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Transcript
Fluid, Electrolyte, and
Acid-Base Balances
Chapter 41
Mosby items and derived items ©
2005 by Mosby, Inc.
Distribution of Body Fluids
Adult human body made up of about
60% water
 Body holds fluid in 2 basic
compartments

Extracellular
 Intracellular
 Distribution of fluid b/w 2 compartments
must remain relatively constant

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Distribution of Body Fluids

Extracellular

Interstitial fluid
 surrounds

the cells
Intravascular fluid
 liquid
portion of blood or plasma
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Distribution of Body Fluids

Transcellular fluid
 Cerebrospinal
column
 pleural
cavity
 Lymph system
 Joints
 Eyes

Intracellular

Inside cells
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Inside the
Cell:intracellular
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Composition of Body Fluids

Water

Full-term neonate
 80%

Premature infant
 90

body weight is water
% of body weight is water
Amount of water % decreases with age
until puberty
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Composition of Body Fluids

Skeletal muscle cells hold much of water, fat
cells contain little water
 Women

have lower ration of water content
Risk of suffering an imbalance increases with
age
 Skeletal
muscle mass declines
 Proportion of fat within body increases
 After age 60, water content drops to about 45%
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Electrolytes:
Anions and Cations
When electrolytes are melted or dissolved
into separates into ions and is able to
carry an electrical current
 Anions



Negatively charged electrolytes
Cations

Positively charged electrolytes
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Fluid Types

Isotonic
Saline solution (0.9% Normal Saline)
 Nearly equals the concentration of sodium in
the blood


Hypotonic
Lower solute concentration than another
solution
 Fluid from hypotonic solution would shift into
the second solution until the two solutions had
equal concentrations
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
2005 by Mosby, Inc.
Fluid Types

½ Normal Saline (0.45% Normal Saline)



Concentration of sodium is lower than concentration of
sodium into patient’s blood
Moves fluid into the cells, causing them to enlarge
Hypertonic



Has a higher concentration than another solution
Fluid from second solution would shift into hypertonic
solution until equilibrium
Dextrose 5% saline solution (D5NS)


Concentration of solutes in solution is greater than
concentration of solutions in patients blood
Pulls fluid from cells, causing them to shrink
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Movement of Body Fluids

Osmosis


Fluid moves passively from areas with more
fluid (and fewer solutes) to areas with less
fluid (and more solutes) through a semipermeable membrane
Diffusion
Solutes move from an area of higher
concentration to lower concentration
across a semi-permeable membrane
 Passive transport

 Doesn’t
require
energy
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Movement of Body Fluids

Filtration
Water and diffusible substances move from
area of higher pressure to lower pressure
 Movement occurs in capillary beds

 Results
from blood pushing against the walls of the
capillary (hydrostatic pressure).

Forces fluids and solutes through capillary wall
 When
the hydrostatic pressure increases inside a
capillary is greater than the pressure in
surrounding interstitial space, fluids and solute
inside the capillary are forced out into interstitial
space.
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Movement of Body Fluids
When pressure inside capillary is less than
pressure outside of it, fluids and solutes move
back into capillary
 Reabsorption

 Prevents
too much fluid from leaving capillaries no
matter how much hydrostatic pressure exists
 When fluid filters through a capillary, albumin
(protein) remains behind in the diminishing volume
of water.

Water magnet
 Has an osmotic effect
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Movement of Body Fluids

Plasma colloid osmotic pressure
 Osmotic
or pulling force of albumin in the
intravascular space


As long as capillary blood pressure (hydrostatic pressure)
exceeds plasma colloid osmotic pressure, water and
solutes can leave capillaries and enter interstitial fluid.
When osmotic pressure falls below plasma colloid osmotic
pressure m water and diffusible solutes return to
capillaries
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Movement of Body Fluids

Active transport

Requires metabolic activity and expenditure
of energy
 ATP
(adenosine triphosphate)
 ATP is stored in all cells
Solutes move from area of lower
concentration to an area of higher
concentration
 Enhanced by carrier molecules within a cell

