1. Fluid, Electrolyte, and Acid-Base Balance

2. Reference
Taylor, C., Lillis, C., & LeMone, P. (2005). Fundamentals of nursing (5th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
Chapter 46

3. Competencies for Ch 46: Fluid, Electrolyte, & Acid-Base Balance
By the end of the unit, the student will:
Describe the anatomy and physiology related to body fluids, fluid & electrolyte, and acid-base balance
Describe age-related differences in body fluid content and effect on fluid balance status
Describe how to promote and maintain fluid & electrolyte, and acid-base balance

4. Competencies for Ch 46: Fluid, Electrolyte, & Acid-Base Balance (continued)
By the end of the unit, the student will:
Describe specific variables that may influence fluid & electrolyte, and acid-base balance
Teach clients about specific conditions that can lead to fluid & electrolyte imbalance, and acid-base imbalance
Describe care for clients at risk for or with actual problems related to fluid & electrolyte, and acid-base balance

5. Functions of Water in the Body
Transporting nutrients to cells and wastes from cells
Transporting hormones, enzymes, blood platelets, and red and white blood cells
Facilitating cellular metabolism and proper cellular chemical functioning
Acting as a solvent for electrolytes and nonelectrolytes
Helping maintain normal body temperature
Facilitating digestion and promoting elimination
Acting as a tissue lubricant

6. Two Compartments of Fluid in the Body
Intracellular fluid (ICF) — fluid within cells (70%)
Extracellular fluid (ECF) — fluid outside cells (30%)
Includes intravascular and interstitial fluids

7. Variations in Fluid Content
Healthy person — total body water is 50% to 60% of body weight
An infant has considerably more body fluid and ECF than an adult
More prone to fluid volume deficits
Sex and amount of fat cells affect body water
Women and obese people have less body water

8. ELECTROLYTES Terminology Ions Electrolytes Cations Anions
Non-electrolytes
Solvents
Solutes
Ions atom or molecule carrying an electric charge
Capable of breaking into electrically charged ions when dissolved in a solution
Ions with a positive charge
Ions with a negative charge
Molecules that don’t break down into an electrical charge
Liquids that hold a substance in solution water is primary in body
Substances that are dissolved in a solution electrolytes and non-electrolytes

9. Electrolytes Ions Homeostasis — total cations equal to total anions
Cations — positive charge
Anions — negative charge
Homeostasis — total cations equal to total anions

10. Fluid Balance
Solvents — liquids that hold a substance in solution (water)
Solutes — substances dissolved in a solution (electrolytes and non-electrolytes)

11. MORE ELECTROLYTES Measurement Based on chemical activity Regulation
Water distribution
Acid-base balance
Neuromuscular excitability
Measurement
1meq of a cation or anion = 1 meq of hydrogen
1meq of a cation = 1 meq of an anion

12. COMMON ELECTROLYTES Sodium (Na++) Functions
Regulates volume of body fluids
Maintains water balance
Regulates ECF
Influences ICF
Generation and transmission of nerve impulses
Sodium-Potassium pump
Sources foods RDA is 2400 mg or 1tsp
Lost in urine and feces
Regulation
ECF concentration meqs/L
Reabsorbed by kidneys stimulated by aldosterone

13. POTASSIUM (K+) Major cation in ICF Reciprocal to sodium Functions
Regulates cellular enzyme activity and water content
Transmission of nerve and muscle impulses
Metabolism of proteins and carbohydrates
Regulation of acid-base balance by cellular exchange with H+
Sources/losses
RDA meq needed to maintain balance
Foods fruit, meat, dairy, some vegies such as broccoli
Eliminated in kidney no means of reabsorption
Also found in gastric secretions
Regulation sodium pump
Aldosterone triggers K+ excretion
Normal is meq/l

14. CALCIUM (Ca++) Most abundant electrolyte in body
99% found in bones and teeth
Functions
Nerve impulse transmission and blood clotting
Catalyst for muscle contraction
Thickness and strength of of cell membranes
Source
RDA 1gm for adults mg/day in post menopausal women and persons over 65
More for children per body weight
Mild cheese dairy dried beans
Use is simulated by vit D promotes absorption and limits excretion
Excreted in urine, feces, bile, sweat, digestive secretions
Regulation:
Parathyroid hormone acts on bnes and teeth to release Ca in blood and kidneys to increase reabsorption
Calcitonin hormone releases by the thyroid glands opposite effect of PTH

15. MAGNESIUM (Mg++) Second most important cation in ICF Functions
Metabolism of carbohydrates and proteins
Vital enzyme actions
Protein and DNA synthesis
Maintaining intracellular levels of Potassium
Maintain electrical activity in nervous tissue and muscle tissue membranes
Sources rda is meq
Vegetables nuts fish whole grains, peas and beans
Regulates
Absorbed by intestine eliminated by kidneys
Lab values meq

