thus verifying that the needle is really in a vein;
INTRAVENOUS THERAPY then the tourniquet is removed before injecting.
http://www.answers.com/topic/intravenous-
This is the most common method of intravenous
therapy?cat=health
drug use for euphoriants such as heroin, or in
any case where a person must self-administer
Intravenous therapy or IV therapy is the
intravenous medication at home. It is also a
administration of liquid substances directly into a
convenient way to deliver life-saving medications
vein. It can be intermittent or continuous;
in an emergency. However, in a controlled
continuous administration is called an
health-care setting, direct injection is rarely used
intravenous drip. The word intravenous
since it only allows delivery of a single dose of
simply means \"within a vein\", but is most
medication.
commonly used to refer to IV therapy. Therapies
administered intravenously are often called
Peripheral IV lines
specialty pharmaceuticals.
This is the most common intravenous access
method in both hospitals and paramedic services.
Compared with other routes of administration,
A peripheral IV line consists of a short catheter
the intravenous route is the fastest way to deliver
(a few centimeters long) inserted through the
fluids and medications throughout the body.
skin into a peripheral vein. A peripheral vein is
Some medications, as well as blood transfusions
any vein that is not in the chest or abdomen.
and lethal injections, can only be given
Arm and hand veins are typically used although
intravenously.
leg and foot veins are occasionally used. On
infants the scalp veins are sometimes used. Part
of the catheter remains outside the skin, with a
hub that can be connected to a syringe or an
An intravenous infusion line, or capped with a bung
intravenous between treatments. The caliber of cannulae is
drip in a commonly indicated in gauge, with 14 being a
hospital very large cannula (used in resuscitation
settings) and 24-26 the smallest. The most
common sizes are 16-gauge (midsize line used
for blood donation and transfusion), 18- and 20-
gauge (all-purpose line for infusions and blood
draws), and 22-gauge (all-purpose pediatric
line). 12 and 14-gauge peripheral lines actually
deliver equivalent volumes of fluid faster than
central lines, accounting for their popularity in
emergency medicine; these lines are frequently
called \"widebores\" or \"trauma lines.\"
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Blood can be drawn from a peripheral IV if
necessary, but only if it is in a relatively large
vein and only if the IV is newly inserted. Blood
Intravenous access devices draws are typically taken with specialized IV
access sets known as phlebotomy kits, and once
Needle and syringe the draw is complete, the needle is removed and
the site is not used again. If a patient needs
The simplest form of intravenous access is a frequent venous access, the veins may scar and
syringe with an attached hollow needle. The narrow, making any future access extremely
needle is inserted through the skin into a vein, difficult or impossible; this situation is known as
and the contents of the syringe are injected a \"blown vein,\" and the person attempting to
through the needle into the bloodstream. This is obtain the access must find a new access site
most easily done with an arm vein, especially one proximal to the \"blown\" area.
of the metacarpal veins. Usually it is necessary to
use a tourniquet first to make the vein bulge; Originally, a peripheral IV was simply a needle
once the needle is in place, it is common to draw that was taped in place and connected to tubing
back slightly on the syringe to aspirate blood, rather than to a syringe; this system is still used
for blood donation sets, as the IV access will only

be needed for a few minutes and the donor may Central IV lines – Hickman Line
not move while the needle is in place. Today,
hospitals use a safer system in which the
catheter is a flexible plastic tube that originally
contains a needle to allow it to pierce the skin;
the needle is then removed and discarded, while
the soft catheter stays in the vein. The external
portion of the catheter, which is usually taped in
place or secured with a self-adhesive dressing,
consists of an inch or so of flexible tubing and a
locking hub. Many sets contain a small amount of
the anticoagulant heparin to keep the line from
clotting off, and frequently are called \"heparin
locks\" or \"hep-locks.\"
Photo courtesy of:
A peripheral IV cannot be left in the vein http://www.cancerhelp.org.uk/help/default.asp?page=3056
indefinitely, because of the risk of insertion-site
infection leading to phlebitis, cellulitis and
bacteremia. Hospital policies usually dictate that Peripherally inserted central catheter
every peripheral IV be replaced (at a different (PICC)
location) every three to four days to avoid this PICC lines are used when intravenous access is
complication. required over a prolonged period of time, as in
the case of long chemotherapy regimens,
Central IV lines extended antibiotic therapy, or total parenteral
Central IV lines flow through a catheter with its nutrition.
tip within a large vein, usually the superior vena
cava or inferior vena cava, or within the right The PICC line is inserted into a peripheral vein,
atrium of the heart. This has several advantages usually in the arm, and then carefully advanced
over a peripheral IV: upward until the catheter is in the superior vena
cava or the right atrium. This is usually done by
It can deliver fluids and medications that feel and estimation; an X-ray then verifies that
•
would be overly irritating to peripheral the tip is in the right place.
veins because of their concentration or
chemical composition. These include some A PICC may have two parallel compartments,
chemotherapy drugs and total parenteral each with its own external connector (double-
nutrition. lumen), or a single tube and connector (single-
Medications reach the heart immediately,
• lumen). From the outside, a single-lumen PICC
and are quickly distributed to the rest of resembles a peripheral IV, except that the tubing
the body. is slightly wider.
