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2© Paradigm Publishing, Inc. Chapter 20 Fluids and Electrolytes.

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2 2© Paradigm Publishing, Inc. Chapter 20 Fluids and Electrolytes

3 Chapter 20 Topics Physiology of Fluid and Electrolyte Balance Dehydration and Edema Electrolyte Imbalances Acidosis and Alkalosis Herbal and Alternative Therapies 3© Paradigm Publishing, Inc.

4 Physiology of Fluid and Electrolyte Balance Fluids and Electrolyte Balance Fluids and electrolytes depend on each other; a change in one component causes a change to the other Electrolytes are solutes (salts and minerals) that dissolve in a solvent, usually water Water moves from areas of low solute concentration to areas of high solute concentration to maintain equilibrium A loss of fluids in an area of the body causes a shift in fluids from another area to replace what was lost  During fluid shifts, electrolytes exchange to balance the solute concentration between fluid compartments 4© Paradigm Publishing, Inc.

5 Physiology of Fluid and Electrolyte Balance Fluids Two-thirds of body fluid is intracellular fluid (inside the cellular membrane); volume is constant One-third of body fluid is extracellular fluid (outside of cells); volume varies; contains most substances that maintain proper solute concentrations  75% of extracellular fluid is in the interstitial spaces between the cells in tissues  25% is in the plasma inside blood vessels Extracellular fluid helps maintain the overall fluid balance and hydration status of the body 5© Paradigm Publishing, Inc.

6 Physiology of Fluid and Electrolyte Balance © Paradigm Publishing, Inc.6 Body Fluid Compartments Extracellular fluid is made up of plasma and interstitial fluid Average quantities of water are given in liters (L) for each body compartment

7 Physiology of Fluid and Electrolyte Balance Fluids (continued) Water is the main fluid in the body  Crucial for dissolving essential substances and transporting these molecules throughout the body  Water content changes with age and body makeup Homeostasis involves proper fluid balance  Multiple systems regulate water intake and output; distribute water into the various body compartments Typically, water intake roughly matches output  Adults take in 2 L of water a day via fluids and food 7© Paradigm Publishing, Inc.

8 Physiology of Fluid and Electrolyte Balance © Paradigm Publishing, Inc.8 Body Water Content In infants, water is 70–80% of the body by weight In the elderly, water content is much lower

9 Physiology of Fluid and Electrolyte Balance © Paradigm Publishing, Inc.9 Daily Fluid Balance

10 Physiology of Fluid and Electrolyte Balance Electrolytes Molecular compounds that form ions dissolved in water They are either positively charged ions (cations) or negatively charged ions (anions)  Cations: sodium, potassium, calcium, magnesium  Anions: chloride, bicarbonate, phosphate (at times) Concentration is measured in milliequivalents (mEq) per liter Concentrations of ions differ in intracellular and extracellular fluid 10© Paradigm Publishing, Inc.

11 Physiology of Fluid and Electrolyte Balance Electrolytes (continued) Pumps (e.g., sodium/potassium ion) and channels (e.g., chloride) maintain concentrations in cell membranes Water passively moves across cell membranes by osmosis  Maintains overall equilibrium in concentration of total molecules on both sides Concentration of intracellular and extracellular fluid typically remains constant 11© Paradigm Publishing, Inc.

12 Physiology of Fluid and Electrolyte Balance Common Electrolytes: Sodium (Na + ) Most abundant cation in extracellular fluid Sodium retains body fluid, helps generate and transmit nerve impulses, maintains acid-balance balance, regulates enzyme activity The main active ion in maintaining fluid isotonicity  Isotonicity is a state of balanced concentration across cell membranes Normal Concentration: 136–145 mEq/L 12© Paradigm Publishing, Inc.

13 Physiology of Fluid and Electrolyte Balance Common Electrolytes: Potassium (K + ) The primary cation in intracellular fluid Potassium helps generate and conduct nerve impulses and muscle contractions (such as in cardiac function and rhythm), maintains acid-base balance, regulates enzyme activity, is involved in carbohydrate metabolism Normal Concentration: 3.5–5.5 mEq/L 13© Paradigm Publishing, Inc.