 Glucose
enters cell after it binds with insulin
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Regulation of Body Fluids

Homeostasis


Physiological balance
Fluid intake (adult: 2200 to 2700 ml/day)

Regulated by thirst mechanism




Losing body fluids or eating highly salty foods leads to
increase in extracellular fluid osmolality.
This increase leads to drying of mucus membranes in
mouth
Which stimulates thirst center in hypothalamus
Infants, clients with neurological or psychological
problems and some older adults at risk for
dehydration

Unable to perceive thirst mechanism
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The Kidneys
Play vital role in fluid balance
 Nephron

Workhorse of kidney-forms urine
 Consists of a glomerulus and a tubule
 The tubule ends in a collecting duct

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The Kidneys

Glomerulus
 Cluster
of capillaries that filters blood
 Surrounded by Bowman’s capsule

Vascular cradle
Capillary pressure forces fluid through the
capillary walls and into Bowman’s capsule at the
proximal end of the tubule
 Along length of tubule, water and electrolytes are
either excreted or retained

 According
to the body’s needs
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The Kidneys
 If
less fluid is needed, less is reabsorbed and excreted
 If more fluid is needed, more fluid is retained
 Na and K (electrolytes) are either filtered or
reabsorbed throughout this same area
 The resulting filtrate flows through tubule into
collecting ducts and eventually into the bladders as
urine

The nephron filters about 125ml blood every
minute (180L/day)
 Glomerular
filtration rate
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The Kidneys
 Leads
to production of 1 to 2 L of urine/day
 Nephrons reabsorb remaining 178L or more fluid

If body loses even 1-2% of its fluid, the
kidneys take steps to conserve fluid
 Kidneys
respond by excreting more dilute urine
Kidneys must continue to excrete at least
30ml of urine every hour to eliminate body
waste
 Urine excretory rate less than 30ml/hr
usually indicates renal pathology

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Hormonal Regulation

ADH (antidiuretic hormone) (vasopressin)
“water retainer”
 Produced by hypothalamus
 Stored and released by posterior pituitary
gland
 Job:

 Restores
blood volume by reducing diuresis and
increasing water retention
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Hormonal Regulation

Aldosterone



Released by adrenal cortex in response to increased
plasma potassium levels or to counteract hypovolemia
Release of aldosterone acts as a volume regulator
Renin-angiotensin-aldosterone system


Proteolytic enzyme secreted by kidney
Responds to decreased renal perfusion 2ndary to
decrease in extracellular volume

Amount of renin secreted depends on blood flow and level of
Na in bloodstream.
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Hormonal Regulation
 If
blood flow to kidneys diminishes, (hemorrhaging)
or if amount of Na reaching the glomerulus, more
renin is secreted.
 This causes vasoconstriction with a subsequent
increase in blood pressure
 If blood flow to kidneys increases, or amount of Na
reaching glomerulus increased, less renin is
secreted

Drop-off in renin secretion reduces vasoconstriction and
helps to normalize blood pressure
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Hormonal Regulation

Fluid output

Occurs through 4 organs of water loss
 Kidneys
 Skin
 Lungs
 GI

tract
Insensible water loss


Can’t be measured or seen
Evaporation (skin)
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Hormonal Regulation



Respiratory rate and depth
 Tachypnea-increased fluid loss
 Bradypnea-decreased fluid loss
Fever
 Losses from skin and lungs
Sensible water loss
 Urination
 Defecation
 Wounds
 Excessive
perspiration (perceivable)
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ELECTROLYTE IMBALANCES
SODIUM (Na+)

Sodium (Na+)
Most abundant at 90% in extracellular
fluid
 Help maintain fluid balance

 Serum
osmalility
 Nerve impulse transmission
 Regulation of acid-base balance

135 to 145 mEq/L
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ELECTROLYTE IMBALANCES
SODIUM: Hyponatremia



