The Comparison Between Dexamethasone and Morphine as an Adjuvant to Epidural Bupivacaine for Post-operative Analgesia in Lower Extremity Surgery

Approval from Ethical Committee of Faculty of Medicine University of Indonesia was acquired prior conducting the study. Subjects were given informed consent before enrolling the study and randomized into two groups. Intravenous (IV) cannula with Ringer Lactate fluid, non-invasive blood pressure monitor, electrocardiogram (ECG) and pulse-oxymetry were set on the subjects in the operation room. Epidural catheter was inserted (4 cm depth inside the epidural space) with 1,5-2 mg IV midazolam and 50 mcg IV fentanyl as premedication. The catheter insertion was confirmed with vacuum aspiration and negative test-dose. General anesthesia induction was done by fentanyl 2 mcg/kg, propofol 2 mg/kg, and atracurium 0,5 mg/kg. Maintenance was done by sevoflurane 2vol%, fentanyl and atracurium. Surgery starts without intraoperative epidural regimen. Surgery duration, blood pressure, heart rate, respiratory rate, oxygen saturation by pulse oximetry (SpO2) were recorded. For post-operative analgesia, subjects received paracetamol 1 gr IV and intermittent epidural analgesia regimen in a 10 cc syringe: Group 1 received Bupivacaine 0,125% 12,5 mg combined with dexamethasone 8 mg plus 0,9% sodium chloride (NaCl) until the volume was 10 cc; Group 2 received Bupivacaine 0,125% 12,5 mg combined with morphine 2 mg plus 0,9% NaCl until the volume was 10 cc. The injection was given by anesthesiology residents without knowing the syringe's content. Patient Controlled Analgesia (PCA) morphine was given in the recovery room. Data recorded were blood pressure, heart rate, respiratory rate, oxygen saturation, visual analog scale, side effects, the time when first additional analgesia was needed by subjects, the opioid requirement within 24 hours post-operation. Data was analyzed using Statistical Package for the Social Sciences (SPSS) software, for numerical data using unpaired T-test or Mann-Whitney-U test, for categorical data using Chi-square or Fisher Exact Test. Data normality was tested by Kolmogorov-Smirnov test. Significant value is p<0.05.