14 Physiology of Fluid and Electrolyte Balance Common Electrolytes: Calcium (Ca 2+ ) Calcium is essential for bone formation, muscle contraction, conduction of nerve impulses, blood coagulation Electrolyte is highly bound to albumin (plasma protein); low albumin levels can result in hypocalcemia Normal Concentration: 4.3–5.3 mEq/L 14© Paradigm Publishing, Inc.

15 Physiology of Fluid and Electrolyte Balance Common Electrolytes: Magnesium (Mg 2+ ) An abundant intracellular cation Magnesium activates enzymes and facilitates nerve impulse production and muscle contraction Electrolyte is important to cardiac function Normal Concentration: 1.5–2.5 mEq/L 15© Paradigm Publishing, Inc.

16 Physiology of Fluid and Electrolyte Balance Common Electrolytes: Chloride (Cl - ) An anion that transports carbon dioxide, forms hydrochloric acid in the stomach, and retains potassium Chloride controls acid–base balance Normal Concentration: 100–106 mEq/L Common Electrolytes: Bicarbonate (HCO 3 - ) An anion that helps to maintain blood pH Its most common salt form, sodium bicarbonate, used in IV preparations to treat acidosis Normal Concentration: 27 mEq/L 16© Paradigm Publishing, Inc.

17 Physiology of Fluid and Electrolyte Balance Common Electrolytes: Phosphate (PO 4 - ) Anion used in energy production for normal cell function Phosphate counterbalances calcium in blood Excessive intake of electrolyte can deplete calcium levels, affecting bone health 17© Paradigm Publishing, Inc.

18 Physiology of Fluid and Electrolyte Balance Acid-Base Balance Electrolytes affect balance of hydrogen ions (H + ) in blood The concentration of hydrogen ions is the pH scale  Low pH is acidic; high pH is alkaline pH of blood is between 7.35 and 7.45  The acid–base buffer pair of carbonic acid (acid) and sodium bicarbonate (base) keep pH in this range Kidneys and lungs also maintain acid-base balance  Kidneys regulate electrolytes in the urine  Respiratory rate (breathing faster or slower) can correct pH imbalance 18© Paradigm Publishing, Inc.

19 Dehydration and Edema Dehydration Excessive loss of water mainly from extracellular compartments Causes: vomiting, diarrhea, sweating from heat or fever, excessive urine output Symptoms: thirst, dry mucous membranes, weakness, dizziness, reduced skin elasticity (turgor), hypotension, rapid heartbeat, reduced or absent urine production Treatment: drinking fluids (mild dehydration); IV fluids and electrolytes (moderate to severe dehydration) 19© Paradigm Publishing, Inc.

20 Dehydration and Edema Edema Accumulation of excessive fluid in interstitial space Most common in lower extremities, lungs, brain Causes: sodium and fluid retention in extracellular space, renal failure, reduced tissue perfusion from CHF Symptoms: swelling in ankles or legs, difficulty breathing Treatment: diuretics to remove excessive fluid through elimination and correct electrolyte imbalances 20© Paradigm Publishing, Inc.

21 Your Turn Question 1: Sodium and potassium are two cations in the human body. How are they alike? Answer: They both help generate and transmit nerve impulses, assist with acid–base balance, and regulate enzyme activity. Question 2: A patient is diagnosed with severe dehydration. What is the physician likely to order? Answer: The physician is likely to order administration of IV fluids and electrolytes. 21© Paradigm Publishing, Inc.

22 Dehydration and Edema Fluids and Solutions Three main uses of IV fluid products  Replace lost fluids and electrolytes due to dehydration  Supply essential trace minerals in parenteral nutrition solutions  Serve as vehicle for administration of IV drug therapy IV fluids are categorized by  Tonicity (isotonic, hypertonic, hypotonic)  Content (colloids versus crystalloids) 22© Paradigm Publishing, Inc.