Actual decrease: pt has inadequate intake
of sodium or excess of sodium
Relative decrease: sodium is not lost from
body but leaves intravascular space and
moves to the interstitial space (third
spacing)
Another relative cause of decrease occurs
when plasma volume increases (fluid
overload) causing dilution effect
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ELECTROLYTE IMBALANCES
SODIUM: Hyponatremia

Prevention
 Administration of sodium for patients at risk is
usually by IV route
 NPO
 Excessive diaphoresis
 Diuretics
 GI suction
 Freshwater near drowning
 Decreased aldosterone
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ELECTROLYTE IMBALANCES
SODIUM: Hyponatremia

Prevention
 Replace both sodium and water in the following
patients experiencing
 High fevers
 Strenuous exercise or physical labor, esp.
with heat excess
 Especially dangerous for elderly
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ELECTROLYTE IMBALANCES
SODIUM: Hyponatremia

Signs & Symptoms
 Mental status changes, including
disorientation, confusion and personality
changes due to cerebral edema
 Postural hypotension
 Abdominal cramping
 Tachycardia
 N&V
 Weakness
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ELECTROLYTE IMBALANCES
SODIUM: Hyponatremia

Medical Treatment
 Focus is to resolve underlying cause &
replace lost sodium
 IV saline ordered if fluid overload is not
present
may be 0.9 NS (isotonic) or 3%BS
(hypertonic) depending on severity
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ELECTROLYTE IMBALANCES
SODIUM: Hypernatremia





Serum sodium level is above 145 mEq/L
Ingestion of large amounts concentrated
salts
Diabetes insipidus
Increased sensible or insensible water loss
Water deprivation
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ELECTROLYTE IMBALANCES
SODIUM: Hypernatremia


Prevention
 Not as simple as hyponatremia
 Most are a result of an acute or chronic illness
 Carefully regulate IV fluids
Signs & Symptoms
 Thirst usually first symptom
 Agitation
 Dry and flushed skin
 Restlessness
 Irritability
 Convulsions
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ELECTROLYTE IMBALANCES
SODIUM: Hypernatremia

Medical Treatment
 If fluid imbalance present..correct first
 If kidneys not excreting…diuretic if
kidney is functional
 Dialysis may be need if not functional
 I&O
 Daily weights
 Treat cause if known
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ELECTROLYTE IMBALANCES
Potassium (K+)




Normal serum value = 3.5-5 mEq/L
Most common electrolyte in the ICF
compartment
Regulates many metabolic activities
Necessary for




Transmission and conduction nerve impulses
Glycogen deposits in liver and skeletal muscle
Skeletal and smooth muscle contraction
Minimal changes in value cause major
changes in body
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ELECTROLYTE IMBALANCES
Potassium: Hypokalemia





Serum potassium level below 3.5 mEq/L
Most cases…inadequate intake or excessive loss of
K+ via the kidneys
Most often occurs as result of medications
 K+ losing diuretic… Furosemide (Lasix)
 Digitalis preparations…Digoxin (Lanoxin)
GI tract losses
 Vomiting, diarrhea, prolonged GI suctioning
Major Surgery and hemorrhage can cause deficit
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ELECTROLYTE IMBALANCES
Potassium: Hypokalemia

Prevention
 Administer K+ supplements prior to
major surgery in IV fluids
 Encourage foods high in K+ if on
medications that causes K+ loss
 Digitalis must be closely monitored
 hypokalemia
can enhance action of
digitalis causing digitalis toxicity
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ELECTROLYTE IMBALANCES
Potassium: Hypokalemia

Signs & Symptoms
 Muscle cramping
 Decreased muscle tone
 Shallow, ineffective respirations
 Pulse weak, irregular, thready due to heart
muscle depletion of K+
 Decreased bowel sounds
 Major danger of dysrhythmia leading to cardiac
arrest
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ELECTROLYTE IMBALANCES
Potassium: Hypokalemia



