Stressors Affecting
Fluid & Electrolyte
Balance
NUR 101
FALL 2008
LECTURE # 15 & #16
K. Burger, MSEd, MSN, RN, CNE
Body Fluids
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Water= most important nutrient for life.
Water= primary body fluid.
Adult weight is 55-60% water.
Loss of 10% body fluid = 8% weight loss SERIOUS
Loss of 20% body fluid = 15% weight loss FATAL
Fluid gained each day should = fluid lost each day
(2 -3L/day average)
What is the minimum output per hour necessary to
maintain renal function? 30ml/hr
Functions of Body Fluid
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Medium for transport
Needed for cellular metabolism
Solvent for electrolytes and other
constituents
Helps maintain body temperature
Helps digestion and elimination
Acts as a lubricant
Mechanisms of
Fluid Gain and Loss
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Gain
Fluid intake 1500ml
Food intake 1000ml
Oxidation of nutrients
300ml
(10ml of H20
per
100 Kcal)
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Loss
“Sensible”
Can be seen.
Urine
1500ml
Sweat
100ml
“Insensible”
Not visible.
Skin (evaporation) 500ml
Lungs
400ml
Feces
200ml
Regulation of Fluids
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Hypothalmus –thirst receptors (osmoreceptors)
continuosly monitor serum osmolarity (concentration). If
it rises, thirst mechanism is triggered.
+Vasopressin (AKA ADH )– increasing H20 reabsorption
Pituitary regulation- posterior pituitary releases
ADH (antidiuretic hormone) in response to increasing
serum osmolarity. Causes renal tubules to retain
H20.
Thirst is a late sign of water deficit
Regulation of Fluids (continued )

Renal regulation- Nephron receptors
sense decreased pressure (low osmolarity)
and kidney secretes RENIN.
Renin – Angiotensin I – Angiotensin II
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Angiotensin II causes Na and H20
retention by kidneys AND…..
Stimulates Adrenal Cortex to secrete
Aldosterone which causes kidneys to
excrete K and retain Na and H20.
Consider This….

The Geriatric Client
-normal physiological aging results in
decreased thirst mechanism
decreased # of sweat glands
decreased renal function
-there also may be decreased mobility
and/or cognitive function which impacts
their ability to get adequate fluid intake.
Variations in Body Fluids
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Elderly: Have lower % of total body fluid
than younger adults
Women: Have lower % total body fluid
than men
WHY DO YOU THINK THIS IS ?????
Muscle tissue has more H20 content THAN adipose tissue
Fluid Compartments
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Intracellular
fluid (ICF)
Fluid inside the
cell
Most (2/3) of
the body’s H20
is in the ICF.
Extracellular Fluid
(ECF)
Fluid outside the cell.
 1/3 of body’s H20
 More prone to loss
 3 types:
Interstitial- fluid
around/between cells
Intravascular- (plasma)
fluid in blood vessels
Transcellular –CSF,
Synovial fluid etc
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Consider this….
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Age variations exist in regards to
H20 content of fluid compartments
Infants =
60% of H20 is found in ECF
40% of H20 is found in ICF
What might this mean in regards to fluid
loss for an infant? Reverse of adults!
Infant MORE PRONE to fluid
LOSS!
Fluid Balance
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Dynamic process
Balance between body fluids and
electrolytes
Attraction between ions
(electrolytes) and water (fluids)
causes fluids to move across
membranes and leave their
compartments.
Solvent (H20) Movement
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Cell membranes are semipermeable
allowing water to pass through
Osmosis- major way fluids transported
Water shifts from low solute
concentration to high solute
concentration to reach homeostasis
(balance).
