Conditions: Pregnancy Cesarean Section Aspiration
Keywords: Pregnancy Gastric Volume Ultrasound Measurement Aspiration Prevention Cesarean Section
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 72
Healthy volunteers: no

Brief summary:
Our objective is to compare gastric volumes (mL) between women who receive metoclopramide versus placebo prior to scheduled cesarean delivery in appropriately fasted patients. If metoclopramide is found not to reduce gastric volumes this would inform future practice guidelines for obstetric anesthesia, which currently recommends metoclopramide administration prior to cesarean deliveries.

We hypothesize that metoclopramide given to women with appropriate fasting prior to cesarean delivery does not result in any clinically significant reduction in gastric volume (mL) and therefore does not provide any additional benefit for aspiration prophylaxis but may expose patients to unnecessary side effects. A secondary objective will be to evaluate if gastric volume is a significant predictor of intraoperative nausea and vomiting.

Detailed description:

Arms:
arm 1: Intravenous administration of 10 mg metoclopramide arm 2: Intravenous administration of sterile normal saline

Interventions: intervention 1: Study drug metoclopramide intervention 2: Study drug placebo administration
Intervention descriptions: intervention 1: Intravenous administration of 4 mg metoclopramide intervention 2: Intravenous administration of placebo (sterile normal saline)

Protocol document:
Prot_SAP_000.pdf: 
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PROTOCOL TITLE:  Comparison of Gastric Volumes by Gastric Ultrasound in Term Parturients 
undergoing Scheduled Elective Cesarean Delivery with and without Metoclopramide 
 
 
PRINCIPAL INVESTIGATOR: 
Jennifer Banayan 
Associate Professor 
Department of Anesthesiology 
312-472-3585 
jennifer.banayan@nm.org 
 
 
VERSION DATE:  V1.1 3/11/2022  
 
  
STUDY SUMMARY: 
 
Investigational Agent(s)  
(Drugs or Devices) 
Metoclopramide vs. Placebo 
IND / IDE / HDE #   
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  
Funding Source  
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: 
Our objective is to compare gastric volumes (mL) between women who receive metoclopramide 
versus placebo prior to scheduled cesarean delivery in appropriately fasted patients. If 
metoclopramide is found not to reduce gastric volumes this would inform future practice 
guidelines for obstetric anesthesia, which currently recommends metoclopramide administration 
prior to cesarean deliveries.  
 
 
 


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BACKGROUND: 
Aspiration is a rare but potentially serious complication of anesthesia. Pregnancy 
increases the risk of aspiration due to increased intragastric pressure from the gravid uterus and 
decreased esophageal sphincter tone from increased levels of progesterone. In addition to the 
standard pre-operative fasting times recommended by the American Society of 
Anesthesiologists (ASA) Practice Guidelines, the aspiration prophylaxis for cesarean deliveries 
recommended by the ASA Practice Guidelines for Obstetric Anesthesia include non-particulate 
antacids, H2-receptor antagonists, and/or metoclopramide.1-3 With the enforcement of fasting 
times and routine aspiration prophylaxis, as well as the increased use of neuraxial anesthesia 
and utilization of rapid sequence induction for general anesthesia, maternal mortality from 
pulmonary aspiration with cesarean deliveries have declined to almost negligible levels.4 
While metoclopramide, a promotility agent, has previously been shown to be effective for 
intra- and post-operative nausea and vomiting prophylaxis, there have not been any recent 
studies evaluating the utility of metoclopramide for aspiration prophylaxis in a patient with 
appropriate fasting prior to surgery.5 Given the unfavorable side effect profile, including akathisia 
and dystonic reactions, there may not be any additional benefit in the routine use of 
metoclopramide in healthy parturients undergoing an elective cesarean delivery who are 
appropriately fasted.6,7 
Gastric ultrasound has been shown as a noninvasive method to evaluate the risk of 
aspiration of gastric contents in pregnant women.8 It has been validated as an assessment of 
gastric volume compared with gastroscopic examination.9 Gastric ultrasound can determine if 
the gastric volume present is consistent with baseline gastric secretions and negligible risk, or if 
it is a higher volume posing a significant aspiration risk.10 Pregnant patients presenting for 
elective cesarean delivery were found by gastric ultrasound to have an empty stomach after 
following conventional fasting guidelines.11 
The objective of this proposed study is to use gastric ultrasound to evaluate the effect of 
metoclopramide in reducing gastric volume prior to elective cesarean delivery. We hypothesize 
that metoclopramide given to women with appropriate fasting prior to cesarean delivery does 
not result in any clinically significant reduction in gastric volume (mL) and therefore does not 
provide any additional benefit for aspiration prophylaxis but may expose patients to 
unnecessary side effects. A secondary objective will be to evaluate if gastric volume is a 
significant predictor of intraoperative nausea and vomiting.  
 