Treatment:
Mild to moderate kypokalemia
 Oral supplements
Severe Hypokalemia
 IV K+ supplements



Add only after pt voids to assure kidney has ability to rid the
body of excess K+
Never give IV push
Monitor serum values closely
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ELECTROLYTE IMBALANCES
Potassium: Hyperkalemia





Serum potassium greater than 5 mEq/L
Renal failure
Excessive intake of oral or IV supplements
Use of K+ sparing diuretics (Aldactone)
Massive cellular damage



Burns
Trauma
Fluid volum deficit
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ELECTROLYTE IMBALANCES
Potassium: Hyperkalemia

Prevention
 Monitor
serum electrolytes values in pt
receiving supplements
 Monitor pt for s/s of imbalance
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ELECTROLYTE IMBALANCES
Potassium: Hyperkalemia

Signs & symptoms
 Usually
occur in hospitalized pt or chronic
conditions with treatment
 Muscle twitches & Cramps Progressing to
 Muscular weakness
 Diarrhea
 Slow,irregular heart rate
 Decreased blood pressure
 Anxiety
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ELECTROLYTE IMBALANCES
Potassium: Hyperkalemia

Medical Treatment
 Mild, chronic
 Limit K+ rich foods
 Stop K+ supplements
 Administer K+ losing diuretic if kidneys healthy

During treatment of moderate to severe
hyperkalemia pt should be hospitalized and
on cardiac monitor
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ELECTROLYTE IMBALANCES
Calcium (Ca++)



Normal Value = 4.5-5.5 mEq/L
Stored in bones, teeth, plasma and body cells
Necessary for:






Bone and teeth formation
Blood clotting
Hormone secretion
Cardiac conduction
Transmission of nerve impulses
Muscle contraction
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ELECTROLYTE IMBALANCES
Calcium: Hypocalcemia (Ca++)


Serum calcium level below 4.5 mEq/L
Postmenopausal women are most at risk






Causes brittle, porous bones that are easily
fractured….osteoporosis
Postmenopausal women have decreased estrogen
Immobility or decreased motility contributes to bone
loss in younger women
Patients at highest risk for osteoporosis are thin,
petite, Caucasian women
Pancreatitis
Vitamin D deficienty
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ELECTROLYTE IMBALANCES
Calcium: Hypocalcemia (Ca++)

Prevention
 Adequate intake 1000 – 1200 mg
 Consume calcium rich food
 Take supplements
 Tums 240 mg/tab
 Vitamin D may be needed if lack of sun
exposure
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ELECTROLYTE IMBALANCES
Calcium: Hypocalcemia (Ca++)

Signs & Symptoms
 Pathological fractures
 Increased and irregular heart rate
 Numbness and tingling of fingers
 Hyperactive deep tendon reflexes
 Increased GI motility…diarrhea , cramps
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ELECTROLYTE IMBALANCES
Calcium: Hypocalcemia (Ca++)

Two classic signs used to assess for
hypocalcemia
 Trousseau’s sign and Chvostek’s sign
 Trousseau’s
sign…inflate bp cuff on the arm 1-4
minutes. If pt’s hand and fingers become spastic
and demonstrate palmar flexion ….test is positive
 Chvostek’s sign…tap face just below and in front of
ear, facial twitching on that side of face indicates
positive test
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ELECTROLYTE IMBALANCES
Calcium: Hypocalcemia (Ca++)

Medical Treatment
 Treat cause
 Replace calcium
 Oral with or without Vitamin D… if mild or chronic
condition

Administer 1-2 h pc to increase absorption
 IV
administration for acute or severe
hypocalcamia

Use calcium gluconate or calcium chloride
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ELECTROLYTE IMBALANCES
Calcium: Hypercalcemia
 Ca+
above 5.5 mEq/L
 Prolonged Immobilization
 Excess intake of calcium or vitamin D
 Osteoporosis
 Hyperparathyroidism
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ELECTROLYTE IMBALANCES
Calcium: Hypercalcemia

