Intravenous (IV) therapy involves infusing liquid substances directly into the vein. It is used to replace fluids and electrolytes, maintain fluid balance, administer medications and blood products, provide nutrition, and monitor cardiac function. There are several types of IV fluids including isotonic, hypotonic, and hypertonic solutions which move fluid in and out of cells differently based on their concentrations. Isotonic solutions like 0.9% saline maintain fluid balance, while hypotonic solutions hydrate cells and hypertonic solutions draw fluid out of cells. Nurses must carefully monitor patients for complications like fluid overload when administering IV fluids and therapies.

1. Intravenous therapy or IV therapy
Definition
Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein
Or
Intravenous therapy, also referred to as ‘IV therapy’, constitutes the administration of
liquid substances directly into a vein and the general circulation through venepuncture
(Mosby 1998).
Reasons for IV Infusion
According to Brooker (2007) and Martin (2003) intravenous fluid therapy may be used to:
• Replace fluids and replace imbalances.
• Maintain fluid, electrolyte and acid-base balance.
• Administer blood and blood products.
• Administer medication.
• Provide parenteral nutrition.
• Monitor cardiac function.
• Immediate results
• To provide avenue for dialysis/apheresis
• To provide avenue for diagnostic testing
• Predictable therapeutic effects
• There are more than 200 types of commercially prepared IV fluids
PRINCIPLES USED FOR MOVEMENT OF FLUID IN AND OUT OF CELL ARE
(OSMOSIS And DIFFUSION)
 In Osmosis,
• fluid moves passively
from areas with more
fluid to areas with less
fluid
• FLUID MOVES
 In Diffusion,
• solutes(particles) move from
an area of high
concentration to an area of
lesser concentration.
• This process mainly occurs in
gases, liquids and solutions
• PARTICLES MOVE

2. Osmolarity is the measure of solute concentration, defined as the number of osmoles (Osm) of solute
per litre (L) of solution (osmol/L or Osm/L).
The osmolarity of a solution is usually expressed as Osm/L
Osmolarity vs. tonicity
Osmolarity and tonicity are related, but different concepts. Thus, the terms ending in -
osmotic (isosmotic, hyperosmotic, hyposmotic) are not synonymous with the terms ending in -tonic (isotonic,
hypertonic, hypotonic).
The terms are related in that they both compare the solute concentrations of two solutions separated
by a membrane.
The terms are different because osmolarity takes into account the total concentration of penetrating
solutes and non-penetrating solutes, whereas tonicity takes into account the total concentration of only non-
penetrating solutes.
[1]
Penetrating solutes can diffuse through the cell membrane, causing momentary changes in cell
volume as the solutes "pull" water molecules with them. Non-penetrating solutes cannot cross the cell
membrane, and therefore osmosis of water must occur for the solutions to reach equilibrium.
A solution can be both hyperosmotic and isotonic.
[1]
For example, the intracellular fluid and
extracellular can be hyperosmotic, but isotonic – if the total concentration of solutes in one compartment is
different from that of the other, but one of the ions can cross the membrane, drawing water with it and thus
causing no net change in solution volume.
Fluid Compartments
Functionally, total body
water can be divided into two
major compartments:
• Extracellular fluid (ECF)
Approximately 80% of
extracellular fluid is interstitial,
which occupies the
microscopic spaces between
cells. Approximately 20% of
extracellular fluid is plasma,
which is the liquid portion of
blood
• Intracellular fluid (ICF).
This is also known as
cytosol and is the fluid within
cells.
• Within the body it is essential that substances move around.
• Substances will move from areas of ‘high’ concentration to ‘low’ concentration and a
‘concentration gradient’ will exist between the two.
• No energy is required for these physiological movements as they are described as ‘passive’.
• Movement is facilitated through processes of ‘osmosis or diffusion’.

