Table 2.
Characteristics of the included studies.
| No. | Study ID | Types of surgery | Intervention time | Sample size(T/C) | Intervention measures | Outcomes | Acupoints | Waveforms | Electrical frequency | |
|---|---|---|---|---|---|---|---|---|---|---|
| Intervention Group | Control Group | |||||||||
| 1 | Mi et al. 2018 [21] | Hepatobiliary surgery | Before induction of anesthesia—the end of surgery | 50/50 | TEAS | Sham-TEAS | ②③ | LI14,PC6,ST36 | Dilatational waveform | 2/100 Hz |
| 2 | Yao et al. 2015 [22] | Gynecologic surgery | Before induction of anesthesia—the beginning of surgery | 35/36 | TEAS | Sham-TEAS | ①②③ | LI14,PC6,ST36,SP6 | Dilatational waveform | 2/10 Hz |
| 3 | Liu et al. 2008 [23] | Hepatobiliary surgery | Before induction of anesthesia—the end of surgery | 48/48 | TEAS | Sham-TEAS | ④ | PC6 | Dilatational waveform | 2/100 Hz |
| 4 | He 2017 [24] | Gynecologic surgery | S-TEAS: before anesthesia induction—the beginning of anesthesia; L-TEAS: before induction of anesthesia—the end of surgery | 34, 33/34 | TEAS | Sham-TEAS | ① | LI14, ST36 | Dilatational waveform | 2/10 Hz |
| 5 | Cai et al. 2020 [25] | Gastrointestinal surgery | Before induction of anesthesia—the beginning of surgery | 24/25 | TEAS | Sham-TEAS | ① | ST36,PC6 | Dilatational waveform | 2/15 Hz |
| 6 | Guo et al. 2016 [26] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 30/30 | TEAS | Sham-TEAS | ⑤ | PC6,ST36 | Dilatational waveform | 2/100 Hz |
| 7 | Zhou 2019 [27] | General surgery& Gynecologic surgery | Before induction of anesthesia—the end of surgery | 32/32 | TEAS | Sham-TEAS | ① | SP6,LI14 | Dilatational waveform | 2/100 Hz |
| 8 | Duan 2017 [28] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 64, 65, 63/64 | Group-D:TEAS (double acupoints); Group-P, S (single acupoint) | Sham-TEAS | ①③ | groupD:PC6,ST36, group-P:PC6, group-S:ST36 | Dilatational waveform | 2/10 Hz |
| 9 | Gu 2019 [29] | Gastrointestinal surgery | S-TEAS, L-TEAS: the beginning of the operation—the end of the operation | 49, 49/48 | S-TEAS+PCIA；L-TEAS+PCIA | Sham-TEAS | ①② | ST36,PC6 | Dilatational waveform | 2/100 Hz |
| 10 | Huang and Liu 2019 [30] | Gastrointestinal surgery | 30 min before induction of anesthesia and lasting for 40 min | 46/46 | TEAS | Sham-TEAS | ② | GV20,PC6,ST36,SP6 | not reported | not reported |
| 11 | Song 2020 [31] | Gastrointestinal surgery | Before induction of anesthesia—the end of surgery | 25/25 | TEAS | Sham-TEAS | ① | LI14,PC6 | Dilatational waveform | 5/100 Hz |
| 12 | Sun et al. 2016 [32] | Hepatobiliary surgery& Gynecologic surgery | Each perioperative treatment lasted 30 min | 91, 91, 89/90 | Group-A, B, C (different intervention time) | Sham-TEAS | ①② | LI14,PC6 | Dilatational waveform | 2/100 Hz |
| 13 | Yin et al. 2013 [33] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 30/30 | TEAS | Blank control | ① | ST36,ST34 | Continuous waveform | 2Hz |
| 14 | Yu et al. 2020 [34] | Gynecologic surgery | Before induction of anesthesia—the beginning of surgery | 30/30 | TEAS | Blank control | ①②③ | GV20,GV29,ST36,PC6 | Dilatational waveform | 2/100 Hz |
