Lecture Notes on Fluids and Electrolytes

Lecture Notes on Fluids and Electrolytes
Prepared By: Mark Fredderick R Abejo R.N, MAN
MS: Fluids and Electrolyte Abejo
STI COLLEGE GLOBAL CITY
College of Nursing
MEDICAL AND SURGICAL NURSING
Fluids and Electrolytes
Lecturer: Mark Fredderick R. Abejo RN, MAN
________________________________________________
FLUIDS & ELECTROLYTES
I. Fluid Status of Human Body
A. Homeostasis: state of the body when
maintaining a state of balance in the presence
of constantly changing conditions
B. Includes balance of fluid, electrolytes, and acid-
base balance
C. Body water intake and output approximately
equal (2500 mL/24 hr.)
Adult body: 40L water, 60% body weight
2/3 intracellular
1/3 extracellular (80% interstitial, 20%
intravascular)
Infant: 70-80% water
Elderly: 40-50% water
II. Body Fluid Composition
A. Water: 60% of body weight
B. Electrolytes: substances that become charged
particles in solution
1. Cations: positively charged (e.g. Na+
,
K+
)
2. Anions: negatively charged (e.g. Cl-
)
3. Both are measured in milliequivalents
per liter (mEq/L)
C. Balance of hydrostatic pressure and osmotic
pressure regulates movement of water
between intravascular and interstitial spaces
III. Body Fluid Distribution:
A. 2 body compartments:
1. Intracellular fluids (ICF): fluids
within cells of body [major
intracellular electrolytes: Potassium
(K+
), Magnesium (Mg +2
)]
2. Extracellular fluids (ECF): fluid
outside cells; [major extracellular
electrolytes: Sodium (Na+
),
Chloride(Cl-
)]; this is where
transportation of nutrients, oxygen,
and waste products occurs
B. Locations of ECF:
1. Interstitial: fluid between most cells
2. Intravascular: fluid within blood
vessels; also called plasma
3. Transcellular: fluids of body
including urine, digestive secretion,
cerebrospinal, pleural, synovial,
intraocular, gonadal, pericardial
solute – the substance dissolved
solvent – substance in which the solute is dissolved
- usually water (universal solvent)
molar solution (M) - # of gram-molecular weights of solute
per liter of solution
osmolality – concentration of solute per kg of water
normal range = 275-295 mOsm/kg of water
osmolarity – concentration of solute per L of solution
* since 1kg=1L, & water is the solvent of the human
body, osmolarity & osmolality are used interchangeably
IV. Mechanisms of Body Fluid Movement (i.e. movement
of solutes, solvents across different extracellular
locations)
A. Osmosis: water is mover; water moves from
lower concentration to higher concentration
1. Normal Osmolality of ICF and ECF:
275 – 295 mOsm/kg
2. Types of solutions according to osmolality
Isotonic: all solutions with osmolality
same as that of plasma .Body cells placed
in isotonic fluid: neither shrink nor swell
Hypertonic: fluid with greater
concentration of solutes than plasma
Cells in hypertonic solution: water in
cells moves to outside to equalize
concentrations: cells will shrink
Hypotonic: fluid with lower concentration
of solutes than plasma Cells in hypotonic
solution: water outside cells moves to
inside of cells: cells will swell and
eventually burst (hemolyze)
3. Different intravenous solutions, used to
correct some abnormal conditions,
categorized according to osmolality:
B. Diffusion: solute molecules move from higher
concentration to lower concentration
1. Solute, such as electrolytes, is the
mover; not the water
2. Types: simple and facilitated
(movement of large water-soluble
molecules)
C. Filtration: water and solutes move from area
of higher hydrostatic pressure to lower
hydrostatic pressure
1. Hydrostatic pressure is created by
pumping action of heart and gravity
against capillary wall
2. Usually occurs across capillary
membranes
D. Active Transport: molecules move across
cell membranes against concentration
gradient; requires energy, e.g. Na – K pump
Hydrostatic pressure -pushes fluid out of vessels into tissue
space; higher to lower pressure
– due to water volume in vessels; greater in arterial end
– swelling: varicose veins, fluid overload, kidney failure
& CHF
Osmotic pressure -pulls fluid into vessels; from weaker
concentration to stronger concentration
- from plasma proteins; greater in venous end
- swelling: liver problems, nephrotic syndrome

V. Mechanisms that Regulate Homeostasis:
How the body adapts to fluid and electrolyte changes?
A. Thirst: primary regulator of water intake
(thirst center in brain)
B. Kidneys: regulator of volume and
osmolality by controlling excretion of water
and electrolytes
C. Renin-angiotension-aldosterone
mechanism: response to a drop in blood
pressure; results from vasoconstriction and
sodium regulation by aldosterone
D. Antidiuretic hormone: hormone to
regulate water excretion; responds to
osmolality and blood volume
E. Atrial natriuretic factor: hormone from
atrial heart muscle in response to fluid
excess; causes increased urine output by
blocking aldosterone
Fluid Balance Regulation
Thirst reflex triggered by:
1. decreased salivation & dry mouth
2. increased osmotic pressure stimulates
osmoreceptors in the hypothalamus
3. decreased blood volume activates the
renin/angiontensin pathway, which simulates the
thirst center in hypothalamus
Renin-Angiotensin
1. drop in blood volume in kidneys = renin released
2. renin = acts on plasma protein angiotensin
(released by the liver) to form angiotensin I
3. ACE = converts Angiotensin I to Angiotensin II in
the lungs
4. Angiotensin II = vasoconstriction & aldosterone
release
ADH – produced by hypothalamus, released by posterior
pituitary when osmoreceptor or baroreceptor is
triggered in hypothalamus
Aldosterone – produced by adrenal cortex; promotes Na &
water reabsorption
Sensible & Insensible Fluid Loss
Sensible: urine, vomiting, suctioned secretions
Insensible: lungs , skin, GI and evaporation
Normal Fluid Intake and Loss in Adults
Intake:
 Water in food 1,000 mls
 Water from oxidation 300 mls
 Water in liquid 1,200 mls
TOTAL 2,500 mls
Output:
 Skin 500 mls
 Lungs 300 mls
 Feces 150 mls
 Kidneys 1,500 mls
TOTAL 2,500 mls

