Estimating Blood Loss Using TritonTM in Vaginal Deliveries: A Validation Trial
Phase: NA
Conditions: Post Partum Hemorrhage, Blood Loss, Vaginal Bleeding, Vaginal Delivery
Sponsor: The University of Texas Medical Branch, Galveston

 
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The University of Texas Medical Branch Galveston 
Research Protocol 
 
Estimating Blood Loss Using TritonTM in Vaginal Deliveries: A Validation Trial 
(ELUSIVE Trial) 
 
Principal Investigator: Antonio Saad, MD  
Co-Investigators: Ruth Soulsby-Monroy, CNM, & George R Saade, MD. 
 
Funding: Department of Maternal Fetal Medicine 
 
1. Introduction/Background/Purpose:  
Postpartum hemorrhage (PPH) is the leading cause of maternal mortality in 
low-income countries and the primary cause of nearly one quarter of all 
maternal deaths globally (1). An estimated blood loss (EBL) in excess of 500 
mL following a vaginal birth has often been used for the definition of PPH, 
but the average volume of blood lost at delivery can approach these amounts 
when actually measured rather than estimated (2). More than half of all 
maternal deaths occur within 24 hours of delivery, most commonly from 
excessive bleeding (3). Worldwide, 140,000 women succumb to postpartum 
hemorrhage each year. The most common antecedents to postpartum 
hemorrhage are uterine atony, placental disorders, and trauma during 
delivery.  Improving maternal health worldwide is one of the WHO’s 8 
Millennium Developmental Goals. The prevention and treatment of PPH is an 
essential step towards the achievement of that goal (4). 
 
Estimates of blood loss at delivery are notoriously inaccurate, with under-
estimation more common than over-estimation (5). Traditionally, the 
clinicians performing the vaginal delivery would estimate the blood loss by 
visually assessing the blood collected in the delivery drape drain and 
counting the number of lap sponges used thru out the delivery. Current 
detection and management of hemorrhage is heavily based on clinical 
judgment, which often leads to delay in recognition and intervention. Often, 
interventions such as fluid resuscitation and blood transfusion are not 
initiated until significant hemorrhage has already taken place. The traditional 
method for estimating blood loss is based on the clinician and nursing staff’s 
subjective assessment that is severely limited by human error and the 
presence of large volumes of amniotic fluid (6).  
Early detection and treatment of this potentially life-threatening obstetric 
complication is of utmost importance in the field of obstetrics. Simulations 
and didactic training have been shown to improve visual estimations, but 
there are still poor associations between experience level and accuracy, and a 
significant decay in blood loss estimation skills over time (7).  

 
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The Triton L&D system (Gauss Surgical, Inc., Menlo Park, CA) is an FDA-
cleared mobile application on a tablet computer (iPad) that facilitates 
quantification of blood loss (QBL) by providing an easy to use process and 
user interface.  Dry weights of all potential blood containing substrates are 
built-in to the device allowing batch weighing with automatic subtraction of 
dry weights. There is also a V-drape simulator accounting for collected fluids 
with automatic subtraction of a measured amount of amniotic fluid.  
 