23 Dehydration and Edema Fluids and Solutions: Tonicity Tonicity refers to the concentration of a solute (dissolved substance) in a solvent (liquid vehicle) Concept of tonicity applies to molecules such as ions and electrolytes that do not move easily across cell membranes IV electrolyte products are used and prepared based on their tonicity (concentration compared with that of blood) Osmolarity: concentration of all molecules in a set volume of fluid; measurement affects tonicity  Measured in milliosmoles (mOsm) per liter (L)  Plasma osmolarity is about 280–300 mOsm/L 23© Paradigm Publishing, Inc.

24 Dehydration and Edema Fluids and Solutions: Isotonic Solutions Isotonic solutions (or maintenance solutions) have similar concentration as blood plasma Indication: replace daily fluid and electrolyte loss, prevent dehydration Most common isotonic solution: normal saline (0.9% NaCl) 24© Paradigm Publishing, Inc.

25 Dehydration and Edema Fluids and Solutions: Hypertonic Solutions Hypertonic solutions have a higher concentration of solute than bodily fluids; osmolarity is usually over 350 mOsm/L Indication: severe sodium depletion from excess sweating, vomiting, or diarrhea; excessive water intake; overuse of enemas or irrigating solutions Cautions: administer through a central IV line due to their irritating and corrosive effects on tissues and blood vessels; must be given slowly and monitored closely  Rapid delivery can damage tissues and lead to fluid overload in blood vessels; heart failure may result 25© Paradigm Publishing, Inc.

26 Dehydration and Edema Fluids and Solutions: Hypotonic Solutions Hypotonic (hydrating) solutions have lower concentration of solute than bodily fluids; osmolarity is usually less than 280 Osm/L Indication: dehydration by diluting the concentration within the bloodstream  This decreases osmolarity (water leaves the blood and enters interstitial and intracellular spaces) Caution: Too rapid administration of solution can cause intracranial pressure and brain damage 26© Paradigm Publishing, Inc.

27 Dehydration and Edema © Paradigm Publishing, Inc.27 Tonicity Effects on Cells in Solution Body cells can be bathed with isotonic solution without a net change between intracellular and extracellular concentrations

28 Dehydration and Edema Fluids and Solutions: Crystalloid IV Solutions Crystalloid IV solutions contain electrolytes and colloids (proteins and other large molecules such as fats) Molecules in colloid products are too large to easily move from the bloodstream to surrounding tissues Like hypertonic solutions, they increase osmolarity of blood plasma by pulling fluid from interstitial spaces Colloid products often called blood volume expanders  Examples of colloids: albumin, dextran, blood Indication : replace lost fluid and treat dehydration; serve as a liquid vehicle to administer IV drugs 28© Paradigm Publishing, Inc.

29 Dehydration and Edema Fluids and Solutions: Crystalloid IV Solutions (continued) Normal saline (0.9% NaCl)and dextrose 5% in sterile water (D 5 W) are isotonic crystalloid solutions  Dextrose used for malnutrition or low glucose levels See Table 20.2 for common crystalloid solutions and their osmolarity Special Caution: use sterile water only for diluting other IV drugs or fluids; never administer it by itself  Technicians: question any order for hydration therapy containing pure water 29© Paradigm Publishing, Inc.

30 Electrolyte Imbalances About Electrolyte Imbalances Causes: loss or excessive production of the electrolyte itself or from a relative reduction or excess of fluid See Table 20.1 for normal electrolyte concentrations Measuring electrolyte concentration in plasma is close estimate of extracellular levels Intracellular levels cannot be measured directly  Lab values are combined with clinical signs and symptoms to determine deficits Technicians can retrieve laboratory values and flag those outside of normal range 30© Paradigm Publishing, Inc.