IV Fluids
Isotonic LR
PNSS (0.9%NSS)
NM
Hypotonic D5W
- isotonic in bag
- dextrose=quickly
metabolized=hypotonic
D2.5W
0.45% NSS
0.3% NSS
0.2% NSS
Hypertonic D50W
D10W
D5NSS
D5LR
3%NSS
Colloids (usually CHONs) & Plasma expanders
Dextran – synthetic polysaccharide, glucose solution
- increase concentration of blood, improving blood
volume up to 24 hrs
- contraindicated: heart failure, pulmonary edema,
cardiogenic shock, and renal failure
Hetastarch – like Dextran, but longer-acting
- expensive
- derived from corn starch
Composition of Fluids
Saline solutions – water, Na, Cl
Dextrose solutions – water or saline, calories
Lactated Ringer‟s – water, Na, Cl, K, Ca, lactate
Plasma expanders – albumin, dextran, plasma protein
(plasmanate) - increases oncotic pressure, pulling fluids
into circulation
Parenteral hyperalimentation – fluid, electrolytes, amino
acids, calories
A. FLUID VOLUME DEFICIT or HYPOVOLEMIA
 Definition: This is the loss of extra cellular fluid
volume that exceeds the intake of fluid. The loss of
water and electrolyte is in equal proportion. It can
be called in various terms- vascular, cellular or
intracellular dehydration. But the preferred term is
hypovolemia.
 Dehydration refers to loss of WATER alone, with
increased solutes concentration and sodium
concentration
Pathophysiology of Fluid Volume Deficit
 Etiologic conditions include:
a. Vomiting
b. Diarrhea
c. Prolonged GI suctioning
d. Increased sweating
e. Inability to gain access to fluids
f. Inadequate fluid intake
g. Massive third spacing
 Risk factors are the following:
a. Diabetes Insipidus
b. Adrenal insufficiency
c. Osmotic diuresis
d. Hemorrhage
e. Coma
f. Third-spacing conditions like ascites,
pancreatitis and burns
PATHOPHYSIOLOGY:
Risk Factors --- inadequate fluids in the body ---- decreased
blood volume ----- decreased cellular hydration ---- cellular
shrinkage ---- weight loss, decreased turgor, oliguria,
hypotension, weak pulse, etc.
ASSESSMENT:
Physical examination
 Weight loss, tented skin turgor, dry mucus membrane
 Hypotension
 Tachycardia
 Cool skin, acute weight loss
 Flat neck veins
 Decreased CVP
Subjective cues
 Thirst
 Nausea, anorexia
 Muscle weakness and cramps
 Change in mental state
Laboratory findings
1. Elevated BUN due to depletion of fluids or decreased
renal perfusion
2. Hemoconcentration
3. Possible Electrolyte imbalances: Hypokalemia,
Hyperkalemia, Hyponatremia, hypernatremia
4. Urine specific gravity is increased (concentrated
urine) above 1.020
NURSING MANAGEMENT
1. Assess the ongoing status of the patient by doing an
accurate input and output monitoring
2. Monitor daily weights. Approximate weight loss 1
kilogram = 1liter!
3. Monitor Vital signs, skin and tongue turgor, urinary
concentration, mental function and peripheral
circulation
4. Prevent Fluid Volume Deficit from occurring by
identifying risk patients and implement fluid
replacement therapy as needed promptly
5. Correct fluid Volume Deficit by offering fluids orally
if tolerated, anti-emetics if with vomiting, and foods
with adequate electrolytes
6. Maintain skin integrity
7. Provide frequent oral care
8. Teach patient to change position slowly to avoid
sudden postural hypotension

B. FLUID VOLUME EXCESS: HYPERVOLEMIA
 Definition : Refers to the isotonic expansion of
the ECF caused by the abnormal retention of
water and sodium
 There is excessive retention of water and
electrolytes in equal proportion. Serum sodium
concentration remains NORMAL
Pathophysiology of Fluid Volume Excess
 Etiologic conditions and Risks factors
a. Congestive heart failure
b. Renal failure
c. Excessive fluid intake
d. Impaired ability to excrete fluid as in renal
disease
e. Cirrhosis of the liver
f. Consumption of excessive table salts
g. Administration of excessive IVF
h. Abnormal fluid retention
PATHOPHYSIOLOGY
Excessive fluid --- expansion of blood volume ----- edema,
increased neck vein distention, tachycardia, hypertension.
The Nursing Process in Fluid Volume Excess
ASSESSMENT
Physical Examination
 Increased weight gain
 Increased urine output
 Moist crackles in the lungs
 Increased CVP
 Distended neck veins
 Wheezing
 Dependent edema
Subjective cue/s
 Shortness of breath
 Change in mental state
Laboratory findings
1. BUN and Creatinine levels are LOW because of
dilution
2. Urine sodium and osmolality decreased (urine
becomes diluted)
3. CXR may show pulmonary congestion
IMPLEMENTATION
ASSIST IN MEDICAL INTERVENTION
1. Administer diuretics as prescribed
2. Assist in hemodialysis
3. Provide dietary restriction of sodium and water
NURSING MANAGEMENT
1. Continually assess the patient‟s condition by
measuring intake and output, daily weight monitoring,
edema assessment and breath sounds
2. Prevent Fluid Volume Excess by adhering to diet
prescription of low salt- foods.
3. Detect and Control Fluid Volume Excess by closely
monitoring IVF therapy, administering medications,
providing rest periods, placing in semi-fowler‟s
position for lung expansion and providing frequent
skin care for the edema
4. Teach patient about edema, ascites, and fluid therapy.
Advise elevation of the extremities, restriction of
fluids, necessity of paracentesis, dialysis and diuretic
therapy.
5. Instruct patient to avoid over-the-counter medications
without first checking with the health care provider
because they may contain sodium
ELECTROLYTES
 Electrolytes are charged ions capable of conducting
electricity and are solutes found in all body
compartments.
Sources of electrolytes
 Foods and ingested fluids, medications; IVF and
TPN solutions
Functions of Electrolytes
 Maintains fluid balance
 Regulates acid-base balance
 Needed for enzymatic secretion and activation
 Needed for proper metabolism and effective
processes of muscular contraction, nerve
transmission
Types of Electrolytes
 CATIONS- positively charged ions; examples are
sodium, potassium, calcium
 ANIONS- negatively charged ions; examples are
chloride and phosphates]
 The major ICF cation is potassium (K+); the
major ICF anion is Phosphates
 The major ECF cation is Sodium (Na+); the major
ECF anion is Chloride (Cl-)
ELECTROLYTE IMBALANCES
SODIUM
 The most abundant cation in the ECF
 Normal range in the blood is 135-145 mEq/L
 A loss or gain of sodium is usually accompanied by a
loss or gain of water.
 Major contributor of the plasma Osmolality
 Sources: Diet, medications, IVF. The minimum daily
requirement is 2 grams
Functions:
1. Participates in the Na-K pump
2. Assists in maintaining blood volume
3. Assists in nerve transmission and muscle
contraction
4. Primary determinant of ECF concentration.
5. Controls water distribution throughout the body.
6. Primary regulator of ECF volume.
7. Sodium also functions in the establishment of the
electrochemical state necessary for muscle
contraction and the transmission of nerve
impulses.
8. Regulations: skin, GIT, GUT, Aldosterone
increases Na retention in the kidney

