Objectives: Among regional anesthesia techniques, spinal anesthesia is more practical due to ease of technique, more speed, reliable nerve block, using minimum dose of local anesthetics, and the cost-effectiveness. However, this method is also associated with complications, and hypotension induced by sympathetic block is the most common of them. Ondansetron, as a serotonin receptor antagonist can reduce hypotension-induced by spinal anesthesia. Next drug is ketamine which is used for analgesia during labor. Ketamine is a N-methyl-D-aspartate (NMDA) receptor antagonist and a common drug used to induce anesthesia in pregnant women. The aim of this study is to compare prophylactic effect of ondansetron and ketamine on spinal anesthesia induced hypotension in cesarean section.
Design: Block randomization, triple blind, with placebo, trial phase 2, including 93 patients under elective cesarean section.
Setting and conduct: Lidocaine 5%, 75 milligrams, injection into the subdural space to induce spinal anesthesia.
Participants including major eligibility criteria: All women who are supposed to undergo elective cesarean section.
Intervention: Ondansetron, 4 milligrams (2 ml), slow IV injection in 30 seconds.
Ketamine, 25 milligrams (volume 2 ml with distilled water), IV injection.
Normal saline, 2 ml, IV injection in control group.
Main outcome measures: Systolic blood pressure, diastolic blood pressure, arterial O2 saturation, heart rate, Level of consciousness.