Osmolarity
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Concentration of particles in solution
The greater the concentration (Osmolarity) of a
solution, the greater the pulling force (Osmotic
pressure)
Normal serum (blood) osmolarity = 280-295 mOSM/kg
A solution that has HIGH osmolarity is one that is
> serum osmolarity = HYPERTONIC solution
A solution that has LOW osmolarity is one that is <
serum osmolarity = HYPOTONIC solution
A solution that has equal osmolarity as serum =
ISOTONIC solution
Hypertonic Fluids
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Hypertonic fluids have a higher
concentration of particles (high
osmolality) than ICF
This higher osmotic pressure
shifts fluid from the cells into the
ECF
Therefore Cells placed in a
hypertonic solution will shrink
Hypertonic Fluids
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Used to temporarily treat hypovolemia
Used to expand vascular volume
Fosters normal BP and good urinary output
(often used post operatively)
Monitor for hypervolemia !
Not used for renal or cardiac disease.
THINK – Why not? Pulmonary Edema
D5% 0.45% NS
D5% NS
D5% LR
Hypotonic Fluids
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Hypotonic fluids have less
concentration of particles (low
osmolality) than ICF
This low osmotic pressure shifts
fluid from ECF into cells
Cells placed in a hypotonic solution
will swell
Hypotonic Fluids
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Used to “dilute” plasma particularly in
hypernatremia
Treats cellular dehydration
Do not use for pts with increased ICP
risk or third spacing risk
0.45%NS
0.33%NS
Isotonic Fluid
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Isotonic fluids have the same
concentration of particles (osmolality)
as ICF (275-295 mOsm/L)
Osmotic pressure is therefore the
same inside & outside the cells
Cells neither shrink nor swell in an
isotonic solution, they stay the same
Isotonic Fluid
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Expands both intracellular and
extracellular volume
Used commonly for: excessive
vomiting,diarrhea
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0.9% Normal saline
D5W
Ringer’s Lactate
Other Osmotic Factors
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ALBUMIN ( a serum protein )
Albumin in the serum has osmotic properties called
colloid pressure
Albumin pulls H20 from the interstitial compartments
into the intravascular compartments (serum). Helps
to maintain BP.
Persons with low serum albumin levels tend to retain
fluid in their interstitial layers.
What abnormal assessments might you find in the
client with low serum albumin levels?
Edema, hypotension
Hmmm…….

What type of IV fluid
(hypotonic – isotonic – hypertonic)
might be of benefit to this client with
low albumin levels?
Consider this….
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When tissue injury occurs, proteins
pathologically leak from the
intravascular space into the intersititial
space.
Termed: Third spacing
EDEMA
This explains __________
as a sign of
the inflammatory process.
Solute Movement Diffusion
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Movement of solutes from high
concentration to low concentration
It is a PASSIVE movement DOWN the
concentration gradiant. (requires no energy)
Many body processes use diffusion.
Example: O2 and CO2 exchange
Rate is affected by: concentration gradiant,
permeability-surface area-thickness of
membranes, and size of particles.
(Fick’s Law)
Solute Movement –other
mechanisms
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Active transport- requires energy (ATP) to
move from low concentration to high
concentration (uphill)
Example: Na / K pump
May be enhanced by carrier molecules with
binding sites on cell membrane
Example: Glucose
(Insulin promotes the insertion of binding
sites for Glucose on cell membranes).
Filtration
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Solvent AND solute movement
Passage from an area of High Pressure to an area
of Low Pressure
Termed: Hydrostatic Pressure
Example:
Arterioles have higher pressure than ICF
Fluid, oxygen and nutrients move into cells
Venules have lower pressure than ICF
Fluid, carbon dioxide and wastes move out of cells
Fluid volume deficit FVD
(Hypovolemia)
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Loss of both H20 and
electrolytes from ECF.