SODIUM DEFICIT: HYPONATREMIA
 Definition : Refers to a Sodium serum level of less
than 135 mEq/L. This may result from excessive
sodium loss or excessive water gain.
Pathophysiology
Etiologic Factors
a. Fluid loss such as from Vomiting and nasogastric
suctioning
b. Diarrhea
c. Sweating
d. Use of diuretics
e. Fistula
Other factors
a. Dilutional hyponatremia
Water intoxication, compulsive water
drinking where sodium level is diluted
with increased water intake
b. SIADH
Excessive secretion of ADH causing
water retention and dilutional
hyponatremia
PATHOPHYSIOLOGY
Decrease sodium concentration --- hypotonicity of plasma --
- water from the intravascular space will move out and go to
the intracellular compartment with a higher concentration ---
cell swelling --Water is pulled INTO the cell because of
decreased extracellular sodium level and increased
intracellular concentration
The Nursing Process in HYPONATREMIA
ASSESSMENT
Sodium Deficit (Hyponatremia)
Clinical Manifestations
 Clinical manifestations of hyponatremia depend on the
cause, magnitude, and rapidity of onset.
 Although nausea and abdominal cramping occur, most
of the symptoms are neuropsychiatric and are probably
related to the cellular swelling and cerebral edema
associated with hyponatremia.
 As the extracellular sodium level decreases, the
cellular fluid becomes relatively more concentrated and
„pulls” water into the cells.
 In general, those patients having acute decline in serum
sodium levels have more severe symptoms and higher
mortality rates than do those with more slowly
developing hyponatremia.
 Features of hyponatremia associated with sodium loss
and water gain include anorexia, muscle cramps, and a
feeling of exhaustion.
 When the serum sodium level drops below 115 mEq/L
(SI: 115 mmol/L), thee ff signs of increasing
intracranial pressure occurs:
 lethargy
 Confusion
 muscular twitching
 focal weakness
 hemiparesis
 papilledema
 convulsions
In summary:
 Altered mental status
 Vomiting
 Lethargy
 Muscle twitching and convulsions (if sodium level is
below 115 mEq/L)
 Focal weakness
Subjective Cues
 Nausea
 Cramps
 Anorexia
 Headache
Laboratory findings
1. Serum sodium level is less than 135 mEq/L
2. Decreased serum osmolality
3. Urine specific gravity is LOW if caused by sodium loss
4. In SIADH, urine sodium is high and specific gravity is
HIGH
IMPLEMENTATION
1. Provide sodium replacement as ordered. Isotonic saline
is usually ordered.. Infuse the solution very cautiously.
The serum sodium must NOT be increased by greater
than 12 mEq/L because of the danger of pontine
osmotic demyelination
2. Administer lithium and demeclocycline in SIADH
3. Provide water restriction if with excess volume
NURSING MANAGEMENT
1. Provide continuous assessment by doing an accurate
intake and output, daily weights, mental status
examination, urinary sodium levels and GI
manifestations. Maintain seizure precaution
2. Detect and control Hyponatremia by encouraging food
intake with high sodium content, monitoring patients
on lithium therapy, monitoring input of fluids like IVF,
parenteral medication and feedings.
3. Return the Sodium level to Normal by restricting water
intake if the primary problem is water retention.
Administer sodium to normovolemic patient and
elevate the sodium slowly by using sodium chloride
solution
SODIUM EXCESS: HYPERNATREMIA
 Serum Sodium level is higher than 145 mEq/L
 There is a gain of sodium in excess of water or a
loss of water in excess of sodium.
Pathophysiology:
Etiologic factors
a. Fluid deprivation
b. Water loss from Watery diarrhea, fever, and
hyperventilation
c. Administration of hypertonic solution
d. Increased insensible water loss
e. Inadequate water replacement, inability to swallow
f. Seawater ingestion or excessive oral ingestion of salts

Other factors
a. Diabetes insipidus
b. Heat stroke
c. Near drowning in ocean
d. Malfunction of dialysis
PATHOPHYSIOLOGY
Increased sodium concentration --- hypertonic plasma ----
water will move out form the cell outside to the interstitial
space ----- CELLULAR SHRINKAGE ----- then to the
blood ---- Water pulled from cells because of increased
extracellular sodium level and decreased cellular fluid
concentration
The Nursing Process in HYPERNATREMIA
Sodium Excess (Hypernatremia)
 primarily neurologic
 Presumably the consequence of cellular dehydration.
 Hypernatremia results in a relatively concentrated ECF,
causing water to be pulled from the cells.
 Clinically, these changes may be manifested by:
o restlessness and weakness in moderate
hypernatremia
o disorientation, delusions, and
hallucinations in severe hypernatremia.
 Dehydration (hypernatremia) is often overlooked as the
primary reason for behavioral changes in the elderly.
 If hypernatremia is severe, permanent brain damage
can occur (especially in children). Brain damage is
apparently due to subarachnoid hemorrhages that result
from brain contraction.
A primary characteristic of hypernatremia is thirst.
Thirst is so strong a defender of serum sodium levels in
normal people that hypernatremia never occurs unless the
person is unconscious or is denied access to water;
unfortunately, ill people may have an impaired thirst
mechanism. Other signs include dry, swollen tongue and
sticky mucous membranes. A mild elevation in body
temperature may occur, but on correction of the
hypernatremia the body temperature should return to
normal.
ASSESSMENT
 Restlessness, elevated body temperature
 Disorientation
 Dry, swollen tongue and sticky mucous membrane,
tented skin turgor
 Flushed skin, postural hypotension
 Increased muscle tone and deep reflexes
 Peripheral and pulmonary edema
Subjective Cues
 Delusions and hallucinations
 Extreme thirst
 Behavioral changes
Laboratory findings
1. Serum sodium level exceeds 145 mEq/L
2. Serum osmolality exceeds 295 mOsm/kg
3. Urine specific gravity and osmolality INCREASED
or elevated
IMPLEMENTATION
ASSIST IN THE MEDICAL INTERVENTION
1. Administer hypotonic electrolyte solution slowly as
ordered
2. Administer diuretics as ordered
Loop diuretics (thiazides ok)
3. Desmopressin is prescribed for diabetes insipidus
NURSING MANAGEMENT
1. Continuously monitor the patient by assessing
abnormal loses of water, noting for the thirst and
elevated body temperature and behavioral changes
2. Prevent hypernatremia by offering fluids regularly
and plan with the physician alternative routes if oral
route is not possible. Ensure adequate water for
patients with DI. Administer IVF therapy cautiously
3. Correct the Hypernatremia by monitoring the
patient‟s response to the IVF replacement. Administer
the hypotonic solution very slowly to prevent sudden
cerebral edema.
4. Monitor serum sodium level.
5. Reposition client regularly, keep side-rails up, the bed
in low position and the call bell/light within reach.
6. Provide teaching to avoid over-the counter
medications without consultation as they may contain
sodium
POTASSIUM
 The most abundant cation in the ICF
 Potassium is the major intracellular electrolyte; in fact,
98% of the body‟s potassium is inside the cells.
 The remaining 2% is in the ECF; it is this 2% that is
all-important in neuromuscular function.
 Potassium is constantly moving in and out of cells
according to the body‟s needs, under the influence of
the sodium-potassium pump.
 Normal range in the blood is 3.5-5 mEq/L
 Normal renal function is necessary for maintenance of
potassium balance, because 80-90% of the potassium is
excreted daily from the body by way of the kidneys.
The other less than 20% is lost through the bowel and
sweat glands.
 Major electrolyte maintaining ICF balance
 Sources- Diet, vegetables, fruits, IVF, medications
Functions:
1. Maintains ICF Osmolality
2. Important for nerve conduction and muscle
contraction
3. Maintains acid-base balance
4. Needed for metabolism of carbohydrates, fats and
proteins
5. Potassium influences both skeletal and cardiac muscle
activity.
( For example, alterations in its concentration change
myocardial irritability and rhythm )
6. Regulations: renal secretion and excretion,
* Aldosterone promotes renal excretion
* Acidosis promotes K exchange for hydrogen

