الفهرس 
1. IntroductionOnly 14 pages are availabe for public view
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Abstract
Optimal perioperative pain control in spine surgeries allows for
faster recovery, short hospital stay, reduced complications and improved
patient satisfaction. Multimodal analgesia is important strategy in
reducing Perioperative pain and decreasing the stress response to surgery.
Spine surgeries are mostly associated with severe bleeding which
has a significant impact on patient morbidity and length of surgery.
Control of blood loss helps to maintain patient’s hemodynamics and also
in creating a blood-free field with a good vision for the surgeon. The
bleeding is particularly sensitive in spine surgeries, because of proximity
to important neural structures which are highly fragile.
Controlled hypotension is a technique wherein the arterial blood
pressure is lowered in a deliberate but controllable manner to minimize
surgical blood loss and enhance the operative field visibility to reduce the
overall duration of surgery and anesthesia. There are several
pharmacological and non-pharmacological techniques of inducing
hypotension, the mechanical ones being tourniquets, table positioning,
and intermittent positive pressure ventilation.
Nitroglycerin can achieve its hypotensive effect by its vasodilatory
effect on arterial and venous bed resulting finally in decreased venous
and right heart filling and so decreased cardiac output. Nitroglycerine
causes either no change or slight tachycardia during continuous infusion
as slight increase in heart rate is reflex phenomenon, baroreceptor
response secondary to hypotension produced.
Intra venous magnesium sulphate may be a good agent for deliberate
hypotension because magnesium intervenes in the activation of
membrane Ca ATPase and Na–K ATPase involved in transmembrane ion
Summary
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exchanges during depolarization and repolarization phases, and thus act
as a stabilizer of cell membrane and intracytoplasmic organelles. The
antagonist effect of magnesium at N-methyl-D-aspartate (NMDA)
receptors has led to studies of its adjuvant effect in perioperative
analgesia.
Dexmedetomidine (DEX) is a potent highly selective α2 adrenergic
agonist, possessing a differential specificity for the α2: α1 receptors. DEX
has sedative, analgesic, anesthetic sparing effect, and sympatholytic
properties. The central and peripheral sympatholytic action of DEX is
mediated by α2 adrenergic receptors and is manifested by dose-dependent
decrease in arterial blood pressure, heart rate, cardiac output and
norepinephrine release.
Our study demonstrates that using dexmedetomidine as a
hypotensive agent shows decrease the number of patients who need an
intraoperative analgesic requirements at different periods of follow up,
there was a highly significant increase in group nitroglycerine for need
for intraoperative analgesic followed by group magnesium sulphate and
group dexmedetomidine showed the lowest need for intraoperative
analgesic.
The hemodynamics data showed a significant increase in mean
arterial blood pressure and heart rate in group nitroglycerine, followed by
group magnesium sulphate and the lowest group was dexmedetomidine.
Also, the sedation score was significantly higher in group
dexmedetomidine more than group nitroglycerine and magnesium
sulphate. The speed of recovery was significantly higher in group
dexmedetomidine more than group nitroglycerine and magnesium
sulphate. The first call for analgesic was significantly higher in group