Validating a New Method to Assess Estimated Blood Loss in the Obstetric Population
Condition: Pregnancy Complications
MeSH terms: Pregnancy Complications; Hemorrhage
Study type: Interventional

Summary: 
      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.
      Estimates of blood loss at delivery are notoriously inaccurate, with under-estimation more
      common than over-estimation. 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. The investigators would like
      to study and validate an FDA approved device called the gauss Triton device used to estimate
      blood loss during scheduled cesarean sections.
    

Detailed description: 
      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. 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. More than
      half of all maternal deaths occur within 24 hours of delivery, most commonly from excessive
      bleeding. 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.

      Estimates of blood loss at delivery are notoriously inaccurate, with under-estimation more
      common than over-estimation. 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. 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 significant decay in blood loss estimation skills over time.

      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. 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. 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.

      However, these studies were performed on patients undergoing a myriad of surgical procedures
      not just limited to obstetrical patients. To the investigators' 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. In that trial, only the accuracy was evaluated, and the investigators believe that
      further evidence is needed to support its use.

      The investigators' hypothesis is that this device will enable clinicians to prospectively and
      objectively assess EBL. Ultimately after its validation, their 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 the investigators 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.
      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. 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 (ΔHgb) between the pre and post cesarean CBCs will be calculated for each patient.
      Patients will be divided into quartiles of ΔHgb. Cases will be those patients whose ΔHgb is
      in the upper quartile, while controls will be those patients whose ΔHgb is in the lower 3
      quartiles. The investigators will be comparing EBL by standard clinical assessment versus
      result from the device between cases and controls.
    

Intervention name(s): Gauss Triton system
Intervention type(s): Device
Intervention description(s): 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. The device is an iPad like imaging device that will assess blood loss via imaging of the surgical sponges used in the surgery.
The device will be used to calculate blood loss on every patient enrolled in the study.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: scheduled cesarean section; term pregnancy; estimated blood loss; postpartum hemorrhage