Transcutaneous Electrical Acupoint Stimulation Accelerates the Recovery of Patients Undergoing Laparoscopic Myomectomy: A Randomized Controlled Trial

Introduction

Uterine leiomyoma is an abnormal hyperplasia of uterine smooth muscle cells. Women aged between 30 and 50 years have a high incidence of this condition, with 20–40% having obvious symptoms, menstrual disorders, dysmenorrhea, abdominal and pelvic pain, and even infertility, abortion and other diseases.^1,2 This can have major adverse effects on their physical and mental health, as well as on their quality of daily life. For patients with serious clinical symptoms and ineffective conservative treatment with drugs, the early treatment plan often involves surgery. Laparoscopic myomectomy is more easily accepted by patients, with less trauma and less intraoperative bleeding. It is a well established and simple operation that is widely performed.^3,4 However, various adverse reactions often occur during the perioperative period, including stress reactions caused by long-term pneumoperitoneum, head low position, anesthesia and surgical stimulation during the operation, the use of drugs to promote uterine contraction, and the use of anesthesia and analgesics after the operation. These can cause postoperative nausea and vomiting, pelvic pain, dizziness and other complications that affect the recovery of patients.^5–9

Transcutaneous electrical acupoint stimulation (TEAS) is a non-invasive operation whereby the acupoint electrode piece is pasted onto the skin of the corresponding acupoint of the patient. Once connected to the corresponding instruments and equipment, a specified intensity of electrical stimulation is given in order to achieve the effect of traditional electric acupuncture.¹⁰ Various studies have demonstrated that TEAS has analgesic and sedative effects.^11–13 Application of TEAS during surgery can protect vital functions of the heart, brain, liver, stomach and other organs.^14,15 TEAS can also reduce inflammatory reactions, improve immune function, and lower the frequency of postoperative complications.^16,17 The goal of this work was to evaluate TEAS with regard to the perioperative rehabilitation of patients undergoing laparoscopic myomectomy.

Materials and Methods

Study Design and Participant Recruitment

In this double-blind randomized control-group clinical trial, we studied about Transcutaneous electrical acupoint stimulation accelerates the recovery of patients undergoing laparoscopic myomectomy. The Ethics Committee of Wenzhou Medical University (WMU) approved this study (clinical trial number: ChiCTR2100045173; Registry URL:YJLCYJ-2020-148). The study was conducted in accordance with the Declaration of Helsinki. Included in the study cohort were 120 women (ASA I and II) aged 18 to 60 years and who received laparoscopic myomectomy at the First Affiliated Hospital, WMU, Zhejiang, China, from May 2021 to December 2021. Patients were assigned to TEAS group (Group T) and control group (Group C) using random number tables. All participants provided informed consent.

Exclusion criteria included: incision or surgical scar at acupoint; infection of acupoint; nerve injury in any limb; prior spinal surgery; allergic reaction to any of the drugs used in this study; sinus bradycardia; severe neurological disease; severe respiratory disease; smoking; severe cardiovascular disease; addiction to an anaesthetic; recent history of opioid use.

Types of Outcomes

Transcutaneous Electrical Acupoint Stimulation (TEAS)

Patients in Group T received TEAS. The anesthesiologist selected acupoints of LI4 (Hegu) and PC6 (Neiguan) on both hands of the patients, stuck the electrodes, and connected Han’s Acupoint Nerve Stimulator (Nanjing Jinan Xinsheng Technology, Jinan, Nanjing, China) capable of producing a dilatational wave with a frequency of 2/100 HZ, which is the maximum tolerable for patients receiving −1 mA of electrical stimulation for 30 minutes before the operation and lasting until the end of anesthesia. Using the same method at bilateral acupoints of ST36 (Zusanli) and SP6 (Sanyinjiao) for 30 minutes while in PACU (Postanesthesia care unit). Patients in Group C did not undergo TEAS. The acupoint locations are shown in Figure 1.

Figure 1 Illustration of the acupoints.

Numerical Rating Scale (NRS)

1h and 24h after the procedure, a PACU nurse, who was unaware of the group of each patient, assisted patients to evaluate their pain level by using a numerical rating scale (NRS: 0–10,0 = none, 10 = most severe, 1–3 mild pain, 4–6 moderate pain, 7–10 severe pain).

