Based on Non-invasive Cardiac Output Monitoring System to Explore the Preventive and Therapeutic Effect of Transcutaneous Acupoint Electrical Stimulation on Hypotension After Intraspinal Anesthesia in Cesarean Section
Phase: NA
Conditions: Hypotension
Sponsor: First Affiliated Hospital Xi'an Jiaotong University

First Affiliated Hospital of Xi'an Jiaotong University              Version number：V4.0              Version date:：October 19，2021 
 
 
 
 
 
Based on non-invasive cardiac output monitoring 
system to explore the preventive and therapeutic 
effect of transcutaneous acupoint electrical 
stimulation on hypotension after intraspinal 
anesthesia in cesarean section 
 
Study Protocol 
 
Research number：KYLLSL-2021-314 
Version number：V4.0 
Version date:：October 19，2021 
Bidding unit ：First Affiliated Hospital of Xi'an Jiaotong University 
The department of the bidding unit：Anesthesia operation department 
Head of clinical research：Bai Juan 
 
 
 
 

First Affiliated Hospital of Xi'an Jiaotong University              Version number：V4.0              Version date:：October 19，2021 
Based on non-invasive cardiac output monitoring system to explore the preventive 
and therapeutic effect of transcutaneous acupoint electrical stimulation on 
hypotension after intraspinal anesthesia in cesarean section 
Study Design 
 
1. Research design 
This study is designed as a randomized, controlled clinical study, with the first affiliated 
Hospital of Xi'an Jiaotong University as the research center. Participants undergoing singleton 
cesarean section under intraspinal anesthesia are recruited from November 1, 2021 to March 1, 
2022. The diagnostic indicators of hypotension in this study are intraoperative systolic blood 
pressure < 90mmHg or blood pressure decreased by more than 30% of basal blood pressure, the 
main outcome measures are the incidence of hypotension during 30 minutes after subarachnoid 
administration, and the secondary indicators are the specific changes of hemodynamic indexes, the 
usage of ephedrine, the incidence of nausea and vomiting, the incidence of dizziness, chest 
tightness and dyspnea during 30 minutes after subarachnoid administration, and fetal Apgar score. 
The patients are selected according to the inclusion and exclusion criteria, and the informed 
consent form are signed. First of all, the selected patients are numbered sequentially, and then the 
participants are randomly divided into control group and TEAS (transcutaneous acupoint electrical 
stimulation) group by SPSS software. In the TEAS group, 15 minutes before anesthesia at bilateral 
Neiguan points and Zusanli points begin to receive dense wave electrical stimulation with the 
frequency of 10/50Hz, and last until 30 minutes after subarachnoid administration. In the control 
group, 15 minutes is performed before anesthesia, and electrodes are connected at the same 
acupoint, but no electrical stimulation is given, the duration is the same as that of the TEAS group. 
During the trial, participants know which group they will be assigned to and which treatment they 
will receive. According to the grouping of random tables generated by SPSS, a researcher will 
independently give corresponding treatment measures to participants who has had signed the 
informed consent form, and cover up the screen of the electroacupuncture instrument. Another 
data collection researcher who does not know about the grouping records the vital signs and other 
complications of the participants. When the total number of cases reaches the minimum number of 
cases required by statistics or reaches the project case collection node (March 1, 2022), the data 
will be statistically analyzed and processed by professional statistical researchers. 
 
Inclusion Criteria: 
• 
18 years ≤ age < 55 years 
• 
ASA classification I ~ II 
• 
full term (37 weeks ≤ gestational weeks < 42 weeks) 
• 
schedule for elective single cesarean section under spinal anesthesia 
• 
no other clinical trial 3 months before the enrollment 
• 
volunteer to participate and sign the informed consent form 

First Affiliated Hospital of Xi'an Jiaotong University              Version number：V4.0              Version date:：October 19，2021 
Exclusion Criteria: 
• 
severe preeclampsia or hypertension 
• 
diabetes 
• 
cardiac insufficiency 
• 
mental abnormality or cognitive impairment or inability to communicate 
• 
acupuncture points skin breakage, infection, allergy 
• 
the researchers believe that there are any conditions that are not suitable for inclusion. 
Elimination Criteria: 
• 
be unwilling to continue the trial during the trial  
• 
have adverse reactions caused by transcutaneous acupoint electrical stimulation during 
the trial  
• 
the effect of intraspinal anesthesia is not good and drugs are added or intubation is 
changed to general anesthesia  during the trial, 
• 
intraspinal block level is too high above T4 or too low to below T10 during the trial  
• 
loss of blood more than 400ml during the trial 
 
