CATHARTHIS
C
catharthis
A word
that means
purification
or
cleansing. The term “ catharsis” is used
in medicine to refer to the process of
cleaning out the bowels. In addition,
the term was used by Sigmund Freud
in
psychoanalytic theory
to describe the
expression of previously repressed feel-
ings and memories. Freud believed that
the revival of “forgotten” memories
and the expression of the emotions
associated with them could bring relief
from anxiety, tension, and a variety of
other psychological symptoms.
cathartic
A term that means “having the power
to purify or cleanse” . A cathartic drug
stimulates movement
of the
bowels
(see
laxative drugs
) .
catheter
A flexible tube that is inserted into the
body to drain or introduce fluids or to
carry out other functions. Catheters are
commonly used to drain urine from
the bladder (see
catheterization, urinary
) .
Other procedures using catheters may
be performed in order to investigate
the condition of the heart (see
cathet-
erization, cardiac
) ,
to widen obstructed
blood vessels, or to control bleeding.
(See also
balloon catheter
. )
catheterization, cardiac
A diagnostic procedure in w hich a fine,
sterile
catheter
(flexible tube) is intro-
duced into the heart through a vein or
artery
in
the
arm
or
leg.
Cardiac
catheterization is used to diagnose and
assess the extent of congenital heart
disease
(see
heart disease, congenital
)
and
coronary artery disease,
and to diag-
nose and treat some disorders of the
heart valves (see
valvuloplasty
) .
During the procedure, the pressure
w ithin the chambers of the heart may
be measured, samples of blood and
tissue
may
be
taken
for
laboratory
analysis, or a radiopaque dye (a sub-
stance that is opaque to X-rays) may be
injected into the arteries in order for
the cavities of the heart to be visible on
an X-ray (see
angiography
) .
The procedure causes little discom-
fort
and
is
performed
under
local
anaesthesia
(see
anaesthesia, local
) .
A
small incision is made in an artery or
vein near the skin surface, and the
catheter is introduced into the vessel.
The tube is passed along the blood ves-
sels and into the heart.
catheterization, urinary
The insertion of a sterile
catheter
(a
flexible tube) into the
bladder
in order
to drain urine from the body
WHY IT IS DONE
U rinary catheterization is carried out
when a person is unable to empty the
bladder normally or is incontinent (see
incontinence, urinary
). The procedure is
also performed during certain opera-
tions in w hich a full bladder might
block the surgeon’s view of surround-
ing organs; in bladder function tests
such as
cystometry
and
cystourethrogra-
phy
;
and to monitor urine production
in critically ill patients.
HOW IT IS DONE
There are two principal techniques:
urethral catheterization
(described in
the illustrated box below), and supra-
pubic catheterization.
Suprapubic catheterization is used if
it is not possible to pass a catheter up
the urethra (for example, if the urethra
is abnormally narrow). This form of
catheterization involves the insertion of
a catheter
into
the bladder
directly
through the abdominal wall, and this is
carried out under local anaesthesia (see
anaesthesia, local).
cation
An
ion
of positive charge. An example
of a cation is the sodium ion in saline
solution. (See also
electrolyte.)
cation exchange resin
A type of drug used to remove excess
potassium
that has accumulated in the
body because of
renal failure.
CAT scanning
An abbreviation for computerized axial
tomographic scanning, w hich is com-
monly known as
CT scanning.
cat-scratch fever
An uncommon disease that develops in
people
(mostly
children)
who
have
suffered a scratch or bite from a cat.
The fever is due to infection with a
bacterium called B
artoneeea henseeae.
URETHRAL CATHETERIZATION OF THE BLADDER
A urinary catheter is usually passed
into the bladder through the urethra.
First, the doctor or nurse cleans the
opening of the urethra with antiseptic
solution to avoid introducing infection
into the urinary tract. He or she then
applies a local anaesthetic gel to the
urethra. The procedure usually takes
about 10 minutes.
Self-retaining catheter
If the catheter is to remain in the bladder,
a self-retaining type is used. This catheter has
a balloon at its tip that can be inflated and filled
with sterile water.
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