Transcript Chapter 10

Medical-Surgical Nursing: An
Integrated Approach, 2E
Chapter 10
FLUID,
ELECTROLYTE, &
ACID-BASE
BALANCE
Homeostasis
The maintenance of the body’s internal
environment within a narrow range of
normal values.
 It is an ongoing process, with changes
constantly occurring in the body.
 Maintaining homeostasis is essential to
life.
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Chemical Organization
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Basic chemical and physical principles,
shown below, are necessary to
understand the higher levels of
organization.
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Elements.
Atoms.
Molecules and Compounds.
Ions.
Water
Water constitutes approximately 60% of
the total body weight of an adult.
 It is involved in many of the physical and
physiological process of the body.
 Fluctuations in the amount of water in the
body can have harmful and even fatal
consequences.
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Gases

Two important gases in the body are
oxygen and carbon dioxide.
Acids, Bases, Salts, and pH
Acids, bases, salts, and Ph are important
for life.
 When blood pH falls below 7.35, acidosis
occurs.
 When blood pH increases about 7.45,
alkalosis occurs.
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Buffers

Substances that attempt to maintain pH
range or H+ ion concentration, in the
presence of added acids or bases.
Buffer Systems

Bicarbonate buffer system (works to regulate pH in both
intracellular and extracellular fluids).

Phosphate buffer system (works to regulate the pH of
intracellular fluid and fluid in kidney tubules).

Protein buffer system (works to regulate pH inside cells,
especially red blood cells).
Substance Movement
Substances must be able to both enter
and leave cells.
 The ability of a membrane to permit
substances to pass through it is called
permeability.
 Substances move by passive or active
transport.
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Types of Passive Transport

Diffusion.

Osmosis.
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Filtration.
Diffusion

The tendency of molecules to move from
a region of higher molecular concentration
to a region of lower molecular
concentration until an equilibrium is
reached.
Osmosis

The diffusion of water through a semipermeable membrane from a region of
higher water concentration to a region of
lower water concentration.
Filtration
Fluids and the substances dissolved in
them are forced through cell membranes
by hydrostatic pressure.
 Hydrostatic pressure is the pressure that
the fluid exerts against the membrane.

Active Transport
Accomplished by means of carrier
molecules, which can latch onto specific
molecules and transport them in or out of
the cell.
 Examples of important ions transported b
this process are calcium, sodium,
potassium, and magnesium.

Fluid & Electrolyte Balance
Human life is suspended in a saline
solution having a salt concentration of
0.9%.
 For life to continue and cells to properly
function, body fluids must remain fairly
constant with regard to amount of water
and specific electrolytes of which they are
composed.
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Body Fluids

Intracellular fluid (All of the water and
ions inside the cells).

Extracellular fluid (fluid outside the
cells).
Edema

When the amount of interstitial fluid (fluid
in tissue spaces around each cell)
returned to the circulatory system lessens
and the fluid accumulates in the tissue
spaces, the tissues become swollen. This
condition is called edema.
Dehydration

When more water is lost from the body
than is replaced.

Caused by water deprivation, excessive
urine production, profuse sweating,
diarrhea, and extended periods of
vomiting.
Sources of Fluid Loss
Skin (loss of 300 to 400ml. per day by
diffusion and perspiration).
 Lungs (300 to 400ml. per day with
expired air, saturated with water vapor).
 Gastrointestinal Tract (200ml. per day in
feces).
 Kidneys (1,200 to 1,500ml. per day).
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Disturbances in Electrolyte
Balance
Around these primary areas:
Sodium.
 Potassium.
 Calcium.
 Magnesium.
 Phosphate.
 Chloride.
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Sodium
Hyponatremia (subnormal serum sodium
value).
 Hypernatremia (above normal serum
sodium value).
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Potassium
Hypokalemia (subnormal serum
potassium value).
 Hyperkalemia (above normal serum
potassium value).
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Calcium
Hypocalcemia (subnormal serum calcium
value).
 Hypercalcemia (above normal serum
calcium value).
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Magnesium
Hypomagnesemia (subnormal serum
magnesium value).
 Hypermagnesemia (above normal serum
magnesium value).
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Phosphate
Hypophosphatemia (subnormal serum
phosphate value).
 Hyperphosphatemia (above normal
serum phosphate value).
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Chloride
Hypochloremia (subnormal serum
chloride value).
 Hyperchloremia (above normal serum
chloride value).
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Acid-Base Balance
The body has three main control systems
that regulate acid-base balance to counter
acidosis or alkalosis:
 Buffer
systems.
 Respiratory Regulation of Acid-Base
Balance.
 Renal Control of Hydrogen Ion
Concentration.
Diagnostic and Laboratory Data

The biochemical indicators of acid-base
balance are assessed by measuring the
arterial blood gases (ABGs).
Acid-Base Imbalances
Respiratory Acidosis
Excess H2CO3
Caused by
hypoventilation
Respiratory Alkalosis
Deficit H2CO3
Caused by
hyperventilation
Metabolic Acidosis
Deficit HCO3
Most common in cases
of kidney disease and
diabetes
Metabolic Alkalosis
Excess HCO3
Can be caused by
diarrhea and steroid or
diuretic therapy.
Assessment and Fluid Balance
Health History.
 Diagnostic and Laboratory Data.
 Physical Examination
 Daily Weight, Vital Signs, Intake and
Output, Thirst, Skin, Buccal (Oral)
Cavity, Eyes, Jugular and Hand Veins,
Neuromuscular System.
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Diagnostic and Laboratory Data
Hemoglobin and Hematocrit Indices.
 Urine pH.
 Serum Albumin.
 Osmolality (a measurement of the total
concentration of dissolved particles per
kilogram of water).
 Serum Osmolality.
 Urine Osmolality.
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Fluid Balance & Nursing Diagnosis
Diagnoses relevant to fluid imbalances may
include:
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Fluid volume excess.
Fluid volume deficit.
Fluid volume deficit, risk
for.
Gas exchange, impaired.
Cardiac output,
decreased.
Knowledge deficit.
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Breathing pattern,
ineffective.
Anxiety.
Thought processes,
altered.
Injury, risk for.
Oral mucous membrane,
altered.
Fluid Balance & Implementation
Common interventions include:
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Monitoring daily weight.
Measuring vital signs.
Measuring intake and output.
Providing oral hygiene.
Initiating oral fluid therapy.
Maintaining tube feeding.
Monitoring intravenous therapy.
IV Therapy

Intravenous therapy is the administration
of fluids, electrolytes, nutrients, or
medications by the venous route.
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Clients receiving IV therapy require
constant monitoring for complications.