Prevention
Many causes cannot be prevented
 Monitor pt receiving calcium supplement
 Education of public regarding proper amount
needed as well as dangers of too much calcium

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ELECTROLYTE IMBALANCES
Calcium: Hypercalcemia

Signs & Symptoms
 Skeletal muscle weakness
 Anorexia, N&V
 Decreased LOC
 Personality changes
 Lethargy
 Low back pain
 Cardiac arrest
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ELECTROLYTE IMBALANCES
Calcium: Hypercalcemia

Medical Treatment
 Severe hypercalcemia
 Hospitalize
 Cardiac monitor
 Administer large amounts of fluids and promote
diuresis if not contraindication by patient condition

Saline infusion most useful to promote excretion
 Discontinue

any thiazide diuretic
Use Lasix
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ELECTROLYTE IMBALANCES
Magnesium(Mg++)



Normal value: 1.50-2.5 mEq/L
Magnesium & calcium work together for proper functioning
of excitable cells
 Cardiac & nerve cells
 An imbalance of magnesium is usually accompanied by
calcium imbalance
Essential for:
 Neurochemical activities
 Cardiac and skeletal muscle excitability
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ELECTROLYTE IMBALANCES
Magnesium: Hypomagnesemia

Serum magnesium level below 1.5 mEq/L
 Malnutrition/Starvation diets
 Alcoholism

Inadequate absorption
 N&V, diarrhea
 Nasogastric drainage
 Fistulas
 Polyuria
 Excessive loss from thiazide diuretics
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ELECTROLYTE IMBALANCES
Magnesium: Hypomagnesemia

Signs & Symptoms similar to hypocalcemia
 Positive Trousseau’s and Chvostek’s sign
 Muscle tremors
 Confusion and disorientation
 Treatment
 Mg
sulfate is administered IV, calcium may also be
administered
 Place on cardiac monitor
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ELECTROLYTE IMBALANCES
Magnesium: Hypermagnesemia




Serum magnesium level above 2.5 mEq/L
Renal failure
Excess oral or parenteral intake
Signs & symptoms
 Usually not apparent until level is > 4 mEq/L
 Bradycardia, decreased depth of resp.
 Hypoactive deep tendon reflexes
 Hypotension
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ELECTROLYTE IMBALANCES
Magnesium: Hypermagnesemia

Treatment
 Loop diuretics if kidney function properly
 IV fluids to increase renal excretion
 If renal failure
 dialysis
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Regulation of Electrolytes: Anions

Chloride (Cl-)
90-110mEq/L
 Major anion in ECF
 Regulated by dietary intake and kidneys
 Hypochloremia

 Vomiting
drainage
or prolonged and excessive NGT
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Regulation of Electrolytes: Anions

Bicarbonate (HCO3-)
22-26 mEq (arterial)
 24-30 mEq (venous)
 Major chemical base buffer in the body
 Found in ECF and ICF
 Essential to acid base balance
 Kidneys regulate bicarb

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Regulation of Electrolytes: Anions

Phosphate (PO4-)
1.7-4.6 mEq/L
 Buffer anion found primarily in ICF
 Assisting in acid base regulation
 Phosphate and calcium help to develop and
maintain bones and teeth
 Calcium and phosphate are inversely
proportional

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Fluid Imbalances


Dehydration: fluid deficit
 Elderly people are at highest risk for life threatening
complications resulting from dehydration
 Infants are at high risk because they take in &
excrete a large portion of their total body water each
day
Fluid overload: fluid excess
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Fluid Imbalances:
Dehydration

Dehydration
 Several types
 Isotonic
 Hypertonic
 Hypotonic
 Dehydration occurs when there is not enough fluid in
the body, especially in the blood…..intravascular area
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Fluid Imbalances:
Dehydration

