Chapter 25 Fluid Electrolyte and AcidBase Balance Copyright

Lesson 25. 1 Fluids and Electrolytes Theory 1) Discuss the various functions water performs in the body. 2) List the major electrolytes and the function of each. 3) Describe three ways in which body fluids are continually being distributed among the fluid compartments. 4) Identify the signs and symptoms of the common fluid and electrolyte imbalances. Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 2

Lesson 25. 1 Fluids and Electrolytes Clinical Practice 1) Assess an assigned patient for signs of fluid and electrolyte imbalance. 2) From patient laboratory results, identify electrolyte values that are abnormal. 3) Implement patient education for someone with hypokalemia. 4) Develop a plan of care for a patient who has a fluid and electrolyte imbalance. Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 3

Composition of Body Fluids Water The two largest constituents of the body are water and electrolytes Ø Water serves four functions: • Is a vehicle for transporting substances to and from Ø cells • Aids in heat regulation • Assists in H+ balance in the body • Is a medium for enzymatic action of digestion Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 4

Water More than half of the body’s weight is water Amount varies with age, sex, and health status Males: approximately 60% Females: approximately 50% Infants and the elderly more easily affected by changes in fluid balance Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 5

Water (cont’d) Infants and the elderly become dehydrated more rapidly Infants’ kidneys reabsorb less fluid Elderly have less antidiuretic hormone and diminished thirst sensation Water is critical to maintaining homeostasis Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 6

Sources of Water and Avenues of Loss Intake Oral Ø Food Ø Metabolism Ø Total Ø 1500 m. L 800 m. L 2500 m. L Output Ø Ø Ø Urine Perspiration Feces Expired air Total 1500 m. L 400 m. L 2500 m. L Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 7

Composition of Body Fluids Electrolytes Minerals or salts dissolved in body fluids Ø In solution, they break up into ions Ø Ions have electrical charges Ø Cations have positive charges Ø Anions have negative charges Ø Each cation must be balanced by an anion Ø The major source of electrolytes is diet Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 8

Electrolytes Sodium: water regulation and balance Potassium: nerve impulse transmission, muscle contraction, plasma, acid-base balance Calcium: muscle activity, blood coagulation Magnesium: nerve impulse transmission, muscle contraction Phosphate: ATP production Chloride: hydrochloric acid production, acid-base balance Bicarbonate: acid-base balance Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 9

Major Electrolytes: Normal Range Electrolyte Sodium Potassium Calcium Magnesium Phosphate Chloride Bicarbonate Normal Range 135 -145 m. Eq/L 3. 5 -5 m. Eq/L 8. 4 -10. 6 mg/d. L 1. 3 -2. 5 mg/d. L 2. 5 -4. 5 mg/d. L 96 -106 m. Eq/L 22 -26 m. Eq/L Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 10

Non-Electrolytes Amino acids (proteins), glucose, and fatty acids Remain bound together when dissolved in body fluid Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 11

Non-Electrolytes: Blood Normal circulating blood volume is 4 to 6 L Composed of: Erythrocytes (red cells) Ø Leukocytes (white cells) Ø Platelets (thrombocytes) Ø Carried in plasma Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 12

Non-Electrolytes: Blood (cont’d) Plasma proteins and colloids contribute to plasma osmotic pressure, which keeps fluid in the vascular compartment Anything that alters body fluid volume also alters plasma volume Plasma volume can affect blood pressure Plasma volume can affect circulation Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 13

Distribution of Body Fluids Body fluids are: Intracellular (within the cell) Ø Extracellular (outside the cell) • Intravascular • Interstitial • Transcellular Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 14

Extracellular Fluid Makes up approximately 1/3 of the total body water Transports nutrients, oxygen, and waste products to and from cells Is regulated by renal, metabolic, and neurologic factors Is high in sodium content Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 15

Intravascular Fluid The fluid within the blood vessels Consists of plasma and fluid within the blood cells Contains large amounts of protein and electrolytes, which help maintain intravascular volume Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 16

Transcellular Fluids Aqueous humor (in the eyes) Saliva Cerebrospinal fluid Pleural, peritoneal, synovial, and pericardial fluids Gastrointestinal secretions Fluid in the urinary tract Lymphatic system fluids Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 17

Movement of Fluids and Electrolytes Water taken in by ingesting fluids and food and through metabolism Thirst mechanism in the hypothalamus regulates thirst based on concentration of electrolytes and solutes in circulation Kidney the main organ of water secretion, with some loss in feces, perspiration, and breathing. Water retention based on aldosterone levels, antidiuretic hormone (ADH) levels, and atrial natriuretic peptide levels. Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 18