POTASSIUM DEFICIT: HYPOKALEMIA
 Condition when the serum concentration of potassium
is less than 3.5 mEq/L
Pathophysiology
 Etiologic Factors
a. Gastro-intestinal loss of potassium such as
diarrhea and fistula
b. Vomiting and gastric suctioning
c. Metabolic alkalosis
d. Diaphoresis and renal disorders
e. Ileostomy
 Other factor/s
a. Hyperaldosteronism
b. Heart failure
c. Nephrotic syndrome
d. Use of potassium-losing diuretics
e. Insulin therapy
f. Starvation
g. Alcoholics and elderly
PATHOPHYSIOLOGY
Decreased potassium in the body impaired nerve
excitation and transmission signs/symptoms such as
weakness, cardiac dysrhythmias etc..
The Nursing Process in Hypokalemia
 Potassium deficiency can result in widespread
derangements in physiologic functions and especially
nerve conduction.
 Most important, severe hypokalemia can result in death
through cardiac or respiratory arrest.
 Clinical signs rarely develop before the serum
potassium level has fallen below 3 mEq/L (51: 3
mmol/L) unless the rate of fall has been rapid.
 Manifestations of hypokalemia include fatigue,
anorexia, nausea, vomiting, muscle weakness,
decreased bowel motility, paresthesias, dysrhythmias,
and increased sensitivity to digitalis.
 If prolonged, hypokalemia can lead to impaired renal
concentrating ability, causing dilute urine, polyuria,
nocturia, and polydipsia
ASSESSMENT
Physical examination
 Muscle weakness
 Decreased bowel motility and abdominal distention
 Paresthesias
 Dysrhythmias
 Increased sensitivity to digitalis
Subjective cues
 Nausea , anorexia and vomiting
 Fatigue, muscles cramps
 Excessive thirst, if severe
Laboratory findings
1. Serum potassium is less than 3.5 mEq/L
2. ECG: FLAT “T” waves, or inverted T waves,
depressed ST segment and presence of the “U” wave
and prolonged PR interval.
3. Metabolic alkalosis
IMPLEMENTATION
ASSIST IN THE MEDICAL INTERVENTION
1. Provide oral or IV replacement of potassium
2. Infuse parenteral potassium supplement. Always dilute
the K in the IVF solution and administer with a pump.
IVF with potassium should be given no faster than 10-
20-mEq/ hour!
3. NEVER administer K by IV bolus or IM
NURSING MANAGEMENT
1. Continuously monitor the patient by assessing the
cardiac status, ECG monitoring, and digitalis
precaution
2. Prevent hypokalemia by encouraging the patient to eat
potassium rich foods like orange juice, bananas,
cantaloupe, peaches, potatoes, dates and apricots.
3. Correct hypokalemia by administering prescribed IV
potassium replacement. The nurse must ensure that the
kidney is functioning properly!
4. Administer IV potassium no faster than 20 mEq/hour
and hook the patient on a cardiac monitor. To
EMPHASIZE: Potassium should NEVER be given IV
bolus or IM!!
5. A concentration greater than 60 mEq/L is not advisable
for peripheral veins.
POTASSIUM EXCESS: HYPERKALEMIA
 Serum potassium greater than 5.5 mEq/L
Pathophysiology
 Etiologic factors
a. Iatrogenic, excessive intake of potassium
b. Renal failure- decreased renal excretion of
potassium
c. Hypoaldosteronism and Addison‟s disease
d. Improper use of potassium supplements
 Other factors
1. Pseudohyperkalemia- tight tourniquet and
hemolysis of blood sample, marked leukocytosis

2. Transfusion of “old” banked blood
3. Acidosis
4. Severe tissue trauma
PATHOPHYSIOLOGY
Increased potassium in the body ---- Causing irritability of
the cardiac cells --- Possible arrhythmias!!
The Nursing Process in Hyperkalemia
 By far the most clinically important effect of
hyperkalemia is its effect on the myocardium.
 Cardiac effects of an elevated serum potassium level
are usually not significant below a concentration of 7
mEq/L (SI: 7 mmol/L), but they are almost always
present when the level is 8 mEq/L (SI: 8 mmol/L) or
greater.
 As the plasma potassium concentration is increased,
disturbances in cardiac conduction occur.
 The earliest changes, often occurring at a serum
potassium level greater than 6 mEq/ L (SI: 6
mmol/L), are peaked narrow T waves and a shortened
QT interval.
 If the serum potassium level continues to rise, the PR
interval becomes prolonged and is followed by
disappearance of the P waves.
 Finally, there is decomposition and prolongation of
the QRS complex. Ventricular dysrhythmias and
cardiac arrest may occur at any point in this
progression.
 Note that in Severe hyperkalemia causes muscle
weakness and even paralysis, related to a
depolarization block in muscle.
 Similarly, ventricular conduction is slowed.
 Although hyperkalemia has marked effects on the
peripheral neuromuscular system, it has little effect on
the central nervous system.
 Rapidly ascending muscular weakness leading to
flaccid quadriplegia has been reported in patients with
very high serum potassium levels.
 Paralysis of respiratory muscles and those required for
phonation can also occur.
 Gastrointestinal manifestations, such as nausea,
intermit tent intestinal colic, and diarrhea, may occur
in hyperkalemic patients.
ASSESSMENT
 Diarrhea
 Skeletal muscle weakness
 Abnormal cardiac rate
Subjective Cues
 Nausea
 Intestinal pain/colic
 Palpitations
Laboratory Findings
1. Peaked and narrow T waves
2. ST segment depression and shortened QT interval
3. Prolonged PR interval
4. Prolonged QRS complex
5. Disappearance of P wave
6. Serum potassium is higher than 5.5 mEq/L
7. Acidosis
IMPLEMENTATION
1. Monitor the patient‟s cardiac status with cardiac
machine
2. Institute emergency therapy to lower potassium level
by:
a. Administering IV calcium gluconate-
antagonizes action of K on cardiac conduction
b. Administering Insulin with dextrose-causes
temporary shift of K into cells
c. Administering sodium bicarbonate-alkalinizes
plasma to cause temporary shift
d. Administering Beta-agonists
e. Administering Kayexalate (cation-exchange
resin)-draws K+ into the bowel
NURSING MANAGEMENT
1. Provide continuous monitoring of cardiac status,
dysrhythmias, and potassium levels.
2. Assess for signs of muscular weakness, paresthesias,
nausea
3. Evaluate and verify all HIGH serum K levels
4. Prevent hyperkalemia by encouraging high risk patient
to adhere to proper potassium restriction
5. Correct hyperkalemia by administering carefully
prescribed drugs. Nurses must ensure that clients
receiving IVF with potassium must be always
monitored and that the potassium supplement is given
correctly
6. Assist in hemodialysis if hyperkalemia cannot be
corrected.
7. Provide client teaching. Advise patients at risk to avoid
eating potassium rich foods, and to use potassium salts
sparingly.
8. Monitor patients for hypokalemia who are receiving
potassium-sparing diuretic
CALCIUM
 Majority of calcium is in the bones and teeth
 Small amount may be found in the ECF and ICF
 Normal serum range is 8.5 – 10.5 mg/dL
 Sources: milk and milk products; diet; IVF and
medications

