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

Background. 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. Methods. 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 mu g and one of the following three solutions: atropine 100 mu g intrathecally and saline intravenously; saline intrathecally and atropine 100 mu g intravenously; saline only both intravenously and intrathecally. We examined the incidence and severity of PONV, pain ratings and the need for analgesics. Results. 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. Conclusion. Intrathecal atropine had a significant antiemetic effect, making it a useful adjunct for intrathecal opioid-related PONV. (Minerva Anestesiol 2011;77:781-8.)