VENEREAL DISEASES
VENTILATORY FAILURE
VENEPUNCTURE
Tourniquet
Syringe
Skin
Needle
Fatty
tissue
Wall of vein
Muscle
INSIDE THE VEIN
pressure applied to stop any bleeding.
The procedure is not usually painful but
may cause some discomfort,
venereal diseases
See
sexually trans-
mitted infections.
venereology
The
medical
discipline
concerned with the study and treatment
of
sexually transmitted infections.
venesection The process of withdrawing
blood from a
vein
for
blood donation
or
therapeutic bloodletting. Regular blood-
letting is performed in the treatment of
polycythaemia
and
haemochromatosis.
venlafaxine A serotonin and noradren-
aline reuptake inhibitor (SNRI) drug
used in the treatment of
depression.
Venlafaxine combines the effects of
sel-
ective serotonin reuptake inhibitors
and
tricyclic antidepressants
to produce fewer
side effects than other types of anti-
depressant. Side effects may include
nausea, dry mouth, and constipation.
venography A diagnostic procedure that
enables
veins
to be seen on an
X-ray
film after they have been injected with a
substance opaque to X-rays. It is used
to detect abnormalities or diseases of
the veins, such as narrowing or blockage
from
thrombosis.
venomous bites and stings The injec-
tion of venom by certain animals via
their mouthparts (bites) or other inject-
ing apparatus (stings). Venoms are often
carried to discourage predators, and are
sometimes used to kill or immobilize
prey. It is rare for a venomous animal to
attack a person unless it has been pro-
voked or disturbed. Specific
antivenoms
are available to treat many, though not
all, types of animal venom. (See also
insect sting's; jellyfish stings; scorpion
stings; snake bites; spider bites.)
ventilation
The use of a machine called a
ventilator
to take over or assist
breathing.
Arrested or severely impaired breathing
may be due to
head injury
, brain dis-
ease, an overdose of
opioid drugs
, chest
injury, respiratory disease, a nerve or
muscle disorder, or major chest or ab-
dominal surgery. Ventilation may be
needed if a muscle relaxant has been
given during an operation as part of
general
anaesthesia
. Premature babies
with
respiratory distress syndrome
may
also need ventilation for a period until
their lungs develop sufficiently. Positive
pressure ventilation (continuous pump-
ing of air under high pressure) may be
used in the home in the treatment
of
sleep apnoea.
ventilator A device used for the artifi-
cial
ventilation
of a person who is
unable to breathe naturally. A ventilator
is an electrical pump connected to an
air supply that works like bellows. Air is
directed through a tube passed down
the windpipe to inflate the lungs. The air
is then expelled by the natural elasticity
of the lungs and ribcage. A valve on the
ventilator prevents the expelled air from
re-entering the lungs.
ventilatory failure A life-threatening
condition in which the amount of car-
bon dioxide in the blood rises, and the
amount of oxygen falls, due to disrup-
tion of the normal exchange of gases
V
581
previous page 579 BMA Illustrated Medical Dictionary read online next page 581 BMA Illustrated Medical Dictionary read online Home Toggle text on/off