3. Infused Substances
1. Volume expanders
 CRYSTALLOIDS
• Isotonic
• Hypotonic
• Hypertonic
 Crystalloids
Crystalloids Solutions with small molecules that flow easily from the bloodstream into
cells and tissues. A clear aqueous solution of mineral salts and other water–soluble
molecules, for example 5% Dextrose Solution.
Isotonic solutions have a concentration of dissolved particles equal to that of
intracellular fluid.
 Osmotic pressure is the same both inside and outside the cell.
 Cells neither shrink nor swell with fluid movement.
 Same tonicity as plasma
 Isotonic solution containing electrolytes such as NaCl, KCl, CaCl, and sodium lactate
Hypotonic solutions have less particles than does intracellular fluid. Fluid flows into
cells
• Osmotic pressure is greater than that of intracellular fluid. Hypertonic solutions have
a large concentration of solutes (particles).
• Water is drawn from the cells to equalize the concentration, which causes the cells
to shrink.
• Hypotonic solution containing glucose to provide calories for metabolism
• Glucose moves into cells rapidly
 Inappropriate use can cause fluid overload and pulmonary edema
Hypertonic solutions have a greater concentration of dissolved particles than does
intracellular fluid. Fluid is pulled from cells
• Osmotic pressure is less than intracellular fluid
• Water is drawn into the cells from the extracellular fluid causing them to swell
• Inappropriate use can result in increased ICP and cardiovascular collapse from
volume depletion.
• May cause blood cells to burst
• Volume Depletion?
 COLLOIDS
• Always hypertonic

4. Isotonic Solutions (250-375 mOsm/L)
EXAMPLES Action: Indications: Nursing Interventions/Concerns
■5% dextrose in
water
■ 0.9% sodium
chloride
Solution (Normal
Saline)
■ Ringer’s injection
■ Lactated Ringer’s
Solution
Will hydrate the
extracellular
compartment;
replaces fluid
volume without
disrupting the
intracellular and
interstitial volumes
Treatment of
vascular
dehydration;
replaces sodium
and chloride
 5% dextrose in water is isotonic
when infused but becomes
hypotonic when the dextrose has
been metabolized.
 Use cautiously in patients who
are fluid-overloaded or who
would be compromised if
vascular volume would increase,
such as renal and cardiac
patients.
Hypotonic solutions (<250 mOsm/L)
EXAMPLES ACTION : Indications: Nursing
Interventions/Concerns
■2.5% dextrose in
water
■0.25% sodium
chloride solution
■0.33% sodium
chloride solution
■0.45% sodium
chloride Solution
Will hydrate the cells;
pulls fluid from the
vascular space into
the cellular space
Treatment of
hypertonic
dehydration
 These solutions may
further exaggerate
hypotension due to fluid
shifting out of vascular
space.
 Do not administer these
solutions to hypotensive
patients.
Hypertonic Solutions (>375 mOsm/L)
EXAMPLES Action: Indications: Nursing
Interventions/Concerns
■ 5% dextrose in
0.45%
sodium chloride
solution
■ 5% dextrose in 0.9%
sodium chloride
solution
■ 5% dextrose in
lactated Ringer’s
solution
■ 10% dextrose in
water
■ 20% dextrose in
water
■ 50% dextrose in
water
■ 70% dextrose in
water
Will draw fluid out of
intracellular space,
leading to increased
extracellular volume
both in vascular and
interstitial space
Treatment of hypotonic
dehydration; treatment
of circulatory collapse;
increase fluid shift from
interstitial space to
vascular space
 These solutions
can be very
irritating to veins,
so observing the IV
site for
inflammation is
imperative.
 may cause
circulatory
overload, so these
solutions should be
infused slowly to
prevent this in
vulnerable patients.
 May increase
serum glucose in
patients with
glucose
intolerance, which
would make more
frequent glucose
monitoring an
important nursing
intervention

5. Isotonic Fluids
• 0.9% Sodium Chloride ( Normal Saline )
• Lactated Ringers
• Dextrose 5% in Water (D5W)
0.9% Sodium Chloride Normal Saline
Uses Special considerations
• Shock
• Resuscitation
• Fluid challenges
• Blood transfusions
• Metabolic alkalosis
• Hyponatremia
• DKA
• Use with caution in patients with heart failure,
edema, or hypernatremia
• Can lead to overload
Lactated Ringers
Uses Special Considerations
• Dehydration
• Burns
• GI tract fluid loss
• Acute blood loss
• Hypovolemia
• Contains Potassium, can cause hyperkalemia
in renal patients
• Patients with liver disease cannot metabolize
lactate
• Lactate is converted into bicarb by liver
Dextrose 5% in Water (D5W)
Uses Special Considerations
• Fluid loss and dehydration
• Hypernatremia
• Solution becomes Hypotonic when dextrose is
metabolized
• Do not use for resuscitation
• Use cautiously in renal and cardiac patients