Functions:
1. Needed for formation of bones and teeth
2. For muscular contraction and relaxation
3. For neuronal and cardiac function
4. For enzymatic activation
5. For normal blood clotting
Regulations:
1. GIT- absorbs Ca+ in the intestine; Vitamin D helps to
increase absorption
2. Renal regulation- Ca+ is filtered in the glomerulus
andreabsorbed in the tubules:
3. Endocrine regulation:
 Parathyroid hormone from the parathyroid glands
is released when Ca+ level is low. PTH causes
release of calcium from bones and increased
retention of calcium by the kidney but PO4 is
excreted
 Calcitonin from the thyroid gland is released when
the calcium level is high. This causes excretion of
both calcium and PO4 in the kidney and promoted
deposition of calcium in the bones.
Sources:
milk, yogurt, cheese, sardines, broccoli, tofu, green leafy
vegetables
HYPOCALCEMIA
 Low levels of calcium in the blood
 Risk Factors
a. Hypoparathyroidism (idiopathic or postsurgical)
b. Alkalosis (Ca binds to albumin)
c. Corticosteroids (antagonize Vit D)
d. Hyperphosphatemia
e. Vit D deficiency
f. Renal failure (vit D deficiency)
 Clinical Manifestation
 Decreased cardiac contractility
 Arrhythmia
 ECG: prolonged QT interval, lengthened ST
segment
 Trousseau’s sign (inflate BP cuff 20mm above
systole for 3 min = carpopedal spasm)
 Chvostek’s sign (tap facial nerve anterior to the
ear = ipsilateral muscle twitching)
 Tetany
 Hyperreflexia, seizures
 Laryngeal spasms/stridor
 Diarrhea, hyperactive bowel sounds
 Bleeding
Collaborative Management
1. Calcium gluconate 10% IV
2. Calcium chloride 10% IV
3. both usually given by Dr, very slowly; venous irritant;
cardiac probs
4. Oral: calcium citrate, lactate, carbonate; Vit D
supplements
5. Diet: high calcium
6. Watch out for tetany, seizures, laryngospasm, resp &
cardiac arrest
7. Seizure precautions

HYPERCALCEMIA
 is an elevated calcium level in the blood
 usually from bone resorption
 Risk Factors / Causes
a. Hyperparathyroidism (eg adenoma)
b. Metastatic cancer (bone resorption as tumor‟s
ectopic PTH effect) – eg. Multiple myeloma
c. Thiazide diuretics (potentiate PTH effect)
d. Immobility
e. Milk-alkali syndrome (too much milk or antacids
in aegs with peptic ulcer)
 groans (constipation)
 moans (psychotic noise)
 bones (bone pain, especially if PTH is elevated)
 stones (kidney stones)
 psychiatric overtones (including depression and
confusion)
 Arrhythmia
 ECG: shortened QT interval, decreased ST
segment
 Hyporeflexia, lethargy, coma
1. If parathyroid tumor = surgery
2. Diet: low Ca, stop taking Ca Carbonate antacids,
increase fluids
3. IV flushing (usually NaCl)
4. Loop diuretics
5. Corticosteroids
6. Biphosphonates, like etidronate (Calcitonin) &
alendronate (Fosamax)
7. Plicamycin (Mithracin) – inhibits bone resorption
8. Calcitonin – IM or intranasal
9. Dialysis (severe case)
10. Watch out for digitalis toxicity
11. Prevent fractures, handle gently
MAGNESIUM
 2nd
most abundant intracellular cation
 50% found in bone, 45% is intracellular
 ATP (adenosine triphosphate), the main source of
energy in cells, must be bound to a magnesium ion in
order to be biologically active.
 competes with Ca & P absorption in the GI
 inhibits PTH
 Normal value : 1.5-2.5 mEq/L
Functions:
1. important in maintaining intracellular activity
2. affects muscle contraction, & especially relaxation
3. maintains normal heart rhythm
4. promotes vasodilation of peripheral arterioles
Sources:
green leafy vegetables, nuts, legumes, seafood, whole
grains, bananas, oranges, cocoa, chocolate
HYPOMAGNESEMIA
 is an electrolyte disturbance in which there is an
abnormally low level of magnesium in the blood.
 Risk Factors and Cause
a. Chronic alcoholism (most common), Alcohol
stimulates renal excretion of magnesium,
b. Inflammatory bowel disease
c. Small bowel resection
d. GI cancer
e. chronic pancreatitis (poor absorption)
f. Loop and thiazide diuretic use (the most common
cause of hypomagnesemia)
g. Antibiotics (i.e. aminoglycoside, amphotericin,
pentamidine, gentamicin, tobramycin, viomycin)
block resorption in the loop of Henle.
h. Excess calcium
i. Excess saturated fats
j. Excess coffee or tea intake
k. Excess phosphoric or carbonic acids (soda pop)
l. Insufficient water consumption
m. Excess salt or sugar intake
n. Insufficient selenium,vitamin D, sunlight
exposure or vitamin B6
o. Increased levels of stress
 Weakness
 muscle cramps
 cardiac arrhythmia
 increased irritability of the nervous system with
tremors, athetosis, jerking, nystagmus and an
extensor plantar reflex. Confusion
 disorientation
 hallucinations
 depression
 epileptic fits
 hypertension, tachycardia and tetany.
* Like hypocalcemia, hypokalemia
Potentiates digitalis toxicity
1. Magnesium sulfate IV, IM (make sure renal
function is ok) – may cause flushing
2. Oral: Magnesium oxide 300mg/day,
3. Mg-containing antacids (SE diarrhea)
4. Diet: high magnesium (fruits,green vegetables,
whole grains cereals, milk, meat, nuts and sea
foods )
5. Promotion of safety, protect from injury
HYPERMAGNESEMIA
 Etiologic Factors
a. Magnesium treatment for pre-eclampsia
b. Renal failure
c. Diabetic Ketoacidosis
d. Excessive use of Mg antacids/laxatives
PATHOPHYSIOLOGY
Increase Mg. ----- Blocks acetylcholine release ---- decrease
excitability of muscle