Grade of Abdominal Distension Severity

Grade 0: No or transient abdominal distension; Grade 1: mild abdominal distension, or temporary sudden abdominal distension, gas movement in the abdomen, but does not affect rest and sleep, mild abdominal bulge, abdominal wall tension; Grade 2: moderate abdominal distension, nausea, rest, sleep, moderate abdominal bulge, large abdominal tension; Grade 3: severe abdominal distension, severe nausea, vomiting, irritability, serious sleep, significant abdominal swelling, and percussion.

Anesthesia, Surgical Procedures, and Analgesia

A 22-gauge trocar was used to obtain venous access on the dorsal side of the non-dominant hand prior when the patient is in the preoperative preparation room. After the infusion channel was connected to the extension tube, 500 mL Ringer’s solution was infused through the channel, with an infusion speed of 20 mL/min. No medications were given. Blood pressure, oxygen saturation and electrocardiography were monitored while in operating theatre. The anesthesia induction sequence was started with intravenous sufentanil (0.5 µg/kg) (Yichang Renfu, Yichang, Hubei, China) over two seconds, propofol (2mg/kg) (Aspen Pharma Trading Limited) and cisatracurium (2mg/kg) (Jiangsu Hengrui, Jiangsu, China) were given and endotracheal intubation was performed. Propofol and remifentanil (Yichang Renfu, Yichang, Hubei, China) were injected by electronic pump during anesthesia maintenance to kept the patient’s blood pressure stable during operation and BIS(Bispectral Index) maintained between 40 and 60. Add the cisatracurium or sufentanil and record the dosage according to the actual situation. Both groups were given tropisetron 5mg immediately at the start of surgery to prevent postoperative nausea and vomiting and flurbiprofen 100mg for postoperative analgesia. The surgeon was instructed to administer ropivacaine for local infiltration analgesia around the incision at the end of the procedure. At the end of surgery, the muscle relaxation antagonism (neostigmine 1mg, atropine 0.5mg) was given immediately, and 20mg was given to promote the recovery of spontaneous breathing. When the patient recovered spontaneous breathing, tidal volume was >6 mL/kg, respiratory waveform was regular, he could respond to oral instructions, and the tracheal tube was removed after sputum suction and the patient was taken to the PACU. Norepinephrine(4ug) was administered intravenously every time when systolic blood pressure fell to <90 mmHg or diastolic blood pressure fell to <60 mmHg. Atropine (0.5 mg) was administered when the heart rate fell below 50 per minute (Figure 2).

Figure 2 Test flowchart. Abbreviations: TEAS, transcutaneousacupoint electrical stimulation; BP, Blood Pressure; SaO2, Arterial Oxygen Saturation; ECG, Electrocardiogram; BIS, Bispectral Index; PACU, Postanesthesia care unit; QoR40, Quality of Recovery Score-40.

Observation Indexes

The main observation indexes included the 40 items in QoR-40 24 hours after surgery to evaluate the quality of postoperative rehabilitation. The secondary outcome measures: the general patient condition, dosage of remifentanil, propofol, any vasoactive drugs, etc used during the operation, incidence of pain caused by propofol injection during the operation, and the incidence of cough induced by sufentanil during anesthesia induction. Ten recordings of the patients’ mean arterial pressure (MAP), HR (Heart Rate), SaO2 (oxygen saturation), BIS were recorded at the following times: in the operating room and patient calmed (T0), immediately before tracheal intubation (T1), one min after tracheal intubation (T2), two min after tracheal intubation (T3), immediately at the beginning of operation (T4), pneumoperitoneum at 5 min (T5), pneumoperitoneum at 30 min (T6), suture of the operation (T7), immediately before extubation (T8), one min after extubation (T9). Records were also made of bleeding, urine volume, liquid, the time of anesthesia, the time of operation, the incidence of intraoperative hemodynamic instability, the utilization rate of vasoactive drugs, the postoperative respiratory recovery time, the conscious time, the extubation time, Aldrete score, highest pain score in PACU, the retention time in PACU, the utilization rate of remedial drugs in PACU, NRS (Numerical Rating Scale) at 1 h and 24 h after the operation, the occurrence of adverse reactions including nausea, vomiting, abdominal distention, the utilization rate of analgesic and antiemetic drugs in 24h, the time to first postoperative anal exhaust, the time to first postoperative water intake, the time to solid food tolerance, the time to catheter removal, the time to first postoperative implantation activity, the time of postoperative hospitalization.

