Validated Intraoperative Bleeding Scale.
| Grade | Visual Presentation | Anatomical Appearance | Qualitative Description | Visually Estimated Rate of Blood Loss (mL/min) |
| 0 | No bleeding | No bleeding | No bleeding | ≤1.0 |
| 1 | Intermittent flow or continuous ooze | Capillary-like bleeding | Mild | >1.0–5.0 |
| 2 | Continuous flow | Venule- and arteriolar-like bleeding | Moderate | >5.0–10.0 |
| 3 | Controllable spurting and/or overwhelming flow | Noncentral venous- and arterial-like bleeding | Severe | >10.0–50.0 |
| 4 | Uncontrollable spurting or gush | Central arterial- or venous-like bleeding | Life-threateninga | >50.0 |
aSystemic resuscitation is required (eg, volume expanders, vasopressors, blood products, etc).