This document discusses fluid and electrolyte balance and homeostasis. It covers the body's fluid compartments, electrolytes, homeostasis mechanisms like feedback, and systems involved like the nervous and endocrine systems. It also addresses fluid regulation, normal fluid intake and output, fluid volume disturbances, electrolyte balances and imbalances, acid-base balance, causes, signs and symptoms, complications, and diagnostic tests for assessing fluid and electrolyte status.

1. MARUDHAR
Fluid and Electrolytes, Acid-Base
Balance

2. INTRODUCTION
 Fluid and electrolyte balance is a dynamic process
that is crucial for life and homeostasis.
 Fluid occupies almost 60% of the weight of an adult.
 Body fluid is located in two fluid compartments:
the intracellular space and the extracellular space.
 Electrolytes in body fluids are active chemicals or
cations that carry positive charges and anions that
carry negative charges.
 The major cations in the body fluid are sodium,
potassium, calcium, magnesium, and hydrogen ions.
 The major anions are chloride, bicarbonate, sulfate,
and proteinate ions.

3. Homeostasis
 Homeostasis is the dynamic process in which the
body maintains balance by constantly adjusting to
internal and external stimuli.

4. Negative and Positive
Feedback
 Feedback is the relaying of information about a
given condition to the appropriate organ or
system.
 Negative feedback. Negative feedback occurs
when the body reverses an original stimulus for
the body to regain physiologic balance.
 Positive feedback. Positive
feedback enhances or intensifies the original
stimulus.
 Examples. Blood pressure control and
maintenance of normal body temperature are
examples of negative feedback while blood
clotting after an injury and a woman in labor are
examples of positive feedback.

5. Systems Involved in Feedback
 The major systems involved in feedback are the
nervous and endocrine systems.
 Nervous system. The nervous system regulates
homeostasis by sensing system deviations and
sending nerve impulses to appropriate organs.
 Endocrine system. The endocrine system uses the
release and action of hormones to maintain
homeostasis.

6. Body Fluids
 Fluids make up a large portion of the body, which
is approximately 50%-60% of the total body
weight.
 Location of Fluids
 Main compartments. Body fluids are divided
between two main compartments: the intracellular
fluid and the extracellular fluid compartments.
 Intracellular fluid. Intracellular fluid functions as a
stabilizing agent for the parts of the cell, helps
maintain cell shape, and assists with transport of
nutrients across the cell membrane, in and out of
the cell.
 Extracellular fluid. Extracellular fluid mostly
appears as interstitial tissue fluid and intravascular
fluid.

7. Fluid Regulation Mechanisms
 The thirst center. The thirst center in
the hypothalamus stimulates or inhibits the desire for
a person to drink.
 Antidiuretic hormone. ADH regulates the amount of
water the kidney tubules absorb and is released in
response to low blood volume or in response to an
increase in concentration of sodium and other solutes
in the intravascular fluids.
 The RAA system. The RAA system controls fluid
volume, in which when the blood volume decreases,
blood flow to the renal juxtaglomerular apparatus is
reduced, thereby activating the RAA system.
 Atrial natriuretic peptide. The heart also plays a
role in correcting overload imbalances, by releasing
ANP from the right atrium.

8. Normal Intake and Output
 Daily intake. An adult human at rest takes
appropriately 2,500 ml of fluid daily.
 Levels of intake. Approximate levels of intake
include fluids 1, 200 ml, foods 1, 000 ml, and
metabolic products 30 ml.
 Daily output. Daily output should approximately
equal in intake.
 Normal output. Normal output occurs as urine,
breathing, perspiration, feces, and in minimal
amounts of vaginal secretions.

9. Overhydration and Edema
 Overhydration. Overhydration is an excess of
water in the body.
 Edema. Edema is the excess accumulation of
fluid in interstitial tissue spaces, also called third-
space fluid.
 Cause of edema. Edema is caused by a
disruption of the filtration and osmotic forces of
the body’s circulating fluids.
 Treatment of edema. Diuretics are commonly
given for systemic edema.

10. Dehydration
 Dehydration. Dehydration is a deficiency of body
water or excessive loss of water.
 External causes. External causes of dehydration
include prolonged sun exposure and excessive
exercise, as well as diarrhea, vomiting, and
burns.
 Treatment of dehydration. Supplemental fluids
and electrolytes are often administered.

11. Electrolytes
 An electrolyte is a substance that will
disassociate into ions when dissolved in water.
 Origins. Electrolytes are found in the form of
inorganic salts, acids, and bases.
 Active chemicals. Electrolyte concentrations are
measured according to their chemical activity and
expressed as milliequivalents.
 Ions. Each chemical element has an electrical
charge, either positive or negative.

