Validating a New Method to Assess Estimated Blood Loss in the Obstetric Population
Phase: NA
Conditions: Pregnancy Complications
Sponsor: The University of Texas Medical Branch, Galveston

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The University of Texas Medical Branch Galveston 
Research Protocol 
 
Validating a New Method to Assess Estimated Blood Loss in the Obstetric 
Population 
 
Principal Investigators: Antonio F. Saad, MD 
Co-Investigator: Fawzi Saoud, MD 
Faculty Sponsor: George R Saade, MD. 
Funding: Department of Maternal Fetal Medicine 
 
 
 
 
 
NCT03404375 
 
 
 
 

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1. Introduction/Background/Purpose:  
According to the World Health Organization, 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 or a 
loss of greater than 1,000 mL following cesarean birth often have been used 
for the definition of postpartum hemorrhage, 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 
surgeon performing the cesarean section would estimate the blood loss by 
visually assessing the blood collected in the surgical drape and counting the 
number of lap sponges used thru out the procedure. 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 surgeon and surgical staff’s subjective assessment 
that is severely limited by human error and the presence of large volumes of 
amniotic fluid, irrigation, or both (6). Another limitation is that blood loss is 
frequently estimated at the end of the procedure. 
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 

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significant decay in blood loss estimation skills over time (7). 
The Triton system (Gauss Surgical, Inc., Palo Alto, CA) is a novel mobile 
monitoring platform that combines mobile computing with Gauss Feature 
Extraction Technology (FET) to directly assess Hb mass (mHb) absorbed by 
surgical sponges from an image (8). The device is an iPad like imaging device 
that will assess blood loss via imaging of the surgical sponges used in the surgery. 
In 2014, Konig at al. showed that mobile blood loss monitoring using the 
Triton system is accurate in assessing mHb on surgical sponges across a 
range of ambient light conditions, sponge saturation, saline contamination, 
and initial blood Hb. Utilization of this tool could significantly improve the 
accuracy of blood loss estimates (9). Holmes et al. also showed that the novel 
mobile monitoring system provides an accurate measurement of mHb on 
surgical sponges as compared with manual rinsing measurements, and is 
significantly more accurate than the gravimetric method (10).  
 
However, these studies were performed on patients undergoing a myriad of 
surgical procedures not just limited to obstetrical patients. To our 
knowledge, this technology has not been validated in the obstetrical 
population at risk for hemorrhage.  
The gauss/triton colorimetric system is not standard of care at UTMB.  Not 
enough data is available to support its use, despite being FDA approved to 
estimate blood loss. Most evidence is available in non-pregnant patients. In 
the obstetric population no definitive evidence exists, and the only trial that 
has been performed was recently published in AJP reports for which one of 
our co-PIs (Dr. Saade) is the chief editor (11). In that trial, only the accuracy 
was evaluated, and we believe that further evidence is needed to support its 
use. 
Our hypothesis is that this device will enable clinicians to prospectively and 
objectively assess EBL. Ultimately after its validation, our results will be used 
to propose a multicenter clinical trial to the NICHD MFMU network to 
evaluate the clinical utility of this system. 
This study will be a prospective cohort study, in which we will evaluate two 
methods of evaluating intraoperative blood loss during cesarean delivery 
(usual clinical assessment versus Device). 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 are scheduled for an elective cesarean and 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 
(Dr. Fawzi Saoud) and by the study collaborators (Dr. Katherine Jelliffe, 

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Mauricio La Rosa, Joe Eid, Nadia Megahed, and Mahmoud Abdelwahab). If 
patients agree to participate, a CBC (complete blood count) will be obtained 
via venous puncture. The device will be used during the delivery in the 
operating room. The device will be used to assess EBL by the research staff 
only and results/ EBL assessment will be masked to the clinical team. 
Unmasking will only occur after collecting the data from the device with 
purpose to perform data analysis. Patient management will be according to 
the clinical team. All patients undergo a CBC postpartum. The drop in Hgb 
(DHgb) between the pre and post cesarean CBCs will be calculated for each 
patient. Patients will be divided into quartiles of DHgb. Cases will be those 
patients whose DHgb is in the upper quartile, while controls will be those 
patients whose DHgb is in the lower 3 quartiles. We will be comparing EBL 
by standard clinical assessment versus result from the device between cases 
and controls. 
 
The colorimetric Triton system which comprises of the device, software 
analysis and staff training will be supplied by the manufacturer free of 
charge. We will be offering our skills, fellows 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 complete 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 242 subjects.  
 
3.2. Baseline procedures: In some patients, there will be no baseline 
procedures aside from using the masked device for assessment of EBL. If a 
preop CBC is not indicated clinically or not available, then a preop CBC will 
be obtained after consent is signed. Funding from the Ob/Gyn department 
will cover the cost of this test. The device will be set by the manufacturer not 

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to reveal the EBL in order to mask the surgical staff hence not affecting the 
standard assessment of EBL already implemented in our surgical suite.  
Neither the subject’s insurance nor the subject will be responsible for any 
charges relating to tests done only for research. Please see attached budget 
and departmental letter of support. 
 
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.  
 
3.7 Outcomes 
• Primary outcome: Differences in EBL between cases and controls using 
clinical estimate versus device assessment. 
• Secondary outcomes: System performance (ROC sensitivity analysis 
and correlation). Delta hemoglobin, transfusion requirements, 
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. 
Scheduled cesarean 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  
• 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 this novel approach of assessing blood loss more 
objectively during cesarean section, there are many potential benefits, 

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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 
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 (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 220 will be able to evaluate our primary outcome. 
Accounting for 10% loss of data or follow-up: N total is 242 subjects. This was 
based on a study of 50 patients having cesarean deliveries using the Triton System 
(the mean measured blood loss was 555.8 ml with a standard deviation of 317 ml 
(11). 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: 
 

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        alpha =    0.0500 
        power =    0.8000 
        delta = -139.0000 
           m1 =  555.0000 
           m2 =  416.0000 
           sd =  317.0000 
        N2/N1 =    3.0000 
 
Estimated sample sizes: 
 
            N =       220 
           N1 =        55 
           N2 =       165 
We will also be using multiple model correlation (Pearson correlation 
coefficient) (secondary outcome) between EBL Device and EBL Standard.  We 
will also perform ROC curve analysis (secondary outcome) to compare the area 
under the curve (AUC) to predict DHgb 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 (EBL Device) from the independent variable (EBL standard). 
 
 
 
 
 

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