Fluids and
Electrolytes
Metropolitan Community College
Fall 2013
Jane Miller, RN MSN
Objectives
• Discuss the nurse’s role in understanding fluid
and electrolytes as needed for safe IV therapy.
• Examine the importance of maintaining
hemostasis.
• Review extracellular fluid, intracellular fluid,
and interstitial fluid dynamics.
• Examine solute and solvent in relation to
osmotic pressure and importance of
maintaining hemostasis.
• Identify the major electrolytes, their function, and
location.
• Describe abnormalities of fluid and electrolyte balance,
and evaluate how each affects homeostasis.
• Discuss the differences between isotonic, hypertonic,
and hypotonic IV solutions and their actions in
osmosis, indications for and contraindications in
various pathophysiological conditions.
• Identify normal acid-base balance.
• Examine abnormalities in acid-base balance.
• Identify the body’s regulatory mechanism for acid-base
balance.
• Examine hormonal regulation of fluid and electrolyte
balance.
Fluid Basics
• Water comprises 70% of living cells
• Average healthy person needs 2 - 2.5 liters of
water per day to meet fluid requirements
• Fluid is lost through
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Respirations
Urine
Feces
Perspiration
Vomit
Diarrhea
Wound drainage
Functions of Body Fluid
• Transport of nutrients, electrolytes, and
oxygen to the cells
• Excretion of waste products
• Regulation of body temperature
• Lubrication of joints and membranes
• Medium for food digestion
Fluid Compartments
• Intracellular (ICF)
– All fluid within the cell wall
• Extracellular (ECF)
– All fluid outside of the cell wall
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Interstitial fluid
Plasma
CSF
Sweat
Urine
GI secretions
Osmolality
• The number of molecules of solute (sodium,
urea, and glucose) per kilogram of water
• Osmolality of blood is 275-295 mOsm/kg
• Isotonic fluids 275-295 mOsm/kg
– Same solute concentration as plasma
• Hypertonic fluids > 295 mOsm/kg
– Higher solute concentration than plasma
• Hypotonic fluids < 275 mOsm/kg
– Lower solute concentration than plasma
Body Fluid Regulation
• Osmosis
– The movement of water from an area of lower
particle concentration to one of higher particle
concentration
Body Fluid Regulation
• Diffusion
– The movement of molecules from an area of
higher concentration to an areas of lower
concentration
Body Fluid Regulation
• Filtration
– The movement of molecules from an area of
higher concentration to one of lower
concentration as a result of hydrostatic pressure
– Hydrostatic pressure is the pressure exerted on
tissue due to the presence of water. It is generated
by the pumping action of the heart.
– Seen in the capillary system
• Arterial pressure is 32 mmHg
• Venous pressure is 15 mmHg
Homeostasis
• Serum osmolality is regulated by the
osmoreceptors of the hypothalamus
• When fluid is lost the hypothalamus
stimulates the pituitary gland to secrete ADH
• ADH signals the kidneys to conserve water
• Promotes the sensation of thirst
Isotonic Fluids
• 275-295 mOsm/kg
• Same solute concentration as plasma
• No net fluid shift
• Examples
– 0.9% NaCl
– Lactated Ringers
– D5W (can be considered hypotonic due to metabolism of dextrose)
Hypertonic Fluids
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> 295 mOsm/kg
Higher solute concentration than plasma
Draw water from the cells and tissues
Expands plasma volume
Examples
– 3% NaCl
– D10W
– D5NS
Hypotonic Fluids
• < 275 mOsm/kg
• Lower solute concentration that plasma
• Causes water to move out of the plasma to
the tissues and cells
• Examples
– 0.45% NaCl
– 0.33% NaCl
– D2.5W
Administration of a IV fluid with an
osmolality of 288 mOsm/kg represents
what kind of fluid?