Fluid, Electrolyte, and Nutrient Transport Mechanisms Diffusion—passive transport Process by which substances move back and forth across the membrane until evenly distributed throughout the available space Ø Substances move from high to low concentration until concentration on both sides of the membrane is equal Ø Glucose, oxygen, carbon dioxide, water, and other small ions and molecules move by diffusion Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 19

Figure 25 -2 A: Diffusion Copyright © 2018, 2014, 2009 by Saunders, an imprint

Fluid, Electrolyte, and Nutrient Transport Mechanisms Osmosis—passive transport Movement of pure solvent (liquid) across a membrane Ø Water moves from area of less solute concentration to area of greater concentration until the solutions in the compartments are of equal concentration Ø Takes place via a semipermeable membrane Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 21

Figure 25 -2 B: Osmosis Copyright © 2018, 2014, 2009 by Saunders, an imprint

Fluid, Electrolyte, and Nutrient Transport Mechanisms Filtration—passive transport Movement of water and suspended substances outward through a semipermeable membrane Hydrostatic pressure Causes fluid to press outward on the vessel Ø The force promotes filtration, forcing movement of water and electrolytes through the capillary wall to the interstitial fluid Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 23

Figure 25 -2 D: Filtration Copyright © 2018, 2014, 2009 by Saunders, an imprint

Fluid, Electrolyte, and Nutrient Transport Mechanisms Active transport Requires cellular energy Ø Can move molecules into cells regardless of their electrical charge or the concentrations already in the cell Ø The energy source for the process is adenosine triphosphate (ATP) Ø Can move amino acids, glucose, iron, hydrogen, sodium, potassium, and calcium through the cell membrane Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 25

Figure 25 -2 C: Active transport Copyright © 2018, 2014, 2009 by Saunders, an

Fluid Volume Deficit At risk: Ø Patients unable to take in enough fluid • Impaired swallowing, extreme weakness, disorientation or coma, or unavailability of water Ø Patients who lose excessive amounts of fluid • Prolonged vomiting, diarrhea, hemorrhage, diaphoresis (sweating), or excessive wound drainage Result is dehydration Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 27

Dehydration When too little water in the plasma, water drawn out of the cells by osmosis to equalize concentration, and the cells shrivel Ø Treated by fluid administration, either orally or intravenously Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 28

Signs and Symptoms of Dehydration Thirst Weakness Dizziness Postural hypotension Decreased urine production Concentrated urine Dry, cracked lips Dry mucous membranes Thick saliva Dry, scaly skin Poor tissue turgor Flat neck veins Increased pulse rate Weak, thready pulse Elevated temperature Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 29

Figure 25 -3: Testing for tissue turgor and signs of dehydration Copyright © 2018,

Fluid Volume Excess Healthy people do not ordinarily drink too much water When people become ill they may take in more water than they excrete Receive intravenous fluid too quickly Given tap-water enemas Drink more fluids than they can eliminate Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 31

Fluid Volume Excess (cont’d) Signs of overhydration Weight gain Ø Crackles in the lungs (wet lungs) Ø Slow bounding pulse Ø Elevated blood pressure Ø Possibly edema Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 32

Figure 25 -4: Example of pitting edema Copyright © 2018, 2014, 2009 by Saunders,

Electrolyte Imbalance: Sodium Hyponatremia Sodium deficit; can be from decreased sodium or increased water intake and retention Ø May be caused by excessive vomiting or diarrhea Ø Hypernatremia Sodium excess; most commonly from water loss from fever or respiratory infection Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 34

Electrolyte Imbalance: Potassium Hypokalemia Ø Occurs with excess potassium or loss of body water; may be from poor diet, vomiting, diarrhea, excessive sweating, or diuretic therapy Hyperkalemia Ø Occurs with burns, crush injuries, uncontrolled diabetes mellitus, and renal failure Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 35

Electrolyte Imbalance: Calcium Hypocalcemia Ø Occurs with nutritional deficiency of calcium or vitamin D or in bone disorders such as metastatic cancer of the bone Hypercalcemia Ø Most cases related to hyperparathyroidism or malignancy such as multiple myeloma Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 36

Electrolyte Imbalance: Calcium (cont’d) Calcium imbalances Ø Hypocalcemia • Calcium level drops below 8. 4 mg/d. L • Can occur from nutritional deficiency of calcium or vitamin D • Occurs in disorders in which there is a shift of calcium into the bone Ø Hypercalcemia • Calcium level above 10. 6 mg/d. L • Most cases are related to hyperparathyroidism or malignancy in which there is metastasis with bone resorption Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 37

