Accuracy of Blood Loss Estimation After Vaginal Delivery

This study has been completed.
Sponsor:
Information provided by (Responsible Party):
Cynthia Wong, Northwestern University
ClinicalTrials.gov Identifier:
NCT00462839
First received: April 17, 2007
Last updated: March 17, 2014
Last verified: March 2014
  Purpose

Post-partum hemorrhage (PPH) is defined as blood loss greater than 500 mL after vaginal delivery. Delayed diagnosis of PPH is a major cause of maternal morbidity and mortality. Obstetricians estimate blood loss at delivery by visual estimation of blood collected in the obstetric drapes. Blood is often mixed with urine and surgical sponges. The urine, blood, and sponges collect in a cone shaped plastic bag that is suspended from the perineum during delivery. Visual estimation of blood loss is insensitive in diagnosing PPH. In one study visual assessment of blood loss underestimated postpartum blood loss by 33% to 50% compared to an objective measurement of blood loss using photospectrometry. Other studies have shown that the magnitude of underestimation increases as the amount of blood loss is increased. A limitation of previous studies is that there is no "gold standard" for blood loss determination in the third stage of labor. Care providers (obstetricians, anesthesiologists, and labor & delivery nurses) need to be able to accurately estimate blood loss in order to better care for mothers and prevent morbidity and mortality. It is unknown whether provider type or experience (obstetric and anesthesiology resident, fellow, attending physicians, and nurses) influences the accuracy of blood loss estimation, or whether blood loss estimation can be improved by providing graduated markings on the vaginal delivery drape.


Condition Intervention
Postpartum Hemorrhage
Procedure: blood loss estimation

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Single Blind (Subject)
Primary Purpose: Health Services Research
Official Title: The Accuracy of Blood Loss Estimation After Simulated Vaginal Delivery

Resource links provided by NLM:


Further study details as provided by Northwestern University:

Primary Outcome Measures:
  • Difference in Actual Blood Volume and Estimated Blood Volume in Milliliters. [ Time Frame: 1 hour ] [ Designated as safety issue: No ]
    Two types of drapes were used: drapes with and without volume calibrations. Calibrated drapes had volume markings beginning at 500ml with 500ml increments to a total of 2500ml. The participants were asked to estimate the volume contained in the bag and the difference in milliliters between the estimate and actual volume was calculated.


Secondary Outcome Measures:
  • Number and Type of Care Providers Assigned to Study Arms. [ Time Frame: 1 hour ] [ Designated as safety issue: No ]
  • Level of Training [ Time Frame: 1 hour ] [ Designated as safety issue: No ]
  • Number of Years of Clinical Experience Providing Patient Care Requiring Blood Loss Estimation. [ Time Frame: 1 hour ] [ Designated as safety issue: No ]

Enrollment: 106
Study Start Date: July 2006
Study Completion Date: April 2008
Primary Completion Date: April 2008 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Calibrated drapes viewed first
Caregivers were shown calibrated drape demonstrating level of blood and asked to estimate amount of blood in collection bag. These same individuals were then crossed over and shown non-calibrated drapes and asked to estimate the amount of blood they contained.
Procedure: blood loss estimation
Participants were randomized in blocks, by provider type to view either the four calibrated stations or the four non-calibrated stations. The order of the volumes within each set of stations was randomized. Participants received a data card for each station on which they wrote the volume estimated. After each station, the data card was collected. Alterations to the estimations were not allowed once the answers were recorded. Subjects were then crossed over to the other group and asked to estimate the blood volumes in the non-calibrated drapes if they had first viewed the calibrated drape or the calibrated drape if they had viewed the non-calibrated drape. The order of viewing the four volumes was again randomized. The volumes were the same at the corresponding station for the calibrated and non-calibrated stations so the impact of the calibration markings on accuracy could be determined.
Other Name: Estimated Blood Loss (EBL)
Active Comparator: Non-calibrated drapes viewed first
Standard vaginal delivery drape (non-calibrated) was shown to caregiver who was asked to estimate amount of blood. These same individuals were then crossed over and shown calibrated delivery drapes and asked to estimate the amount of blood they contained.
Procedure: blood loss estimation
Participants were randomized in blocks, by provider type to view either the four calibrated stations or the four non-calibrated stations. The order of the volumes within each set of stations was randomized. Participants received a data card for each station on which they wrote the volume estimated. After each station, the data card was collected. Alterations to the estimations were not allowed once the answers were recorded. Subjects were then crossed over to the other group and asked to estimate the blood volumes in the non-calibrated drapes if they had first viewed the calibrated drape or the calibrated drape if they had viewed the non-calibrated drape. The order of viewing the four volumes was again randomized. The volumes were the same at the corresponding station for the calibrated and non-calibrated stations so the impact of the calibration markings on accuracy could be determined.
Other Name: Estimated Blood Loss (EBL)

Detailed Description:

Packed red blood cells discarded by the blood bank will be mixed with normal saline to simulate whole blood with a hematocrit of 33%. A total of eight isolated study stations will be set up (study participants will only be able to visualize the vaginal delivery drape for one station at a time). The simulated blood will be mixed with urine and sponges and be placed in suspended blood collection drapes which are used during vaginal deliveries at Northwestern Memorial Hospital. Two types of drapes will be used: drapes without calibrated markings and drapes with calibrated markings. Calibrated volume markings will begin at 500 mL at 500 mL intervals to 2500 mL.

Study participants will be randomized to one of two groups. Randomization will occur in blocks depending on provider type. Group 1 will view the unmarked vaginal collection drapes first and Group 2 will view the collection drapes with the calibrated markings first. Both groups will analyze the initial four study stations in random order. At the completion of the four study stations, the group which evaluated the drapes without markings will cross over to view the stations with calibrated markings and the group that views uncalibrated drapes will then view the calibrated drapes.

Each study participant will view a station and write his/her estimation of blood loss on a data card. Study participants will NOT be allowed to change answers once they have been recorded.

Demographic data on study participants will include provider type, level of training/years of practice, and gender.

  Eligibility

Ages Eligible for Study:   18 Years to 65 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Any anesthesia or obstetric attending or resident may participate provided that they have rotated through obstetrics/obstetric anesthesia.

Exclusion Criteria:

  • Any provider that does not complete all of the stations will be excluded from analysis. Any participant who chooses to withdraw from the study will also be excluded from the analysis.
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT00462839

Locations
United States, Illinois
Northwestern University
Chicago, Illinois, United States, 60611
Sponsors and Collaborators
Northwestern University
Investigators
Principal Investigator: Cynthia A Wong, M.D. Northwestern University
  More Information

Publications:
Responsible Party: Cynthia Wong, Professor of Anesthesiology, Northwestern University
ClinicalTrials.gov Identifier: NCT00462839     History of Changes
Other Study ID Numbers: 0524-029
Study First Received: April 17, 2007
Results First Received: June 22, 2011
Last Updated: March 17, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Northwestern University:
Estimated Blood Loss
Obstetrics
postpartum hemorrhage

Additional relevant MeSH terms:
Hemorrhage
Postpartum Hemorrhage
Obstetric Labor Complications
Pathologic Processes
Pregnancy Complications
Puerperal Disorders
Uterine Hemorrhage

ClinicalTrials.gov processed this record on October 23, 2014