References 
1. Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the 
Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures: 
An Updated Report by the American Society of Anesthesiologists Task Force on Preoperative 
Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration. 
Anesthesiology. 2017 Mar;126(3):376-393. PMID: 28045707. 
2. Mendelson CL. The aspiration of stomach contents into the lungs during obstetric anesthesia. Am 
J Obstet Gynecol. 1946 Aug;52:191-205. PMID: 20993766. 
3. Practice Guidelines for Obstetric Anesthesia: An Updated Report by the American Society of 
Anesthesiologists Task Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia 
and Perinatology. Anesthesiology. 2016 Feb;124(2):270-300. PMID: 26580836. 
4. Knight M, Bunch K, Tuffnell D, Shakespeare J, Kotnis R, Kenyon S, Kurinczuk JJ (Eds.) on behalf 
of MBRRACE-UK. Saving Lives, Improving Mothers’ Care - Lessons learned to inform maternity 
care from the UK and Ireland Confidential Enquiries into Maternal Deaths and Morbidity 2016-18. 
Oxford: National Perinatal Epidemiology Unit, University of Oxford 2020. 
5. Leus M, van de Ven A. Images in Clinical Medicine. An Acute Dystonic Reaction after Treatment 
with Metoclopramide. N Engl J Med. 2015 Oct;373(14):e16. PMID: 26422744. 


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6. Mishriky BM, Habib AS. Metoclopramide for nausea and vomiting prophylaxis during and after 
Caesarean delivery: a systematic review and meta-analysis. Br J Anaesth. 2012 Mar;108(3):374-
83. PMID: 22307240. 
7. Paranjothy S, Griffiths JD, Broughton HK, Gyte GM, Brown HC, Thomas J. Interventions at 
caesarean section for reducing the risk of aspiration pneumonitis. Cochrane Database Syst Rev. 
2014 Feb 5;(2):CD004943. PMID: 20091567. 
8. Carp H, Jayaram A, Stoll M. Ultrasound examination of the stomach contents of parturients. 
Anesth Analg. 1992 May;74(5):683-7. PMID: 1567035. 
9. Perlas A, Mitsakakis N, Liu L, Cino M, Haldipur N, Davis L, Cubillos J, Chan V. Validation of a 
mathematical model for ultrasound assessment of gastric volume by gastroscopic examination. 
Anesth Analg. 2013 Feb;116(2):357-63. PMID: 23302981. 
10. Van de Putte P, Perlas A. Ultrasound assessment of gastric content and volume. Br J Anaesth. 
2014 Jul;113(1):12-22. PMID: 24893784. 
11. Arzola C, Perlas A, Siddiqui NT, Carvalho JC. Bedside Gastric Ultrasonography in Term Pregnant 
Women Before Elective Cesarean Delivery: A Prospective Cohort Study. Anesth Analg. 2015 
Sep;121(3):752-8. PMID: 26097988. 
12. Arzola C, Perlas A, Siddiqui NT, Downey K, Ye XY, Carvalho JCA. Gastric ultrasound in the third 
trimester of pregnancy: a randomised controlled trial to develop a predictive model of volume 
assessment. Anaesthesia. 2018 Mar;73(3):295-303. PMID: 29265187. 
13. Chen X, Chen F, Zhao Q, Zhang L, Liu Z. Ultrasonographic measurement of antral area for 
estimating gastric fluid volume in pregnant women. J Clin Anesth. 2019 Mar;53:70-73. doi: 
10.1016/j.jclinane.2018.06.040. Epub 2018 Oct 18. PMID: 30343226. 
14. Barnes TR. A rating scale for drug-induced akathisia. Br J Psychiatry. 1989;154:672-676. 
 
