Spinal Anesthesia for Cesarean Section

This study will examine whether addition of dexmedetomidine or clonidine (two alpha-2 adrenergic agonists) will improve the comfort of patients during spinal anesthesia for cesarean delivery. When added to standard spinal anesthesia consisting of bupivacaine (a local anesthetic) and fentanyl and morphine (two opioids), these medications may decrease some of the pulling/tugging/pressure sensations that patients sometimes feel during cesarean delivery, may prolong the anesthetic time, and may decrease postoperative pain.

Echocardiography will be used to measure cardiac output and calculate other important hemodynamic variables in healthy patients with full-term singleton pregnancy during cesarean delivery under conventional spinal anesthesia using 2 different vasopressor drugs: norepinephrine in 1 group versus ephedrine in another group.