Blood on the drapes: A multispecialty comparison of blood spill estimates

Estimated blood loss (EBL) is an important part of the perioperative process. This project aims to determine the accuracy of perioperative team members to estimate blood volume on drapes and the operating room floor.

Aliquots of unused human blood were used to create surgical scenarios, and standardized pictures and videos were taken. Physicians, residents, nurses, medical students, and surgical technicians were surveyed and asked to estimate the blood volume for each series. Accuracy and consistency of responses was analyzed.

One hundred and forty five responses were recorded: 57 attending physicians, 36 residents, 27 registered nurses, 17 medical students, and seven circulating surgical techs. Median percent error (PE) for all cases was 211.11%, demonstrating a global overestimation of blood volume. PE for the 150 mL images was statistically significantly lower than that of the 50 and 100 mL images. Circulating Surgical Technicians were the most accurate group, with a median PE of 125%, followed closely by Medical Students (PE = 158.33%). The most accurate specialty was Orthopedics (PE = 168.06%). The least accurate groups were Attending Physicians (PE = 286.11%) and General surgery (GSGY) (PE = 327.78%). The most accurate orthopedic surgery and GSGY subspecialties were Hand (PE = 237.64%) and Vascular (PE = 108.33%), respectively. Statistical analyses showed no significant differences by clinical role, surgical specialty, or subspecialty.

This study demonstrates a global overestimation of blood volume when using the visual method, with improved accuracy at higher volumes. Our findings highlight the limitations of visual estimation methods for EBL.