Most common is fluid loss from body
 Results in decreased blood volume called
hypovolemia
 Fluid loss may occur from
 Hemorrhaging
 Severe
vomiting
 Severe diarrhea
 Severely draining wound
 Profuse diaphoresis
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Fluid Imbalances:
Dehydration
Burns
 Trauma
 Surgery
 Respiratory disorders
 Cancer
 CV disease
 Diet
 Medications

Mosby items and derived items ©
2005 by Mosby, Inc.
Fluid Imbalances:
Dehydration

Prevention
 Identify patients at high risk
 Elderly
 Infants
 Children
 Adequate hydration
 Drink enough fluids
 Administer IV therapy if unable to take PO
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2005 by Mosby, Inc.
Fluid Imbalances:
Dehydration

Signs & Symptoms
 Thirst is the first symptom in healthy adults
 Tachycardia results from heart pumping faster but
not as strongly
 Weak rapid pulse
 Low blood pressure
 Decreased tears
 Dry skin
 Dry mucous membranes
Mosby items and derived items ©
2005 by Mosby, Inc.
Fluid Imbalances:
Dehydration




Poor skin turgor….”tenting”
Temperature increase
 Body less able to cool itself through perspiration
Urine output decreases
Symptoms of dehydration in the elderly client may be
atypical
 Altered mental status
 Light-headedness
 Syncope
 Symptoms are a result of hypovolemia causing
inadequate blood supply resulting in decreased oxygen
supply to the brain
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2005 by Mosby, Inc.
Fluid Imbalances:
Dehydration

Medical Treatment


Goal: replace fluids and resolve cause of dehydration
Moderate or severe dehydration:
 IV therapy using fluid with same osmolarity of
blood (isotonic)
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2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload



Overhydration
 Too much fluid in body
 Most problems result from too much fluid in
bloodstream or from dilution of electrolytes and
RBC’s
Most common result of overload is
Hypervolemia… excess fluid in intravascular
space
Healthy adult kidneys can compensate for mild
to moderate hypervolemia
 Increase urinary
output
Mosby items
and derived items ©
2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload

Causes related to excess intake of fluid or
inadequate excretion of fluid
 Poorly controlled IV therapy
 Excessive irrigation of wounds or body cavities
 Excessive ingestion of water
 Renal failure
 Heart failure
 Inappropriate ADH
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2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload

Prevention




Avoid excessive fluid intake
Monitor IV fluids carefully
 Pumps or burrette
Assess patient for S/S of fluid overload
Monitor amount of fluid used for irrigations
 Gastric lavage, enemas etc.
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2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload

Signs & Symptoms
 Vitals sign changes (opposite of dehydration)
 Blood pressure elevated
 Pulse bounding
 Respirations increased and shallow
 Neck vein distention
 Pitting edema esp. feet and legs
 Pale, cool skin
 Increased urine output, urine diluted almost like water
 Rapid weight gain
 Severe overload
 Moist crackles, dyspnea & ascites
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2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload

Medical Treatment
 After supporting patient’ s breathing…..goal
of treatment is to rid body of excess fluid &
resolve underlying cause of overload
 Drug therapy & diet therapy are commonly
used

Positioning: semi Fowler's or high Fowler’s
 Facilitate ease of breathing
 Greater lung expansion aiding respiratory effort
Mosby items and derived items ©
2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload

Oxygen therapy
 Ensure
adequate perfusion of major organs
 Minimizes dyspnea
 Hx of COPD…limit to no more than 2l/min

Higher oxygen concentrations may cause patient to lose
stimulus to breathe causing respiratory arrest
 Diuretics…rapidly

rid body of excess water
Lasix or furosemide is drug of choice if kidney function
is adequate
Mosby items and derived items ©
2005 by Mosby, Inc.
Fluid Imbalances:
Fluid Volume Excess/Overload

Diet Therapy
 Mild
to moderate fluid restriction may be used
 Sodium restricted diets may be necessary
 1-2 g Na+ for sever overload
 Specific diet therapy depends on patient condition,
medication as well as any other medical conditions
that may exist
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2005 by Mosby, Inc.
ACID-BASE IMBALANCES



