The Use of P6 Acupressure for the Reduction of Intraoperative and Postoperative Nausea and Vomiting in Women Undergoing Cesarean Delivery: a Randomized Trial
Phase: NA
Conditions: Pregnancy Related, Cesarean Delivery, Nausea, Vomiting
Sponsor: Northwestern University

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PROTOCOL TITLE:  The use of P6 Acupressure for the Reduction of Intraoperative 
and Postoperative Nausea and Vomiting in Women undergoing Cesarean Delivery: a 
Randomized Trial 
 
 
PRINCIPAL INVESTIGATOR: 
Feyce M. Peralta, MD, MS 
Department of Anesthesiology 
(312) 472-3585 
feyce.peralta@northwestern.edu 
 
 
VERSION DATE: 
Version 1.1 07/27/2023 
 
 
STUDY SUMMARY: 
Investigational Agent(s)  
(Drugs or Devices) 
N/A 
IND / IDE / HDE #  N/A 
Indicate 
Special Population(s) 
 Children  
 Children who are Wards of the State  
 Adults Unable to Consent   
 Cognitively Impaired Adults  
 Neonates of Uncertain Viability  
 Pregnant Women  
 Prisoners (or other Detained/Paroled Individuals)  
 Students/Employees  
Sample Size 200 
Funding Source Department of Anesthesiology 
Indicate the type of 
consent to be obtained 
 Written  
 Verbal/Waiver of Documentation of Informed 
Consent 
 Waiver of HIPAA Authorization  
 Waiver/Alteration of Consent Process   
Site 
 Lead Site (For a Multiple Site Research Study) 
 Data Coordinating Center (DCC) 
Research Related 
Radiation Exposure 
 Yes  
 No  
DSMB / DMC / IDMC 
 Yes  
 No 
 
 
OBJECTIVES: 
The purpose of this study is to evaluate if the addition of P6 pressure point stimulation 
as opposed to sham-point stimulation will decrease intraoperative and postoperative 

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nausea and vomiting (IONV and PONV) for patients undergoing non-emergent 
cesarean delivery. We hypothesize that the addition of stimulation of the P6 pressure 
point to our institutional current standard of care (phenylephrine infusion, intravenous 
fluid bolus, and as needed intraoperative ondansetron) will decrease the occurrence of 
intraoperative emesis.   
 
 
BACKGROUND: 
Intraoperative and postoperative nausea and vomiting (IONV and PONV) are very 
common among parturients undergoing cesarean delivery with neuraxial anesthesia, 
with an incidence up to 80% without intervention.1 IONV and PONV are thought to be 
reduced with the use of prophylactic phenylephrine infusion post spinal anesthesia, 
however, a recent Cochrane review noted only low-quality evidence to support this 
hyopthesis.2 IONV may decrease maternal satisfaction, increase the risk of aspiration, 
and impair surgical conditions.3 IONV during cesarean delivery is multifactorial, 
secondary to hypotension, visceral stimulation from uterine/peritoneal manipulation, 
physiologic changes of pregnancy, and neuraxial opioids.  
 
Although the mechanism is unknown, there are multiple studies demonstrating that 
stimulation of the P6 acupressure point decreases PONV in a variety of surgical 
procedures.4,5 Stimulation of the P6 acupressure point for antepartum patients has also 
been demonstrated to improve nausea.6  
 
There is mixed data on stimulation of the P6 pressure point alone preventing IONV 
during cesarean delivery.7,8 Studies have demonstrated inferiority of stimulation of the 
P6 acupressure point alone compared to ondansetron during cesarean delivery.9 
However, there are no studies that evaluate if P6 stimulation in addition to ondansetron 
decreases IONV during cesarean delivery. Benefits of P6 stimulation include simplicity, 
quick onset of action (~2-3 min of pressure), minimal adverse events, no drug-drug 
interactions, low cost, and lack of transfer to the fetus through placenta and breast milk. 
An evaluation of the efficacy of P6 acupressure stimulation in addition to the current 
standard of care (phenylephrine infusion, intravenous fluid bolus, and ondansetron) is 
warranted. 
 
