European Journal of Molecular & Clinical Medicine

Abstract

Spinal anesthesia (SA) is considered a safe procedure, but it may have some side
effects including hypotension and bradycardia. Sympathetic fiber blockade and
vasodilation are the main causes of hypotension. SA is performed more frequent in
elderly patients despite the higher risk of hypotension and its consequences. The
percentage of hypotension in elderly patients is estimated to be over 70%[1].
For prevention of hypotensive side effect may have risk of hypervolemia or
myocardial ischemia in elderly population. Hypotension and bradycardia both may
arise from Bezold-Jarish reflex (BJR), spinal anesthesia causes decrease in preload
that stimulates BJR which may be mediated by peripheral serotonin receptors
(5HT-3)[2]. These receptors are located peripherally as cardiac chemoreceptors on
the cardiac vagal afferent and centrally as chemoreceptor trigger zone[3].
Shivering is a common association with spinal anesthesia during intra and
postoperative periods. The causes of shivering are not clearly understood it may be
due to union of some mechanisms including modulation of thermoregulatory
thresholds, decreasing body core temperature, body heat distribution changes and
the cooling effect of the injected fluids into neuraxis[4].
While patients feel very uncomfortable due to shivering, it causes monitors artifacts
and increases the postoperative pain, heart rate,oxygen consumption and metabolic
rate.These effects may lead to myocardial ischemia, hypoxemia, hypercarbia and
lactic acidosis [5].