2. Research methods 
In this study, a randomized, controlled design method is used to study the pregnant women 
who meet the inclusion criteria of singleton cesarean section. 
Sample size estimation: 
Based on the pre-experimental results from July 5, 2021 to July 28, 2021, the incidence of 
hypotension is 40% in the TEAS group and 80% in the control group. The sample size and the 
incidence of hypotension in the TEAS group is compared with that in the control group are 
estimated by GPOWER3.1 software,. Using the z test of two independent samples in the non-
parametric test, double tails, α=0.05、1-β=0.85、N2/N1=1，P1=0.40、P2=0.80, 26 cases in 
each group are calculated. A total of 52 cases. According to the 10% lost follow-up rate, the 
minimum sample size in each group is 29 cases, with a total of 58 cases.  
Random: 
Randomized grouping is obtained by using SPSS software programming. First of all, the 
determined sample size is numbered from small to large according to the order of the operation, 
and then the number is inputted into the SPSS software. The random number is generated by the 
random number generator in the SPSS software program, and the generated random numbers are 
randomly grouped.  
Control: 
The number,Rrandom,group appears in the software in the running program is the patient 
serial number that has been arranged before, the random number generated by the software, and 
the grouping after randomization. 0 is defined as control group (Control group), and 1 is defined 
as transcutaneous acupoint electrical stimulation group (TEAS group). 
Open: 
The specific method of operation is that  participants know which group they will be assigned 

First Affiliated Hospital of Xi'an Jiaotong University              Version number：V4.0              Version date:：October 19，2021 
to and what kind of treatment they will receive. According to the grouping of random tables 
generated by SPSS, a researcher will independently give corresponding treatment measures to the 
participant who has had signed the informed consent form, and cover up the screen of the 
electroacupuncture instrument. Another data collection researcher who does not know about the 
grouping records the vital signs and other complications of the participant. Finally, all the data will 
be saved, and after all the data are collected, the professional statistical researchers will deal with 
the data accordingly. 
 
Clinical intervention program 
 
(1) group  
◼ 
transcutaneous acupoint electrical stimulation group (TEAS group): 15 minutes before 
anesthesia, begin to receive dense wave electrical stimulation with the frequency of 
10/50Hz at bilateral Neiguan and Zusanli points, and last until 30 minutes after 
subarachnoid administration.  
◼ 
Control group (Control group): 15 minutes before anesthesia, begin to connect the 
electrode at the same acupoint, but no electrical stimulation is given, the duration is the 
same as that of the TEAS group.  
 
(2) selection of acupoints 
⚫ 
Neiguan (PC6): be located on the palmar side of the forearm, two inches above the 
transverse carpal stria, between the tendon of the palmar longus muscle and the tendon of the 
radial carpal flexor muscle.  
⚫ 
Zusanli (ST36):  be located in the anterolateral leg, three inches under the calf nose point, a 
transverse finger (middle finger) from the anterior tibial crest. 
 
(3) TEAS stimulation parameters  
◼ 
frequency: 10/50Hz 
◼ 
waveform: dense wave  
◼ 
intensity: from low to high, adjust the stimulation intensity until the patient feels slight 
tingling, taking the maximum inductance that the patient can tolerate, no muscle convulsions, 
no discomfort as the standard, and record the final stimulation intensity.  
◼ 
duration: 45 minutes 
 
3. Research steps: 
Blood pressure (BP), electrocardiogram (ECG) and pulse oxygen saturation (SpO2) are 
measured routinely after participants included in the study entered the operating room. At the 
same time, the changes of cardiac function indexes such as stroke volume (SV), stroke index (SI), 
cardiac output (CO), cardiac index (CI), cardiac function index (CPI), systemic peripheral 
vascular resistance (TPR) and systemic peripheral vascular resistance index (TPRI) are monitored 
by impedance cardiac output measurement system. At the same time, the venous channel is 
established, and after the venous channel is established, the compound sodium chloride injection 
10ml / kg is infused for 15 minutes to eliminate the hypotension caused by the lack of blood 

