The Accuracy of Blood Loss Estimation After Simulated Vaginal Delivery
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 106
- 试验地点
- 2
- 主要终点
- Difference in Actual Blood Volume and Estimated Blood Volume in Milliliters.
研究概览
简要总结
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.
详细描述
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Health Services Research
- 盲法
- Single (Participant)
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Any anesthesia or obstetric attending or resident may participate provided that they have rotated through obstetrics/obstetric anesthesia.
排除标准
- •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.
结局指标
主要结局
Difference in Actual Blood Volume and Estimated Blood Volume in Milliliters.
时间窗: 1 hour
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.
次要结局
- Level of Training(1 hour)
- Number of Years of Clinical Experience Providing Patient Care Requiring Blood Loss Estimation.(1 hour)
- Number and Type of Care Providers Assigned to Study Arms.(1 hour)
研究者
Cynthia Wong
Professor of Anesthesiology
Northwestern University