Table 2.
American College of Surgeons Advanced Trauma Life Support classification of haemorrhage severity
| Haemorrhage severity according to ACS/ATLS classificationa | Class I | Class II | Class III | Class IV |
| Blood loss (ml) | <750 | 750–1,500 | 1,500–2,000 | >2,000 |
| Pulse rate (per minute) | <100 | >100 | >120 | >140 |
| Blood pressure | Normal | Normal | Decreased | Decreased |
| Pulse pressure (mm Hg) | Normal | Decreased | Decreased | Decreased |
| Respiratory rate (per minute) | 14–20 | 20–30 | 30–40 | >40 |
| Urine output (ml/hour) | >30 | 20–30 | 5–15 | Negligible |
| Central nervous system (mental status) | Slightly anxious | Mildly anxious | Anxious, confused | Lethargic |
aValues are estimated for a 70-kg adult. Table reprinted with permission from the American College of Surgeons [26]. ACS/ATLS, American College of Surgeons/Advanced Trauma Life Support.