A. Isotonic
B. Hypertonic
C. Hypotonic
Evaluation of Fluid Status
• Specific gravity of urine
– Normal 1.005-1.030
– < 1.005 = overhydration
– > 1.030 = dehydration
• Hematocrit
– Normal Male 42-52%
– < 42% = overhydration
– > 52% = dehydration
• Electrolytes
– < normal = overhydration
– > normal = dehydration
Causes of Overhydration
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Renal failure
Congestive heart failure
Liver cirrhosis
Syndrome of inappropriate antidiuretic
hormone (SIADH)
• Excessive oral or IV intake
Clinical Manifestations
Overhydration
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Edema
Crackles in the lung bases
Dyspnea
SOB
Serum pH <7.35, respiratory acidosis
Ascites
Increased blood pressure
Bounding pulses
Extra heart sound (most common in children)
Activity intolerance
Increase in body weight
Nursing Management
Overhydration
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I&O
Daily weights
Vital signs
Labs – CBC, BMP, Urinalysis, BUN, Creatinine
Prop pt up in bed to reduce dyspnea
Allow adequate time for rest
Skin assessment and daily care
Administer diuretics
Stop or slow IV fluids
Pt teaching – diet, fluid restriction, diuretics, daily
weights, S&S to report
Causes of Dehydration
• Decreased oral intake
– Elderly
– Altered mental status
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Diabetes Insipidus
Diabetes Mellitus
Vomiting and diarrhea
Burns
Excessive sweating
Overuse of diuretics
Clinical Manifestations
Dehydration
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Severe thirst (may be absent in the elderly)
Dry mucous membranes
Decreased skin turgor
Tachycardia
Weak pulse
Hypotension
Decreased urine output
Headache
Dizziness
Mental status changes
Mottled extremities
Nursing Management
Dehydration
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I&O
Daily weights
Vital signs
Labs – CBC, BMP, Urinalysis, BUN, Creatinine
Monitor neurological status
Provide oral care
Assess for signs of constipation
Administer IV fluids
Pt teaching – hydration needs, S&S to report
Electrolyte Overview
• Calcium, Chloride, Magnesium, Phosphorus,
Potassium, and Sodium
• Support normal bodily functions
• Have either a positive or negative charge
• Each electrolyte has a normal range where
there is optimal body function
• When outside of this normal range
dysfunction occurs
Sodium:
+
Na
• 135-145 mEq/L
• Most numerous cation in the ECF
• Maintains ECF volume through osmotic
pressure
• Regulates acid-base balance by combining
with chloride and bicarb
• Conducts nerve impulses via sodium channels
in cell
Regulation
• Aldosterone: Secreted by the adrenal cortex
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Low ECF sodium levels
Increased ICF potassium
Low cardiac output
Stress
Increases retrieval of
sodium from kidney filtrate
• ADH: Secreted by the pituitary gland
– Increased ECF osmolality
• Atrial natriuretic peptide (ANP): Secreted by
the atrium of the heart
– Excessively stretched atria
Antagonist to aldosterone
Hypernatremia
• > 145mEq/L
• Causes
– Cushing’s syndrome
– Diabetes insipidus
– Excessive sweating
– Increased oral intake
– Infusion of 3% NaCL
– Severe vomiting
– Decreased renal function
Clinical Manifestations
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Thirst
Dry mucous membranes
Low-grade fever
Edema
Tachycardia
Mental status changes
Seizures
> 180mEq/L =
high mortality
Nursing Management
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Administer medications to control Cushing’s Syndrome
Administer ADH (diabetes insipidus)
Use 3% NaCl infusions carefully
Monitor labs
Oral care
Skin care and turning
Vital signs
Monitor neurological status
Low sodium diet
Encourage oral intake of water
Which of these situations can cause
an increased serum sodium level?
a.
b.
c.
d.
e.
f.
Excessive use of table salt
Consuming large quantities of canned soup
Increased water intake
Use of intravenous 3% NaCl
Use of diuretics
Severe vomiting
Hyponatremia
• < 135mEq/L
• Causes
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Inadequate oral intake
Excessive water intake
Diuretics
Vomiting and diarrhea
Infusion of 5% Dextrose
Burns
Head trauma
Syndrome of inappropriate antidiuretic hormone
Addison’s disease
Clinical Manifestations
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Headache
Confusion
Seizures
Tachycardia
Hypotension
Muscle weakness
Abdominal cramping
Possibly no manifestations
< 115 mEq/L =
high mortality
Nursing Management
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Monitor VS
Monitor labs
Monitor neurological status
Fluid restriction
Administer 0.9% NaCl
Administer 3% NaCl carefully
Allow plenty of time for rest
Potassium:
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K
3.5 – 5.0 mEq/L
Intracellular cation
98% is found within the cells
Essential for cellular integrity
Transmission of neuromuscular impulses
Acid-base balance
Conversion of carbs to energy
Formation of amino acids into proteins
Hyperkalemia
• > 5.0 mEq/L
• Causes
– Increased oral or IV intake
– Decreased urinary excretion
– Cellular damage
– Severe acidosis
– Potassium sparing diuretics
– Addison’s disease
Clinical Manifestations
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Muscle cramps
Tachycardia
Nausea
Diarrhea
Weakness
Numbness
Oliguria or anuria
ECG changes
– Peaked T waves, shortened QT interval, prolonged PR
followed by a disappearance of the P wave, Prolonged
QRS.