15. Pringsheim T, Gardner D, Addington D, et al. The Assessment and Treatment of Antipsychotic-
Induced Akathisia. Can J Psychiatry. 2018;63(11):719-729. 
 
 
STUDY ENDPOINTS: 
Primary study endpoints:  
- Change in gastric volume (mL) before medication and 30 minutes after 
Secondary study endpoints:  
- Rates of intraoperative nausea and vomiting during cesarean delivery and post-
operative nausea and vomiting after cesarean delivery (correlated to metoclopramide 
administration and gastric volume) 
- Side effects after administration (akathisia, dystonia, abdominal cramping, 
extrapyramidal symptoms) 
 
STUDY INTERVENTION(S)  / INVESTIGATIONAL AGENT(S): 
Metoclopramide 10mg (dopamine receptor antagonist, promotility agent) vs. placebo (normal 
saline). Metoclopramide 10mg/mL will be pre-drawn and diluted with normal saline into a 10mL 
syringe and stored with pharmacy. Placebo will be normal saline in a 10mL syringe. Medications 
will be made and stored by pharmacy. Patients will be randomized 1:1 for either drug by our 
anesthesia research nurses, who will request the drug from pharmacy. 
  
PROCEDURES INVOLVED: 
Study Design: This project will be conducted as a double-blind, randomized controlled trial 
 


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Study procedures: A baseline gastric ultrasound examination will be performed in the pre-
operative holding area an hour prior to the scheduled cesarean delivery by a study investigator 
trained in the use of gastric ultrasound. All of the investigators will have been trained in the use 
of gastric ultrasound by Dr. Banayan, an expert in point of care ultrasonography. Gastric 
ultrasound will utilize the SonoSite X-Porte Ultrasound System with a low frequency curvilinear 
probe (C60xp). 
 
After the initial examination, the patient will receive either 10 mg IV of metoclopramide or 
placebo according to a computer generated, randomized assignment in a double-blind fashion. 
Thirty minutes after the administration of the study medication, a follow-up gastric ultrasound 
examination will be completed by the same provider. For the gastric ultrasound examinations, 
we will position the patients in both the supine and right lateral decubitus positioning. Initially a 
qualitative assessment will be completed to determine the type of gastric content (empty, fluid, 
or solid content). Then, the cross-sectional area of the antrum will be measured in the right 
lateral decubitus positioning. This area can then be used to determine the estimated gastric 
volume using a mathematical model. There have been multiple models published specifically for 
third trimester pregnant women including ones by Arzola et al. and Chen et al.12,13  
 
Following the second ultrasound, metoclopramide-related side effects will be assessed using 
the Barnes Akathisia Rating scale, a validated scale for assessing akathisia, and a drowsiness 
scale.14,15 All patients will receive odanstetron (4mg) intravenous and after neuraxial anesthesia 
performed but prior to the start of the surgery and decadron (4mg) intravenous after delivery, 
which is standard of care. Intraoperative incidence of patient reported nausea and vomiting will 
be recorded along with the administration any rescue antiemetic medications given 
intraoperatively or post-operatively. The postoperative period will include the time until the 
patient is discharged from the post-anesthesia care unit (PACU). Anesthesia staff will be able to 
record nausea and vomiting episodes in Epic. Intraoperative and PACU data will be collected 
afterwards by a member of the research team. 
 
Of note, administration of metoclopramide is considered standard of care for cesarean 
deliveries; at Northwestern Medicine Prentice Hospital, it is usually only given to women who 
have labored prior to cesarean delivery but administration is recommended to be considered 
according to the ASA practice guidelines. Decision to give metoclopramide to elective cesarean 
deliveries ultimately depends on patient characteristics and provider preference. 
 
