Table 2 Pain-related outcomes (Abbreviations: RCT, randomized Clinical Trial; DEX, dexmedetomidine; LA, local anesthetic; CI, confidence interval)
Outcome | RCT | DEX + LA | LA | Mean Difference (95% CI) | I 2(%) | P Value for Overall Effect | P Value for Subgroup Differences | Quality of Evidence (GRADE) | ||
|---|---|---|---|---|---|---|---|---|---|---|
Mean (SD) | N | Mean (SD) | N | |||||||
Pain score at rest at 12 h postoperatively (analog scale, 0–10) |  |  |  |  |  |  |  |  | ||
DEX ≤ 60 μg | Bisui (0.75 μg/kg) 2017 | 4.27(0.45) | 33 | 5.76(0.65) | 34 | −1.43(−1.88 to −0.99) | 8 | <0.00001 |  |  |
|  | Shahtaheri (0.5 μg/kg) 2020 | 0.50(4.76) | 33 | 1.02(2.33) | 33 |  |  |  |  |  |
DEX>60 μg | Elyazed (100 μg) 2018 | 1.90(1.00) | 35 | 2.86(0.60) | 35 | − 1.63(−2.07 to − 1.20) | 76 | <0.00001 |  |  |
|  | Fritsch (150 μg) 2014 | 0.23(0.97) | 16 | 2.19(1.76) | 15 |  |  |  |  |  |
|  | Hanoura (100 μg) 2012 | 3.70(1.20) | 25 | 4.50(1.40) | 25 |  |  |  |  |  |
|  | He (1 μg/kg) 2018 | 0.93(0.98) | 28 | 1.93(1.15) | 28 |  |  |  |  |  |
|  | Hwang (100 μg) 2020 | 4.20(2.50) | 25 | 6.10(2.20) | 25 |  |  |  |  |  |
|  | Jung (1.5 μg/kg) 2018 | 0.61(0.99) | 25 | 2.80(1.40) | 23 |  |  |  |  |  |
|  | Jung (1 μg/kg) 2018 | 0.52(0.79) | 25 | 2.80(1.40) | 23 |  |  |  |  |  |
|  | Jung (2 μg/kg) 2018 | 0.00(0.00) | 24 | 2.80(1.40) | 23 |  |  |  |  |  |
|  | Liu (100 μg) 2018 | 2.20(0.90) | 57 | 4.20(1.10) | 57 |  |  |  |  |  |
|  | Singh (1 μg/kg) 2020 | 0.00(0.74) | 20 | 2.00(2.04) | 20 |  |  |  |  |  |
total |  |  |  |  |  | −1.57(−1.91 to −1.23) | 71 | <0.00001 | 0.53 | Very low |
Pain score at rest at 24 h postoperatively (analog scale, 0–10) |  |  |  |  |  |  |  |  | ||
DEX ≤ 60 μg | Abdallah (0.5 μg/kg) 2016 | 5.50(0.45) | 33 | 5.60(0.45) | 32 | −0.10(−0.32 to 0.12) | 0 | 0.38 |  |  |
|  | Shahtaheri (0.5 μg/kg) 2020 | 0.97(3.24) | 33 | 0.90(5.58) | 33 |  |  |  |  |  |
DEX>60 μg | Elyazed (100 μg) 2018 | 1.60(0.50) | 35 | 1.80(0.60) | 35 | −0.71(−1.93 to 0.52) | 98 | 0.26 |  |  |
|  | Fritsch (150 μg) 2014 | 2.68(2.93) | 16 | 2.10(2.20) | 15 |  |  |  |  |  |
|  | He (1 μg/kg) 2018 | 1.54(0.84) | 28 | 4.36(1.31) | 28 |  |  |  |  |  |
|  | Hwang (100 μg) 2020 | 3.30(1.30) | 25 | 3.70(1.50) | 25 |  |  |  |  |  |
|  | Jung (1.5 μg/kg) 2018 | 5.13(1.15) | 25 | 4.35(1.01) | 23 |  |  |  |  |  |
|  | Jung (1 μg/kg) 2018 | 4.10(1.04) | 25 | 4.35(1.01) | 23 |  |  |  |  |  |
|  | Jung (2 μg/kg) 2018 | 4.90(1.20) | 24 | 4.35(1.01) | 23 |  |  |  |  |  |
|  | Liu (100 μg) 2018 | 2.10(0.40) | 57 | 5.40(0.80) | 57 |  |  |  |  |  |
|  | Singh (1 μg/kg) 2020 | 0.00(0.74) | 20 | 1.00(1.48) | 20 |  |  |  |  |  |
total |  |  |  |  |  | −0.60(−1.61 to 0.42) | 98 | 0.25 | 0.34 | Very low |
Cumulative IV morphine consumption at 24 h postoperatively (mg) |  |  |  |  |  |  |  |  | ||
DEX ≤ 60 μg | Abdallah (0.5 μg/kg) 2016 | 21.3(0.87) | 33 | 27.3(1.16) | 32 | −6.01(−6.50 to −5.52) | 0 | <0.00001 |  |  |
|  | Kathuria (50 μg) 2015 | 5.63(3.33) | 20 | 12.0(5.66) | 20 |  |  |  |  |  |
DEX>60 μg | Akhondzadeh (1 μg/kg) 2018 | 12.04(6.74) | 36 | 26.62(7.58) | 36 | −5.03(−8.52 to −1.11) | 96 | 0.01 |  |  |
|  | Ammar (0.75 μg/kg) 2012 | 4.90(5.93) | 30 | 13.6(8.89) | 30 |  |  |  |  |  |
|  | Elyazed (100 μg) 2018 | 1.67(3.12) | 35 | 7.31(1.6) | 35 |  |  |  |  |  |
|  | He (1 μg/kg) 2018 | 7.30(4.40) | 28 | 15.9(7.60) | 28 |  |  |  |  |  |
|  | Jung (1.5 μg/kg) 2018 | 8.00(3.49) | 25 | 6.5(3.38) | 23 |  |  |  |  |  |
|  | Jung (1 μg/kg) 2018 | 7.00(3.16) | 25 | 6.5(3.38) | 23 |  |  |  |  |  |
|  | Jung (2 μg/kg) 2018 | 6.92(2.53) | 24 | 6.5(3.38) | 23 |  |  |  |  |  |
total |  |  |  |  |  | −5.03(−7.54 to −2.51) | 95 | <0.0001 | 0.53 | Very low |