16. CHLORIDE (Cl-) Chief extracellular anion Functions
Works with sodium to maintain osmotic pressure of blood
Regulates acid-base balance
Buffering action during O2/CO2 exchange
Production of Hydrochloric acid in digestion
Source
Unknown rda
Dairy and meat
Regulation,
Paired with sodium
Excreted and conserved by the kidneys
Found in dairy and meat
Deficits are associated with potassium deficits
Nl meq/l

17. BICARBONATE (HCO3-) Major chemical base buffer Found in ECF and ICF
Function
Essential for acid base balance. Works with carbonic acid to make up the body’s acid base buffer system
Source results of carbon dioxide formation during metabolism
Nl levels meq
Regulated by the kidneys

18. PHOSPHATE (PO4-) Major anion in body cells Buffer in ICF and ECF
Functions
Maintains body’s acid-base balance
Cell division and transmission of heredity
Chemical reactions use of Vit B, CHO metabolism, nerve and muscle action
RDA similar to CA++
Found in most foods but mostly in beef, pork, dried peas and beans
Metabolized like Ca++
Regulated by Parathyroid hormone
Inversely proportional to Ca++
Nl range is

19. OTHER ELECTROLYTES Sulfate Lactic acid Anion ICF
Excreted in the kidney
Lactic acid
Facilitates diffusion to and from capillaries

20. FLUID AND ELECTROLYTE MOVEMENT
Osmosis – Fluid passes from areas of low solute concentration to areas of high solute concentration
Diffusion – tendency of solutes to move freely from areas of high concentration to low concentration (down hill)
Active Transport – requires energy to move through a cell membrane from area of lesser concentration to one of greater concentration
Filtration – passage of fluid through a permeable membrane. Movement is from high to low pressure
Osmolarity – concentration of particles in a solution. Pulling power
Isotonic same concentration as plasma
Hypertonic higher concentration of particles than plasma
Hypotonic lower concentration of particles than plasma
Gases ie. Oxygen and CO2 water bottle
Filtration arterioles positive pressure push fluid out to cells.
Veins neg pressure pull fluid into vessels.
Intake vs Output. Should balance in general. 400cc insensible (nonmeasurable Loss)

21. Osmolarity of a solution
Isotonic — same concentration of particles as plasma
Hypertonic — greater concentration of particles than plasma
Hypotonic — lesser concentration of particles than plasma

22. Filtration
Colloid osmotic pressure
Hydrostatic pressure

23. Source of Fluids for the Body
Ingested liquids
Food
Metabolism

24. Fluid Losses Kidneys — urine Intestinal tract — feces
Skin — perspiration
Insensible water loss

25. Fluid Imbalances
Involves either volume or distribution of water or electrolytes
Hypovolemia — deficiency in amount of water and electrolytes in ECF with near normal water/electrolyte proportions
Dehydration — decreased volume of water and electrolyte change
Third-space fluid shift — distributional shift of body fluids into potential body spaces

26. Fluid Volume Excess
Hypervolemia — excessive retention of water and sodium in ECF
Overhydration — above normal amounts of water in extracellular spaces
Edema — excessive ECF accumulates in tissue spaces
Interstitial-to-plasma shift — movement of fluid from space surrounding cells to blood

27. Electrolyte Imbalances
Hyponatremia and hypernatremia
Hypokalemia and hyperkalemia
Hypocalcemia and hypercalcemia
Hypomagnesemia and hypermagnesemia
Hypophosphatemia and hyperphosphatemia
Natremia hyper because of osmotic pressure, fluids move from the cells leaving them without enough fluid deficient or excess in ECF
Kalemia deficient or excess in ECF hypo muscle weekness and leg cramps
Hyper slows conduction cardiac arrest
Calcemia hypo takes Ca++ from bones osteomalacia soft bones numbness and tingling muscle cramps tetany Hyper excess in ECF cardiac arrest
Magnesium hypo results in hypo kalemia hyper seen in end stage renal failure

28. Nursing Assessments Identify patients at risk for imbalances.
Determine a specific imbalance is present and its severity, etiology, and characteristics.
Determine effectiveness of plan of care.

29. Parameters of Assessment
Nursing history and physical assessment
Fluid intake and output
Daily weights
Laboratory studies

30. Lab Studies to Assess for Imbalances
Complete blood count
Serum electrolytes
Urine pH and specific gravity
Arterial blood gases

31. Risk Factors for Imbalances
Pathophysiology underlying acute and chronic illnesses
Abnormal losses of body fluids
Burns
Trauma
Therapies that disrupt fluid and electrolyte balance

32. Nursing Diagnoses Related to Imbalances
Excess fluid volume
Deficient fluid volume
Risk for imbalanced fluid volume

33. Expected Outcomes
Maintain approximate fluid intake and output balance (2500mL intake and output over 3 days)
Maintain urine specific gravity within normal range (1.010 to 1.025)
Practice self-care behaviors to promote balance

34. Implementing Dietary modifications Modifications of fluid intake
Medication administration
IV therapy
Blood and blood products replacement
TPN

35. Administering Medications
Mineral-electrolyte preparations
Diuretics
Intravenous therapy

36. Intravenous Therapy Vascular access devices
Peripheral venous catheters
Midline peripheral catheter
Central venous access devices
Implanted ports