• Cardiac arrest
Peaked t-wave
Nursing Management
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Monitor VS & ECG
Monitor labs
Diet restriction
Slow or stop IV fluids with potassium added
– Normally no more than 10mEq of KCL per hour
• Administer Kayexalate
• Administer insulin and glucose (temporary tx)
• Administer IV sodium bicarb (temporary tx)
Hypokalemia
• < 3.5 mEq/L
• Causes
– Potassium wasting diuretics
– Decreased oral intake
– Alcoholism
– Vomiting
– Diarrhea
– Alkalosis
– Steroid use
Clinical Manifestations
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Nausea & Vomiting
Diarrhea
Abdominal distention
Vertigo
Malaise
Confusion
ECG changes
– Flat or inverted T waves, depressed ST, may have a U
wave
Nursing Management
• Monitor VS & ECG
• Monitor labs
• Encourage diet rich is potassium
– Sweet potatoes, broccoli, bananas, squash
• Administer potassium supplement
– Irritating to the gastric mucosa, give with 6-8 ounces
of water
• Use caution when administering IV
• Never give K+ as a bolus
Your patient has this ECG tracing.
What do you suspect?
Calcium:
2+
Ca
• Normal serum values 8.5- 10.5 mg/dL
• Ionized calcium 4.0 – 5.5 mg/dL
• Cation found in both ECF and ICF, but greater
concentration in ECF
• Maintains cellular membrane stability
• Sedative effect on nerves
• 98% in bones and teeth, 2% in the serum
• Serum pH greatly affects calcium levels –
metabolic acidosis increases levels, alkalosis
opposite effect
Functions of Calcium
• Neuromuscular
– transmission of nerve impulses and contraction of skeletal
muscle
• Cardiac
– contraction of the myocardium
• Cellular and Blood
– Maintains cellular permeability - decreased calcium
increases cellular permeability
– Promotes clotting by converting prothrombin into
thrombin
• Bone and teeth construction
– Calcium along with phosphorous forms bones and teeth
Regulation of Calcium
• Vitamin D
– Aides in absorption of calcium from the gut
• Calcitonin from the thyroid gland
– Increases renal excretion, deposits it in the bones
• PTH from the parathyroid gland
– Mobilizes calcium from the bone and increases
reabsorption by the kidneys
Hypercalcemia
• Serum calcium > 10.5 mg/dL
• Ionized calcium > 5.5 mg/dL
• Causes
– Primary hyperparathyroidism
– Bone malignancy
– Drug toxicity
• Thiazide diuretics, lithium carbonate, vitamin A & D
– Prolonged bed rest
– Rhabdomyolysis
– Excessive use of calcium supplements
Clinical Manifestations
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Fatigue
Weakness
Headache
Confusion
Polyuria
Kidney stones
Nausea & vomiting
ECG changes
– Shortening of the ST segment and QT interval, prolonged
PR interval
• Soft tissue calcifications
• Pathological fractures
Nursing Management
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Monitor VS & ECG
Monitor labs
Stop vitamin A, D and calcium supplements
Low calcium diet
Discontinue thiazide diuretics
Allow plenty of time for rest
Administer antiemetics
Turn and reposition carefully
Monitor neurological status
Hypocalemia
• Serum < 8.5 mg/dL
• Ionized Ca is < 4.0 mg/dL
• Causes
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Decreased oral intake (rare)
Inadequate vitamin D
Hypoalbuminemia
Citrated blood transfusions
Decreased PTH
Alkalosis
GI surgery
Chronic pancreatitis
Small bowel disease
Loop diuretics
Clinical Manifestations
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Numbness and tingling of the fingers
Muscle cramps
Hyperactive reflexes
Anxiety
Bradycardia
Hypotension
ECG changes
– Prolonged QT intervals
Clinical Tests
Chvotsek’s Sign
Trousseau’s Sign
Tap the facial nerve just
below the temple on the
zygomatic arch
Inflate BP cuff 20 mm
above systolic pressure for
3 minutes
Nursing Management
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Monitor VS & ECG
Monitor labs
Give oral supplements of calcium and Vit. D
Infuse IV calcium supplements slowly
– 60mg/min
• Do not give with sodium bicarb because
precipitation could result
• Encourage dietary consumption
– Yogurt, cheese, spinach, sardines
Magnesium:
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2+
Mg
1.4- 2.1 mg/dL
Intracellular cation
Neuromuscular activity transmission
Cardiac contraction
Cellular
– Activates enzymes for carbohydrate and protein