 Hyporeflexia
 Hypotension, bradycardia, arrhythmia
 Flushing
 Weakness, lethargy, coma
 Decreased RR & respiratory paralysis
 Loss of DTR‟s
*like hypercalcemia
1. Diuretics
2. Stop Mg-containing antacids & enemas
3. IV fluids rehydration
4. Calcium gluconate – (antidote, antagonizes
cardiac & respiratory effects of Mg)
5. Dialysis – if RF
PHOSPHORUS
 primary intracellular anion
 part of ATP – energy
 85% bound with Ca in teeth/bones, skeletal muscle
 reciprocal balance with Ca
 absorption affected by Vit D, regulation affected by
PTH (lowers P level)
 Normal value : 2.5-4.5 mg/dL
Functions:
1. bone/teeth formation & strength
2. phospholipids (make up cell membrane integrity)
3. part of ATP
4. affects metabolism, Ca levels
Sources:
red & organ meats (brain, liver, kidney), poultry, fish, eggs,
milk, legumes, whole grains, nuts, carbonated drinks
HYPOPHOSPHATEMIA
 Risk Factors
a. Decreased Vit D absorption, sunlight exposure
b. Hyperparathyroidism (increased PTH)
c. Aluminum & Mg-containing antacids (bind P)
d. Severe vomiting & diarrhea
 Anemia, bruising (weak blood cell membrane)
 Seizures, coma
 Muscle weakness, paresthesias
 Constipation, hypoactive bowel sounds
*Like hypercalcemia
1. Sodium phosphate or potassium phosphate IV
(give slowly, no faster than 10 mEq/hr)
2. Sodium & potassium phosphate orally (Neutra-
Phos, K-Phos) – give with meals to prevent gastric
irritation
3. Avoid Phos-binding antacids
4. Diet: high Mg, milk
5. Monitor joint stiffness, arthralgia, fractures,
bleeding
HYPERPHOSPHATEMIA
 Risk Factors
a. Acidosis (Ph moves out of cell)
b. Cytotoxic agents/chemotherapy in cancer
c. Renal failure
d. Hypocalcemia
e. Massive BT (P leaks out of cells during storage of
blood)
f. Hyperthyroidism
 Calcification of kidney, cornea, heart
 Muscle spasms, tetany, hyperreflexia
*like hypocalcemia
Collaborative ManagementM
1. Aluminum antacids as phosphate binders: Al
carbonate (Basaljel), Al hydroxide (Amphojel)
2. Ca carbonate for hypocalcemia
3. Avoid phosphate laxatives/enemas
4. Increase fluid intake
5. Diet: low Phos, no carbonated drinks
CHLORIDE
 extracellular anion, part of salt
 binds with Na, H (also K, Ca, etc)
 exchanges with HCO3 in the kidneys (& in RBCs)
 Normal value: 95 -108 mEq/L
Functions:
1. helps regulate BP, serum osmolarity
2. part of HCl
3. acid/base balance (exchanges with HCO3)
Sources:
salt, canned food, cheese, milk, eggs, crab, olives
HYPOCHLOREMIA
 Risk Factors
a. Diuresis
b. Metabolic alkalosis
c. Hyponatremia, prolonged D5W IV
d. Addison‟s
 Slow, shallow respirations (met. Alkalosis)
 Hypotension (Na & water loss)
1. Administer IV or Oral : KCl, NaCl
2. Diet: high Cl (& usually Na)
HYPERCHLOREMIA
 Risk Factors / Cause
a. Metabolic acidosis
b. Usually noted in hyperNa, hyperK

 Deep, rapid respirations (met. Acidosis)
 hyperK, hyperNa S/S
 Increased Cl sweat levels in cystic fibrosis
1. Diuretics
2. Hypotonic solutions, D5W to restore balance
3. Diet: low Cl (& usually Na)
4. Treat acidosis
Acid-Base Balance Mechanisms
Buffer - prevents major changes in ECF by releasing or
accepting H ions
Buffer mechanism: first line (takes seconds)
1. combine with very strong acids or bases to
convert them into weaker acids or bases
2. Bicarbonate Buffer System
- most important
- uses HCO3 & carbonic acid/H2CO3 - (20:1)
- closely linked with respiratory & renal
mechanisms
3. Phosphate Buffer System
- more important in intracellular fluids, where
concentration is higher
- similar to bicarbonate buffer system, only uses
phosphate
4. Protein Buffer System
- hemoglobin, a protein buffer, promotes
movement of chloride across RBC membrane in
exchange for HCO3
Respiratory mechanism: 2nd
line (takes minutes)
1. increased respirations liberates more CO2 =
increase pH
2. decreased respirations conserve more CO2 =
decrease pH
carbonic acid (H2CO3) = CO2 + water
Renal mechanism: 3rd
line (takes hours-days)
1. kidneys secrete H ions & reabsorb bicarbonate ions =
increase blood pH
2. kidneys form ammonia that combines with H ions to
form ammonium ions, which are excreted in the urine
in exchange for sodium ions
Review: Acid-Base Imbalance
pH – 7.35-7.45
pCO2 – measurement of the CO2 pressure that is being
exerted on the plasma
- 35-45mmHg
PaO2- amount of pressure exerted by O2 on the plasma
- 80-100mmHg
SaO2- percent of hemoglobin saturated with O2
Base excess – amount of HCO3 available in the ECF
- -3 to +3
Interpretation Arterial Blood Gases
 If acidosis the pH is down
 If alkalosis the pH is up
 The respiratory function indicator is the PCO2
 The metabolic function indicator is the HCO3
Step 1
 Look at the pH
 Is it up or down?
 If it is up - it reflects alkalosis
 If it is down - it reflects acidosis
Step 2
 Look at the PCO2
 Is it up or down?
 If it reflects an opposite response as the pH,
 then you know that the condition is a
respiratory imbalance
 If it does not reflect an opposite response as the
pH - move to step III
Step 3
 Look at the HCO3
 Does the HCO3 reflect a corresponding
 response with the pH
 If it does then the condition is a metabolic
imbalance
FACTORS AFFECTING BODY FLUIDS,
ELECTROLYTES AND ACID-BASE BALANCE
AGE
 Infants have higher proportion of body water than
adults
 Water content of the body decreases with age
 Infants have higher fluid turn-over due to immature
kidney and rapid respiratory rate
GENDER AND BODY SIZE
 Women have higher body fat content but lesser
water content
 Lean body has higher water content
ENVIRONMENT AND TEMPERATURE
 Climate and heat and humidity affect fluid balance
DIET AND LIFESTYLE
 Anorexia nervosa will lead to nutritional depletion
 Stressful situations will increase metabolism,
increase ADH causing water retention and
increased blood volume
 Chronic Alcohol consumption causes malnutrition
ILLNESS
 Trauma and burns release K+ in the blood
 Cardiac dysfunction will lead to edema and
congestion
MEDICAL TREATMENT, MEDICATIONS AND
SURGERY
 Suctioning, diuretics and laxatives may cause
imbalances