Causes include:
Increased output, Hemorrhage,
vomiting, diarrhea, burns,
OR
Fluid shift out of vascular space ( “third
spacing” ) into interstitial spaces
Dehydration
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Isotonic dehydration = H20 &
electrolyte loss in equal amounts; diarrhea
and vomiting
Hypertonic dehydration = H20 loss
greater than electrolyte loss; excessive
perspiration, diabetes insipidus
Assessment
FVD - Hypovolemia
Cardiovascular:
 Diminished peripheral pulses; quality 1+(thready)
 Decreased BP & orthostatic hypotension
 Increased HR
 Flat neck & hand veins in dependent position
 Elevated Hematocrit (Hct)
Gastrointestinal:
 Thirst
 Decreased motility; diminished bowel sounds,
possible constipation
Assessment
FVD – Hypovolemia
Neuromuscular:
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Decreased CNS activity
(lethargy to coma)
Possible fever
Skeletal muscle weakness
Hyperactive DTR
Renal:
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(continued)
Integumentary:
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Dry mouth & skin
Poor turgor (tenting)
Pitting edema
Sunken eyeballs
Respiratory:
Decreased output
 Increased rate and depth
Increased spec grav of urine
Weight loss
Hypernatremia
Nursing Diagnosis - FVD
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Deficient Fluid Volume
R/T loss of GI Fluids via vomiting
AEB elevated Hct, dry mucous
membranes, decreased output, thirst
Planning - FVD
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Client will demonstrate fluid
balance aeb moist mucous
membranes, balanced I & O
measurements, Hct WNL, by ….
Interventions for
FVD - Hypovolemia
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Prevent further fluid loss
Oral rehydration therapy
IV therapy
Medications; antiemetics, antidiarrheals
Monitor CV, Resp, Renal, GI status
Monitor electrolytes – possible supplement rx
MONITOR WEIGHT and I & O
NCLEX Practice
Intravenous fluids are ordered for your client
who is experiencing diarrhea and vomiting for
the past 2 days. Which IV solution would the
nurse expect to see prescribed?
a.
D5NS
b.
0.45%NS
c.
D51/2NS
d.
RL
Fluid Volume Excess
FVE - Hypervolemia
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Fluid overload is an excess of body
fluid - overhydration
Excess fluid volume in the
intravascular area-hypervolemia
Excess fluid volume in interstitial
spaces edema
Fluid Volume Excess
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Causes:
Increased Na/H2O retention
Excessive intake of Na (PO or IV)
Excessive intake of H2O ( PO or IV)
(Water intoxication)
Syndrome of inappropriate antidiuretic
hormone (SIADH)
Renal failure, congestive heart failure
Assessment
FVE - Hypervolemia
CV:
Elevated pulse; 4+
bounding, elevated BP,
distended neck & hand
veins, ventricular gallop (S3)
Hyponatremia
Resp:
Dyspnea, Moist
Crackles,Tachypnea
Integumentary:
Periorbital edema
Pitting or Non-pitting edema
GI:
Increased motility
Stomach cramps
Nausea & Vomiting
Renal:
Weight gain
Decreased spec grav of
urine
Neuromuscular:
Altered LOC, headache,
skeletal muscle twitching
Nursing Diagnosis - FVE
Fluid volume excess
R/T excessive H20 intake
AEB confusion, headache, muscle
twitching, abdominal cramps, elevated
BP and HR, hyponatremia.
Planning - FVE
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Client will demonstrate fluid balance by
balanced I & O measurements, Serum
Na WNL, etc. by ….
Interventions
FVE - Hypervolemia
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Restore normal fluid balance, prevent
further overload
Drug therapy; diuretics
Diet therapy; decrease Na & fluids
Monitor intake and output (I & O)
Monitor weights
Monitor electrolytes
Monitor CV, Resp, Renal systems
Clinical Application
You have been assigned to care for an 80y.o. client
admitted with hypernatremia that has an IV
infusing 0.45% NS @ 100ml/hr via pump and an
indwelling urinary catheter. At 11am you assess
an output in the urinary drainage bag of 150ml dk
amber urine. You also notice that the client is SOB
while speaking on the phone to her daughter.
 What do you think is happening??