 
STUDY ENDPOINTS: 
Primary Endpoint: Presence of emesis during scheduled cesarean delivery. 
 
Secondary Endpoints: Presence of emesis after scheduled cesarean delivery, presence 
of nausea during scheduled cesarean delivery, presence of nausea after scheduled 
cesarean delivery, number of additional antiemetic rescue medications given 
intraoperatively and postoperatively, maternal satisfaction with IONV/PONV 
management. 
 
 
 

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STUDY INTERVENTION(S) / INVESTIGATIONAL AGENT(S): 
The P6 pressure point is 2 inches proximal to the flexor retinaculum, between the flexor 
carpi radialis and palmaras longus.  
 
A non-coated ferrite 0.09-inch by 0.2-inch diameter magnet with a small protrusion with 
an adhesive sticker will be used for P6 acupressure point stimulation bilaterally. The 
magnets used are the same magnets used in clinical practice by Northwestern Medicine 
Osher Center for Integrative Medicine (150 E Huron St UNIT 1100, Chicago, IL 60611). 
 
The sham pressure point used will be more distal to the P6 acupressure point, which 
has been used in other studies comparing the effectiveness of acupressure to sham 
point.10 
 
 
PROCEDURES INVOLVED: 
Prospective, double-blinded, sham controlled, randomized clinical trial. 
 
After signing the informed consent form, study subjects will be randomized to P6 
acupressure group (P6) vs sham point group (Sham control). Randomization will occur 
by randomly selecting a single envelope from a mixed pile of 1:1 P6 vs sham group 
sealed envelopes (total 200, 100 designating P6 group, 100 designating sham group, 
will decrease by 1 envelope after every patient enrollment). Each study subject will be 
assigned a study number. An envelope containing two pressure point magnets, two 
adhesive stickers, and diagram showing where to place the magnet will be opened by 
the research team member. The magnets will be placed on the patient by a research 
team member. The study subject will be in one (1) of two (2) groups:  
- 
P6 group: the pressure point will be stimulated by the presence of the magnet 
when positioned properly on the P6 acupressure point. Additional pressure may 
be applied as desired by the study subject but is not necessary for P6 
stimulation. 
- 
Sham group: the sham pressure point (distal to the P6 acupressure point) will not 
provide any benefit.  
 
The study subject will then be taken to the operating room where a spinal anesthetic will 
be administered according to current standard of practice. Maternal hypotension will be 
defined by systolic blood pressure less than 100mmHg or mean arterial pressure less 
than 65mmHg or mean arterial pressure less than 20% of the baseline mean arterial 
pressure (baseline blood pressure will be considered the value in mmHg obtained by 
the nursing staff in the preoperative area). Maternal hypotension will be treated with 
phenylephrine, ephedrine and/or intravenous fluid boluses as per our current standard 
of care.  
 
A surgical anesthetic level check will be completed per our current standard of care. If 
the anesthesia level is noted to be above T2, the magnets and adhesive will be 
removed and the patient will be excluded from the study.   

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Ondansetron 8mg IV and dexamethasone 8mg IV will be given after delivery per our 
current institutional standard of care (Northwestern University Enhanced Recovery after 
Cesarean) or prior to delivery on an as needed basis. Additional antiemetic medications 
will be given as needed by the anesthesia provider. Patients will not be denied 
additional antiemetic medications when participating in the study. All medications will be 
documented in EPIC. If the patient experiences IONV, the “nausea” or “vomiting” icons 
will be documented in their electronic anesthesia record (EPIC).  
 
There will be routine postoperative orders placed by the anesthesia team in the post-
anesthesia care unit (PACU). These orders include antiemetic medications, which can 
be administered by the PACU nursing staff as needed. Routine postoperative orders, 
including antiemetic medications as needed, will be placed by the OB team on 
admission to postpartum per our institution’s current standard of care. Medications will 
be administered and documented by the nursing staff in standard fashion, and this data 
will be collected by the study personnel. Patients can provide additional pressure point 
stimulation as needed throughout their postoperative course, for up to 72 hours or until 
discharge, whichever comes first. The patients can contact a research team member by 
phone if a magnet is lost or moved, and the team member will help replace the 
magnet(s) in the appropriate location.  
 
