Transcript 01. Fluid, Electrolyte, and Acid

Fluid, Electrolyte, and
Acid-Base Balance
Physiology of Fluid and Acid-Base
Balance
 The body normally maintains a balance
between the amount of fluid taken in and the
amount excreted.
 Homeostasis is the maintenance of this
balance in response to changes in the
internal and external environments.
Physiology of Fluid and Acid-Base
Balance
 Fluid Compartments
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Cells
Blood vessels
Tissue space (interstitial space)
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Space between the cells and blood vessels
Fluid Compartments
 Two Types of Body Fluids
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Intracellular fluid (ICF) is fluid within the cell.
Extracellar fluid (ECF)
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Intravascular fluid (within blood vessels)
Interstitial fluid (between cells; fluid that
surrounds cells)
 Solute: Substance dissolved in a solution.
 Solvent: Liquid that contains a substance in
solution.
 Permeability: Capability of a substance,
molecule, or ion to move across a membrane.
 Cells have semi-permeable membranes that
allow fluid and solutes to pass into and out of
the cell.
 Blood vessels have semi-permeable
membranes that bathe and feed the cells.
Body Water Distribution
 Water represents 45% to 75% of the body’s
total weight.
 About two-thirds of the body fluid is
intracellular.
 One-third of body fluid is extracellular.
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One-fourth of this fluid is intravascular.
Three-fourths is interstitial fluid.
Functions of Body Water
 Water acts as a solvent for essential nutrients.
 Water transports nutrients and oxygen from the blood
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to the cells.
Water removes waste material and other substances
from the cells and returns it to the blood for excretion
by the body.
Gives shape and form to cells.
Regulates body temperature.
Acts as a lubricant in joints.
Cushions body organs.
FLUID REQUIREMENTS
Sources
Losses
Water
1500 ml
Urine
1500 ml
Food
800 ml
Stool
200 ml
Oxidation
300 ml
Skin
500 ml
Resp. Tract
400 ml
Total
2600 ml
Total
2600 ml
Electrolytes
 Compounds that, when dissolved in water or
another solvent, form or dissociate into ions
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Sodium (Na+)
Potassium (K+)
Calcium (Ca2+)
Magnesium (Mg2+)
ELECTROLYTES IN
BODY FLUID COMPARTMENTS
INTRACELLULAR
EXTRACELLULAR
POTASSIUM
SODIUM
MAGNESIUM
CHLORIDE
PHOSPHOROUS
BICARBONATE
Normal Laboratory Values
Sodium
135-145 meq/L
Potassium
3.5-5.0 meq/L
Chloride
95-105 meq/L
Bicarbonate
22-28 meq/L
Calcium
9-11 mg/dL
Phosphate
3.2-4.3 mg/dL
Glucose
70-110 mg/dL
BUN
8-18 mg/dL
Creatinine
0.6-1.2 mg/dL
Osmolality (P) 280-295 mOsm/kg
Osmolality (U) 50-1200 mOsm/kg
Electrolytes
 Promote normal neuromuscular excitability.
 Maintain body fluid osmolarity.
 Regulate acid base balance.
 Distribute body fluids between fluid
compartments.
 Extracellular fluid contains the largest
quantities of sodium, chloride, and
bicarbonate ions, and small quantities of
potassium and calcium.
 Intracellular fluid contains only small
quantities of sodium and chloride, almost no
calcium ions, and large quantities of
potassium.
Movement of Body Fluids
 Physiological forces affect the transport of molecules
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of water, foods, gases, wastes, and ions.
Maintain a balance between extracellular and
intracellular fluid compartments.
Diffusion
Osmosis
Active Transport
Hydrostatic Pressure
Filtration
Colloid Osmotic Pressure
Diffusion – movement of particles down a
concentration gradient.
Osmosis – diffusion of water across a
selectively permeable membrane
Active transport – movement of particles up
a concentration gradient ; requires energy
Regulators of Fluid Balance
 Fluid and Food Intake and Loss
 Skin
 Lungs
 Gastrointestinal Tract
 Kidneys
Acid-Base Balance
 Acid-base balance refers to the homeostasis
of the hydrogen ion concentration in
extracellular fluid.
