High dose dexamethasone offers better postoperative analgesia than dexmedetomidine when added to intra articular ropivacaine following knee arthroscopic surgery

Abstract

Objective: Adequate pain relief after knee arthroscopy reduces surgical stress response and postoperative morbidity and improves recovery and rehabilitation. The objective of our study was to compare the duration of postoperative analgesia produced by high dose with that of low dose dexamethasone when added to dexmedetomidine and ropivacaine for intra-articular injection following knee arthroscopy.

Methodology: Prospective multicenter double blind study of 60 patients undergoing arthroscopic knee surgery from January 2015 to May 2015, randomly assigned into 3 groups; Group I (20 ml 0.2% ropivacaine), Group II (16 ml of 0.2% ropivacaine + dexmedetomidine- 1 µg/kg diluted to 4 ml) and Group III (dexamethasone 300 µg/kg diluted with  0.2% ropivacaine upto 20 ml). The duration of analgesia (VAS Score less than 4) and time to first postoperative analgesic request, total analgesic used during first 24 hours were recorded. Clinical incidences of nausea, vomiting, bradycardia, hypotension or other side-effects requiring intervention were observed in all the groups. The numerical data were expressed as mean ± standard deviation (SD). Student's t-test was employed to calculate the statistical differences in continuous variables between the groups, categorical variables were compared with chi-square test or Fisher's exact test as applicable. A P < 0.05 was considered to be statistically significant.

Results: Group III had significantly low pain scores for first twenty hours as compared to Group II and Group I. Time to first postoperative analgesia request was longest in Group III (1356.2 ± 193.10 min) as compared to the Group II (433.2 ± 54.3 min) and Group I (311.8 ± 61.56 min)(p < 0.01). Mean total analgesic consumption in first 24 hrs was least in Group III (38.2 ± 27.83 mg) followed by Group I (221.25 ± 56.93 mg) and Group II (153.75 ± 51.5 mg) (p < 0.01). No significant side-effects were noted.

Conclusion: Dexamethasone 300 µg/kg is as safe and free from side effects, but offers a prolonged postoperative analgesia as compared to dexmedetomidine, when added to intra articular ropivacaine following arthroscopic knee surgeries.

Key words: Knee, Arthroscopy; Pain; Local anesthesia; Dexamethasone; Dexmedetomidine; Ropivacaine

Citation: Panigrahi R, Roy R, Prasad A, Mahapatra AK, Priyadarshi A, Palo N. High dose dexamethasone offers better postoperative analgesia than dexmedetomidine when added to intra articular ropivacaine following knee arthroscopic surgery. Anaesth Pain & Intensive Care 2016;20(3):273-277

Received: 30 October 2015; Reviewed: 10 November 2015; 30 March 2016; Corrected: 20 November 2015; 4 August 2016; Accepted: 10 August 2016