 What will you do??
SUMMARY
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EVOLVE
Electrolytes
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Work with fluids to keep the body healthy and
in balance
They are solutes that are found in various
concentrations and measured in terms of
milliequivalent (mEq) units
Can be negatively charged (anions) or
positively charged (cations)
For homeostasis body needs:
Total body ANIONS = Total body CATIONS
Electrolytes
Cations
Positively charged
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Sodium Na+
Potassium K+
Calcium Ca++
Magnesium Mg++
Anions
Negatively charged
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Chloride ClPhosphate PO4Bicarbonate HCO3-
Electrolyte Functions
Regulate water distribution
 Muscle contraction
 Nerve impulse transmission
 Blood clotting
 Regulate enzyme reactions (ATP)
 Regulate acid-base balance
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Sodium Na+
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135-145mEq/L
Major Cation
Chief electrolyte of the ECF
Regulates volume of body fluids
Needed for nerve impulse & muscle
fiber transmission (Na/K pump)
Regulated by kidneys/ hormones
Hmmm…
Hyper and Hypo Natremia are the most
common electrolyte disturbances. Why do
you think that is?
It is most abundant in the EXTRACELLULAR
FLUID and therefore more prone to
fluctuation.
Hyponatremia
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Serum Na+ <135mEq/L
Results from excess of water or loss
of Na+
Water shifts from ECF into cells
S/S: abd cramps, confusion, N/V,
H/A, pitting edema over sternum
Tx: Diet/IV therapy/fluid restrictions
Lets think about …
Hyponatremia
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What are some medical conditions that may cause a dilutional
hyponatremia?
CHF
Renal Failure
SIADH ( Cancer, pituitary trauma )
Addisons Disease ( hypoaldosteronism & Na loss )
What are some conditions that might cause actual loss of
sodium from the body?
GI losses – nasogastric suctioning, vomiting, diarrhea
Certain diuretic therapies
Permanent neurological damage can occur when serum Na
levels fall below 110 mEq/L. Why?
Hypotonic environment swells cells, increasing ICP – brain
damage
Hypernatremia
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Serum Na+> 145mEq/L
Results from Na+ gained in excess of H2O
OR Water is lost in excess of Na+
Water shifts from cells to ECF
S/S: thirst, dry mucous membranes &
lips, oliguria, increased temp &
pulse,flushed skin,confusion
Tx: IV therapy/diet
Let’s think about….
Hypernatremia
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What are some medical conditions that may cause elevated
serum Na?
Renal failure
Diabetes Insipidus
Diabetes Mellitus ( hyperglycemic dehydration)
Cushings syndrome (hyperaldosteronism)
What are some other patient populations at risk for
hypernatremia?
Elderly ( decreased thirst mechanism )
Patient’s receiving:
-tube feedings
-corticosteroid drugs
-certain diuretic therapies
Seizures, coma, death my result if hypernatremia is left
untreated. Why?
Critical Thinking
Hypo / Hyper Natremia
For the client experiencing
FVE & hyponatremia d/t
excessive intake of water,
which IV solution would you
expect the physician to
order?
a.
D5NS
b.
NS
c.
D5W
d.
½ NS
For the client experiencing
FVD and hypernatremia
d/t excessive water loss,
which IV solution would
you expect the physician
to order?
a.
D5 ½ NS
b.
D5RL
c.
D5W
d.
½ NS
Potassium
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K+
3.5-5.0 mEq/L
Chief electrolyte of ICF
Major mineral in all cellular fluids
Aids in muscle contraction, nerve &
electrical impulse conduction, regulates
enzyme activity, regulates IC H20 content,
assists in acid-base balance
Regulated by kidneys/ hormones
Inversely proportional to Na
Hypokalemia
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Serum level < 3.5mEq/L
Results from decreased intake, loss via
GI/Renal & potassium depleting diuretics
Life threatening-all body systems affected
S/S muscle weakness & leg cramps,
decreased GI motility, cardiac arrhythmias
Tx: diet/supplements/IV therapy
Lets think about …
Hypokalemia
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What are some medical conditions that may cause a
hypokalemia?
