Accuracy of Blood Loss Estimation After Vaginal Delivery

NCT ID: NCT00462839

Last Updated: 2014-04-14

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 106 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2006-07-31
• Study Completion Date: 2008-04-30

Brief Summary

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.

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.

Conditions

Postpartum Hemorrhage

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: HEALTH_SERVICES_RESEARCH
• Blinding Strategy: SINGLE

Study Groups

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.

Group Type: EXPERIMENTAL

blood loss estimation

Intervention Type: PROCEDURE

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.

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.

Group Type: ACTIVE_COMPARATOR

blood loss estimation

Intervention Type: PROCEDURE

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.

Interventions

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.

Intervention Type: PROCEDURE

Other Intervention Names

Estimated Blood Loss (EBL)

Eligibility 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.

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

Northwestern University

OTHER

Sponsor Role: lead

Responsible Party

Cynthia Wong

Professor of Anesthesiology

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Cynthia A Wong, M.D.

Role: PRINCIPAL_INVESTIGATOR

Northwestern University

Locations

Northwestern University

Chicago, Illinois, United States

Countries

United States

References

C. Beckman. Obstetrics and Gynecology. Post Partum Hemorrhage, Chapter 12. 3rd edition. Lippincott Williams & Wilkins 1998; 154-161.

Reference Type: BACKGROUND

Cunningham FG, Leveno KL, Bloom SL, et al. Williams Obstetrics, 22th ed, New York: McGraw-Hill, 2005.

Reference Type: BACKGROUND

Patel A, Goudar SS, Geller SE, Kodkany BS, Edlavitch SA, Wagh K, Patted SS, Naik VA, Moss N, Derman RJ. Drape estimation vs. visual assessment for estimating postpartum hemorrhage. Int J Gynaecol Obstet. 2006 Jun;93(3):220-4. doi: 10.1016/j.ijgo.2006.02.014. Epub 2006 Apr 12.

Reference Type: BACKGROUND

PMID: 16626718 (View on PubMed)

Prasertcharoensuk W, Swadpanich U, Lumbiganon P. Accuracy of the blood loss estimation in the third stage of labor. Int J Gynaecol Obstet. 2000 Oct;71(1):69-70. doi: 10.1016/s0020-7292(00)00294-0. No abstract available.

Reference Type: BACKGROUND

PMID: 11044547 (View on PubMed)

Other Identifiers

0524-029

Identifier Type: -

Identifier Source: org_study_id