The patient will be instructed to remove the magnets 48 hours postoperatively or upon 
discharge, whichever occurs first. Data collection will terminate at this point. Removing 
the magnets involves only removal of the adhesive stickers. The magnets can be 
disposed in the trash or patients may keep the magnets if desired. Patients will then 
complete a 5-minute survey to record their incidence and experience of nausea. This 
survey includes a validated PONV intensity and visual analog scale.11,12 
 
Standard of care is not altered in this study. All participants will receive the same level 
of care if they choose to participate in the study, regardless of which study group they 
are in.  
 
 
SHARING RESULTS WITH PARTICIPANTS 
Results will not be shared with participants.  
 
 
STUDY TIMELINES 
For research team: 
- IRB approval is expected to take 4 weeks. 
- Patient enrollment and data collection will likely occur for 3-6 months (assuming 
there are approximately 5 scheduled caesarean deliveries per day Monday-
Friday and 2 scheduled caesarean deliveries on Saturday and Sunday). Data 
collection ends when 200 patients are enrolled in the study 
- Data analysis occurs after 50 and 150 participants or in the event of an adverse 
event related to a magnet 

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- Statistical analysis will occur after data collection and will take 1 month 
- Manuscript production and editing will occur over the following 2 months 
 
For patients: 
At admission: 
- Informed consent obtained 
- Demographics obtained including: age, weight, height, BMI, race/ethnicity, parity, 
number of prior caesarean deliveries 
- Patient randomized into P6 or sham group 
- Magnets placed by research team member using enclosed diagram 
- Spinal anesthesia administered in standard fashion with accompanying 
phenylephrine infusion, rate documented in EPIC 
- Patient can apply additional pressure to magnets as needed intraoperatively 
- Nausea and vomiting icons utilized by in-room anesthesia provider 
- The following protocol will be followed for intraoperative nausea/vomiting and all 
medications will be documented appropriately in EPIC:  
o If nausea begins prior to delivery:  
 With the first complaint of nausea, phenylephrine or ephedrine can 
be administered to treat hypotension, and intravenous fluids will be 
given as a bolus 
 With the 2nd complaint of nausea, or at the onset of emesis, 
encourage use of additional pressure on magnets 
o After delivery: 
 Administer 8mg Ondansetron and 8mg Dexamethasone 
 If continued IONV, encourage use of additional pressure on 
magnets 
 If continued IONV, consider the following medications: IV Fentanyl, 
Prochlorperazine, Propofol, Diphenhydramine 
- Additional rescue medications administered as needed after delivery and 
documented in EPIC 
 
PACU/floor: 
- Patient can apply additional pressure to magnets as needed postoperatively 
- Rescue medications administered as needed and documented in EPIC by 
nursing staff 
 
At 48 hours post-delivery or discharge, whichever is first: 
- Magnets removed by patient by removing adhesive 
- Survey given to patient by anesthesia provider 
 
 
INCLUSION AND EXCLUSION CRITERIA 
Inclusion: age ≥18 years of age, English-speaking, pregnant patients presenting for 
scheduled cesarean delivery of a full-term fetus (>37 weeks’ gestation), patients 
scheduled as ERAC, parturients undergoing spinal anesthesia. 
  

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Exclusion: patients requiring emergent delivery, fetal demise, patients with adhesive 
allergy/sensitivity,patients with allergy/sensitivity to nickel, patients with inability to 
consent, patients with known abnormal placentation, patients with 
pacemakers/defibrillators, patients with positive COVID-19 tests. 
 
 
VULNERABLE POPULATIONS 
This study includes pregnant patients. See attached HRP-412. 
 
 
PARTICIPANT POPULATION(S) 
Accrual 
Number: 
Category/Group: 
(Adults/Children 
Special/Vulnerable 
Populations) 
Consented: 
Maximum Number to be 
Consented or 
Reviewed/Collected/Screen
ed 
Enrolled: 
Number to 
Complete the 
Study or Needed 
to Address the 
Research 
Question 
Local 
200 HRP 412 
200 
200 
 
 
 
Study-wide 
 
 
 
 
 
 
Total: 
200 
200 
200 
 
 
RECRUITMENT METHODS 
Anesthesia providers will be educated on the project, the consent process, and will 
remain blinded to P6/sham pressure point during the education process. A study team 
member will be available at all times to answer questions during the education process.  
 