Renal Disease / CHF (dilutional)
Metabolic Alkalosis
Cushings Disease ( Na retention leads to K loss )
What are some conditions that might cause actual loss of
potassium from the body?
GI losses – nasogastric suctioning, vomiting, diarrhea
Certain diuretic therapies
Inadequate intake – ( body cannot conserve K, need PO intake)
Cardiac arrest may occur when serum K levels fall below 2.5
mEq/L. Why?
Increased cardiac muscle irritability leads to PACs and PVCs,
then AF
Hyperkalemia
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Serum level >5 mEq/L
Results from excessive intake,
trauma, crush injuries, burns, renal
failure
S/S muscle weakness, cardiac
changes, N/V, parathesias of
face/fingers/tongue
Tx:diet/meds/IV therapy/ possible
dialysis
Lets think about …
Hyperkalemia
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What are some medical conditions that may cause
hyperkalemia?
Renal Disease=most common cause
Burns and other major tissue trauma
Metabolic Acidosis
Addison’s Disease ( Na loss leads to K retention )
What are some conditions that might cause potassium levels to
rise in the body?
Certain diuretic therapies
Excessive intake – ( inappropriate supplements)
Cardiac arrest may occur when serum K levels rise above
mEq/L. Why?
Decreased electrical impulse conduction leads to bradycardia
and eventual asystole.
Critical Thinking
Potassium IV additives
Which of the following interventions will the
nurse undertake when administering
parenteral K additives?
Monitor the IV site for phlebitis
Place on cardiac monitor if > 10 mEq
Assure of adequate mixing of K in solution
Monitor for elevated K levels
Monitor for decreased Na levels
Administer potassium by slow IV push method
Calcium Ca++
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4.5-5.5mEq/L
Most abundant in body but:
99% in teeth and bones
Needed for nerve transmission, vitamin B12
absorption, muscle contraction & blood
clotting
Inverse relationship with Phosphorus
Vitamin D needed for Ca absorption
Hypocalcemia
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Serum Ca < 4.3mEq/L
Results from low intake, loop diuretics,
parathyroid disorders, renal failure
S/S osteomalacia, EKG changes,
numbness/tingling in fingers, muscle
cramps / tetany, seizures, Chovstek
Sign & Trousseau Sign
Tx: diet/IV therapy
Chovstek
Trousseau
Lets think about …
Hypocalcemia
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What are some medical conditions that may cause
hypocalcemia?
Hypoparathyroidism (low PTH levels = decreased release of Ca
from bones)
S/P thryoid surgery ( low Calcitonin = decreased release of Ca
from bones) Acute pancreatitis
Crohns Disease
Hyperphosphatemia ( ESRF)
What are some other conditions that might cause low Ca?
GI losses – nasogastric suctioning, vomiting, diarrhea
Long term immobilization
Lactose intolerance
If hypocalcemia is prolonged, the body will utilize stored Ca
from bones.
What complication might arise?
Hypercalcemia
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Serum Ca > 5.3mEq/L
Results from hyperparathyroidism, some
cancers, prolonged immobilization
S/S muscle weakness, renal calculi,
fatigue, altered LOC, decreased GI
motility, cardiac changes
Tx: medication/ IV therapy
Lets think about …
Hypercalcemia


What are some medical conditions that may cause
hypercalcemia?
Hyperparathyroidism (high PTH levels = increased release of Ca
from bones)
Paget’s Disease
Some Cancers – Multiple Myleoma
Chronic Alcoholism ( with low serum phosphorus )
What are some other conditions that might cause low Ca?
Excessive intake of Ca OR Vitamin D
Excessive intake of OTC antacids
If hypercalcemia is uncorrected, AV block and cardiac arrest
may occur.