6. Hypotonic Solutions
• 0.45% Sodium Chloride (1/2 normal saline)
0.45% Sodium Chloride (1/2 normal saline)
Uses Special Considerations
• Gastric fluid loss
• Cellular dehydration from
excessive diuresis
• Hypertonic dehydration
• Slow rehydration
• Do not give to patients at risk for ICP
• Not for rapid rehydration
• Electrolyte disturbances can occur
Hypertonic Solutions
• 5% Dextrose in 0.9% Sodium Chloride(D5NS)
• 5% Dextrose in Lactated Ringers (D5LR)
• 5% Dextrose in 0.45% Sodium Chloride (D51/2NS)
5% Dextrose in 0.9% Sodium Chloride(D5NS)
Uses Special Considerations
• Heat related disorders
• Fresh water drowning
• Peritonitis
• Should not be given to patients with
impaired cardiac or renal function
• Draw blood before administering to
diabetics
5% Dextrose in Lactated Ringers (D5LR)
Uses Special Considerations
• Hypovolemic Shock
• Hemorrhagic Shock
• Certain cases of acidosis
•
• Do not administer in patients with
cardiac or renal dysfunction
• Monitor for circulatory overload
5% Dextrose in 0.45% Sodium Chloride (D51/2NS)
Uses Special Considerations
• Heat exhaustion
• Diabetic disorders
• TKO solution in patients with
renal or cardiac dysfunction
• Not for rapid fluid replacement

7. COLLIDES
 Colloids - contain large insoluble particles which are referred to as solutes,
such as gelatin. Blood is a colloid
Colloids are made up of much larger solutes than are crystalloids
Used if crystalloids do not improve blood volume
Colloids pull fluid into the bloodstream, remember they are always Hypertonic
Watch for increased BP, Dyspnea, and bounding pulse
For Example:
o Blood, or blood products.
o Albumin
o Plasma Protein fraction
o Dextran
o Hetastarch
Plasma Expanders
EXAMPLES Action: Indications Nursing
Interventions/Concerns
■ Dextran 70
(isotonic)
■ Dextran 40
(isotonic)
■ 10% mannitol
(hypertonic)
■ 20% mannitol
(hypertonic)
■ 5% albumin
■ 25% albumin
■ 6% hetastarch
in 0.9% sodium
chloride
■10% hetastarch
in 0.9% sodium
chloride
 Increases
volume in the
vascular
space.
 Will draw fluid
out of
intracellular
space, leading
to increased
extracellular
volume both
in vascular
and
interstitial
space
 Emergency
treatment of
shock due
to fluid or
blood loss.
 Treatment
of hypotonic
dehydration.
 Treatment
of
circulatory
collapse.
 Increase
fluid shift
from
interstitial
space to
vascular
space
 Monitor patients
carefully for
circulatory overload.
 monitor for
hypersensitivity
reactions.
 medications should
not be given with or
added to these
solutions
 These solutions can
be very irritating to
veins, so observing
the IV site for
inflammation is
imperative.
 May cause circulatory
overload, so these
solutions should be
infused slowly to
prevent this in
vulnerable patients.
 May increase serum
glucose in patients
with glucose
intolerance, which
would make more
frequent glucose
monitoring an
important nursing
intervention.

8. 2. Buffer solutions:
Buffer solutions are used to correct acidosis or alkalosis. Lactated Ringer's
solution also has some buffering effect. A solution more specifically used for buffering
purpose is intravenous sodium bicarbonate.
3. Other medications
Medications may be mixed into the fluids mentioned above. Certain types of
medications can only be given intravenously, such as when there is insufficient uptake
by other routes of administration such as enterally. Examples include intravenous
immunoglobulin and propofol.
4. Other
 Parenteral nutrition is feeding a person intravenously, bypassing the usual
process of eating and digestion. The person receives nutritional formulas
containing salts, glucose, amino acids, lipids and added vitamins.
 Drug injection used for recreational substances usually enters by the intravenous
route.