Prophylactic Perioperative Infusion of Ephedrine Versus Noradrenaline in Patients Undergoing Cesarean Delivery Under Spinal Anesthesia

Neuraxial anesthesia for cesarean delivery (CD) has significantly reduced maternal mortality by avoiding Manipulation of the airway, the mother being awake, and promoting early bonding of mother and child, adequate Postoperative analgesia, and quicker maternal recovery. Systemic vascular resistance decreases as a result of a reduction in sympathetic tone of the arterial circulation, leading to peripheral arterial vasodilation, the extent of which depends on the number of spinal segments involved. Other theories are proposed to explain hypotension during spinal anesthesia, among them: 1)direct depressive circulatory effect of local anesthetics, 2) relative adrenal insufficiency, 3) skeletal muscle paralysis, 4) ascending medullary vasomotor block, and 5) concurrent mechanical respiratory insufficiency. Loss of sympathetic input to the heart, leaving vagal parasympathetic innervations unopposed, and a decrease in cardiac preload are the main reasons for bradycardia during spinal anesthesia.