The SPOT GRADE: A New Method for Reproducibly Quantifying Surgical Wound Bleeding

Benchtop model with prospective surgeon video testing.

To create a surface bleeding severity scale, the SPOT GRADE (SG), for quantitative assessment of target bleeding site (TBS) blood loss. This is of particular interest for spinal surgery due to epidural bleeding and an inability to use diathermy and radiofrequency cautery close to nerve roots.

A novel apparatus perfusable at known flow rates and simulating different sized wounds was used to create movies to educate surgeons on specific degrees of bleeding.

Training (36) and testing (108) videos were created using a benchtop apparatus employing different bleeding severities based on the six-level SG (none, minimal, mild, moderate, severe, and extreme) and TBS sizes (1, 10, and 50 cm). Fourteen surgeons in four specialties (cardiothoracic, abdominal, spine, and orthopedic lower extremity) were trained and tested to evaluate SG characteristics including inter-rater and intrarater reliability.

The interclass correlation coefficient was estimated to be 0.89840 (95% confidence interval [CI]: 0.85771, 1), whereas the intraclass correlation coefficient was estimated to be 0.93673 (95% CI: 0.89603, 1). In 98% of cases (95% CI: 0.9736, 0.9927), surgeons correctly identified eligible bleeds for a future clinical trial (scores = 1, 2, or 3) and in 91% of cases (95% CI: 0.8895, 0.9344), surgeons correctly identified noneligible bleeds (scores = 4 or 5). In 98.6% of cases (95% CI: 0.9777, 0.9945), physicians correctly identified true hemostasis (score = 0). Based upon these data the probability of a physician rating a bleed incorrectly as hemostasis (score = 0) is estimated to be 1.51% (95% CI: 0.0061, 0.0363).

This SG is reproducible and reliable providing a basis for educating surgeons on TBS blood loss. It appears to be a new standard for evaluating wound blood loss.

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