Potential study subjects will first be identified on the Labor and Delivery board as being 
both a scheduled cesarean delivery and part of ERAC. Potential study subjects will not 
be approached by a research team member until there is a documented negative result 
of their COVID-19 test. Given COVID-19, we will attempt to minimize the number of 
people entering the subjects’ room. Subjects that meet inclusion criteria will be 
approached after the anesthesia evaluation/consent by a study team member. The 
study team member will: ask potential participants to sign the informed consent form; 
answer all subjects’ questions; and place the magnets on all subjects.  
 
 
COMPENSATION FOR PARTICIPATION IN RESEARCH ACTIVITIES 
Study subjects will not be compensated for their participation in this study. As noted 
above, they can keep their magnets at study completion if desired.  

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WITHDRAWAL OF PARTICIPANTS 
A subject can request withdrawal from the study at any time. The study subject can self-
terminate their study involvement by magnet removal, an event which will be addressed 
by our post-intervention survey. Surveys will be evaluated regularly to address any 
questions/concerns found on the post-intervention survey, and the subject will be 
contacted if follow-up is required/requested. A research team member will contact the PI 
by secured email to inform her about the event leading to early study termination. If the 
subject requests, all data collected will not be used. 
 
 
RISKS TO PARTICIPANTS 
Due to COVID19, we will attempt to minimize the number of people entering patients’ 
rooms.  
 
The magnets may cause mild discomfort at the pressure point site. The magnets will not 
puncture skin. There are no known systemic risks to patients with short-term stimulation 
of the P6 pressure point.  
 
The main risk in study participation is skin irritation from adhesive that holds the 
magnets in place. Subjects with known adhesive sensitivity/allergy will be excluded from 
participation. 
 
The magnets are ferrite magnets, composed of ceramic and iron, which are the same 
magnet components used intraoperatively for deactivating defibrillators that 
Northwestern currently uses in operating rooms with electrocautery. The magnets could 
theoretically cause the patient to be at an increased rate of burns related to the 
electrocautery used during the operation, however, this risk is minimal to none. There 
are zero case reports of hand/wrist jewelry-related burns during any surgical procedures 
using electrocautery. A study involving metal microdermal implants in pigs with 
electrocautery did not show any evidence of tissue damage13. A grounding pad will be 
placed on the patient, as per the current standard of care, decreasing the risk of 
electrical current conducting through the magnet. The magnets will be a great distance 
away from the site where electrocautery will be used. The magnets could also 
uncommonly cause contact dermatitis, redness of skin, skin breakdown, and possible 
temporary discoloration of the skin. 
 
Study subjects will be excluded from the study with immediate magnet removal prior to 
incision if a sensory dermatomal level higher than T2 to sharp tactile sensation is 
observed. This measure will be taken to prevent any potential burn injury from occurring 
without the patient having completely intact thermal nociception. The study subject will 
also be excluded from the study with immediate magnet removal in the event general 
anesthesia is required at any point during their operative course. The subject can 
verbalize to the anesthesia provider if she is experiencing discomfort at the site of the 

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magnets during the operation, and the magnets will be immediately removed by the 
anesthesia provider. 
 
There will be no known risk to the fetus from magnet use. These magnets are frequently 
used for pregnancy-related nausea for patients in all trimesters.  
 
If the study subject experiences any magnet discomfort, it will be immediately removed 
by the in-room provider. 
 
 
POTENTIAL BENEFITS TO PARTICIPANTS 
Study subjects utilizing the magnets may experience a reduction in IONV and PONV 
and have increased satisfaction. Subjects with the magnets over the P6 point will 
experience a benefit only while the magnets are in place (intraoperatively and up to 
~48h post operatively or upon discharge).  
 
Subjects with the magnets over the sham point will likely not experience a benefit. 
 