metabolism
– Responsible for proper transportation of sodium and
potassium across cell membranes
– Influences utilization of K, Ca, and proteins
– Magnesium deficits are FREQUENTLY accompanied by a
Potassium and/or Calcium deficit
Hypermagnesemia
• > 2.1 mg/dL
• Causes
– Renal failure
– IV infusion (common in OB)
– Adrenal insufficiency
– Intake of magnesium containing antacids
• Maalox, MOM, Mylanta
Clinical Manifestations
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Hypotension
Bradycardia
Nausea & Vomiting
Decreased deep tendon reflexes
Drowsiness
Respiratory depression
Flushing
Nursing Management
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Stop magnesium-containing products
IV push calcium gluconate
Monitor VS & ECG
Monitor labs
Assess neurological status
Administer 0.45% NaCl and diuretics
Dialysis
Hypomagnesemia
• < 1.4 mg/dL
• Causes
– Malnutrition
– Alcoholism
– Loop diuretics
– Vomiting
– Diarrhea
– Increased calcium intake
– Diuresis from diabetic ketoacidosis
Clinical Manifestations
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Confusion
Lethargy
Seizures
Tetany
Increased tendon reflexes
Hypertension
PVCs
V tach
V fib
Nursing Management
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Monitor VS & ECG
Monitor labs
Assess neurological status
Administer magnesium supplements
Monitor IV administration closely
Encourage dietary intake
– Spinach, nuts, fish, beans
Phosphorus
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2.5 – 4.5 mg/dL
Major intracellular anion
85% is in teeth and bones
Essential for carb, protein, and fat metabolism
Nerve and muscle function
Form ATP and ADP
Essential for acid-base balance
Hyperphosphatemia
• > 4.5 mg/dL
• Causes
– Excessive oral intake
– Decreased levels of PTH
– Chemotherapy
– Radiation therapy
– Rhabdomyolysis
– Renal insufficiency
– Acidosis
Clinical Manifestations
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Calcium phosphate deposits in soft tissues
Muscle weakness
Tachycardia
Nausea
Diarrhea
Abdominal cramps
Nursing Management
• Monitor VS & ECG
• Monitor labs
• Administer phosphorous binding antacids
– Calcium carbonate, calcium acetate
• Dietary restriction
• Administer insulin and glucose (temp tx)
Hypophosphatemia
• < 2.0 mg/dL
• Causes
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Vitamin D deficiency
Phosphate binding antacids
Alcoholism
Vomiting & diarrhea
Diabetic ketoacidosis
Elevated PTH
Alkalosis
Burns
Clinical Manifestations
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Confusion
Seizures
Peripheral neuropathy
Tissue hypoxia
Dysrhythmias
Bleeding from platelet dysfunction
Weakness
Bone pain
Tremors
Anorexia
Nursing Management
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Monitor VS & ECG
Monitor labs
Watch for signs of bleeding
Monitor neurological status
Administer oral supplements
Encourage dietary intake
– Dried beans, fish, organ meats, whole grains
Chloride:
Cl
• 95-108 mEq/L
• Primary anion in the ECF
• Combines with sodium to create electrical
neutrality
• Assists in reabsorption of sodium from kidneys
• Combines with hydrogen to for hydrochloric
acid for digestion
• Buffers carbonic acid
• Used to calculate the anion gap
Hyperchloremia
• > 108 mEq/L
• Causes
– Hyperparathyroidism
– Dehydration
– Metabolic acidosis
– Respiratory alkalosis
– Excessive dietary intake
Clinical Manifestations
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Increased depth and rate of respirations
Lethargy
Stupor
Disorientation
Coma
Hypochloremia
• < 95 mEq/L
• Causes
– Vomiting
– Excessive sweating
– Diuretics
– Diabetic ketoacidosis
– It rarely occurs in isolation
Clinical Manifestations
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Reflects alkalosis
Paresthesias of the face and extremities
Muscle spasms
Slow shallow respirations
Hypoxia
Tetany
Confusion
Hypertension
Dehydration
Resources
• Osborn, Wraa, & Watson chapter 18
• Fluid and Electrolyte Balance
http://www.nlm.nih.gov/medlineplus/fluidandelectrolytebalance.html
• I.V. fluids: What nurses need to know.
http://www.nursingcenter.com/lnc/pdf?AID=1156868&an=00152193201105000-00010&Journal_ID=54016&Issue_ID=1156791
• IV Fluid Basics
http://faculty.weber.edu/kbarton1/IV%20Therapy%20Basics.pdf