Akbuga Ozel Betul, Ozel Gurkan, Mamak Ekinci Elmas Burcu, Demirtola Ahmet Eren, Sahin Gizem, Aksoy Gokcen, Yanikyurek Ilke, Karaaslan Mehmet Ufuk
Department of Emergency Medicine, Ankara Yıldırım Beyazıt University Faculty of Medicine, Ankara Bilkent City Hospital, Ankara, Turkey.
County of Renfrew Paramedic Services, ON, Renfrew, Canada.
Sci Rep. 2025 Aug 24;15(1):31091. doi: 10.1038/s41598-025-16169-0.
Accurately estimating blood loss is critical for managing hemorrhagic shock in prehospital and hospital settings. The Visual Estimation (VE) method is widely used, while the MAR method proposes using a fist measurement to estimate external blood on flat surfaces. A randomized, double-blind, parallel-group, controlled, and educational study was conducted involving 140 medical and paramedic students. The study compared the accuracy and duration of blood loss estimates made with the MAR and VE methods. The secondary objective was to assess whether MAR estimates varied by participants' height, weight, or gender. Three simulated stations featured three different, non-absorbent, flat surfaces containing 75 mL, 150 mL, or 750 mL of blood. Participants were divided into two groups (Group 1: VE method, n = 70; Group 2: MAR method, n = 70) and asked to estimate blood loss using the assigned method at each of the three stations (Station 1 to Station 3). Analytical tests evaluated absolute differences and percentage errors in both intergroup and intragroup comparisons. In the intergroup analysis, comparisons were made between Group 1 using the VE method and Group 2 using the MAR method. In the intragroup analysis, Group 1 was compared using the VE method versus the MAR method. Given the non-normality, repeated measures were analyzed using F1 LD F1 and F2 LD F1 models via nparLD in R. Improvement in estimations after the MAR method was evidenced by a reduction in errors relative to the actual blood volumes, and this was statistically significant. It also reduced outlier estimates and took longer. The MAR volume estimates were not affected by participants' phenotypic characteristics. In conclusion, incorporating the MAR method into structured clinical skills training for external bleeding management could be beneficial.Trial registration: ClinicalTrials.gov Identifier NCT06855472 (18/02/2025).
准确估计失血量对于在院前和医院环境中管理失血性休克至关重要。视觉估计（VE）方法被广泛使用，而MAR方法建议使用拳头测量来估计平面上的外部出血量。一项随机、双盲、平行组、对照和教育性研究纳入了140名医学生和护理人员学生。该研究比较了使用MAR和VE方法进行失血量估计的准确性和持续时间。次要目标是评估MAR估计值是否因参与者的身高、体重或性别而异。三个模拟站点设有三个不同的、不吸水的平面，分别含有75毫升、150毫升或750毫升血液。参与者被分为两组（第1组：VE方法，n = 70；第2组：MAR方法，n = 70），并被要求在三个站点（站点1至站点3）中的每个站点使用指定方法估计失血量。分析测试评估了组间和组内比较中的绝对差异和百分比误差。在组间分析中，对使用VE方法的第1组和使用MAR方法的第2组进行了比较。在组内分析中，使用VE方法的第1组与MAR方法进行了比较。鉴于数据非正态性，通过R中的nparLD使用F1 LD F1和F2 LD F1模型对重复测量进行了分析。相对于实际血容量，MAR方法后估计误差的减少证明了估计的改善，且具有统计学意义。它还减少了异常值估计，但耗时更长。MAR体积估计不受参与者表型特征的影响。总之，将MAR方法纳入外部出血管理的结构化临床技能培训可能是有益的。试验注册：ClinicalTrials.gov标识符NCT06855472（2025年2月18日）。
