Athar M W, Abir G, Seay R C, Guo N, Butwick A, Carvalho B
Department of Anesthesiology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA.
Int J Obstet Anesth. 2022 May;50:103539. doi: 10.1016/j.ijoa.2022.103539. Epub 2022 Mar 18.
Postpartum hemorrhage is the leading cause of maternal mortality worldwide, and optimal management requires accurate blood loss estimations. The aim of this study was to assess whether differences exist between visually estimated blood loss vs. actual blood loss based on delivery mode, blood volume or distribution/location and knowledge of patient's current cardiovascular status.
For this observational cohort study, photographs were taken of 18 blood loss scenarios for vaginal delivery and cesarean delivery, and six photographs were duplicated and annotated with maternal vital signs. Scenarios were categorized into 50% (500 mL), 100% (1000 mL) and 200% (2000 mL) of the defined blood loss volume for postpartum hemorrhage and the photographs were shown to participants to visually estimate blood loss volumes.
The mean ± standard deviation estimates of actual 500 mL, 1000 mL and 2000 mL blood loss volumes were 1208 ± 438 mL, 1676 ± 630 mL and 2637 ± 1123 mL, respectively (P <0.001 among groups). The difference was significantly greater in vaginal delivery than cesarean delivery scenarios (1064 ± 849 mL vs. 284 ± 456 mL; P <0.001). Estimated blood loss volume was not influenced by blood loss distribution/location, or by provider group or experience. The cardiovascular status of the patient impacted estimations only if tachycardia and hypotension were present.
Most providers significantly overestimated blood loss volumes (by nearly 700 mL). Provider and scenario factors that impact inaccuracies in visual estimated blood loss identified in this study can be used to guide education and training.
产后出血是全球孕产妇死亡的主要原因，而最佳管理需要准确估计失血量。本研究的目的是评估基于分娩方式、血容量或分布/位置以及患者当前心血管状态的知识，视觉估计失血量与实际失血量之间是否存在差异。
在这项观察性队列研究中，拍摄了18张阴道分娩和剖宫产失血场景的照片，并复制了6张照片并标注了产妇生命体征。场景被分为产后出血定义失血量的50%（500毫升）、100%（1000毫升）和200%（2000毫升），并向参与者展示照片以视觉估计失血量。
实际500毫升、1000毫升和2000毫升失血量的平均±标准差估计值分别为1208±438毫升、1676±630毫升和2637±1123毫升（组间P<0.001）。阴道分娩场景中的差异明显大于剖宫产场景（1064±849毫升对284±456毫升；P<0.001）。估计失血量不受失血分布/位置、提供者组或经验的影响。仅当出现心动过速和低血压时，患者的心血管状态才会影响估计。
大多数提供者显著高估了失血量（近700毫升）。本研究中确定影响视觉估计失血量不准确的提供者和场景因素可用于指导教育和培训。