37. Vein Site Selection Accessibility of a vein Condition of vein
Type of fluid to be infused
Anticipated duration of infusion

38. Administering Blood and Blood Products
Typing and cross-matching
A, B, AB, and O type blood
Rh Factor
Selecting blood donors
Initiating transfusion
Transfusion reactions

39. PROCESS OF MAINTAINING A STABLE STATE UNDER VARIABLE CONDITIONS
HOMEOSTASIS
PROCESS OF MAINTAINING A STABLE STATE UNDER VARIABLE CONDITIONS

40. MECHANISMS OF HOMEOSTASIS
Kidneys
Cardiovascular system
Lungs
Adrenal Glands
Thyroid Gland
Parathyroid Gland
Gastrointestinal tract
Nervous system
Table 45-2 page 1280
Kidneys filter170L of plasma qd excrete only 1.5 L urine retain or eliminate electrolytes master chemists of the body. Regulate b/p
C-v system pump and carry nutrients
Lungs regulate O2 and CO2 levels maintain acid base balance
Adrenal secrete aldosterone helps body to retain sodium, chloride and water and excrete potassium.
Thyroid throxine increases blood flow in the body to increase glomerular filtration in the kidney
Parathyroid hormone regulates ca++ in the ECF
GI tract absorbs water and nutrients
Nervous system osmoreceptors are sensitive to changes in ECF and send messages to approp spot to maintain homeostasis. Thalmus gland to stimulate thirst, pituitary gland to release or inhibit ADH for fluid regulation.

41. Primary Organs of Homeostasis
Kidneys normally filter 170 L plasma, excrete 1.5 L urine.
Cardiovascular system pumps and carries nutrients and water in body.
Lungs regulate oxygen and carbon dioxide levels of blood.

42. Primary Organs of Homeostasis, continued
Adrenal glands help body conserve sodium, save chloride and water, and excrete potassium.
Thyroid gland increases blood flow in body and increases renal circulation.

43. ACID – BASE BALANCE Acid contains hydrogen atoms that can be released
Acidosis too many circulating H+ ions
Base accepts hydrogen atoms
Alkalosis not enough H+ ions in the ECF
pH is the unit of measure used to describe acid base balance
Buffer prevents ECF from becoming too acidic or too alkaline

44. BUFFER SYSTEMS Carbonic Acid-Sodium Bicarbonate System
Phosphate Buffer System
Protein Buffer System
Buffers either bind H+ or release it. Regulate ECF to keep as normal as possible. pH range is 7.35 –7.45 too high or too low = death see figure 45-7 on page 1281
Sodium bicarb/carbonic acid buffers up to 90% most significant in the system. Exist n body in a 20:1 ration of HCO3- tp H2CO3
Phosphate buffer in ICF converts sodium phosphate base to sodium phosphate acid in the kidneys
Protein and hemoglobin in plasma can combine with free h+ ions to act as buffer
Lungs respirations increase and decrease to retain or eliminate CO2
Kidneys excrete or retain bicarbonate and H+ atoms depending on body needs

45. IMBALANCE IN ACID – BASE BALANCE
Respiratory Alkalosis
Deficit in carbonic acid in the ECF
Respiratory Acidosis
Excess in carbonic acid in the ECF
Metabolic Alkalosis
Excess of bicarbonate in the ECF
Metabolic Acidosis
Deficit of bicarbonate in the ECF
Lab test are on arterial blood supplies Measured in partial pressure to PaO2 is partial pressure of the arterial oxygen PaCO2
SaO2 or “sats” are the Saturation of O2 in the blood
Respiratory disturbances kidney compensate. For metabolic disturbances lungs compensate
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46. EXERCISE #1
For the patient with hyperkalemia related to decreased renal excretion secondary to potassium conserving diuretic therapy” an appropriate expected outcome would be which of the following?
Bowel motility will be restored within 24 hours after beginning supplemental K+
ECG will show no cardiac arrhythmias within 48 hours after removing salt substitutes, coffee, tea and other K+ rich foods from the diet
ECG will show no cardiac arrhythmias within 24 hours after beginning supplemental K+
Bowel motility will be restored within 24 hours after eliminating salt substitutes, coffee, tea, and other K+ rich foods from the diet
Answer.b

47. EXERCISE #2
Which of the following nursing diagnoses would you expect to find based on the effects of fluid and electrolyte imbalance on human functioning?
Constipation related to immobility
Pain related to surgical incision
Altered thought processes related to cerebral edema, including mental confusion and disorientation
Health risk for infection related to inadequate personal hygiene
Answer: c.

48. EXERCISE #3
A nurse who diagnoses a patient as having “fluid volume excess” related to compromised regulatory mechanisms (kidneys) may have been alerted by which of the following symptoms?
Muscular twitching
Distended neck veins
Fingerprinting over sternum
Nausea and vomiting
Answer: b

49. EXERCISE #4
Pumping uphill would describe which of the following means or transporting materials to and from intercellular compartments?
Osmosis
Diffusion
Filtration
Active transport