Fluid, Electrolyte, and Acid-Base Balance

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Fluid, Electrolyte, and Acid-Base Balance
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Reference

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

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Competencies for Ch 46Fluid, 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

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Competencies for Ch 46Fluid, 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

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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

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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

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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

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ELECTROLYTES

• Terminology
• Ions
• Electrolytes
• Cations
• Anions
• Non-electrolytes
• Solvents
• Solutes

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Electrolytes

• Ions
• Cations positive charge
• Anions negative charge
• Homeostasis total cations equal to total anions

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Fluid Balance

• Solvents liquids that hold a substance in
  solution (water)
• Solutes substances dissolved in a solution
  (electrolytes and non-electrolytes)

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MORE ELECTROLYTES

• Measurement
• Based on chemical activity
• Regulation
• Water distribution
• Acid-base balance
• Neuromuscular excitability

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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

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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

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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

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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

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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

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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 bodys acid base
  buffer system

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PHOSPHATE (PO4-)

• Major anion in body cells
• Buffer in ICF and ECF
• Functions
• Maintains bodys acid-base balance
• Cell division and transmission of heredity
• Chemical reactions use of Vit B, CHO metabolism,
  nerve and muscle action

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OTHER ELECTROLYTES

• Sulfate
• Anion
• ICF
• Excreted in the kidney
• Lactic acid
• Anion
• Facilitates diffusion to and from capillaries

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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

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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

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Filtration

• Colloid osmotic pressure
• Hydrostatic pressure

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Source of Fluids for the Body

• Ingested liquids
• Food
• Metabolism

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Fluid Losses

• Kidneys urine
• Intestinal tract feces
• Skin perspiration
• Insensible water loss

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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

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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

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Electrolyte Imbalances

• Hyponatremia and hypernatremia
• Hypokalemia and hyperkalemia
• Hypocalcemia and hypercalcemia
• Hypomagnesemia and hypermagnesemia
• Hypophosphatemia and hyperphosphatemia

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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.

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Parameters of Assessment

• Nursing history and physical assessment
• Fluid intake and output
• Daily weights
• Laboratory studies

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Lab Studies to Assess for Imbalances

• Complete blood count
• Serum electrolytes
• Urine pH and specific gravity
• Arterial blood gases

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Risk Factors for Imbalances

• Pathophysiology underlying acute and chronic
  illnesses
• Abnormal losses of body fluids
• Burns
• Trauma
• Therapies that disrupt fluid and electrolyte
  balance

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Nursing Diagnoses Related to Imbalances

• Excess fluid volume
• Deficient fluid volume
• Risk for imbalanced fluid volume

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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

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Implementing

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

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Administering Medications

• Mineral-electrolyte preparations
• Diuretics
• Intravenous therapy

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Intravenous Therapy

• Vascular access devices
• Peripheral venous catheters
• Midline peripheral catheter
• Central venous access devices
• Implanted ports

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Vein Site Selection

• Accessibility of a vein
• Condition of vein
• Type of fluid to be infused
• Anticipated duration of infusion

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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

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HOMEOSTASIS

• PROCESS OF MAINTAINING A STABLE STATE UNDER
  VARIABLE CONDITIONS

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MECHANISMS OF HOMEOSTASIS

• Kidneys
• Cardiovascular system
• Lungs
• Adrenal Glands
• Thyroid Gland
• Parathyroid Gland
• Gastrointestinal tract
• Nervous system

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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.

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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.

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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

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BUFFER SYSTEMS

• Carbonic Acid-Sodium Bicarbonate System
• Phosphate Buffer System
• Protein Buffer System

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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

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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

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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

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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

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EXERCISE 4

• Pumping uphill would describe which of the
  following means or transporting materials to and
  from intercellular compartments?
• Osmosis
• Diffusion
• Filtration
• Active transport