Most are caused by acute and chronic illness or
conditions
Primary treatment is to manage the underlying
cause…correcting imbalance
Role of nurse
 Identify patients at risk
 Monitor lab test values
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2005 by Mosby, Inc.
ACID-BASE IMBALANCES



Lab tests
 ABG (arterial blood gases)
Types of imbalances
 Acidosis
 Alkalosis
Imbalances can be acute or chronic
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2005 by Mosby, Inc.
Acid-Base Balance:
ABG Analysis

pH


PaCO2




7.35 (acidic)-7.45 (alkalotic)
35 – 45 mm Hg
Less than 35-hyperventilation has occurred
Greater than 45-hypoventilation has occurred
PaO2



80 to 100 mm Hg
Less than 60-anaerobic metabolism
Normal decline in PaO2 in older adults
Mosby items and derived items ©
2005 by Mosby, Inc.
Acid-Base Balance:
ABG Analysis

Oxygen saturation
Hemoglobin is saturated by oxygen
 95-99%
 Below 60=large drop in saturation


Base excess


+ or - 2
Bicarbonate (HCO3-)
Mosby items and derived items ©
2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Acidosis
 pH below 7.34
 Blood becomes more acidic than normal
 Too much acid in body or too little base causes
acidosis
 Two types
 Respiratory: caused by problems in respiratory
system
 Metabolic: problems in the rest of the body
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2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Alkalosis
 pH increases above 7.45
 Blood becomes more alkaline than normal
 Too much base in body or too little acid causes
acidosis
 Two types
 Respiratory: caused by problems in respiratory
system
 Metabolic: problems in the rest of the body
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2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Respiratory Acidosis
 Caused primarily by respiratory problems
 CO2 is not “blown off” well enough during expiration
 Build up of CO2 in blood, mixes with water …creates a weak
acid in body….increasing acidity of blood
 Acute acidosis
 Hypoventilation
 Acute flare up of chronic respiratory disease (may have
chronic resp acidosis)
 Drugs (decreased respirations)
 Neurological problems (decrease respirations)
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2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Respiratory Acidosis
 Signs & Symptoms
 Involve CNS and MS systems
 As CO2 increases, mental status is altered
 Progresses from confusion & lethargy to stupor &
coma if untreated
 Lungs are unable to rid body of excess CO2
 Respirations become more depressed & shallow as
muscles weakness progresses
 Treatment
 Aggressive management of underlying problems
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2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Metabolic Acidosis
 Can result from too much acid in body (usually fixed acids) or
too little bicarbonate in body
 Uncontrolled diabetes mellitus and end-stage renal
disease are the two main causes of too much fixed acids
 GI tract is rich in bicarbonate
 Diarrhea or prolonged suctioning place pt at high risk
 Bicarbonate or base loss
 Serum pH decreases and bicarbonate level decreases
 Serum K+ increases in metabolic acidosis
 Excess H+ in ECF moves into cells in exchange for K+,
which leaves the cells and enters the blood
 A method of compensating for the acidotic state
Mosby items and derived items ©
2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Metabolic Acidosis
 Signs & Symptoms
 Similar to respiratory acidosis except for
respiratory pattern
 Lungs rid of extra carbon dioxide through
Kussmaul’s respiration…deep & rapid, in pt
with healthy lungs
 Treatment
 Management of underlying disease or condition
Mosby items and derived items ©
2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Respiratory Alkalosis
 Least common acid-base imbalance
 Occurs when there is excessive loss of carbon dioxide
through hyperventilation
 May occur with anxious or fearful
 Have rapid shallow respirations
 Light headed
 May be confused
 Heart rate increases and pulse becomes weak and thready
 Serum pH is inceased & PaCO2 is very low
 May occur as a result of high altitudes
Mosby items and derived items ©
2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Respiratory Alkalosis
 Treatment
 Have pt rebreathe own CO2
 Rebreathing mask
 Paper bag
 Treat underlying cause
Mosby items and derived items ©
2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Metabolic Alkalosis
 Results form excessive ingestion of bicarbonate or
other bases or loss of acids from body
 Overuse of antacid or baking soda (Na
bicarbonate)
 Prolonged vomiting or NG suctioning can lead to
loss of acids since stomach contains HCL
 Serum pH is increased
 Serum Bicarbonate
 Serum Potassium decreases
Mosby items and derived items ©
2005 by Mosby, Inc.
ACID-BASE IMBALANCES