Electrolyte Imbalance: Magnesium Hypomagnesemia Ø Results from malabsorption, malnutrition, renal tubular dysfunction, thiazide diuretic use, extensive gastric suction, or diarrhea Hypermagnesemia Ø Occurs only in presence of renal failure Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 38

Electrolyte Imbalances Anion imbalances Ø Hypochloremia • Chloride level below 96 m. Eq/L is associated with hyponatremia Ø Hyperchloremia • Chloride level above 106 m. Eq/L • Occurs along with hypernatremia and a form of metabolic acidosis Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 39

Electrolyte Imbalances (cont’d) Anion imbalances Ø Hypophosphatemia • Occurs when the level of phosphate falls below 3. 0 mg/d. L • May result from use of aluminum-containing antacids, from vitamin D deficiency, or from hyperparathyroidism Ø Hyperphosphatemia • A phosphate level above 4. 5 mg/d. L • Commonly occurs in renal failure Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 40

Question 1 Kimberly’s patient is on strict intake and output measurements. Her patient’s total output is 2200 m. L. What should the total be for an average adult? 1) 2) 3) 4) 1200 m. L 2000 m. L 2400 m. L 3800 m. L Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 41

Question 2 The predominant electrolyte in extracellular fluid is _________ and the predominant electrolyte in intracellular fluid is ___________. 1) potassium, sodium 2) calcium, magnesium 3) sodium, potassium 4) magnesium, calcium Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 42

Question 3 Amanda’s patient is going home from the hospital. Her patient has a history of congestive heart failure. She includes in her discharge teaching for the patient to weigh herself: 1) 2) 3) 4) at the same time in the evening, on the same scale, wearing the same clothes. in the morning with the same scale and same clothes. weekly in the evening with the same scale and same clothes just before going to bed. Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 43

Question 4 After Amanda’s patient goes home, she notices her rings are tighter around her fingers. She has gained 5 lb in 2 days. She is experiencing fluid overload. In fluid overload, a patient’s vital signs change. Which of the following might be anticipated regarding the blood pressure? 3) A rise in the systolic blood pressure A rise in the diastolic blood pressure A fall in the systolic blood pressure 4) A fall in the diastolic blood pressure 1) 2) Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 44

Lesson 25. 2 Acid-Base Imbalance Overview Theory 5) State the main signs and symptoms of acidbase imbalances Clinical Practice 5) Identify patients who might be at risk for an acid-base imbalance. Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 45

Acid-Base Balance Important in maintaining homeostasis p. H: measure of the degree of acidity or alkalinity Normal serum p. H is 7. 35 to 7. 45 Death may occur if p. H is less than 6. 8 or greater than 7. 8 Balance between bicarbonate and carbonic acid Carbonic acid retained or removed by respiratory system Ø Bicarbonate retained or removed by kidneys Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 46

Acid-Base Balance (cont’d) Bicarbonate Normal range is 22 to 26 m. Eq/L Ø Acts as buffer to neutralize excess acids in the body and maintain bicarbonate-to-carbonic acid ratio at 20: 1 Ø Kidneys selectively reabsorb or excrete bicarbonate to regulate serum levels and help maintain acid-base balance Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 47

Acid-Base Balance (cont’d) Control mechanisms Blood buffer system • Consists of weak acids and weak bases Ø Lungs • Carbon dioxide and water are expired from the lungs Ø Urinary system • Enzymes promote the dissociation of carbonic acid to Ø free hydrogen ions Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 48

Acid-Base Imbalance: Respiratory Acidosis Increased carbon dioxide levels from: Airway obstruction Ø Pneumonia, asthma Ø Chest injuries Ø Opiate intake Ø Chronic obstructive lung disease Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 49

Acid-Base Imbalance: Metabolic Acidosis An excessive loss of bicarbonate ions or retention of hydrogen ions caused by: Kidney disease Ø Diabetic ketoacidosis Ø Circulatory failure Ø Shock states Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 50

Acid-Base Imbalance: Respiratory Alkalosis Usually caused by: Anxiety Ø High fever Ø Hyperventilation Ø Salicylate poisoning (ASA overdose) Ø Encephalitis Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 51

Acid-Base Imbalance: Metabolic Alkalosis Caused by: Vomiting Ø Gastric suctioning Ø Excessive antacid consumption Ø Diuretic therapy Ø Potassium deficit Ø Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 52

Question 5 Terry’s patient is critical. She has poor circulation, uncontrolled diabetes, a history of renal failure, and diarrhea. She is at high risk for which acid-base imbalance? 1) 2) 3) 4) Respiratory acidosis Metabolic acidosis Respiratory alkalosis Metabolic alkalosis Copyright © 2018, 2014, 2009 by Saunders, an imprint of Elsevier Inc. All rights reserved. Slide 53