Data to be collected: 
Patient 
demographics 
Age, race/ethnicity, co-morbidities, GERD with pregnancy vs. currently, 
NPO time solids and liquids, BMI 
Obstetric data 
Gravida/parity, gestational age, number of prior cesarean deliveries, 
indication for cesarean delivery 
Ultrasound data 
Time of administration of study drug, time to obtaining ultrasound image 
from study drug administration, type of gastric content (empty, fluid, or 
solid content), cross-sectional area of the antrum and total gastric volume 
in supine and right lateral decubitus positioning 
Anesthesia data 
Method of anesthesia (ie. spinal vs. CSE), dose of neuraxial bupivacaine 
and neuraxial opioids, incision time, delivery time, administration of 
systemic opioids, anti-emetics given intra-op and in PACU, 
nausea/vomiting episodes intraoperatively, time from neuraxial 
administration to nausea/vomiting 
Neonatal data 
Apgar, need for resuscitation, admission to NICU, umbilical cord gases. 


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Survey data 
Barnes Akathisia Rating scale, drowsiness score, time of survey 
 
 
 
DATA AND SPECIMEN BANKING 
All data will be kept for a minimum of 7 years after publication, as required by Northwestern 
University. 
 
SHARING RESULTS WITH PARTICIPANTS 
Individual results will not be shared with participants.  Final study results will not be shared with 
participants. 
 
STUDY TIMELINES 
Patients who are scheduled for an elective cesarean delivery who meet inclusion criteria will be 
invited to participate in the study. We plan to enroll 72 patients (36 in each group) in 1 year. 
Primary study analyses will occur in the following 6 months. 
 
INCLUSION AND EXCLUSION CRITERIA 
Pregnant women greater than 37 weeks gestation who have been scheduled for elective 
cesarean deliveries will be screened upon admission via chart review. If patient meets criteria 
for study, the research team will invite them to participate in our study.  
 
Inclusion criteria: Any healthy (ASA Physical Status 2), age >18 years old, non-obese (BMI 
<40 kg/m2), age >18 years old term (>37 week), non-laboring parturient, single gestation, 
scheduled for a cesarean delivery and appropriately NPO is eligible for inclusion.  
 
Exclusion criteria: Systemic disease such as diabetes mellitus (type 1, type 2, or gestational 
diabetes), multiple gestation, abnormality of upper GI tract, history of GI tract related surgical 
procedures, use of gastric motility medications, active labor, renal impairment (creatinine >2), 
non-English speaking, cognitively impaired, history of QT prolongation, and general anesthesia. 
 
 
VULNERABLE POPULATIONS 
Pregnant women, see attachment of checklist 
 
PARTICIPANT POPULATION(S) 
Accrual 
Number: 
Category/Group: 
(Adults/Children 
Special/Vulnerable 
Populations) 
Consented: 
Maximum Number to be 
Consented or 
Reviewed/Collected/Screened 
Enrolled: 
Number to Complete 
the Study or Needed 
to Address the 
Research Question 
Local 
Pregnant women 
80 
72 
 
 
 
Study-wide 
 
 
 
 
 
 
Total: 
 
80 
72 


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RECRUITMENT METHODS 
Subjects will be approached and recruited by a member of the anesthesia research team after 
admission for elective cesarean section on the 8th floor labor and delivery of Prentice Women’s 
Hospital. The study team members will use Dashboard from the Labor and Delivery Unit at 
Prentice Women’s Hospital and obstetric medical histories to identify potential participants. The 
research team will discuss participation with the eligible patients and obtain written consent if 
amenable to participating in study. Subjects who are willing to participate in the study will 
provide consent on a tablet provided by study staff. Paper consent forms will also be made 
available if necessary. 
 
There will be no materials used to recruit participants. There is no need for solicitation or 
advertising for participation in the study. 
 
COMPENSATION FOR PARTICIPATION IN RESEARCH ACTIVITIES 
Participants will not receive compensation for participation in this study.  
 
