الفهرس 
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Abstract
SUMMARY
ypotension following spinal anaesthesia is mainly occurs
due to sympathetic blockade leading to peripheral
vasodilatation and venous pooling of blood. As a result, there is
decreased venous return and cardiac output leading to
hypotension (Williamson et al., 2009).
The spectrum of morbidity associated with hypotension
may include but is not limited to a higher incidence of nausea,
vomiting, dizziness, aspiration, syncope and cardiac
arrhythmias (Ngan Kee et al., 2005).
One of the most commonly used methods to reduce
spinal anaesthesia induced hypotension is administration of
fluids before implementation of spinal anaesthesia, a technique
named ‘pre-loading’ first described by Wollman and Marx.
This preloading with intravenous fluids offset the vasodilating
effects of sympathetectomy caused by spinal anaesthesia
thereby maintaining the venous return and thus the DROP in
blood pressure is prevented (Wollman and Marx, 1968).
Crystalloids have shorter half-life in the intravascular
compartment and generally exit the intravascular space within 1
hour so that their ability to expand the intravascular volume is
limited due to shorter duration of action. Pre-loading with
crystalloids has been found to be less effective due to the
shorter half-life as they are less successful in maintaining the
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Summary
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intravascular volume during the dynamic establishment of
spinal anaesthesia effect and the resulting vasodilatation
(Bajwa et al., 2013).
Colloids, on the other hand, have a longer half-life in the
intravascular compartment and are able to maintain the increase
in intravascular volume for longer durations (Tamilselvan et
al., 2009