The effect of intravenous dexamethasone on postoperative nausea and vomiting after Cesarean delivery with intrathecal morphine: a randomized-controlled trial.

PURPOSE: Intrathecal morphine administered during spinal anesthesia for Cesarean delivery is associated with a high incidence of postoperative nausea and vomiting (PONV). Small studies performed to date provide conflicting evidence on the effectiveness of dexamethasone as prophylaxis in this setting, raising the possibility that efficacy may be linked to dose timing. This study hypothesized that intravenous dexamethasone given prior to intrathecal morphine during spinal anesthesia may reduce the incidence of PONV.

METHODS: In this double-blind, placebo-controlled trial, 108 patients undergoing Cesarean delivery were randomized to receive 8 mg dexamethasone or placebo prior to spinal anesthesia that included 0.2 mg intrathecal morphine. Outcomes were assessed on postanesthesia care unit arrival, as well as at postoperative hours one, three, six, 24, and 48. The primary outcome was the total number of subjects experiencing PONV during the study period of 48 hr postpartum. Secondary outcomes included severity of pain via the numeric rating scale pain score, and the use of rescue antiemetics and analgesics.

RESULTS: No significant difference in the number of patients experiencing PONV was found between the treatment (n = 44, 80.0%) and control groups (n = 45, 84.9%) (difference -4.9%; 95% confidence interval, -19.2 to 9.4; P = 0.50), nor for median numeric rating scale pain scores (P = 0.24), total consumption of rescue antiemetics (P = 0.40), or opioid analgesics (P = 0.26).

CONCLUSIONS: This trial does not support the use of dexamethasone prior to intrathecal morphine for PONV prophylaxis in Cesarean delivery.

TRIAL REGISTRATION: www.clinicaltrials.gov (NCT01734161); registered 27 November, 2012.