| 15 | Wang and Zhang 2015 [35] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 58/58 | TEAS | Blank control | ① | ST34,ST36 | Continuous waveform | 2Hz |
| 16 | Xun et al. 2014 [36] | Hepatobiliary surgery | Before induction of anesthesia—the end of surgery | 25/25 | TEAS | Blank control | ⑤ | PC6,ST36 | Dilatational waveform | 2/100 Hz |
| 17 | Huang 2015 [37] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 50/50 | TEAS | Blank control | ① | ST36,ST34 | Continuous waveform | 2Hz |
| 18 | Chen et al. 2017 [38] | General surgery | Before anesthesia induction—the beginning of anesthesia | 20, 20/20 | Group A: TEAS; group B: TEAS (different acupoints) | Blank control | ①② | group-A:PC6,ST36; group- B:PC6,ST36,BL32,BL34 | Dilatational waveform | 2/100 Hz |
| 19 | Guo et al. 2017 [39] | Hepatobiliary surgery | Before anesthesia induction—after surgery | 40/40 | TEAS + PCIA | PCIA | ① | EX-HN1,HT7,PC6 | not reported | 2/100 Hz |
| 20 | Deng et al. 2013 [40] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 100/100 | TEAS + PCEA | PCEA | ① | PC6,ST36 | not reported | 2/100 Hz |
| 21 | Zheng et al. 2017 [41] | Gynecologic surgery | after the surgery | 30/30 | TEAS + PCIA | PCIA | ①②⑤ | LI14,PC6,ST36,SP6 | Dilatational waveform | 2/100 Hz |
| 22 | Gu et al. 2018 [42] | Gastrointestinal surgery | S-TEAS: the induction of anesthesia—the end of surgery; L-TEAS:before anesthesia induction—after surgery | 60, 60/60 | S-TEAS+PCIA;L-TEAS+PCIA | Sham-TEAS + PCIA | ①② | ST36,PC6 | Dilatational waveform | 2/100 Hz |
| 23 | Zhao 2014 [43] | Gynecologic surgery | Before induction of anesthesia—the beginning of surgery | 35/36 | TEAS + PCIA | Sham-TEAS + PCIA | ①②③ | LI14,PC6,ST36,SP6 | Dilatational waveform | 2/10 Hz |
| 24 | Wei et al. 2017 [44] | Gynecologic surgery | Before induction of anesthesia—the end of surgery | 30/30 | TEAS + analgesics | analgesics | ① | ST36,ST34 | Dilatational waveform | 2/100 Hz |
| 25 | Liu et al. 2020 [45] | Gastrointestinal surgery | Before anesthesia induction—after surgery | 30/30 | TEAS + standard analgesic regimen | standard analgesic regimen | ① | LI14,PC8,ST36 | Dilatational waveform | 2/100 Hz |
| 26 | Bing et al. 2016 [46] | Gynecologic surgery | after the surgery | 30/30 | TEAS + postoperative routine nursing | postoperative routine nursing | ① | GB21,BL12,GV6, GV4, etc. | Dilatational waveform | 0.02 Hz |
| 27 | Huang et al. 2019 [47] | Gastrointestinal surgery | Before induction of anesthesia—the end of surgery | 29/28 | TEAS + TAP + PCIA | TAP + PCIA | ① | ST36 | Dilatational waveform | 2/10 Hz |
| 28 | Huang 2018 [48] | Gastrointestinal surgery | Before induction of anesthesia—the end of surgery | 32/35 | TEAS + TAP + PCIA | TAP + PCIA | ① | ST36 | Dilatational waveform | 2/10 Hz |
Explanation: Outcomes: ① VAS values at different time points after operation; ② consumption of analgesics; ③ QoR-40 scare score; ④ VRS values at different time points after operation; ⑤ incidence of postoperative pain; acupoints: Zusanli ST36, Neiguan PC6, Hegu LI14, Sanyinjiao SP6, Baihui GV20, Liangqiu ST34, Yintang GV29, Ciliao BL32, Xialiao BL34, Shenmen HT7, Laogong PC8, Guanyuan GV4, Qihai GV6, Jianjing GB21, Fengmen BL12, Sishencong EX-HN1.