Uterotonics and tocolytics for anesthesiologists

Obstetric anesthesiologists are supposed to understand the uterotonics and tocolytics used in the perinatal period to provide a better clinical practice. This review describes current consensus of uterotonics and tocolytics used in the perinatal period that an obstetric anesthesiologist should know.

Rational use of uterotonics for cesarean section has been well studied in the past decades. Oxytocin remained as a first line uterotonics for cesarean section. For continuous infusion, it is reported that ED90 is higher for laboring parturients than for nonlaboring parturients (6.2 vs. 44.2 IU/h) implying that protocol for oxytocin infusion should be different between laboring patients with prior exposure to oxytocin and nonlaboring patients. For bolus administration, 'rule of three' has been proposed and its efficacy has been reported. When oxytocin fails to achieve sufficient uterine contraction, second-line agents must be administered, and it has been reported that methylergonovine is a superior second-line uterotonic to carboprost. On the other hand, the role of tocolytic agents in obstetric anesthesia has not been well studied.

Anesthesiologists involved in obstetric anesthesia should be able to determine the appropriate uterotonic for cesarean section and know the indication of tocolytics in perinatal period.