 An acid is a substance that donates hydrogen
ions.
 A base is a substance that accepts hydrogen
ions.
 The pH symbol indicates the hydrogen ion
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concentration of body fluids.
7.35 to 7.45 is the normal pH range of extracellular
fluid.
Acidity increases as the pH decreases.
Alkalinity decreases as the pH increases.
Buffer Systems
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Two or more chemical compounds that prevent marked
changes in hydrogen ion concentration when either an
acid or a base is added to a solution
 Respiratory Regulation of Carbon Dioxide in
Extracellular Fluid
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Increased carbon dioxide levels in
extracellular fluid increase rate and depth of
respirations so that more carbon dioxide is
exhaled.
Decreased carbon dioxide levels depress
respirations to maintain carbon dioxide.
 Renal Control of Hydrogen Ion Concentration
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The kidneys control extracellular fluid pH by
removing hydrogen or bicarbonate ions from
body fluids.
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When the kidneys excrete more bicarbonate ions,
the urine becomes more alkaline.
When the kidneys excrete more hydrogen ions,
the urine becomes more acidic.
Factors Affecting Fluid and Electrolyte
Balance
 Age
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Adult, 60% water
Child, 60% to 77% water
Infant, 77% water
Embryo, 97% water
 In the elderly, body water diminishes because
of tissue loss.
Factors Affecting Fluid and
Electrolyte Balance
 Lifestyle
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Stress
Exercise
Warm or humid environment
Diet
Disturbances in Electrolyte and
Acid-Base Balance
 In illness, one or more of the homeostatic
regulating mechanisms may be affected, or
the imbalance may become too great for the
body to correct without treatment.
 Sodium is the primary determinant of
extracellular fluid concentration.
 Alterations in sodium concentration can
produce profound effects on the central
nervous system and circulating blood volume.
Electrolyte Disturbances
 Hyponatremia is a deficit in the extracellular
level of sodium.
 The ratio of water to sodium is too high (a
hypo-osmolar state).
 Water moves out of the vascular space into
the interstitial space, causing edema.
Electrolyte Disturbances
 Hypernatremia is an excess of sodium in the
extracellular fluid.
 The ratio of sodium to water is too high
(hyperosmolar state).
 Extracellular osmotic pressure pulls fluid out
of the cells into the extracellular space,
causing edema.
Electrolyte Disturbances
 Potassium
 The normal range of extracellular potassium is
narrow (3.5-5.0 mEq/L).
 Small deviations cause serious or lifethreatening effects on physiologic functions.
 A reciprocal relationship exists between
sodium and potassium.
Electrolyte Disturbances
 Hypokalemia is a decrease in the
extracellular level of potassium.
 Gastrointestinal disturbances and the use of
potassium wasting diuretics, laxatives,
corticosteroids, and antibiotics place the
client at risk for hypokalemia.
Electrolyte Disturbances
 Hyperkalemia is an increase in the
extracellular level of potassium.
 Three major drug groups may cause
hyperkalemia.
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Potassium-sparing diuretics
Central nervous system agents
Oral and intravenous replacement potassium
salts
Electrolyte Disturbances
 Calcium
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Essential for normal bone and teeth formation
Critical factor in normal blood clotting
Maintenance of normal nerve and muscle
excitability
 Hypocalcemia is a decrease in the
extracellular level of calcium.
 Hypercalcemia is an increase in the
extracellular level of calcium.
Electrolyte Disturbances
 Magnesium
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Coenzyme in the metabolism of carbohydrates
and proteins
Mediator in neuromuscular activity
 Hypomagnesemia is a decrease in the
extracellular level of magnesium and usually
occurs with hypokalemia and hypocalcemia.
 Hypermagnesemia refers to an increase in
the extracellular level of magnesium.
Electrolyte Disturbances
 Phosphate
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Main intracellular anion
Appears as phosphorus in the serum.
Similar to calcium in that Vitamin D is needed
for its reabsorption from the renal tubules.
 Hypophosphatemia is a decreased
extracellular level of phosphorus.