First Affiliated Hospital of Xi'an Jiaotong University              Version number：V4.0              Version date:：October 19，2021 
volume. The blood pressure, heart rate and other hemodynamic parameters of the 5 minutes after 
the participants enter the room are recorded as basic values. According to the grouping situation, 
the participants are intervened to deal with 45 minutes. During anesthesia, the participants take the 
left lying position, routinely use No. 17 Tuohy needle for puncture, the puncture point is L3-4, and 
the No. 25 lumbar anesthesia needle is placed after reaching the epidural space. After confirming 
the cerebrospinal fluid outflow, the equal specific gravity local anesthetic solution is injected, the 
solution is 0.75% bupivacaine 2ml and cerebrospinal fluid 1ml mixture, the drug dose 2ml is 
injected, the injection time is 15 seconds, the lumbar anesthesia needle is pulled out, the No. 20 
epidural catheter is placed, and 3-4cm is placed on the side of the head. In order to prevent the 
hypotension syndrome in supine position caused by uterine compression of inferior vena cava, the 
participants adjust the bed inclination to the left 15°~20 °immediately aft er supine position. The 
mask is given to inhale oxygen with a flow rate of 2~3L/min. The anesthesia level is determined 
by acupuncture along the midline of the left clavicle, and the upper limit of the sensory block 
plane is controlled between T6~T8 by adjusting the height of the operation bed. The other 
adjuvant drugs are consistent. 
After subarachnoid administration, the hemodynamic data of the participants are recorded in 
30 minutes every 2 minutes. When hypotension occurs, ephedrine 5-10mg is given. If the blood 
pressure is still low after 2 minutes, ephedrine 5-10mg can be given again until the blood pressure 
recovers. Atropine 0.3mg is given intravenously when bradycardia occurred. 
The incidence of hypotension, nausea, vomiting, dizziness, chest tightness and dyspnea in the 
participants in 30 minutes after subarachnoid administration are recorded. 
24 hours after operation, the satisfaction of the participants are investigated. 
4. Evaluation index  
Main indicators: 
⚫ 
the incidence of hypotension during 30mintes after subarachnoid administration 
Secondary indicators: 
⚫ 
specific changes of hemodynamic parameters during 30minutes after subarachnoid 
administration 
⚫ 
 the usage of ephedrine during 30minutes after subarachnoid administration 
⚫ 
 the incidence of nausea and vomiting during 30minutes after subarachnoid 
administration 
⚫ 
 the incidence of dizziness chest tightness and dyspnea during 30minutes after 
subarachnoid administration 
5. Follow-up content 
The satisfaction of the participants will be evaluated by follow-up 24 hours after the 
participants’ operation. 
 
 
Note:  
◼ 
definition of hypotension: intraoperative systolic blood pressure < 90mmHg or blood 
pressure decreased by more than 30% of basal blood pressure 
◼ 
definition of sinus bradycardia: heart rate < 50 beats / min 

First Affiliated Hospital of Xi'an Jiaotong University              Version number：V4.0              Version date:：October 19，2021 
◼ 
satisfaction score: scores range from 0 to 10, the higher the score, the higher the 
participants' satisfaction with anesthesia 
 
 
 
6. Technical route 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Participants undergoing singleton cesarean section under intraspinal anesthesia in the First 
Affiliated Hospital of Xi'an Jiaotong University from November 1, 2021 to March 1, 2022 
Screening based on inclusion and exclusion criteria 
Randomly grouped according to the proportion of 1:1 
There are 29 cases in Control group 
and 29 cases in TEAS group. 
The data are collected after intervention, the 
usage of ephedrine and atropine, the specific 
changes of hemodynamic indexes, the 
incidence of hypotension and other adverse 
events during 30 mintes after subarachnoid 
administration, and the satisfaction of 
participants with anesthesia 24 hours after 
operation 
Basic data collection before 
corresponding intervention 
Statistical analysis