The effect of intravenous dexamethasone on postoperative pain, nausea and vomiting after intrathecal pethidine and bupivacaine in lower limb orthopedic surgery

Abstract

Background: Intrathecal pethidine provides excellent post-operative analgesia but is associated with
significant nausea, vomiting and other side effects. Present study was done to evaluate the efficacy of
intravenous dexamethasone to enhance post-operative analgesia and to reduce the side effects.
Methodology: In this prospective, randomized, double blind, placebo controlled study a total of 80
patients of American Society of Anesthesiologists (ASA) grade I and II, undergoing elective lower limb
orthopedic surgery under sub-arachnoid block were randomized into two groups. Group C (n=40)
received 2 ml saline (as placebo) and Group D (n=40) received 0.1 mg/kg dexamethasone intravenously
as a bolus before intrathecal anesthesia. In all patients spinal anesthesia was administered with 15 mg
bupivacaine and 15 mg pethidine. After surgery, patients were asked to score their pain at 2, 4, 6, 12, 18
and 24 hr by VAS score. The presence of post-operative nausea vomiting (PONV), pruritus and respiratory
depression were recorded and compared between the two groups.
Results: The pain score on Visual Analogue Scale (VAS) at 6, 12, 18, 24 hours after surgery, mean number
of rescue analgesic doses in 24 hours and the incidence of PONV were significantly lower (p<0.05) in
dexamethasone group (Group D).
Conclusion: Administration of intravenous dexamethasone (0.1 mg/kg) just before subarachnoid block is
an effective mode of enhancing post-operative analgesia with intrathecal pethidine and it reduces incidence
of PONV.