31 Electrolyte Imbalances Electrolyte Imbalances: Sodium Hyponatremia is low sodium concentration from sodium loss or a relative excess of water in extracellular space  Causes: high water intake, kidney or liver failure, salt- wasting diuretics overuse, adrenal gland insufficiency  Causes (other): fluid loss caused by excessive vomiting or sweating Hypernatremia is elevated sodium concentration  Causes: dehydration from lack of fluid intake, diarrhea, ADH deficiency, heart disease, kidney failure 31© Paradigm Publishing, Inc.

32 Electrolyte Imbalances Electrolyte Imbalances: Potassium Hypokalemia is low potassium concentration  Causes: overuse of potassium-wasting diuretics, vomiting or gastric suctioning, or excessive urine output  Symptoms: reduced muscle tone, weakness, confusion, drowsiness, depression, low BP, cardiac arrhythmias Hyperkalemia is elevated potassium; severely affects heart  Causes: kidney failure, diarrhea, potassium-sparing diuretics overuse, Cushing’s syndrome, severe burns  Symptoms: depressed breathing, diarrhea, nausea, vomiting, confusion, anxiety, cardiac arrhythmias 32© Paradigm Publishing, Inc.

33 Electrolyte Imbalances Electrolyte Imbalances: Calcium Hypocalcemia is low calcium levels in the body  Causes: insufficient calcium intake, parathyroid disease  Symptoms: hyperexcitability of nerves and muscle contraction, muscle spasms, seizures  Death may result Hypercalcemia is elevated calcium concentration  Causes: excessive intake of calcium supplements, some cancerous tumors  Symptoms: kidney stones 33© Paradigm Publishing, Inc.

34 Electrolyte Imbalances Electrolyte Imbalances: Magnesium Hypomagnesemia is low levels of magnesium in the body  Causes: alcohol abuse, pregnancy-induced hypertension, drugs causing increased magnesium excretion (digoxin, estrogen, diuretics)  Symptoms: muscle cramps, confusion, tachycardia, arrhythmias, tremors, hallucinations, seizures Hypermagnesemia is elevated magnesium concentration  Causes: renal failure, IV infusion overdose, enemas  Symptoms: reduced deep tendon reflexes, changes in cardiac function 34© Paradigm Publishing, Inc.

35 Electrolyte Imbalances Electrolyte Imbalances: Chloride Hypochloremia is low levels of chloride in the body  Causes: loss of fluid from excessive production of urine or sweat, gastric suctioning, some diuretics Hyperchloremia is elevated chloride concentration  Causes: diarrhea, kidney disease, diabetes 35© Paradigm Publishing, Inc.

36 Electrolyte Imbalances Electrolyte Imbalances: Phosphate Hypophosphatemia is low levels of phosphate in the bloodstream  Causes: anorexia, severe malnutrition, kidney failure  Symptoms: weakness, respiratory or heart failure, hemolysis, rhabdomyolysis Hyperphosphatemia is elevated phosphate concentration  Causes: tumor lysis syndrome, rhabdomyolysis, lactic acidosis, diabetic ketoacidosis, bisphosphonates, too much vitamin D, overuse of bowel prep products  Symptoms: kidney damage or failure 36© Paradigm Publishing, Inc.

37 Electrolyte Imbalances Electrolytes Indication: electrolyte deficiency, or if anticipated Electrolytes in body fluids can be replaced in various ways Parenteral nutrition: electrolyte solutions combined with carbohydrates, proteins, and fats in large-volume bags  Infused through an IV line If mild depletion, replace by including the absent mineral in the diet or taking an oral supplement  For example, athletes consuming sports drinks 37© Paradigm Publishing, Inc.

38 Electrolyte Imbalances Electrolytes (continued) Oral OTC liquid electrolyte mixtures treat mild dehydration from vomiting or diarrhea  Safe to use; contain small amounts of electrolytes IV electrolyte products are used for severe deficiencies  Electrolytes added to IV fluids and administered Oral potassium supplements for potassium loss (diuresis) Oral calcium products for prevention and treatment of bone loss from osteoporosis, rickets; also used for tetany Oral magnesium products for magnesium loss Phosphorus products for malnourishment 38© Paradigm Publishing, Inc.

