DEXAMETHASONE VERSUS A COMBINATION OF DEXAMETHASONE AND ONDANSETRON AS PROPHYLACTIC ANTIEMETIC AND ANTIPRURITIC IN PATIENTS RECEIVING INTRATHECAL MORPHINE FOR CAESAREAN SECTION

Abstract

Intrathecal morphine for caesarean delivery provides excellent postoperative analgesia but it is commonly associated with nausea, vomiting and pruritus.
This prospective, randomized, double blinded study was carried out to compare the effectiveness of a combination of dexamethasone and ondansetron with dexamethasone alone for prevention of postoperative nausea and vomiting (PONV) and pruritus following intrathecal morphine injection for caesarean section.
A total of 116 parturients with ASA I and II physical status, aged 18-40 years scheduled for elective caesarean section were randomized into 2 groups (n=58) to receive either intravenous dexamethasone 8mg (Group A) or a combination of intravenous dexamethasone 8mg and ondansetron 4mg (group B). The study drug for each group was diluted with sterile water in identical syringes to a volume of 5ml before administering spinal anaesthesia which consisted of 0.5% hyperbaric bupivacaine and 0.2mg morphine. The primary outcome variables were postoperative nausea and vomiting (PONV) and pruritus which were assessed for a period of 24 hours postoperatively using the visual analogue scale (VAS). The severity of the emetic symptoms were scored as follows: no symptoms = 0, mild = 1, moderate 2 =, severe = 3. The pain intensity was measured using VAS for 24 hours postoperative period, with 0cm = no pain, 1-3cm = mild pain, 3-7cm= moderate pain,7-10cm = severe pain.
The patient’s vital signs (pulse, BP,RP, Sa02) were monitored and documented.
The two groups were comparable with respect to demographic characteristics. The incidence of nausea and vomiting was significantly reduced in patients who received a combination of dexamethasone and ondansetron compared with dexamethasone alone (9.3% Vs 37%, respectively, P =
0.003). The incidence of pruritus was also significantly reduced (16.7% Vs 37%, respectively, P = 0.003) The mean duration of analgesia with intrathecal morphine was found to be 4.89 + 1.77 hours in the dexamethasone group and 4.49 + 1.68 hours in the dexamethasone and ondansetron group with no significant statistical difference (P = 0.24).
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It was found from this study that a combination of dexamethasone and ondansetron administered prophylactically significantly reduced in the incidence of PONV and pruritus in pregnant women on intrathecal morphine for caesarean section.