 
DATA MANAGEMENT AND CONFIDENTIALITY 
This sample size was determined by assuming there is a baseline rate of 33% 
intraoperative vomiting and that there will be a relative decrease of approximately 50% 
in the group that receives acupressure during cesarean delivery14. Using a two-sided 
Fisher’s Exact Test, with a significance level of 0.05, it was determined each group 
should contain 98 participants to achieve 80.01% power to detect a difference between 
the group proportions of 0.18. The proportion in the P6 group is assumed to be 0.15 
under the null hypothesis and 0.33 under the sham group. The proportion in sham 
group is 0.15.  Each group was rounded up to 100 participations for a total sample size 
of 200. 
 
The hypothesis will be analyzed using a two-sided two-tailed independent sample t-test 
with a significance level of 0.05. The primary and secondary outcomes will be analyzed 
by two-tailed independent sample t-test or Chi-square test. All of the above information 
will be entered into clinicaltrials.gov prior to enrollment of the first research subject and 
within 1 year of study completion. 
 
All participants will be assigned a participant study number. A single password-
protected document will link the participant name to their participant number. This 
document will be kept in a password-protected computer in a locked office in of the 
Section of Obstetrical Anesthesiology suite in Prentice Women’s Hospital. The survey 
data and the signed consent form, will be stored in REDcap, a secure web application 
specifically geared for data capture and research studies. Only study team members 
listed in the eIRB will have access to the REDcap files and study data. De-identified 
data will also be password protected on a Department of Anesthesiology dedicated 
computer.  
 After the data set has been reviewed by the PI it will be deidentified.   

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 The deidentified data set will be kept in NM password protected computer 
located on the 10th floor Arkes Pavilion (Anesthesiology Administrative 
Office). Access of the data is controlled by the PI. The deidentified data set 
will be sent to Rush University statistician Robert McCarthy PharmD for 
complete statistical analysis.  The data will be sent via Northwestern 
University encrypted email after IRB approval and completion and execution 
of a one-way data use agreement (Northwestern University to Rush 
University).     
 
 
 
Only study ID numbers will be used to identify participants during data analysis. Data, 
including final analysis, will be stored on the departmental computer until study 
completion. Electronic and paper data will be destroyed 5 years after study completion 
using current standards. 
 
 
PROVISIONS TO MONITOR THE DATA TO ENSURE THE SAFETY OF 
PARTICIPANTS 
A data safety monitoring board consisting of a Department of Anesthesiology attending 
physician, a statistician, and study research personnel will regularly review the data 
collected to evaluate participants’ safety. Adverse event data and study withdraw data 
will be reviewed using the both medical record and surveys and stored in password-
protected adverse event/withdrawal form. It will be reviewed after 50 and 150 subjects 
have completed the study or if one of the study subject experiences symptoms 
concerning for an intra-operative burn from the magnet(s). If the follow-up surveys 
reveal concerns for frequent adhesive intolerance or frequent magnet removal prior to 
study end, the study will be halted for an investigation.  
 
If any study subject request removal of the magnets due to pain or symptoms 
concerning for a burn intraoperatively, the magnets will be immediately removed by the 
anesthesia provider with subsequent physician evaluation of the site. This information 
will be relayed to the PI via secure email.  
 
These magnets are considered safe for use and are frequently used by the 
acupuncturists at Northwestern Medicine Osher Center for Integrative Medicine. 
Adhesive intolerance is the most likely complication (redness, irritation, pruritus, and 
rash) and removal the adhesive should resolve symptoms with no long-term 
consequences. Subjects will be instructed during the consent to immediately remove 
the magnets/adhesive if they experience any discomfort. The follow-up survey will 
include a question specifically asking if the magnets were removed early and the 
circumstances leading up to removal.  
 
Participants are at risk for loss of confidentiality, however, there will be strict measures 

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to prevent such an occurrence. Refer to the section “DATA MANAGEMENT AND 
CONFIDENTIALITY” (above) for a detailed description. 
 