12. CONT….
 Intracellular electrolytes. Important intracellular
electrolytes are potassium, magnesium, sulfate,
and phosphate, and the most dominant cation iss
potassium while the most dominant anion is
phosphate.
 Extracellular electrolytes. Important
extracellular electrolytes include sodium, chlorine,
calcium, and bicarbonate, and the most essential
cation is sodium while chlorine is the most
important anion.

13. Fluid and Electrolyte Transport
 Total electrolyte concentration affects the body’s
fluid balance.
 The body cells. Nutrients and oxygen should
enter body cells while waste products should exit
the body.
 The cell membrane. The cell membrane
separates the intracellular environment from the
extracellular environment.
 Permeability. The ability of a membrane to allow
molecules to pass through is known as
permeability.

14. Permeability of Membranes
 Freely permeable membranes. These
membranes allow almost any food or waste
substance to pass through.
 Selectively permeable. The cell membrane is
selectively permeable, meaning that each cell’s
membrane allows only certain specific
substances to pass through.

15. Passive Transport
 Passive transport. Passive transport mechanisms
include diffusion, osmosis, and filtration.
 Diffusion. Diffusion, or the process of “being widely
spread”, is the random movement of molecules from
an area of higher concentration to an area of lower
concentration.
 Osmosis. Osmosis is the diffusion of a pure solvent,
such as water, across a semipermeable membrane in
response to a concentration gradient in situations
where the molecules of a higher concentration are
non diffusible.
 Filtration. Filtration is the transport of water and
dissolved materials concentration already exists in the
cell.

16. Active Transport
 Mechanisms. Active transport mechanisms
require specific enzymes and an energy
expenditure in the form of adenosine
triphosphate (ATP).
 Processes. Active transport processes can move
solutes “uphill”, against the normal rules of
concentration and pressure.

17. Fluid and Electrolyte Balance
 Fluid and electrolyte balance is vital for proper
functioning of all body systems.
 Osmolarity. This is the property of particles in a
solution to dissociate into ions.
 Electroneutrality. This is the balance of positive
and negative charges.

18. Acid-Base Balance
 Acid-base balance is another important aspect of
homeostasis.
 Acid, Bases, and Salts
 Acid. An acid is one type of compound that contains the
hydrogen ion.
 Base. A base or alkali is a compound that contains the
hydroxyl ion.
 Salt. A salt is a combination of a base and an acid and is
created when the positive ions of a base replace the
positive hydrogen ions of an acid.
 Important salts. The body contains several important
salts like sodium chloride, potassium chloride, calcium
chloride, calcium carbonate, calcium phosphate, and
sodium phosphate.

19. Potential of Hydrogen
 pH. The symbol of pH refers to the potential or
power of hydrogen ion concentration within the
solution.
 Low pH. If the pH number is lower than 7, the
solution is an acid.
 High pH. If the pH is greater than 7, a solution
is basic or alkaline.
 Neutral pH. If the pH is 7, then the solution
is neutral.
 Changes. A change in the pH of a solution by
one pH unit means a tenfold change in hydrogen
concentration

20. Buffers
 Buffers. A buffer is a chemical system set up to resist
changes, particularly in hydrogen ion levels.
 Bicarbonate buffer system. Sodium bicarbonate
and carbonic acid are the body’s major chemical
buffers.
 Carbon dioxide. The major compound controlled by
the lungs is CO2, and the respiratory system can very
rapidly compensate for too much acid and too little
acid by increasing or decreasing the respiratory rate,
thereby altering the level of CO2.
 Bicarbonate. Bicarbonate ions are basic components
in the body, and the kidneys are key in regulating the
amount of bicarbonate in the body.
 Measurement of arterial blood gas. The pH level
and amounts of specific gases in the blood indicate if
there is more acid or base and their associated
values.

21. CONT….
 Respiratory acidosis. Respiratory acidosis
occurs when breathing is inadequate and PaCO2
builds up.
 Respiratory alkalosis. Respiratory alkalosis
occurs as a result of hyperventilation or excess
aspirin intake.
 Metabolic acidosis. In metabolic acidosis,
metabolism is impaired, causing a decrease in
bicarbonates and a buildup of lactic acid.
 Metabolic alkalosis. Metabolic alkalosis occurs
when bicarbonate ion concentration increases,
causing an elevation in blood pH.

22. Classification
 There are different fluid volume disturbances that
may affect an individual.
 Fluid volume deficit or hypovolemia occurs when
loss of ECF volume exceeds the intake of fluid.
 Fluid volume excess or hypervolemia refers to an
isotonic volume expansion of the ECF caused by
the abnormal retention of water and sodium in
approximately the same proportions in which they
normally exist in the ECF.

