Accuracy of Blood Loss Estimation After Vaginal Delivery
Condition: Postpartum Hemorrhage
MeSH terms: Postpartum Hemorrhage; Hemorrhage
Study type: Interventional

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.
    

Intervention name(s): blood loss estimation
Intervention type(s): Procedure
Intervention description(s): 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 intervention name(s): Estimated Blood Loss (EBL)
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Health Services Research
Keywords: Estimated Blood Loss; Obstetrics; postpartum hemorrhage