Metabolic Alkalosis
 H+ from ICF moves into blood in exchange for
K+ and K+ moves from the blood into the cells
 Body attempting to keep acid-base in balance
 Hypocalcemia may also accompany hypokalemia
 Signs & symptoms
 Related to hypokalemia and hypocalemia
 Treatment
 Identify and manage underlying cause
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2005 by Mosby, Inc.
Assessment of Risk Factors
Age
 Acute illness
 Chronic illness
 Environmental factors
 Diet
 Lifestyle
 Medication

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2005 by Mosby, Inc.
Client Assessment

Physical assessment

Intake and output
Laboratory studies
 Client expectations

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2005 by Mosby, Inc.
Nursing Diagnoses
Decreased cardiac output
 Deficient fluid volume
 Excess fluid volume
 Impaired mobility
 Impaired skin integrity
 Ineffective tissue perfusion

Mosby items and derived items ©
2005 by Mosby, Inc.
Planning

Goals and outcomes
– Client will demonstrate fluid
balance by moist, mucous
membranes, balanced I&O, and
stable daily weights within 48 hours
Setting priorities
 Continuity of care

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2005 by Mosby, Inc.
Implementation
Client education
 Daily weights and I&O measurement
 Enteral replacement of fluids
 Restriction of fluids
 Parenteral replacement of fluids and
electrolytes

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2005 by Mosby, Inc.
Intravenous Therapy

The primary goals of intravenous therapy (IV)
include




Achieving normal fluid and electrolyte balances
Achieving optimal nutrition status
Maintaining homeostasis through blood and blood
component administration
Treating numerous conditions with medication
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2005 by Mosby, Inc.
Nurse Responsibilities





Verify Physicians order
Obtain the correct solution as ordered
Collect equipment needed
Explain procedure to client
Perform venipuncture & initiate the infusion
according to agency P & P
Mosby items and derived items ©
2005 by Mosby, Inc.
IV Fluids

Isotonic


Has the same effective osmolality as body fluids
 Sodium chloride solution (0.9%)-normal saline
Hypertonic

Have an effective osmolality greater than body fluids
( pulls fluids into the vascular space by osmosis,
resulting in an increased vascular volume that can lead
to pulmonary edema, particularly in clients with heart
or renal failure).
 10% dextrose in normal saline
 3% sodium chloride
 5% sodium chloride
Mosby items and derived items ©
2005 by Mosby, Inc.
IV Fluids
•
Hypotonic
• Have an effective osmolality less than body
fluids
 ½ hypotonic saline (0.45%)
 5% dextrose in 0.45% saline
Mosby items and derived items ©
2005 by Mosby, Inc.
IV Medications




LPN & RN’s may hang piggyback medications
Assess patency of existing IV infusion line
before hanging piggyback medication
Check compatibility of drug with existing IV
solution before administering
Review client’s history of drug allergies
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2005 by Mosby, Inc.
Complications


Fluid volume excess
 SOB
 Crackles in the lung
 Tachycardia
Circulatory overload







SOB
Cough
Elevated BP
Periorbital edema
Dependent edema
Engorged neck veins
Moist breath sounds
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2005 by Mosby, Inc.
Evaluation
Client care
 Client expectations

Mosby items and derived items ©
2005 by Mosby, Inc.