Magnesium Mg2+
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1.5-2.5mEq/L
Most located within ICF
Needed for activating enzymes,
electrical activity, metabolism of
carbs/proteins, DNA synthesis
Regulated by intestinal absorption
and kidney
Hypomagnesemia
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Serum < 1.5mEq/L
Results from decreased intake, prolonged NPO
status, chronic alcoholism & nasogastric
suctioning
S/S: muscle weakness, cardiac changes,
mental changes, hyperactive reflexes & other
hypocalcemia S/S.
Tx: replacement IV therapy
restore normal Ca levels ( Mg mimics Ca)
seizure precautions
Hypomagnesemia
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Common in critically ill patients
Associated with high mortality rates
Increases cardiac irritability and ventricular
dysrhythmias - especially in patients with
recent MI
Maintenance of adequate serum Mg has been
shown to reduce mortality rates post MI
Hypermagnesemia
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Serum>2.5mEq/L
Results from renal failure, increased
intake
S/S: flushing, lethargy, cardiac changes
(decreased HR),decreased resp, loss of
deep tendon reflexes
Tx: restrict intake
diuretic rx
Chloride
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Cl-
95-105mEq/L
Most abundant anion in ECF
Combines with Na to form salts
Maintains water balance, acid-base balance,
aids in digestion (hydrochoric acid) & osmotic
pressure (with Na and H20)
Regulated by kidneys
Follows Sodium (Na)
Hypochloremia
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Serum level 96mEq/L
Results from prolonged vomiting &
suctioning
S/S metabolic alkalosis, nerve
excitability, muscle cramps, twitching,
hypoventilation, decreased BP if severe
Tx: diet/IV therapy
Hyperchloremia
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Serum level > 106mEq/L
Results from excessive intake or
retention by kidneys – metabolic
acidosis
S/S Arrhythmias, decreased cardiac
output, muscle weakness, LOC changes,
Kussmauls’s respirations
Tx: restore fluid & electrolyte balance
Phosphate PO4
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2.5-4.5mg/dl
Needed for acid-base balance,neurological
& muscle function, energy transfer ATP &
affects metabolism of carbs/proteins/lipids,
B vitamin synthesis
Found in the bones
Regulated by intake and kidneys
Inversely proportional to Calcium
Therefore some regulation by PTH as well
Hypophosphatemia
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Serum level < 1.8mEq/L
Results from decreased intestinal
absorption and increased excretion
S/S bone & muscle pain, mental
changes, chest pain, resp. failure
Tx: Diet/ IV therapy
Hyperphosphatemia
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Serum level> 2.6mEq/L
Results from renal failure, low intake of
calcium
S/S: neuromuscular changes (tetany), EKG
changes, parathesia-fingertips/mouth
Tx: Diet; hypocalcemic interventions
Medications: phosphate binding
The body can tolerate hyperphosphatemia
fairly well BUT the accompanying
hypocalcemia is a larger problem!
Critical Thinking - NCLEX

a.
b.
c.
d.
The nurse is caring for a client with renal
failure whose magnesium level is 3.6
mg/dL. Which of the following signs would
the nurse most likely expect to note in the
client based on this Mg level?
Twitching
Hyperactive reflexes
Irritability
Loss of deep tendon reflexes
Electrolyte homeostasis

This means to maintain balance…
to control by balancing the dietary
intake of electrolytes with the renal
excretion and reabsorption of
electrolytes
Interventions for F/E balance

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Assess patient carefully- note changes
Monitor I & O (Intake & Output)
Monitor weight changes
Monitor urine
Monitor vs
Monitor lab results and dx test
Maintain proper IV therapy
Summary
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Fluid compartments in the body must
balance
Body systems regulate F&E balance
Assessment of body fluid is important
to determine causes of imbalance
Interventions for imbalances are based
on the cause