ACID-BASE BALANCE PROBLEMS
RESPIRATORY ACIDOSIS
 pH < 7.35
 pCO2 > 45 mm Hg (excess carbon dioxide in the
blood)
 Respiratory system impaired and retaining CO2;
causing acidosis
Common Stimuli
a. Acute respiratory failure from airway obstruction
b. Over-sedation from anesthesia or narcotics
c. Some neuromuscular diseases that affect ability to
use chest muscles
d. Chronic respiratory problems, such as Chronic
Obstructive Lung Disease
Signs and Symptoms
 Compensation: kidneys respond by generating and
reabsorbing bicarbonate ions, so HCO3 >26 mm Hg
 Respiratory: hypoventilation, slow or shallow
respirations
 Neuro: headache, blurred vision, irritability,
confusion
 Respiratory collapse leads to unconsciousness and
cardiovascular collapse
1. Early recognition of respiratory status and treat
cause
2. Restore ventilation and gas exchange; CPR for
respiratory failure with oxygen supplementation;
intubation and ventilator support if indicated
3. Treatment of respiratory infections with
bronchodilators, antibiotic therapy
4. Reverse excess anesthetics and narcotics with
medications such as naloxone (Narcan)
5. Chronic respiratory conditions
 Breathe in response to low oxygen levels
 Adjusted to high carbon dioxide level
through metabolic compensation (therefore,
high CO2 not a breathing trigger)
 Cannot receive high levels of oxygen, or will
have no trigger to breathe; will develop
carbon dioxide narcosis
 Treat with no higher than 2 liters O2 per
cannula
6. Continue respiratory assessments, monitor further
arterial blood gas results
RESPIRATORY ALKALOSIS
 pH < 7.35
 pCO2 < 35 mm Hg.
 Carbon dioxide deficit, secondary to
hyperventilation
Common Stimuli
a. Hyperventilation with anxiety from uncontrolled
fear, pain, stress (e.g. women in labor, trauma
victims)
b. High fever
c. Mechanical ventilation, during anesthesia
Signs and Symptoms
 Compensation: kidneys compensate by
eliminating bicarbonate ions; decrease in
bicarbonate HCO3 < 22 mm Hg.
 Respiratory: hyperventilating: shallow, rapid
breathing
 Neuro: panicked, light-headed, tremors, may
develop tetany, numb hands and feet (related to
symptoms of hypocalcemia; with elevated pH
more Ca ions are bound to serum albumin and less
ionized “active” calcium available for nerve and
muscle conduction)
 May progress to seizures, loss of consciousness
(when normal breathing pattern returns)
 Cardiac: palpitations, sensation of chest tightness
1. Treatment: encourage client to breathe slowly in a
paper bag to rebreathe CO2
2. Breathe with the patient; provide emotional
support and reassurance, anti-anxiety agents,
sedation
3. On ventilator, adjustment of ventilation settings
(decrease rate and tidal volume)
4. Prevention: pre-procedure teaching, preventative
emotional support, monitor blood gases as
indicated
METABOLIC ACIDOSIS
 pH <7.35
 Deficit of bicarbonate in the blood NaHCO3 <22
mEq/L
 Caused by an excess of acid, or loss of
bicarbonate from the body
Common Stimuli
a. Acute lactic acidosis from tissue hypoxia (lactic
acid produced from anaerobic metabolism with
shock, cardiac arrest)
b. Ketoacidosis (fatty acids are released and
converted to ketones when fat is used to supply
glucose needs as in uncontrolled Type 1 diabetes
or starvation)
c. Acute or chronic renal failure (kidneys unable to
regulate electrolytes)
d. Excessive bicarbonate loss (severe diarrhea,
intestinal suction, bowel fistulas)
e. Usually results from some other disease and is
often accompanied by electrolyte and fluid
imbalances
f. Hyperkalemia often occurs as the hydrogen ions
enter cells to lower the pH displacing the
intracellular potassium; hypercalcemia and
hypomagnesemia may occur
Signs and Symptoms
 Compensation: respiratory system begins to
compensate by increasing the depth and rate of
respiration in an effort to lower the CO2 in the blood;
this causes a decreased level of carbon dioxide: pCO2
<35 mm HG.
 Neuro changes: headache, weakness, fatigue
progressing to confusion, stupor, and coma
 Cardiac: dysrhythmias and possibly cardiac arrest from
hyperkalemia
 GI: anorexia, nausea, vomiting
 Skin: warm and flushed

