A randomized double-blind study to evaluate efficacy and safety of epidural magnesium sulfate and clonidine as adjuvants to bupivacaine for postthoracotomy pain relief

Abstract

Background:The aim of the study was to compare postoperative pain relief in patients undergoing an elective thoracotomy with thoracic epidural analgesia using single shot magnesium and clonidine as adjuvants to bupivacaine.Methods:In a randomized prospective study, 60 patients of American Society of Anesthesiologists physical status I–III of either sex, between 20 and 60 years undergoing elective unilateral thoracotomy, were allocated to three equal groups of 20 patients. Each patient received thoracic epidural analgesia using bupivacaine alone (Group A) or with magnesium (Group B) or clonidine (Group C) at the end of surgery during skin closure. Postoperatively, pain was measured using a visual analog scale (VAS). Rescue analgesia (50 mg tramadol intravenous) was given at a VAS score of ≥4. Duration of analgesia and total dose of rescue analgesic during 24 h was calculated. Postoperative sedation and other side effects if any were recorded.Results:All the groups were homogeneous with respect to their demographics. The 24 h cumulative mean VAS score in Groups A, B, and C was 3.12 ± 0.97, 2.86 ± 0.43, and 1.83 ± 0.59, respectively. The duration of analgesia was prolonged in Group C (165 ± 49.15 min), followed by Group B (138 ± 24.6 min), and Group A (118.5 ± 52.8 min). The duration of analgesia was significantly prolonged in the clonidine group as compared to the control group (P = 0.001). The number of rescue analgesia doses were more in Group A (3.3 ± 1.65) followed by Group B (2.35 ± 0.98) and Group C (1.75 ± 0.71). The sedation scores were significantly higher in Group C. However, shivering was seen in Group A (40%) and Group C (20%) and absent in Group B (P = 0.003).Conclusion:Thoracic epidural analgesia using bupivacaine with clonidine is an efficient therapeutic modality for postthoracotomy pain. Magnesium as an adjuvant provided quality postoperative analgesia decreasing the need for postoperative rescue analgesia and incidence of postoperative shivering without causing sedation.

Effect of magnesium added to local anesthetics for caudal anesthesia on postoperative pain in pediatric surgical patients: A systematic review and meta-analysis with Trial Sequential Analysis

“…Fewer patients experienced postoperative shivering in the magnesium group than in the control group. Epidural administration of magnesium was shown to reduce the incidence of shivering in another study [ 29 ], and magnesium may be effective in reducing shivering. Even though all six trials prospectively monitored for adverse events, and magnesium was not associated with an increased number of adverse events, the total number of patients receiving caudal magnesium was only 179, so the possibility of rare but serious adverse events cannot be excluded.…”

The effects of magnesium sulfate added to epidurally administered local anesthetic on postoperative pain: a systematic review

“…The seventeen studies 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 (1150 patients) used only magnesium as an adjuvant to local anesthetic in the intervention group. Only data applicable to the meta-analyses of the current study were extracted from these studies.…”

“…Time to the first analgesic request was reported in 12 studies (790 patients). 29 , 31 , 33 , 34 , 36 , 37 , 38 , 39 , 40 , 41 , 42 Analgesic consumption during the first 24 postoperative hours was reported in six studies (416 patients). 30 , 31 , 32 , 34 , 37 , 44 Postoperative pain intensity was reported as visual analog pain scores during the first six postoperative hours in eight studies 31 , 32 , 33 , 34 , 37 , 39 , 41 , 43 (540 patients), and during the first 24 postoperative hours in five studies 30 , 31 , 32 , 34 , 37 (356 patients).…”

“…29 , 31 , 33 , 34 , 36 , 37 , 38 , 39 , 40 , 41 , 42 Analgesic consumption during the first 24 postoperative hours was reported in six studies (416 patients). 30 , 31 , 32 , 34 , 37 , 44 Postoperative pain intensity was reported as visual analog pain scores during the first six postoperative hours in eight studies 31 , 32 , 33 , 34 , 37 , 39 , 41 , 43 (540 patients), and during the first 24 postoperative hours in five studies 30 , 31 , 32 , 34 , 37 (356 patients). Postoperative nausea and vomiting were reported in 12 studies 29 , 30 , 31 , 32 , 33 , 35 , 37 , 39 , 40 , 41 , 42 (818 patients), shivering was reported in ten studies 29 , 31 , 33 , 35 , 37 , 38 , 40 , 41 , 42 (640 patients), and pruritus was reported in five studies 31 , 32 , 35 , 37 (318 patients).…”

“…Included studies were performed on patients undergoing the following surgical procedures: cesarean section (n = 2), 31 , 45 lower limb surgery (n = 6), 29 , 30 , 35 , 40 , 42 , 44 lower abdominal and pelvic surgeries (n = 5), 32 , 34 , 36 , 39 , 41 mixed lower limb and low abdominal surgery (n = 2), 33 , 38 spine surgery (n = 1), 43 and thoracotomy (n = 1). 37 …”