 Hyperphosphatemia is an increased
extracellular level of phosphorus.
Electrolyte Disturbances
 Chloride and water move in the same direction as
sodium ions.
 A loss of chloride can be compensated for by an
increase in bicarbonate.
 Hypochloremia is a decrease in the extracellular level
of chloride.
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Gastrointestinal tract losses because of the acid
content of gastric juices (hydrogen chloride), placing
the client at risk for metabolic alkalosis
 Hyperchloremia usually occurs with dehydration,
hypernatremia, and metabolic acidosis.
Acid-Base Disturbances
 Laboratory Data
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Arterial blood gases
Blood pH
Bicarbonate ion concentration
Sodium, potassium, chloride levels
 Respiratory Acidosis (Carbonic Acid Excess)
 Respiratory Alkalosis (Carbonic Acid Deficit)
 Metabolic Acidosis (Bicarbonate Deficit)
 Metabolic Alkalosis (Bicarbonate Excess)
Assessment
 Health History
 Clients receiving certain treatments, such as
medications and IV therapy
 Data specific to fluids
 Physical Examination
 Daily weight
 Vital signs
 Intake and output
 Edema
 Skin turgor
Assessment
 Physical Examination
 Buccal (oral) cavity
 Eyes
 Jugular and hand veins
 Neuromuscular system
 Diagnostic and Laboratory Data
 Hemoglobin and hematocrit indices
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With severe dehydration and hypovolemic shock,
the hematocrit is increased.
Overhydration reduces the hematocrit by dilution.
Laboratory Data
 Osmolality
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Measurement of the total concentration of
dissolved particles (solutes) per kilogram of
water
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Serum osmolality
Urine osmolality
 Diagnostic and Laboratory Data
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Urine pH
Serum albumin
Deficient Knowledge
 Dehydration is one of the most common and
most serious fluid balances.
 Information obtained from a client’s health
history may indicate the client’s level of
understanding and perception of alterations in
fluid, electrolyte and acid-base balance.
Planning and Outcome
Identification
 Expected outcomes for clients with fluid
imbalances include outcomes relative to
interventions.
 Achievement of the goals and the client’s
expected outcomes indicates resolution of the
problem.
Implementation
 Monitor Daily Weight
 Measure Vital Signs
 Measure Intake and Output
 Provide Oral Hygiene
 Initiate Oral Fluid Therapy
 Nothing by Mouth
 Restricted Fluids
 Forced Fluids
 Maintain Tube Feedings
 Monitor Intravenous Therapy
Implementation
 Monitor Intravenous Therapy
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Administration of fluids, electrolytes, nutrients,
or medications by the venous route when fluid
losses are severe or the client cannot tolerate
oral or tube feedings
Intravenous Therapy
 Parenteral Fluids
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Hypotonic
Isotonic
Hypertonic
 Equipment
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Administration Set
Health Hazard
Intravenous Filters
Intravenous Therapy
 Equipment
 Needles and venous peripheral-short catheters
 Butterfly needles
 Intracath
 Angiocatheter
 Peripheral intravenous (PI)
 Heparin locks (intermittent venous locks)
 Equipment
 Needle-Free System
 Vascular Access Devices (VAD)
 Various catheters, cannulas, infusion ports that allow
for long-term IV therapy or repeated access to the
central venous system
Intravenous Therapy
 Preparing an Intravenous Solution
 Initiating IV therapy
 Vein finder
 Administering IV Therapy
 Flushing
 Regulating IV solution flow rates
 Calculation of flow rates
 Flow Control Devices
 Manual flow-control devices
 Electronic infusion devices
Intravenous Therapy
 Managing IV Therapy
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Hypervolemia
Infiltration
Phlebitis
Intravenous dressing change
Intravenous Therapy
 Discontinuation of Intravenous Therapy
 Blood Transfusion
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Whole blood and blood products
Initial assessment and preparation
Administering whole blood or a blood
component
Safety measures
Complementary Therapy
 Herbs and certain foods
 Naturopathic health care practitioners
 Considerations for using complementary
therapies with traditional medications