23. Disturbances in electrolyte balances are
common in clinical practice and must be
corrected.
 Hyponatremia refers to a serum sodium level
that is less than 135 mEq/L
 Hypernatremia is a serum sodium level higher
than 145 mEq/L.
 Hypokalemia usually indicates a deficit in total
potassium stores.
 Hyperkalemia refers to a potassium
level greater than 5.0 mEq/L.
 Hypocalcemia are serum levels below 8.6
mg/dl.

24. CONT….
 Hypercalcemia is calcium level greater than
10.2 mg/dl.
 Hypomagnesemia refers to a below-
normal serum magnesium concentration.
 Hypermagnesemia are serum levels over 2.3
mg/dl.
 Hypophosphatemia is indicated by a
value below 2.5 mg/dl.
 Hyperphosphatemia is a serum phosphorus
level that exceeds 4.5 mg/dl in adults.

25. Pathophysiology
 Nurses need an understanding of the
pathophysiology of fluid and electrolyte balance
to anticipate, identify, and respond to possible
imbalances.
 Concentrations. Electrolyte concentrations vary
from those in the ICF to those in the ECF.
 Sodium. Sodium ions outnumber any other cations
in the ECF; therefore it is essential in the fluid
regulation of the body.
 Potassium. The ECF has a low concentration of
potassium and can tolerate only small changes in
its concentrations.

26. CONT…
 Maintenance. The body expends a great deal of
energy in maintaining the sodium and potassium
concentrations through cell membrane pumps
that exchange sodium and potassium ions.
 Osmosis. When two different solutions are
separated by a membrane that is impermeable to
the dissolved substances, fluid shifts from the
region of low solute concentration to the high
solute concentration until the solutions are of
equal concentrations.
 Diffusion. Diffusion is the natural tendency of a
substance to move in an area of higher
concentration to an area of lower concentration.

27. Causes
Causes of fluid and electrolyte imbalances are
discussed below in general.
 Fluid retention. Retention of sodium is associated
with fluid retention.
 Loss of sodium. Excessive loss of sodium is
associated with decreased volume of body fluid.
 Trauma. Trauma causes release of intracellular
potassium which is extremely dangerous.
 Loss of body fluids. FVD results from loss of body
fluids and occurs more rapidly when coupled with
decreased fluid intake.

28. CONT…
 Fluid overload. Fluid volume excess may be
related to a simple fluid overload or diminished
function of the homeostatic mechanisms
responsible for regulating fluid balance.
 Low or high electrolyte intake. Diets low or
excessive in electrolytes could also cause
electrolyte imbalances.
 Medications. There are certain medications that
could lead to electrolyte imbalances when taken
against the physician’s orders.

29. Clinical Manifestations
 Signs and symptoms that occur in fluid and electrolyte
imbalances are discussed below.
 Fluid volume deficit. Clinical signs and symptoms
include acute weight loss, decreased skin turgor,
oliguria, concentrated urine, orthostatic hypotension, a
weak, rapid heart rate, flattened neck veins, increased
temperature, thirst, decreased or delayed capillary refill,
cool, clammy skin, muscle weakness, and cramps.
 Fluid volume excess. Clinical manifestations for FVE
include edema, distended neck veins, and crackles.
 Hyponatremia. Signs and symptoms include anorexia,
nausea and vomiting, headache, lethargy, dizziness,
confusion, muscle cramps and weakness, muscular
twitching, seizures, dry skin, and edema.

30. CONT..
 Hypernatremia. The signs and symptoms are
thirst, elevated body temperature, hallucinations,
lethargy, restlessness, pulmonary edema,
twitching, increased BP and pulse.
 Hypokalemia. Clinical manifestations are fatigue,
anorexia, muscle weakness, polyuria, decreased
bowel motility, paresthesia, ileus, abdominal
distention, and hypoactive reflexes
 Hyperkalemia. Signs and symptoms include
muscle weakness, tachycardia, paresthesia,
dysrhythmias, intestinal colic, cramps, abdominal
distention, and anxiety.

31. CONT.
 Hypocalcemia. The signs and symptoms are
numbness, tingling of fingers, toes, and circumoral
region, positive Trousseau’s sign and Chvostek’s
sign, seizures, hyperactive deep tendon reflexes,
irritability, and bronchospasm.
 Hypercalcemia. The signs and symptoms include
muscle weakness, constipation, anorexia, nausea and
vomiting, dehydration, hypoactive deep tendon
reflexes lethargy, calcium stones, flank pain,
pathologic fractures, and deep bone pain.
 Hypomagnesemia. Clinical manifestations include
neuromuscular irritability, positive Trousseau’s and
Chvostek’s sign, insomnia, mood changes, anorexia,
vomiting, and increased deep tendon reflexes.