There is room for multiple parallel
•
compartments (lumens) within the The insertion site must be covered by a larger
catheter, so that multiple medications can sterile dressing than would be required for a
be delivered at once even if they would peripheral IV, due to the higher risk of infection if
not be chemically compatible within a bacteria travel up the catheter. However, a PICC
single tube. poses less of a systemic infection risk than other
Caregivers can measure central venous
• central IVs, because bacteria would have to
pressure and other physiological variables travel up the entire length of the narrow catheter
through the line. before spreading through the bloodstream.
Central IV lines carry higher risks of bleeding, The chief advantage of a PICC over other types of
bacteremia, and gas embolism (see Risks below). central lines is that it is easy to insert, poses a
relatively low risk of bleeding, is externally
There are several types of central IVs, depending unobtrusive, and can be left in place for months
on the route that the catheter takes from the to years for patients who require extended
outside of the body to the vein. treatment. The chief disadvantage is that it must
travel through a relatively small peripheral vein
and is therefore limited in diameter, and also

somewhat vulnerable to occlusion or damage
from movement or squeezing of the arm.
Peripherally inserted central catheters
Courtesy of :
Port-a-cath
http://www.zefon.com/medical/griplok.htm
http://faculty.mercer.edu/summervill_j/jeanchiang/Mvc-
083s.jpg
Central venous lines
Forms of intravenous therapy
There are several types of catheters that take a
more direct route into central veins. These are
Intravenous drip
collectively called central venous lines.
An intravenous drip is the continuous infusion
of fluids, with or without medications, through an
In the simplest type of central venous access, a
IV access device. This may be to correct
catheter is inserted into a subclavian, internal
dehydration or an electrolyte imbalance, to
jugular, or (less commonly) a femoral vein and
deliver medications, or for blood transfusion.
advanced toward the heart until it reaches the
superior vena cava or right atrium. Because all of
IV fluids
these veins are larger than peripheral veins,
There are two types of fluids that are used for
central lines can deliver a higher volume of fluid
intravenous drips; crystalloids and colloids.
and can have multiple lumens.
Crystalloids are aqueous solutions of mineral
salts or other water-soluble molecules. Colloids
Another type of central line, called a Hickman line contain larger insoluble molecules, such as
or Broviac catheter, is inserted into the target gelatin; blood itself is a colloid.
vein and then \"tunneled\" under the skin to
emerge a short distance away. This reduces the
The most commonly used crystalloid fluid is
risk of infection, since bacteria from the skin
normal saline, a solution of sodium chloride at
surface are not able to travel directly into the
0.9% concentration, which is close to the
vein; these catheters are also made of materials
concentration in the blood (isotonic). Ringer's
that resist infection and clotting.
lactate or Ringer's acetate (ASERING, patented
brandname of Otsuka Indonesia) is another
Implantable ports isotonic solution often used for large-volume fluid
A port (often referred to by brand names such as replacement. A solution of 5% dextrose in water,
Port-a-Cath or MediPort) is a central venous line sometimes called D5W, is often used instead if
that does not have an external connector; the patient is at risk for having low blood sugar
instead, it has a small reservoir implanted under or high sodium. The choice of fluids may also
the skin. Medication is administered depend on the chemical properties of the
intermittently by placing a small needle through medications being given.
the skin into the reservoir. Ports cause less
inconvenience and have a lower risk of infection
Intravenous fluids must always be sterile.
than PICCs, and are therefore commonly used for
patients on long-term intermittent treatment.
Effect of Adding One Litre
Change in Change in
Solution
ECF ICF
D5W 333 mL 667 mL
2/3D & 1/3S 556 mL 444 mL
Half-normal 667 mL 333 mL

the injection to push the medicine into the
saline
bloodstream more quickly.
Normal saline 1000 mL 0 mL
Risks of intravenous therapy
Ringer's lactate 900 mL 100 mL
Intravenous therapy has many risks and should
therefore only be performed by trained personnel
Infusion equipment
under medical supervision, using proper
A standard IV infusion set consists of a pre-filled,
equipment.
sterile container (glass bottle, plastic bottle or
plastic bag) of fluids with an attached drip
Infection
chamber which allows the fluid to flow one drop
Any break in the skin carries a risk of infection.
at a time, making it easy to see the flow rate
Although IV insertion is a sterile procedure, skin-
(and also reducing air bubbles); a long sterile
dwelling organisms such as Coagulase-negative
tube with a clamp to regulate or stop the flow; a
Staphylococcus or Candida albicans may enter
connector to attach to the access device; and
through the insertion site around the catheter, or
connectors to allow \"piggybacking\" of another
bacteria may be accidentally introduced inside
infusion set onto the same line, e.g., adding a
the catheter from contaminated equipment.
dose of antibiotics to a continuous fluid drip.