WITHDRAWAL OF PARTICIPANTS 
Participation in the completion of the survey is completely voluntary. Participants can ask to stop 
the ultrasound or surveys at any point. Participants may withdraw from the study at any time 
without penalty by notifying the research staff that they would no longer like to participate. For 
individuals who withdraw from the study, the data collected prior to withdrawal will be 
maintained  
 
We do not foresee any circumstances which will cause research participants to be forcibly 
withdrawn from the study without their consent. 
 
RISKS TO PARTICIPANTS 
Risks are minimal but include the side effects of metoclopramide including abdominal cramps, 
akathisia, dystonia, and extrapyramidal symptoms. Metoclopramide also can cause QT 
prolongation, which may cause arrythmias in patients with QT prolongation. The risk of saline 
administration includes hypernatremia. We feel that these risks are minimal since we are only 
administering 10 mL of saline; metoclopramide is routinely administered as part of clinical care.   
 
In addition, the potential for loss of confidentiality and the feeling of being emotionally 
uncomfortable completing the surveys. We feel that this will cause no more than minimal risk to 
the participants. Confidentiality will be strictly maintained throughout the study.  
 
Gastric ultrasonography is safe to use during pregnancy. There are no risks to the mother or 
fetus associated with the performance of two-dimensional ultrasound during pregnancy. The 
participant may experience some discomfort associated with the pressure of the ultrasound 
probe on the skin during the procedure which should resolve upon completion of the 
examination.  
 
POTENTIAL BENEFITS TO PARTICIPANTS 
There is no direct benefit to the participants that is associated with completion of the study. 
Future patients may benefit from the knowledge gained from this study, as it will inform practice 
guidelines for obstetric anesthesia.   
 
DATA MANAGEMENT AND CONFIDENTIALITY 


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Statistical analysis: The primary outcome will be the change in calculated gastric volume. The 
secondary outcomes will be the incidence of intraoperative nausea and vomiting and side 
effects. Categorical data will be compared using the chi-squared test or Fisher’s exact test. 
Normal distribution for continuous variables will be determined using the Shapiro–Wilk test. 
Normally distributed continuous data will be compared using a two-tailed t-test and non-
parametrically distributed data will be compared using the Mann-Whitney U test. The criterion 
for rejection of the null hypothesis will be P < 0.05. 
 
Power calculation: In an equivalence test of means using two one-sided tests on data from a 
parallel-group design, sample sizes of 36 in the first group and 36 in the second group achieve 
81% power at a 5% one-sided significance level when the reference mean is 50 mL, the 
treatment mean is 40 mL, the standard deviation is 25 mL, and the range of the difference 
between these means that still results in the conclusion of equivalence is -25 mL to 25 mL. 
 
Data Security and Confidentiality: Each study participant will be assigned a study ID number 
that will be used to link study data to patient identification information (name and birth date) in a 
separate database. This database will be stored on a secured, password-protected network, 
accessible only by the study investigators. The completed data forms will be kept in folders with 
only the study ID number as an identifier. These folders will be placed in a secure, locked 
cabinet in the office of the Section of Obstetrical Anesthesiology located in Prentice Women’s 
Hospital 9th floor.  
 
All surveys will be completed and stored in the RedCAP online survey management system that 
is held in a secured server on the Northwestern University campus.  All surveys will be identified 
with the study ID number and will not include any direct patient identifiers.  When the survey is 
closed, all data will be transferred to a secure Northwestern University computer which is only 
accessible to study team members.  
 
Only study team members listed in the eIRB will have access to the data files. Data will be 
password protected using a Department of Anesthesiology dedicated computer which is backed 
up nightly by the departmental server which is located on the 5th floor Arkes Pavilion. The 
access is controlled by key card and password protected by the departmental data manager. 
Only the study ID number will be used to identify participants during data analysis. The data will 
be stored in the departmental computer until the completion of the study, including the final data 
analysis. Members of the anesthesia team collecting these data will be educated on the process 
prior to approaching prospective participants. Under no circumstances will individually 
identifiable data be released to anyone without the written consent of the subject. Results will be 
reported as group findings only. Seven years after study completion, all data will be destroyed 
using departmental standards and current vendors, in compliance with NU policy. 
 