 
PROVISIONS TO PROTECT THE PRIVACY INTERESTS OF PARTICIPANTS 
Research subjects will have limited interactions with study team members, unless the 
patient requests further information, given COVID19 and to minimize disruption. The 
patient will discuss the research study with an anesthesia team member who will obtain 
written informed consent after pre-anesthesia evaluation and consent per our current 
standard of care. All further questions and follow-up will be conducted by phone by a 
research team member. Participants will complete a short survey (requiring less than 5 
minutes) prior to discharge or at approximately 48 hours post-operatively if that time 
frame falls between 7am and 6pm. Patients outside this time frame will be contacted the 
following morning to not disrupt their lives/sleep.  
  
 
ECONOMIC BURDEN TO PARTICIPANTS 
Participants are responsible for all costs of their care; however, these costs are the 
same costs they would incur if not participating in the study. 
 
 
CONSENT PROCESS 
Consent will occur in the preoperative area or in the patient’s private room, prior to 
transport to the operating room on the Labor and Delivery Unit, 8th floor, at Prentice 
Women’s Hospital. Written informed consent will be obtained from all study participants 
by the in-room anesthesia provider with a study team research member available for 
additional questions. There will be no waiting period. Consent document HRP-502 will 
be followed. Anesthesia providers will spend greater than 5 minutes discussing the 
study with each subject and should plan for an additional 5 minutes for any patient 
questions regarding the study or consent document. If the subject has further questions, 
a research team member will provide any additional information prior to transportation to 
the operative room. The subject will be notified that there is no conflict of interest 
between any research team member and the protocol, nor will any research team 
member receive financial compensation. Participants will be notified that study 
participation will not affect their medical care costs. 
 
 
NON-ENGLISH SPEAKING PARTICIPANTS 
Only English-speaking participants will only be enrolled. 
 
 
PROTECTED HEALTH INFORMATION (PHI AND HIPAA) 
This study involves the use of Protected Personal Health Information. HIPAA 
Authorization will be obtained from all participants. PHI collected will include only the 
following: 
- Names 

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- Dates and Age: Including birth date, admission date, and discharge date 
- Telephone numbers 
- Medical Record Numbers 
- Email address 
 
 
QUALIFICATIONS TO CONDUCT RESEARCH AND RESOURCES AVAILABLE 
Northwestern’s section of Obstetrical Anesthesiology provides obstetric care to 
approximately 4,000 patients per year undergoing caesarian delivery. The principal 
investigator (Feyce M. Peralta, MD, MS) is an Associate Professor in the obstetrical 
anesthesiology section who regularly supervises fellows, residents, and CRNAs 
providing care to patients on labor and delivery. An obstetric anesthesia fellow 
(Stephanie Woodward, MD) will have ample time for data collection and evaluation 
during the course of the study. The section of Obstetrical Anesthesiology has a 
dedicated group of clinical research nurses and study coordinator who assist with 
recruitment and follow-up of patients in clinical anesthesiology trials. All study team 
members have CITI training. 
 
Northwestern’s Integrative Medicine Acupuncturists were used to educate anesthesia 
providers on acupressure. These acupuncture providers maintain certification and 
regularly see patients in clinic to treat a variety of diseases/symptoms, including 
nausea/emesis. This study will utilize the same type of magnets used in their clinical 
practice.   
 
 
REFRENCES 
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section under regional anesthesia. Int J Obstet Anesth. 2005 Jul;14(3):230-41. 
doi: 10.1016/j.ijoa.2004.12.004. PMID: 15935649. 
2. Chooi  C, Cox  JJ, Lumb  RS, Middleton  P, Chemali  M, Emmett  RS, Simmons  
SW, Cyna  AM. Techniques for preventing hypotension during spinal anaesthesia 
for caesarean section. Cochrane Database of Systematic Reviews 2020, Issue 7. 
Art. No.: CD002251. DOI: 10.1002/14651858.CD002251.pub4. PMID: 28976555. 
3. Ho CM, Tsai HJ, Chan KH, Tsai SK. P6 acupressure does not prevent emesis 
during spinal anesthesia for cesarean delivery. Anesth Analg. 2006;102(3):900-
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Acupuncture and Metoclopramide on Postoperative Nausea and Vomiting after 
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29696109. 
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