Infection of IV sites is usually local, causing
An infusion pump allows precise control over the
easily visible swelling, redness, and fever. If
flow rate and total amount delivered, but in cases
bacteria do not remain in one area but spread
where a change in the flow rate would not have
through the bloodstream, the infection is called
serious consequences, or if pumps are not
septicemia and can be rapid and life-threatening.
available, the drip is often left to flow simply by
An infected central IV poses a higher risk of
placing the bag above the level of the patient and
septicemia, as it can deliver bacteria directly into
using the clamp to regulate the rate; this is a
the central circulation.
gravity drip.
Phlebitis
A rapid infuser can be used if the patient requires
Phlebitis is irritation of a vein that is not caused
a high flow rate and the IV access device is of a
by infection, but from the mere presence of a
large enough diameter to accommodate it. This is
foreign body (the IV catheter) or the fluids or
either an inflatable cuff placed around the fluid
medication being given. Symptoms are swelling,
bag to force the fluid into the patient or a similar
pain, and redness around the vein. It does not
electrical device that may also heat the fluid
necessarily mean the IV device must be
being infused.
removed; warmth, elevation of the affected limb,
or a change in the rate of flow may resolve the
Intermittent infusion symptoms.
Intermittent infusion is used when a patient Due to frequent injections and recurring phlebitis,
requires medications only at certain times, and the peripheral veins of intravenous drug addicts,
does not require additional fluid. It can use the and of cancer patients undergoing chemotherapy,
same techniques as an intravenous drip (pump or become hardened and difficult to access over
gravity drip), but after the complete dose of time.
medication has been given, the tubing is
disconnected from the IV access device. Some
Infiltration
medications are also given by IV push, meaning
This occurs when the tip of the IV catheter
that a syringe is connected to the IV access
withdraws from the vein or pokes through the
device and the medication is injected directly
vein into surrounding tissue, or when the vein's
(slowly, if it might irritate the vein or cause a
wall becomes permeable and leaks fluid (in this
too-rapid effect). Once a medicine has been
instance it is said that the cannula has 'tissued').
injected into the fluid stream of the IV tubing
It occurs frequently with peripheral IVs, and
there must be some means of ensuring that it
requires replacement of the IV at a different
gets from the tubing to the patient. Usually this
location. The symptoms of pain and swelling are
is accomplished by allowing the fluid stream to
temporary and not dangerous, unless giving a
flow normally and therby carry the medicine into
highly irritating medication, such intravenous
the bloodstream; however, a second fluid
contrast or amiodarone. Additionally it can
injection is sometimes used, a \"flush\", following
become dangerous if the person monitoring the
IV site fails to recognize that an infiltration has

occurred and fluid continues to drip in the tissue
under the skin. It can cause a compression
injury. This known as an infiltration injury.
Fluid overload
This occurs when fluids are given at a higher rate
or in a larger volume than the system can absorb
or excrete. Possible consequences include
hypertension, heart failure, and pulmonary
edema.
Electrolyte imbalance
Administering a too-dilute or too-concentrated
solution can disrupt the patient's balance of
sodium, potassium, magnesium, and other
electrolytes. Hospital patients usually receive
blood tests to monitor these levels.
Embolism
A blood clot or other solid mass, or an air bubble,
can be delivered into the circulation through an
IV and end up blocking a vessel; this is called
embolism. Peripheral IVs have a low risk of
embolism, since large solid masses cannot travel
through a narrow catheter, and it is nearly
impossible to inject air through a peripheral IV at
a dangerous rate. The risk is greater with a
central IV.
Air bubbles of less than 30 milliliters generally
dissolve into the circulation harmlessly. A larger
amount of air, if delivered all at once, can cause
life-threatening damage to pulmonary circulation,
or, if extremely large (3-8 milliliters per kilogram
of body weight), can stop the heart.
One reason veins are preferred over arteries for
intravascular administration is because the flow
will pass through the lungs before passing
through the body. Air bubbles can leave the
blood through the lungs. A patient with a heart
defect causing a right-to-left shunt is vulnerable
to embolism from smaller amounts of air.
Fatality by air embolism is vanishingly rare, in
part because it is also difficult to diagnose.
Extravasation
Extravasation is the accidental administration of
IV infused medicinal drugs into the surrounding
tissue, either by leakage (e.g. because of brittle
veins in very elderly patients), or directly (e.g.
because the needle has punctured the vein and
the infusion goes directly into the arm tissue).