All ultrasound data will be de-identified at the time of enrollment with the participant’s six-digit 
study ID number. The ultrasound images will be exported from the ultrasound machine on 
Qpath, which is a secure and HIPPA compliant ultrasound workflow manager. These images 
will only be accessible to study team members. All data will be stored on the same computer 
and backed up in the PI’s office. Seven years after study completion all ultrasound data will be 
destroyed in compliance with NU policy. 
 
All data access will be password protected and only available to study investigators listed on the 
IRB application. Data access will be controlled by the Principal Investigator. All members of the 
study team will have completed Northwestern University requirements for the responsible 


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conduct of research including the Collaborative Institutional Training Initiative (CITI) Training 
Modules 
 
PROVISIONS TO MONITOR THE DATA TO ENSURE THE SAFETY OF PARTICIPANTS 
A data monitoring committee consisting of the Department of Anesthesiology Director of 
Research, a statistician, and a faculty member from the obstetrics department along with the 
study research personnel will periodically evaluate the data collected to determine whether 
participants remain safe. Safety data and adverse event data will be reviewed using the medical 
record and data collection form. It will be reviewed once half subjects (40 patients) are enrolled. 
Any adverse events will be reported to the IRB.  
 
PROVISIONS TO PROTECT THE PRIVACY INTERESTS OF PARTICIPANTS  
Research subjects will have a few interactions with study team members. First, they will  
discuss the study and the research study team member will obtain written informed  
consent. A second interaction will occur during the first ultrasound and the drug study 
drug administration. The third interaction will be an assessment survey for side effects. 
The fourth interaction will be the second ultrasound scan. Participants may be contacted 
in the PACU after delivery to ask them about any nausea and vomiting they may have 
experienced. The research study team is only to be allowed to view the data sheets of 
the mother and REDCap for selected data within the parameters of the study.  
 
COMPENSATION FOR RESEARCH-RELATED INJURY N/A  
 
ECONOMIC BURDEN TO PARTICIPANTS 
N/A 
 
CONSENT PROCESS 
Written consent will be obtained from all study participants by a member of the study  
team. The consent process will occur prior to delivery. Consent will occur in the 
patient’s room in the Labor and Delivery Unit, 8th floor, at Prentice Women’s Hospital. 
There is no waiting period. SOP HRP 090 will be followed. The research study team will 
spend greater than 10 minutes discussing the study. With each subject ample time will 
be allowed for patient to answer questions regarding the study and the consent 
document. The subject will also be informed that there is no conflict of interest between 
the PI and the protocol. The PI will not receive financial remuneration nor will the study  
participation affect the subject’s financial charges for their care.  
 
NON-ENGLISH SPEAKING PARTICIPANTS 
We will only be enrolling English speaking patients.  
 
PROTECTED HEALTH INFORMATION (PHI AND HIPAA) 
For the purposes of this study we will collect the following Protected Personal Health 
Information: participant name, birth date, and zip code.  We also intend to access the medical 
chart of all study participants to obtain relevant information about medical history.  We have 
included a section on HIPAA authorization in our consent form.   
 
WAIVER OR ALTERATION OF CONSENT PROCESS 


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Written informed consent will be required for all patients. There will be no waiver, or alteration of 
the consent process. Only English-speaking, adult patients, who are not cognitively impaired, 
and capable of consenting will be recruited. 
 
QUALIFICATIONS TO CONDUCT RESEARCH AND RESOURCES AVAILABLE 
There is allotted time for 44 scheduled cesarean deliveries each week at Northwestern Medicine 
Prentice Women’s Hospital. We hope to recruit 72 patients in 1 year, which should be easily 
achieved, given there could potentially be over 2,000 scheduled cesarean deliveries in one year 
(3.4% recruitment rate). Recruitment can be performed by our research team members and 
research nurses. It can occur any day anesthesia fellows or investigators who have been 
trained in gastric ultrasound are present. Any anesthesia staff will be able to care of the patient 
in the operating room.