sound and cough if heart is failing; dependent edema Lethargy, nausea, apathy, muscle cramps, muscular twitching, confusion (in severe states) Decreased hemoglobin and hematocrit with whole blood loss; increased hematocrit with plasma fluid shift from intravascular to interstitial spaces; increased BUN, serum sodium levels Decreased hematocrit, BUN; normal serum sodium levels with decreased potassium levels Hypokalemia Potassium deficiency (serum potassium level 5 mEq/L) Hypocalcemia Calcium deficiency (serum calcium level 12 mg/dl) Fluid volume deficit Hypervolemia Fluid volume excess Inadequate potassium intake, diarrhea, vomiting, chronic renal disease, gastric suction, polyuria, corticosteroid therapy, digoxin therapy Excessive potassium intake, renal failure, Addison’s disease, burns, use of potassium-conserving diuretics, ACE inhibitors, NSAIDs, chronic heparin therapy Inadequate intake or absorption, bone or softtissue deposition, blood transfusions, decreased PTH and vitamin D Hyperparathyroidism, bone metastases, sarcoidosis, excess vitamin D Decreased urine and serum sodium levels; elevated hematocrit and plasma protein levels Elevated body temperature; lethargy or restlessness; thirst; dry, flushed skin; weakness; irritability; hyperreflexia; ataxia; tremors; tachycardia; hypertension or hypotension; oliguria; pulmonary edema Fatigue; muscle weakness; slow, weak pulse; ventricular fibrillation; paresthesias; leg cramps; constipation; decreased BP Vague muscle weakness, nausea, initial tachycardia followed by bradycardia, dysrhythmia, flaccid paralysis, paresthesia, irritability, anxiety Confusion, paresthesias, muscle spasms, hyperreflexia Increased serum sodium and decreased urine sodium levels Fatigue, weakness, lethargy, anorexia, nausea, constipation Shortened QT segment or depressed and widened T waves on ECG ST depression or prolonged PR interval on ECG, increased arterial pH and bicarbonate levels, slightly elevated glucose levels ST depression; tall, tented T waves; or absent P waves on ECG; decreased arterial pH level Prolonged QT segment on ECG, hyperactive bowel sounds CHAPTER 15    Fluid and Electrolyte Imbalances 359 TABLE 15-1  Fluid Imbalances—cont’d Imbalance Definition Contributing Factors Clinical Manifestations Diagnostic Test Findings Hypophosphatemia Phosphate deficiency (serum phosphate level 4.5 mg/dl) Magnesium deficiency (serum magnesium 2.5 mEq/L) Malnutrition, intestinal malabsorption, alcoholism, renal dysfunction, use of loop and thiazide diuretic agents Renal failure, excessive antacid intake Prolonged QT segment on ECG, hyperactive bowel sounds Tachyarrhythmias Bradycardia, decreased BP 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 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 Clinical manifestations may include decreased blood pressure, 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   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 compartments 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 Clinical 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 Electrolyte Imbalance Fluid imbalances are often accompanied by changes in electrolytes 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 Imbalance 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 360 CHAPTER 15    Fluid and Electrolyte Imbalances Na Cl BUN BS K HCO3 Cr FIGURE 15-1  Schematic representation of electrolyte levels BUN, Blood urea nitrogen; BS, blood sugar; Cl, chloride; Cr, creatinine; HCO3, bicarbonate; K, potassium; Na, sodium 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 • Patients who have a fluid volume deficit are at risk for orthostatic 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 appropriateness 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 angiotensin receptor blockers (ARBs).11 • Refer to Chapter for more information on cardiac arrhythmias • Refer to Chapter for more information on ABGs • Refer to Chapter for more information on fluid and electrolyte imbalances caused by renal dysfunction • Refer to Chapter 10 for more information on fluid and electrolyte imbalances caused by endocrine dysfunction • Refer to Chapter 19 for more information on antihypertensive medications References 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 Rose BD, editor: Clinical physiology of acid-base and electrolyte disorders, ed 2, New York, 1984, McGraw-Hill Cotran RS, Kumar V, Robbins S et al, editors: Robbins pathologic basis of disease, Philadelphia, 1994, Saunders Kokko J, Tannen R, editors: Fluids and electrolytes, ed 2, Philadelphia, 1990, Saunders McGee S, Abernethy WB 3rd, Simel DL: Is this patient hypovolemic? JAMA 281(11):1022-1029, 1999 Springhouse: Portable fluids & electrolytes, Philadelphia, 2008, Lippincott William & Wilkins 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  ... (ARBs).11 • Refer to Chapter for more information on cardiac arrhythmias • Refer to Chapter for more information on ABGs • Refer to Chapter for more information on fluid and electrolyte imbalances caused... level Prolonged QT segment on ECG, hyperactive bowel sounds CHAPTER 15    Fluid and Electrolyte Imbalances 359 TABLE 1 5- 1  Fluid Imbalances cont’d Imbalance Definition Contributing Factors Clinical... of causative factors and ongoing monitoring of electrolyte imbalances with laboratory testing of blood and urine These tests include 360 CHAPTER 15    Fluid and Electrolyte Imbalances Na Cl BUN