Intrathecal atropine to prevent postoperative nausea and vomiting after Cesarean section: a randomized, controlled trial.

Postoperative nausea and vomiting (PONV) is a common adverse effect of intrathecal morphine, especially after Cesarean section. This randomized controlled trial investigated the effects of intrathecal administration of a small-dose of atropine on postoperative nausea and vomiting after Cesarean section.Parturients with ASA physical status class I-II scheduled for elective Cesarean section and consenting to spinal anesthesia were enrolled. They received 0.5\% hyperbaric bupivacaine 12.5 mg, morphine 200 µg and one of the following three solutions: atropine 100 µg intrathecally and saline intravenously; saline intrathecally and atropine 100 µg intravenously; saline only both intravenously and intrathecally. We examined the incidence and severity of PONV, pain ratings and the need for analgesics.We followed 204 parturients. The incidence of PONV was 15\%, 37\% and 49\% in the three groups, respectively (P<0.001). The relative risk reduction for PONV when using intrathecal atropine was 69\% vs. placebo and 59\% vs. intravenous atropine. No differences were noted in terms of postoperative pain.Intrathecal atropine had a significant antiemetic effect, making it a useful adjunct for intrathecal opioid-related PONV.