Statistical Analysis

The necessary sample size was estimated based on an improvement of 4 points in the QoR-40 evaluation. With a = 0.05 and β = 0.20, at least 49 patients were needed in each group. All data were analyzed by SPSS 23.0. The mean ± standard deviation of measurement data that had a normal distribution was used in statistical descriptions. The median (with interquartile spacing) was used for statistical description of measurement data not conforming to a normal distribution. Two-sample independent t-test was employed to evaluate measurement indexes with normal distribution and to test the homogeneity of variance. Rank sum test was employed to evaluate non-conforming normal distribution. Numerical data were expressed as a percentage (%) and was compared using chi-square test. Statistical tests were bilateral, with p < 0.05 considered as statistically significant.

Results

The overall study cohort was comprised of 105 patients, with 52 in Group T and 53 in Group C. Six patients used analgesic drugs other than those in the experimental plan, 6 patients underwent a different surgical procedure, two patients used PCIA (Patient-controlled intravenous analgesia), and one patient had intraoperative bleeding (Figure 3).

Figure 3 Flowchart for inclusion, exclusion and missing interviews.

General Characteristics

The general preoperative (Table 1) and intraoperative (Table 2) conditions were compared between Groups T and C. No statistically significant differences were observed for ASA, age, weight, BMI, MAP, HR, BIS, temperature, duration of anesthesia, duration of operation, intraoperative blood loss, intraoperative urine volume, dosage of sufentanil, propofol, or atracurium cisbenzenesulfonate. However, the dosage of remifentanil used in Group T was significantly lower by almost 15% relative to Group C.

Table 1 Preoperative General Conditions Between Two Groups

Table 2 Intraoperative General Conditions in Between Two Groups

Intraoperative Evaluation Index and PACU Evaluation Index

The incidence of propofol injection pain was significantly lower in Group T (Table 3). Group T also showed a lower incidence of sufentanil-induced cough response, although this was not statistically different. Several significant differences in hemodynamics were apparent between Groups T and C at all of the T0-T9 times (Table 4). The frequency of intraoperative hypotension and the use of vasoactive drugs were also lower in Group T (Table 5). No significant difference was observed between the two Groups for the anesthesia recovery index (Table 6). The maximum NRS score for Group T was significantly less than that of Group C. Remedial drug use in PACU was lower in Group T, but this was not significantly different. No significant differences between the two groups were seen for PACU aldrete score and retention time (Table 6).

Table 3 The Incidence of Propofol Injection Pain and Sufentanil-Induced Cough in the Two Groups

Table 4 Intraoperative Hemodynamic Comparison Between the Two Groups

Table 5 The Incidence of Intraoperative Hemodynamic Instability and the Utilization Rate of Vasoactive Drugs Were Compared in the Two Groups

Table 6 Comparison of Anesthesia Indicators and the Indicators of PACU in the Two Groups

Postoperative Recovery Evaluation Index

The NRS score while in the mobile state was significantly lower in Group T at 1 hour and at 24 hours after operation (Table 7). Within the first 24 hours, vomiting was significantly less in Group T than in Group C. Analgesic and antiemetic drug use at 24 h were also both less frequent in Group T. However, these did not reach statistical significance (Table 7). Some mild and moderate abdominal distension was recorded for Group T (Table 8), but this was not significantly different to Group C (P = 0.24). Group T patients had significantly shorter times for first postoperative anal exhaust and solid food tolerance. However, the times for first postoperative water intake, removal of the catheter, first postoperative implantation activity, and postoperative hospitalization were not statistically different between the two Groups (Table 9). At 24 hours after operation, Group T had significantly higher QoR-40 scores for physical comfort, emotional state, pain, and total score. However, no significant differences were observed for self-care ability and psychological support (Table 10).

Table 7 Comparison of NRS, the Incidence of Vomiting and Utilization Rate of Analgesic and Antiemetic Drugs in 24h Between the Two Groups

Table 8 Abdominal Distension at 24h After Surgery Between Both Groups

Table 9 Postoperative Gastrointestinal Function Recovery Between the Two Groups

Table 10 Comparison of QoR-40 Recovery Quality Score Scale at 24h Between the Two Groups

Discussion

This study found that TEAS was associated with a reduced dosage of anesthetic, better hemodynamic stability, a lower postoperative pain NRS score, reduced incidence of postoperative vomiting, better recovery of gastrointestinal function, improved quality of postoperative recovery, and an accelerated recovery process.

