We Are Bad at Estimating Operative Blood Loss


Submitted on Fri, 07/01/2016 - 10:12

It is definitely true: we are all totally bad at estimating operative blood loss!

A most pertinent and practically useful study on surgeons’ ability to estimate operative blood loss (EBL) was presented at the recent Annual Meeting of the Central Surgical Association in Montreal last April 2016. The study was designed and predicated on the well-established notion that surgeons, operating room nurses, and anesthesiologists are all notoriously inaccurate at estimating blood loss occurring during surgery. And this extends to “experienced operators” who are more confident on their abilities to do so, but still off the mark almost as badly as their junior colleagues.

The study, presented by a Surgical Resident at Case Western Reserve University (Dr. Luke Rothermel), simulated operating room scenarios and asked providers to estimate blood loss. He noted that although the Joint Commission requires operative notes to contain estimated blood loss, “no study in the United States has compared the characteristics of O.R. personnel or conditions associated with improved accuracy or reliability of blood loss estimation”. And as recognized by all, EBL constitutes an important guidance for peri-operative care. And yet, previous studies have shown the inaccuracy of such estimates.

The investigators designed a study that simulated surgical scenarios with high, medium, and low blood loss volumes (porcine blood use for the simulations). They recruited providers from the surgery, anesthesia, and nursing services at an urban level 1 trauma center. Each scenario included a written description of the procedure performed and the course of surgery, and participants could handle study materials for each scenario under the supervision of study staff. A total of 60 participants (22 from surgery, 17 from anesthesia, and 21 from nursing) participated; they had an average of 12.8 years of experience. The surgical participants included surgical scrub techs, trainees, and attending physicians. Anesthesia participants included anesthesia assistants, CRNAs, trainees, and attending physicians. Nursing participants were all RNs.

The findings were startling, if unsurprising: “There was no association between specialty, years of experience, or confidence in ability with the consistency or accuracy of EBL,” said Dr. Rothermel. Only 5% of study participants were able to come within 25% accuracy in estimating EBL in all scenarios. These results held true across surgical scenarios, disciplines, and regardless of the years of experience.

Appropriately, the investigators highlighted the limitations of this small study that did not involve real-life surgery scenarios. But it served nonetheless to characterize the questionable validity of using EBL as a quality indicator to assess patient outcomes and physician performance.