39 Electrolyte Imbalances Electrolytes: Common Side Effects Sodium: water retention, high blood pressure Potassium: nausea, vomiting, diarrhea, abdominal pain, GI ulceration (severe) Calcium: constipation; back or flank pain, painful urination, nausea and vomiting (symptoms of kidney stones) Magnesium: diarrhea Phosphorus: stomach upset; diarrhea; back or flank pain, painful urination, nausea and vomiting (symptoms of kidney stones) 39© Paradigm Publishing, Inc.

40 Electrolyte Imbalances Electrolytes: Cautions Do not use most electrolyte products if have kidney failure or impairment Dilute injectable potassium products before administering  Maximum safe concentration is 80 mEq/L  Administer infusion slowly; if too fast, could cause cardiac arrest (black tops to remind technicians) Calcium and phosphate salts cannot always be mixed in the same IV bags; they can chelate  Precipitate appears as small white specks or lumps of material; can clog capillaries if infused through an IV  Technicians: follow accepted procedures to mix these products; use correct order of mixing 40© Paradigm Publishing, Inc.

41 Your Turn Question 1: What is the reason isotonic solutions are known as maintenance solutions? Answer: Isotonic solutions have the same concentration as blood. They are used to maintain fluid status in normal range. Question 2: What is a restriction of using electrolyte products? Answer: Most electrolyte products cannot be used in patients with kidney failure or impairment. 41© Paradigm Publishing, Inc.

42 Acidosis and Alkalosis About Acidosis Condition occurs when extracellular fluid (blood) contains excess hydrogen ions, causing the pH to drop below normal range Metabolic acidosis: excess acid is produced and bicarbonate is lost (e.g., diarrhea), or kidneys do not excrete enough acid Respiratory acidosis: slow breathing and retention of carbon dioxide in the blood 42© Paradigm Publishing, Inc.

43 Acidosis and Alkalosis About Alkalosis Condition caused by a loss in hydrogen ions, producing a relative increase in bicarbonate; this increases blood pH Metabolic alkalosis: excess acid excreted by kidneys or acid is lost from the stomach (from vomiting or gastric suction) Respiratory alkalosis: rapid breathing and elimination of carbon dioxide from the blood 43© Paradigm Publishing, Inc.

44 Acidosis and Alkalosis Acidifying and Alkalinizing Agents Acidic electrolyte products treat alkalosis; basic products treat acidosis Ammonium chloride (acidic) treats hypochloremia and metabolic alkalosis  Can result in ammonium toxicity; monitor patient Sodium bicarbonate (basic) used as an antacid and as a urinary alkalinizer for hemolytic emergencies; also used to treat metabolic acidosis and drug overdoses  Can result in sodium toxicity, causing fluid overload  Can cause ulceration of tissue at injection site 44© Paradigm Publishing, Inc.

45 Acidosis and Alkalosis Acidifying and Alkalinizing Agents (continued) Cautions:  Technician must carefully mix and label these agents  Concentrations and rates of infusion must be precise to avoid adverse effects  Healthcare providers need to be attentive to signs of extravasation 45© Paradigm Publishing, Inc.

46 Herbal and Alternative Therapies Electrolytes often categorized as dietary supplements rather than OTC or prescription drug products Many electrolyte drinks are available for rehydration  Use after physical exercise  Use to treat diarrhea and vomiting associated with intestinal illness 46© Paradigm Publishing, Inc.

47 Summary Common electrolytes in the body are sodium, potassium, calcium, magnesium, phosphate, and chloride Excess or loss of a common ion can cause major illness Various types of IV fluids and electrolyte products are used to prevent and treat imbalances Some IV fluid products are used as delivery vehicles for IV drug therapy IV electrolyte solutions containing ammonium chloride and sodium bicarbonate are used for acid–base disorders 47© Paradigm Publishing, Inc.

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