TEAS is a non-invasive operation compared to traditional electroacupuncture (EA). The stimulation intensity is more moderate, stable and continuous, and similar clinical results to traditional EA can be obtained.¹⁸ A large number of clinical and animal studies have shown numerous beneficial effects of TEAS, and there is now consensus both at home and abroad regarding the advantages of TEAS.¹⁹ However, the parameters and acupoints used for stimulation have varied in different studies. In the present study, Hegu (LI4), Neiguan (PC6), Zusanli (ST36) and Sanyinjiao (SP6) were used (Figure 1). Some studies have reported that the analgesic effect of TEAS derives from release of the endogenous opioids enkephalin, β-endorphin, and dendorphine.^20,21 The analgesic effect obtained from high-frequency (100 Hz) EA occurs after the release of dynorphins from the central nervous system. The levels of endorphins and of mandorphins in human CSF both increase after 30 minutes of low (2 Hz) and high frequency (100 Hz) electroinjection.

TEAS can significantly reduce propofol injection pain and TEAS may activate sympathetic nerve fibers, inhibit inflammatory mediators, reduce vascular permeability (directly and indirectly), and reduce the contact opportunity between propofol and peripheral nerves, thus lowering the injection pain. Moreover, TEAS is able to increase the patient pain threshold and produce a reliable endogenous opioid effect by inducing the central release of multiple opioid peptides.²² This could also explain why the highest NRS score for PACU, as well as postoperative NRS at 1 h and 24 h, were lower in Group T than Group C.

Endogenous opioid peptides induced by TEAS can positively and negatively regulate blood pressure through the blood pressure regulation zone. Central blood pressure regulation is somewhat related to the central analgesic mechanism of TEAS.^23–25 The reduction in MAP at 2 min after intubation was less in Group T, whereas differences in intraoperative MAP, HR, oxygen saturation, and BIS between the two groups at other T0-T9 times were not statistically significant. However, the dosage of remifentanil required for intraoperative maintenance was reduced by about 15% in Group T relative to Group C. Intraoperative hypotension was also significantly less frequent in Group T, as well as the need for vasoactive drugs. These results indicate that TEAS plays a role in maintaining the stability of intraoperative circulation, thus reducing the need for drug intervention.

LI4 and PC6 have been shown in many clinical trials to reduce the incidence of PONV (Postoperative Nausea and Vomiting).^26–28 In the present study, Group T showed less frequent vomiting within 24 h than Group C. However, the incidence of vomiting within 1 h was not significantly different between the two groups, possibly because preoperative antiemetic drug use effectively prevented the occurrence of early postoperative nausea and vomiting. ST36 is the classic acupuncture point of traditional Chinese medicine used in the treatment of gastrointestinal diseases. It stimulates the parasympathetic nerve and improves gastrointestinal smooth muscle excitability, gastrointestinal microcirculation, and intestinal and endocrine function, thereby promoting the recovery of gastrointestinal function.^29–31 In the current study, the times for first postoperative anal exhaust and postoperative solid food tolerance were significantly shorter in Group T patients, indicating that TEAS promotes the recovery of gastrointestinal function after surgery.

Previous studies found that TEAS could reduce the dosage of intraoperative propofol used in craniotomy patients,³² as well as accelerating analepsia.³³ In the present study, however, no significant differences were observed between Groups T and C for the use of propofol, respiratory recovery time, anesthesia awake time, and tracheal catheter extraction time. This may have been due to the short operation time, or because the benefits of TEAS are acupoint-specific.

QoR-40 is an objective measure of the quality of anesthesia and of postoperative recovery, and has been widely used to evaluate postoperative rehabilitation. It consists of 40 questions and provides a total score from five dimensions of subitem scores, comprised of psychological support, physical comfort, emotional status, self-care ability and pain.^34–36 This study indicates that TEAS can improve the quality of recovery after laparoscopic myomectomy and concur with those of Chen et al³² who studied patients treated with gynecological laparoscopic surgery. The improvements are probably due to the reduction of postoperative pain, a lower frequency of adverse reactions (nausea, vomiting, abdominal distension), reduced complications from high-dose opioid use, and improved patient satisfaction and comfort. In addition, it was easier for patients to turn over in bed, get out of bed, and to perform other activities after surgery, thus helping with gastrointestinal recovery. Postoperative gastrointestinal nutritional support can be carried out in advance to further accelerate the recovery of patients.

In the current study, we evaluated patient recovery only within 24 h of surgery, and continuous postoperative recovery thereafter was not assessed. Nevertheless, this limitation was partially compensated by observing multiple indicators for each patient, which is likely to have more clinical significance.

Conclusion

TEAS promotes rapid perioperative recovery of patients who undergo laparoscopic uterine myomectomy by reducing the incidence of postoperative complications. TEAS is a simple operation with no obvious toxic or side effects and with high economic benefits, thereby justifying its wide use in clinical practice.