32. CONT..
 Hypermagnesemia. Signs and symptoms are
flushing, hypotension, muscle weakness,
drowsiness, hypoactive reflexes, depressed
respirations, and diaphoresis.
 Hypophosphatemia. Signs and symptoms
include paresthesias, muscle weakness, bone
pain and tenderness, chest pain, confusion,
seizures, tissue hypoxia, and nystagmus.
 Hyperphosphatemia. Clinical manifestations are
tetany, tachycardia, anorexia, nausea and
vomiting, muscle weakness, and hyperactive
reflexes.

33. Complications
 luid and electrolyte imbalances could result in
complications if not treated promptly.
 Dehydration. Fluid volume deficit could result in
dehydration of the body tissues.
 Cardiac overload. Fluid volume excess could
result in cardiac overload if left untreated.
 SIADH. Water is retained abnormally in SIADH.
 Cardiac arrest. Too much potassium administered
could lead to cardiac arrest.

34. Assessment and Diagnostic
Findings
 BUN. BUN may be decreased in FVE due to
plasma dilution.
 Hematocrit. Hematocrit levels in FVD are
greater than normal because there is a
decreased plasma volume.
 Physical examination. Physical exam is
necessary to observe the signs and
symptoms of the imbalances.

35. CONT…
 Serum electrolyte levels. Measurement of
electrolyte levels should be performed to
check for presence of an imbalance.
 ECG. ECG changes can also contribute to the
diagnosis of fluid and electrolyte imbalance.
 ABG analysis. ABG analysis may reveal
acid-base imbalances.

36. Medical Management
 Isotonic electrolyte solutions. These solutions are
used to treat the hypotensive patient with FVD
because they expand plasma volume.
 Accurate I&O. Accurate and frequent assessments of
I&O should be performed when therapy should be
slowed or increased to prevent volume deficit or
overload.
 Dialysis. Hemodialysis or peritoneal dialysis is
performed to remove nitrogenous wastes and control
potassium and acid-base balance, and to remove
sodium and fluid.
 Nutritional therapy. Treatment of fluid and electrolyte
imbalances should involve restrictions or enforcement
of the concerned electrolyte.

37. Pharmacologic therapy
 AVP receptor agonists. These are new
pharmacologic agents that treat hyponatremia by
stimulating free water excretion.
 Diuretics. To decrease fluid volume in FVE, diuretics
are administered.
 IV calcium gluconate. If serum potassium levels are
dangerously elevated, it may be necessary to
administer IV calcium gluconate.
 Calcitonin. Calcitonin can be used to lower the
serum calcium level and is particularly useful for
patients with heart disease or heart failure who cannot
tolerate large sodium loads.

38. Nursing
Management

39. Nursing Assessment
 Close monitoring should be done for patients with
fluid and electrolyte imbalances.
 I&O. the nurse should monitor for fluid I&O at least
every 8 hours, or even hourly.
 Daily weight. Assess the patient’s weight daily to
measure any gains or losses.
 Vital signs. Vital signs should be closely monitored.
 Physical exam. Physical exam is needed to
reinforce other data about a fluid or electrolyte
imbalance.

40. Diagnosis
 The following diagnoses are found in patients with
fluid and electrolyte imbalances.
 Excess fluid volume related to excess fluid intake and
sodium intake.
 Deficient fluid volume related to active fluid loss or
failure of regulatory mechanisms.
 Imbalanced nutrition: less than body
requirements related to inability to ingest food or
absorb nutrients.
 Imbalanced nutrition: more than body
requirements related to excessive intake.
 Diarrhea related to adverse effects of medications or
malabsorption.

41. Nursing Interventions
 Monitor turgor. Skin and tongue turgor are
indicators of the fluid status of the patient.
 Urine concentration. Obtain urine sample of the
patient to check for urine concentration.
 Oral and parenteral fluids. Administer oral or
parenteral fluids as indicated to correct the deficit.

42. CONT…
 Oral rehydration solutions. These solutions
provide fluid, glucose, and electrolytes in
concentrations that are easily absorbed.
 Central nervous system changes. The nurse
must be alert for central nervous system changes
such as lethargy, seizures, confusion, and muscle
twitching.
 Diet. The nurse must encourage intake of
electrolytes that are deficient or restrict intake if
the electrolyte levels are excessive.

43. Discharge and Home Care
Guidelines
 After hospitalization, treatment and maintenance
of the condition must continue at home.
 Diet. A diet rich in all the nutrients and electrolytes
that a person needs should be enforced.
 Fluid intake. Fluid intake must take shape
according to the recommendations of the physician.
 Follow-up. A week after discharge, the patient must
return for a follow-up checkup for evaluation of
electrolyte and fluid status.
 Medications. Compliance to prescribed
medications should be strict to avoid recurrence of
the condition.