Postoperative Analgesic Efficacy of Ear Acupuncture in Patients Undergoing Abdominal Hysterectomy

A Randomized Controlled Trial

Hamdy A. Hendawy; Mohamed E. Abuelnaga

Disclosures

BMC Anesthesiol. 2020;20(279) 

In This Article

Methods

The current study is a single-blinded randomized controlled clinical trial. After Obtaining approval by the Hospital Ethics Committee, and Written informed patient consent with an explanation regarding the purpose, methods, effects, and complications of techniques, 56 patients were randomly allocated into two equal groups using simple random tables generated from a computer software program (http://www.randomizer.org). The allocation sequence was concealed in opaque numbered envelopes. The outcome assessor was another anesthesiologist who was blind to the study group. Inclusion criteria included patients aged between 21–60 years old and have an American society of anaesthesiologist (ASA) physical status I & II. Patients who have contraindications for spinal anesthesia as (infection at the site of puncture, coagulopathy, platelet abnormalities, and concurrent treatment with anticoagulant drugs), allergy to morphine, and/or bupivacaine, morbid obesity (body mass index (BMI) > 35 Kg/m2), psychological disease, narcotic abuse, prolonged use of sedatives or opioid drug use, contraindications for ear acupuncture (infection at the acupuncture site) and patients refused to participate in the study were excluded. The primary objective was to assess the influence of auricular acupuncture regarding the postoperative analgesic requirement in patients scheduled for abdominal hysterectomy, while secondary objectives were intraoperative hemodynamic parameters, Post-operative pain scores, and Postoperative 1st request of analgesia.

The 56 patient were randomized into two equal groups:-

  • Group I (EEA group): 28 females received electric ear acupuncture after spinal anesthesia.

  • Group II (control group): 28 females received spinal anesthesia without ear acupuncture.

Preoperative Visit to the Chosen Patients was Done Where

Explanation of the whole procedure including the expected benefits and complications was done. All Patients were instructed preoperatively for the use of the PCA apparatus.

A) Pre-operative assessment

The patient's age, ASA status, and BMI were recorded. Medical history was reviewed to rule out excluded patients from the study. General examination, vital signs: heart rate (HR), blood pressure (BP), temperature, chest, heart, abdominal examination, and airway evaluation were done. Investigations done were complete blood count, random blood sugar, bleeding profile as prothrombin time, International Randomized Ratio, and partial thromboplastin time.

B) Intra-operative measures

The patient was reassured and the procedure was explained to her. Airway devices and anesthesia machines, ventilators, flowmeters, and equipment were checked promptly. Routine Monitoring equipment (Datex-Ohmeda®) was attached to the patient including 3 leads electrocardiogram (ECG), non-invasive BP, and pulse oximetry. An 18- gauge intravenous cannula was inserted into the patient's forearm and 500 mills of intravenous (I.V.) fluid (ringer acetate) were administrated. No premedications were given. All patients in both groups were given spinal anesthesia by 25 G needle with hyperbaric bupivacaine 0.5% (15–20 mg) according to the patient's height, in the L4- L5 intervertebral space. During spinal injection, no supplementary opioids were given; the level of anesthesia was assessed by pin-prick every 5 min in the first 20 min till it reached T4-T6 which would be considered sufficient to start the surgery.

The Procedure of Acupuncture. Acupuncture was done based on our institutional experience. EEA was done by fine needles (10 mm x 30guage) to the anatomically defined 4 points of ear acupuncture which are called; Shen Men Point (Divine Gate Point) or point 55 which is a sedative analgesic anti-inflammatory point, thalamus Point 26 which is an analgesic point in acute and chronic severe pain, Analgesia Point 3, and Uterus Point 58.[7,8]

Then four pre-sterilized single-use acupuncture needles were inserted in the predetermined acupoints and connected to clamps of electrode cords that were connected to the electro-acupuncture therapeutic apparatus (KWD-808I MULTIPURPOSE HEALTH DEVICE, Changzhou Yingdi Electronic Medical Device Co., China. (Figure 1).

Figure 1.

KWD-808I MULTIPURPOSE HEALTH DEVICE is connected to grey acupoint detecting pen for acupoint detection APD and six electrode cords with 6 different colors for electro-acupuncture

The EA device was switched on and adjusted according to the instruction manual for use to provide continuous-wave with a frequency of 2 Hz and output impulse amplitude of 6–10 V according to the patient's ability. At the end of the surgery, the electro-acupuncture device was switched off and the fine needles were replaced by press needles in the same acupoints to be removed after 24 hours.

Measurements and Postoperative Care

All intraoperative and postoperative recordings were done by another anesthesiologist who was blind to the allocation group. Vital signs (BP, HR, respiratory rate) and oxygen saturation were recorded and analyzed every 5 min in the first 20 min, then every 20 min for the rest of the surgery. At the end of the operation, the duration of surgery and spinal level were recorded for both groups, and Diclofenac potassium 75 mg was administered to all patients by intramuscular injection. Postoperative BP and HR were recorded immediately after transfer to the post-anesthesia care unit (PACU), then after 1, 3,6,12, and 24 hours. Post-operative pain assessment was done by visual analog scale .when the reported visual analog scale (VAS) was 3 or more, a loading dose of morphine 0.05 mg/kg was administered via slow I.V. route. Then, a PCA was administered. The PCA pump was loaded with 1 mg/ml of morphine and set to deliver on-demand doses of 2 ml with 10 min lockout intervals and 4 h limit of 20 mg. No background infusion was allowed. The pain score was reassessed at the end of the 1st postoperative 24 hours. The time to the 1st postoperative request of analgesia was recorded using the PCA delivery system. The total amount of morphine consumption over the 1st 24 hours postoperatively was recorded. Side effects associated with morphine consumption as nausea, vomiting, and over sedation were recorded. Nausea and vomiting were assessed using a 5 point scale from zero to four, where 0 is no nausea or vomiting, 1 = mild nausea, 2 = severe nausea, 3 = vomiting once, 4 = vomiting more than one. These assessments were performed in the PACU immediately after discharge and after 1, 3, 6, 12, and 24 h postoperatively. Side effects associated with auricular acupuncture-like bleeding, excessive pain, fainting, broken needles, and local infection were recorded.

Statistical Analysis

The statistical analysis was performed using IBM SPSS Statistics® 22 for Windows 10 operating system. Normality was assessed using the Kolmogorov–Smirnov test and visual inspection of histograms. For demographic and baseline comparison, the standardized difference was calculated using a web-based effect-size calculator.[14] 2-tailed t-test was used to analyze the continuous variables (hemodynamic parameters, pain score, 1st request of analgesia, 24 hours analgesic consumption) between the two studied groups while chi-square test was used for categorical and dichotomous variables (incidence of nausea, vomiting and level of the block at end of surgery). Values were expressed as mean ± standard deviation (SD) for continuous variables or as a percentage of the group from which they were derived (categorical variables). P-value < 0.05 was considered significant. Presentation of the statistical outcomes in the form of tables and graphs was performed using the "Microsoft Office Excel® 2010" program.

24 patients per group were needed to detect 5.39 mg difference between the means of total 24 hours postoperative morphine consumption in patients undergoing cesarean section between electro-acupuncture and control groups, at a standard deviation of 5.18,[15] with 95% power and a level of significance 5%. After considering a 20% dropout rate, the required sample size was 56 patients (28 patients/group).

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