Am J Perinatol 2021; 38(10): 1031-1035
DOI: 10.1055/s-0040-1701507
Original Article

Automated Quantification of Blood Loss versus Visual Estimation in 274 Vaginal Deliveries

Andrew F. Rubenstein
1   Department of Obstetrics and Gynecology, Hackensack Meridian Health, Hackensack, New Jersey
Stacy Zamudio
2   Division of Maternal-Fetal Medicine and Surgery, Department of Obstetrics and Gynecology, Hackensack Meridian Health, Hackensack, New Jersey
Claudia Douglas
3   Institute for Evidence Based Practice and Nursing Research, Hackensack University Medical Center, Hackensack Meridian Health, Hackensack, New Jersey
Sharon Sledge
4   Center for Bloodless Medicine and Surgery, Department of Patient Safety and Quality, Hackensack Meridian Health, Hackensack, New Jersey
Robert L. Thurer
5   Medical Department, Gauss Surgical, Inc., Menlo Park, California
› Author Affiliations
Funding Gauss Surgical, Inc. provided statistical support services for this study and financial support to Hackensack Meridian Health for on-site research activities. Gauss personnel also participated in study design, data analysis, and manuscript preparation.


Objective The aim of the study is to compare quantified blood loss measurement (QBL) using an automated system (Triton QBL, Menlo Park, CA) with visual blood loss estimation (EBL) during vaginal delivery.

Study Design During 274 vaginal deliveries, both QBL and EBL were determined. The automated system batch weighs blood containing sponges, towels, pads, and other supplies and automatically subtracts their dry weights and also the measured amount of amniotic fluid. Each method was performed independently, and clinicians were blinded to the device's results.

Results Median QBL (339 mL [217–515]) was significantly greater than median EBL (300 mL [200–350]; p < 0.0001). The Pearson's correlation between EBL and QBL was poor (r = 0.520) and the Bland–Altman's limits of agreement were wide (>900 mL). QBL measured blood loss >500 mL occurred in 73 (26.6%) patients compared with 14 (5.1%) patients using visual estimation (p < 0.0001). QBL ≥  1,000 mL was recorded in 11 patients (4.0%), whereas only one patient had an EBL blood loss of 1,000 mL and none had EBL >1,000 mL (p = 0.002).

Conclusion Automated QBL recognizes more patients with excessive blood loss than visual estimation. To realize the value of QBL, clinicians must accept the inadequacy of visual estimation and implement protocols based on QBL values. Further studies of clinical outcomes related to QBL are needed.

Key Points

  • QBL detects hemorrhage more frequently than visual estimation.

  • Median QBL is significantly greater than median EBL.

  • There is poor agreement between QBL and EBL.

Publication History

Received: 29 July 2019

Accepted: 22 December 2019

Article published online:
12 February 2020

© 2020. Thieme. All rights reserved.

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA

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