 Respiratory: tries to compensate by hyperventilation:
deep and rapid respirations known as Kussmaul‟s
respirations
Diagnostic test findings:
1. ABG: pH < 7.35, HCO3 < 22
2. Electrolytes: Serum K+
>5.0 mEq/L
3. Serum Ca+2
> 10.0 mg/dL
4. Serum Mg+2
< 1.6 mg/dL
1. Medications: Correcting underlying cause will
often improve acidosis
2. Restore fluid balance, prevent dehydration with
IV fluids
3. Correct electrolyte imbalances
4. Administer Sodium Bicarbonate IV, if acidosis is
severe and does not respond rapidly enough to
treatment of primary cause. (Oral bicarbonate is
sometimes given to clients with chronic metabolic
acidosis) Be careful not to overtreat and put client
into alkalosis
5. As acidosis improves, hydrogen ions shift out of
cells and potassium moves intracellularly.
Hyperkalemia may become hypokalemia and
potassium replacement will be needed.
6. Assessment
 Vital signs
 Intake and output
 Neuro, GI, and respiratory status;
 Cardiac monitoring
 Reassess repeated arterial blood gases and
electrolytes
METABOLIC ALKALOSIS
 pH >7.45
 HCO3 > 26 mEq/L
 Caused by a bicarbonate excess, due to loss of
acid, or a bicarbonate excess in the body
Common Stimuli
a. Loss of hydrogen and chloride ions through
excessive vomiting, gastric suctioning, or
excessive diuretic therapy Response to
hypokalemia
b. Excess ingestion of bicarbonate rich antacids or
excessive treatment of acidosis with Sodium
Bicarbonate
Signs and Symptoms
 Compensation: Lungs respond by decreasing the
depth and rate of respiration in effort to retain carbon
dioxide and lower pH
 Neuro: altered mental status, numbness and tingling
around mouth, fingers, toes, dizziness, muscle spasms
(similar to hypocalcemia due to less ionized calcium
levels)
 Respiratory: shallow, slow breathing
Diagnostic test findings
1. ABG‟s: pH> 7.45, HCO3 >26
2. Electrolytes: Serum K+
< 3.5 mEq/L
3. Electrocardiogram: as with hypokalemia
1. Correcting underlying cause will often improve
alkalosis
2. Restore fluid volume and correct electrolyte
imbalances (usually IV NaCl with KCL).
3. With severe cases, acidifying solution may be
administered.
4. Assessment
 Vital signs
 Neuro, cardiac, respiratory assessment
 Repeat arterial blood gases and electrolytes
Selected Water and Electrolyte
Solutions
Isotonic Solutions
A. 0.9% NaCl (isotonic, also called NSS)
Na+ 154 mEq/L
Cl- 154 mEq/L
(308 mOsm/L)
Also available with varying concentrations of dextrose (the
most frequent used is a 5% dextrose concentration
 An isotonic solution that expands the ECF
volume, used in hypovolemic states, resuscitative
efforts, shock, diabetic ketoacidosis, metabolic
alkalosis, hypercalcemia, mild Na deficit
 Supplies an excess of Na and Cl; can cause fluid
volume excess and hyperchloremic acidosis if
used in excessive volumes, particularly in patients
with compromised renal function, heart failure or
edema
 Not desirable as a routine maintenance solution,
as it provides only Na and Cl (and these are
provided in excessive amounts)
 When mixed with 5% dextrose, the resulting
solution becomes hypertonic in relation to plasma,
and in addition to the above described
electrolytes, provides 170cal/L
 Only solution that may be administered with
blood products
B. Lactated Ringer’s solution (Hartmann’s solution)
Na+ 130 mEq/L
K+ 4 mEq/L
Ca++ 3 mEq/L
Cl- 109 mEq/L
Lactate (metabolized to bicarbonate) 28 mEq/L (274
mOsm/L)
Also available with varying concentration of dextrose (the
most common is 5% dextrose)
 An isotonic solution that contains multiple
electrolytes in roughly the same concentration as
found in plasma (note that solution is lacking in
Mg++) provides 9 cal/L
 Used in the tx of hypovolemia, burns, fluid lost as
bile or diarrhea, and for acute blood loss
replacement
 Lactate is rapidly metabolized into HCO3- in the
body. Lactated Ringer‟s solution should not be
used in lactic acidosis because the ability to
convert lactate into HCO3- is impaired in this
disorder.

 Not to be given with a pH > 7.5 because
bicarbonates is formed as lactate breaks down
causing alkalosis
 Should not be used in renal failure because it
contains potassium and can cause hyperkalemia
 Similar to plasma
C. 5% Dextrose in Water (D5W)
No electrolytes
50 g of glucose
 An isotonic solution that supplies 170 cal/L and
free water to aid in renal excretion of solutes
 Used in treatment of hypernatremia, fluid loss and
dehydration
 Should not be used in excessive volumes in the
early post-op period (when ADH secretion is
increased due to stress reaction)
 Should not be used solely in tx of fluid volume
deficit, because it dilutes plasma electrolyte
concentrations
 Contraindicated in head injury because it may
cause increased intracranial pressure
 Should not be used for fluid resuscitation because
it can cause hyperglycemia
 Should be used with caution in patients with renal
or cardiac dse because of risk of fluid overload
 Electrolyte-free solutions may cause peripheral
circulatory collapse, anuria in pt. with sodium
deficiency and increased body fluid loss
 Converts to hypotonic solution as dextrose is
metabolized by body. Overtime D5W without
NaCl can cause water intoxication (ICF vol.
excess bec. solution is hypotonic)
Hypotonic Solutions
D. 0.45% NaCl
half-strength saline)
Na+ 77 mEq/L
Cl- 77 mEq/L
(154 mOsm/L)
Also available with varying concentration of dextrose (the
most common is 5% dextrose)
 Provides Na, Cl and free water
 Free water is desirable to aid the kidneys in
elimination of solute
 Lacking in electrolytes other than Na and Cl
 When mixed with 5% dextrose, the solution
becomes slightly hypertonic to plasma and in
addition to the above-described electrolytes
provides 170 cal/L
 Used in the tx of hypertonic dehydration, Na and
Cl depletion and gastric fluid loss
 Not indicated for third-space fluid shifts or
increased intracranial pressure
 Administer cautiously, because it can cause fluid
shifts from vascular system into cells, resulting in
cardiovascular collapse and increased intracranial
pressure
Hypertonic Solutions
E. 3% NaCl (hypertonic saline)
Na+ 513 mEq/L
Cl- 513 mEq/L
(1026 mOsm/L)
 Used to increase ECF volume, decrease cellular
swelling
 Highly hypertonic solution used only in critical
situations to treat hyponatremia
 Must be administered slowly and cautiously,
because it can cause intravascular volume
overload and pulmonary edema
 Supplies no calories
 Assists in removing ICF excess
F. 5% NaCl (hypertonic solution)
Na+ 855 mEq/L
Cl- 855 mEq/L
(1710 mOsm/L)
 Highly hypertonic solution used to treat
symptomatic hyponatremia
 Administered slowly and cautiously, because it
can cause intravascular volume overload and
pulmonary edema
 Supplies no calories
Colloid Solutions
G. Dextran in NS or 5% D5W
Available in low-molecular-weight (Dextran 40) and high-
molecular-weight (Dextran 70) forms
 Colloid solution used as volume/plasma expander
for intravascular part of ECF
 Affects clotting by coating platelets and
decreasing ability to clot
 Remains in circulatory system up to 24 hours
 Used to treat hypovolemia in early shock to
increase pulse pressure, CO, and arterial BP
 Improves microcirculation by decreasing RBC
aggregation
 Contraindicated in hemorrhage,
thrombocytopenia, renal dse and severe
dehydration
 Not a substitute for blood or blood products

Lecture Notes on Fluids and Electrolytes

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