Comparative study of pre-loading and co-loading with crystalloids on the incidence of hypotension after spinal anaesthesia in cesarean delivery

Hypotension after spinal anaesthesia is a complication that occurs in general population and in patients undergoing cesarean section .this hypotension is mainly due to sympathetic blockade which causes peripheral vasodilation and venous pooling. The risk of hypotension increases in pregnant women undergoing cesarean section that requires block levels as high as 4th thoracic segment dermatome. In addition, the risk of hypotension is also increased due to anatomic and physiological changes in pregnant women with aortocaval compression. Hypotension can cause adverse effects on both mother and foetus. Several techniques and methodologies have been adopted for the prevention of this neuraxial hypotension with varying degree of success. The administration of intravenous fluids to optimize the blood volume during sympathectomy has been the most popular and widely used as the first line of therapy. The intravenous fluids can be used both before and during the administration of spinal anaesthesia, the techniques appropriately named as pre-loading and co-loading respectively.