QBL is not regularly used at UTMB.  Although widely recommended, little 
data is available to support its use in the obstetrical population. We believe 
that gathering further evidence regarding its value is appropriate. 
Our hypothesis is that use of this device for QBL will enable clinicians to 
objectively measure blood loss in real-time.  
This study will be a prospective cohort study, in which we will evaluate two 
methods of evaluating blood loss during vaginal delivery (usual visual EBL 
assessment versus Device QBL). Of note, the subjects consented will be used 
as self-controls. 
2. Summary of project: This study will be a prospective cohort study. Patients 
who meet criteria for inclusion in the study will be approached for 
participation at same day of admission. Written informed consent will be 
obtained from the patients by the Co-PI and by the study collaborators. If 
patients agree to participate, a CBC (complete blood count) will be obtained 
via venous puncture routine in our facility as part of the admission labs 
which will be around 10 cc of blood. The device will be used during the 
delivery in laboring room. The device will be used to assess QBL by the 
research staff only and results/ QBL assessment will be masked to the 
clinical team. Unmasking will only occur following study completion with 
purpose to perform data analysis. Patient management will be according to 
the clinical team without the knowledge of the QBL. All patients undergo a 
CBC postpartum as part of post-partum evaluation, this will also be 
performed by venipuncture where 10 cc of blood will be collected. The drop 
in Hgb (Hgb) between the pre and post partum CBCs will be calculated for 
each patient. The post-partum CBC will be collected approximately 24-30 
hours from delivery as standard in our unit. The blood will be collected from 
each patient by the nursing staff who are experienced in withdrawing blood. 
Patients will be divided into quartiles of Hgb. Cases will be those patients 
whose Hgb is in the upper quartile, while controls will be those patients 
whose Hgb is in the lower 3 quartiles. We will be comparing visual EBL by 
standard clinical assessment versus the QBL result from the device between 
cases and controls. 
 

 
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The Triton L&D system which comprises of the device, software analysis and 
staff training will be supplied by the manufacturer free of charge. Research 
staff will be trained by the manufacturer. We will be offering our skills, 
fellows, midwifes and residents, who will be collecting data and we will be 
performing the data analysis. Results will be available to the manufacturer 
after results are completed. The results of this study will be presented in 
conferences or published in a peer-review journal. 
 
Demographic information will be obtained from the electronic medical 
record. The data will be kept on a password secured UTMB computer. An 
encrypted USB flash drive will be used to transfer data. The data will be 
identified and linked to the patient using the medical record number (MRN).  
During data analysis, all patient identifiers will be deleted. 
 
 
3. Study procedures:                          VISIT#1 
3.1 Screening, Recruitment and Consenting: When a patient meets 
inclusion criteria for participation in our study, the obstetrical team will 
contact the research team. Written informed consent will be obtained from 
the patient by the PI, study coordinator, or collaborator. Study participation 
will be completed when the patient is discharged from the hospital. The data 
collected will be kept on a password secured UTMB computer. An encrypted 
USB flash drive will be used to transfer data. The data will be linked via MRN, 
which is needed to access the demographic data and will be deleted when the 
data is analyzed. Our target sample size is 556 subjects.  
 
3.2. Baseline procedures: In some patients, there will be no baseline 
procedures aside from using the masked device for assessment of QBL. Every 
effort will be made to mask the clinical staff from the QBL information so as 
not to affect the standard assessment of visual EBL and medical decision 
making.  During blood loss assessment, clinicians will be instructed not to 
place any sponges and other junk or materials into the callibrated v-drape 
following placental delivery (before placenta is delivered this is allowed), 
since it can artificially inflate or interfere with the accuracy of QBL. Subjects , 
where this protocol deviation occurs, will be removed from the  final analysis 
and replaced by other cases in order to meet our final sample size. Neither 
the subject’s insurance nor the subject will be responsible for any charges 
relating to tests done only for research.  
 
3.3. Study visits/Follow-up: One study visit will be needed during the trial. 
The subject participation will be considered complete when the subject is 
discharged home. 
 
3.6. Withdrawals: Subjects who withdraw from the study after inclusion 
will be excluded from further follow-up. Data collected until the time of 
withdrawal will be analyzed.  

 
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3.7 Outcomes 
 Primary outcome: Differences in blood loss between cases and controls 
using clinical estimate (visual EBL) versus device assessment (QBL). 
 Secondary outcomes: System performance (ROC sensitivity analysis and 
correlation). Delta hemoglobin, hemorrhage recognition (defined as >500 
ml blood loss), transfusion requirements (timing, rate, dose, etc.), 
administration of uterotonics, colloid resuscitation, post-partum 
hemorrhage or hemorrhagic shock. 
 
