الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 125 |  |  |
| | | from | 125 | | |
Abstract
Summary
Intrathecal b
lock is widely used as a safe anesthetic technique for
both elective and emergency operations. Shivering is known to be a frequent
complication, reported in
40 to 70
%
of patients undergoing surgery under
regional anesthesia.
Processing of thermoregulatory information occurs in three phases:
afferent thermal sensing, central regulation, and efferent responses
which
include: voluntary behavior changes
,
vaso
constriction of arteriovenous
shunts, shivering and non shivering
-
producing thermogenesis as a response
to cold and precapillary vasodilatation and sweating as a response to heat.
Central thermoregulatory control is slightly impaired by neuraxial
anesthe
sia
.
Post
-
anesthetic shivering is spontaneous,
involuntary, rhythmics
,
oscillating, tremor
-
like muscle hyperactivity
.
Shivering is very unpleasant
,
physiologically streesful for
the patient undergoing surgery
,
and some
patients find the accompanying cold
sensation to be worse than surgical
pain
.
Although the precise origin of postoperative shivering remains
uncertain, a number of hypotheses have been advanced.
Shivering
-
like tremor is common during neuraxial anesthesia and has
at least four potential etio
logies: (1) normal thermoregulatory shivering in
response to core hypothermia, (2) normal shivering in normothermic or even
hyperthermic patients who are developing a fever, (3) direct stimulation of
cold receptors in the neuraxis by injected local anesthe
tic, and (4)
nonthermoregulatory muscular activity that resembles thermoregulatory
shivering.
The cause of this muscular activity remains unknown, but it is
associated with pain and may thus result from activation of the sympathetic
nervous system.
Shiver
ing intra/post operative may be also due to decreased
sympathetic tone and systemic release of pyrogens.
Postanesthesia shivering can cause a series of potential complications
with varying seriousness in patients undergoing surgery. Shivering typically
inc
reases the basal metabolic rate to a value 2 to 5 times greater than the
normal rate. Shivering is associated with inc
reased
consumption of oxygen,
and production of carbon dioxide. It is als
o associated with
hemodynamic
changes in
vital signs, including
increase
in heart rate, blood pressure,
respiratory rate, and intracranial pressure. In addition, shivering may retard
the cooling process as heat is transferred from the core to the peripher
y.
By
increasing the work of muscles, shivering can increase a pa
tient’s
postoperative pain by stressing and stretching the mus
cles near incisions.
Not only
shivering
is
uncomfortable for patients, but it is also associated
with certain adve
rse effects, including increase
in a patient’s: circulating
catecholamines, lac
tic acid levels. It also interferes with hemodynamic
monitoring intraoperatively
.
There are various methods available to control shivering during
anesthesia, which include non
-
pharmacological methods and
pharmacological methods using drugs which have anti
shivering properties
.
A number of physical methods have b
een used to alleviate shivering
which include:
Forced
-
air patient warming systems,
increasing the ambient
temperature of the operative room, preventing convective heat loss by
insulation with surgic
al drapes, space blankets, warm cotton blankets,
ensuring warm skin disinfectant is used prior to draping, and the use of
warm intravenous fluids and w
arm local an
esthetics for neuroaxial blockade
.
Non
-
pharmacological methods using equipments to maintain
normothermia
are effective but may be expensive and are not practical in all the settings
.
Several pharmacological options can be used for preventing or
treating postoperative shivering .
These pharmacological options include
opioids (pethidine, nalbuphine
, or tramadol), ketanserin, propofol,
granisetron, doxapram, physostigmine, clonidine, and nefopam, but debate
on an ‘ideal anti
-
shivering drug’ continues
.
Meperidine (pethidine)
,
i
s the most widely studied d
rug in the
treatment of post an
esthesia shiverin
g. 25mg of pethidine has been found to
be an effective antishivering agent when administered intravenously.
Tramadol, a synthetic opioid
.
Tramadol acts as a weak agonist at all
types of opioid receptor, with some selectivity for the μ receptor.
It has
gain
ed a reputation in many clinical trials for the control of shivering
.
N
albuphine is an agonist
-
antagonist opioid . Nalbuphine acts as an
antagonist at the μ
-
receptor and as an agonist at the κ
-
receptor.
While the
mechanism of action for nalbuphine is still
up for debate, studies have found
that
this drug
is effective in
the treatment of PAS(post anesthesia
shivering).
Intravenous midazolam is indicated for procedural sedation, for
preoperative sedation
. In our study we added midazolam as an adjuvant to
bo
th tramadol and nalbuphine to control post spinal anesthesia shivering.
In this study we
evaluate the efficacy, potency and side effects of
tramadol plus midazolam as compared to nalbuphine plus midazolam in
control of shivering after spinal
anesthesia
in two groups
of patients.
As regarding the demographic data(age, sex, weight, height) there was
no
statistically
significant difference between
the
two groups also duration
of surgery, motor and sensory block
levels
were not statistically different
betwee
n the two groups.
In the present study,
we found that tramadol
plus
midazolam
and
nalbuphine
plus
midazolm had the same effect in the treatment of post spinal
anesthesia shivering.
In our study the number of patients who developed any
side effect from th
e two drugs in both g
roups was only one patient
in
tramadol group who had hypotension
.
In conclusion both
tramadol plus midazolam and nalbuphine plus
midazolm had the same effect in the treatment of post spinal anesthesia
shivering
, with no statistica
lly significant difference between them.
We recommend further studies with a large number of patients, and
with measurement of core temperature using the same drugs or other drugs
to detect their effect in the treatment of post spinal anesthesia shiverin
g.