4. Criteria for inclusion of subjects:  
Pregnant women between the ages of 18-50. 
Plan of care is vaginal delivery. 
 
5. Criteria for exclusion of subjects:  
• Incarcerated patients.  
• Patient unwilling or unable to provide consent. 
• Intrauterine fetal demise (no fetal heart beat identified and documented by 
two physicians).  
• Placenta previa or other known placental anomalies. 
•Any contraindications to vaginal delivery. 
•Enrolled in another trial that may affect outcome. 
 
 
6. Sources of research material: Electronic medical records. 
 
7. Recruitment methods and consenting process: See 3.1 above. 
 
8. Potential risks 
8.1 Loss of confidentiality: Any time information is collected, there is a 
potential risk for loss of confidentiality. Every effort will be made to keep the 
subject’s information confidential; however, this cannot be guaranteed.   
 
9. Potential benefits: With the QBL approach of assessing blood loss more 
objectively during vaginal delivery, there are many potential benefits to 
future patients, including: decrease in the delay in diagnosis of hemorrhagic 
shock, decrease in delay in interventions and improved postpartum 
surveillance. In addition, this data will be useful in designing a level 1 trial to 
measure outcomes such as transfusion rates, transfusion complications, 
hemorrhage and maternal death. 
 
10. Data monitoring: The PI, research coordinator, and collaborators will 
ensure that all aspects of data quality adhere to the study design. This will 
include monitoring for adherence to consent procedures, inclusion and 
exclusion criteria, valid abstraction, correct entry, timeliness and 

 
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responsiveness to data queries. Data will be collected and stored with the 
participant ID code only. The master enrollment log linking patient 
identifiers with study ID numbers will be kept in a password protected 
database on the Ob/Gyn department’s internal server. Several data collection 
forms will be used. Data on these forms will be devoid of personal identifiers 
and will be securely stored at the division offices. The research coordinator 
will be available to monitor the data and correct any discrepancies based on 
source documents if needed. 
 
11. Procedures to maintain confidentiality: Each subject will be assigned a 
study number with personally identifiable information deleted or removed. If 
needed, charts will be reviewed in the medical records area. Subjects' 
information will be de-identified and tagged with a number. Data will be 
collected and stored on a UTMB password-protected computer. 
 
Statistical approach: We will be performing a prospective study. After defining 
cases and controls using the cutoff of upper quartile for pre- to postop- hemoglobin 
drop. We will use univariable and multivariable analysis to check for association 
between both blood loss assessment techniques using the device and the subjective 
clinical assessment among our cases and controls. We will be comparing cases 
versus controls (two groups) and EBL/QBL (continuous variable and primary 
outcome) hence t tests/means were used for our sample calculation; For the 
purpose of the study, we believe a sample size of 500 will be able to evaluate our 
primary outcome. Accounting for 10% loss of data or follow-up: N total is 556 
subjects. This was based on a study of 30,937 patients having vaginal deliveries 
using the TritonTM System (the mean measured blood loss was 383.87ml with a 
standard deviation of 330.52 ml (unpublished data supplied by the 
manufacturer). For a power of 80% and alpha of 0.05 and 25% effect size 1: 3 
allocation (25%ile versus 75%ile PP delta hemoglobin): 
 
Estimated sample sizes for a two-sample means test 
t test assuming sd1 = sd2 = sd 
Ho: m2 = m1  versus  Ha: m2 != m1 
 
Study parameters: 
 
        alpha =    0.0500 
        power =    0.8000 
        delta =  -95.9700 
           m1 =  383.8700 
           m2 =  287.9000 
           sd =  330.5200 
        N2/N1 =    3.0000 
 
Estimated sample sizes: 
 

 
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            N =       500 
           N1 =       125 
           N2 =       375 
We will also be using multiple model correlation (correlation coefficient) 
(secondary outcome) between QBL Device and EBL Standard.  We will also 
perform ROC curve analysis (secondary outcome) to compare the area under the 
curve (AUC) to predict Hgb in the upper quartile by clinical estimate versus 
device assessment. The coefficient of multiple correlation takes values between 
0 and 1; a higher value indicates a better predictability of the dependent variable 
(QBL Device) from the independent variable (EBL standard). 
 
 
 
 
 

 
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