The ATLS classification of hypovolaemic shock1
| Class I | Class II | Class III | Class IV | |
|---|---|---|---|---|
| Blood loss in % | <15 | 15–30 | 30–40 | >40 |
| Pulse rate | <100 | 100–120 | 120–140 | >140 |
| Systolic blood pressure | Normal | Normal | Decreased | Decreased |
| Pulse pressure | Normal or increased | Decreased | Decreased | Decreased |
| Respiratory rate | 14–20 | 20–30 | 30–40 | >35 |
| Mental status | Slightly anxious | Mildly anxious | Anxious, confused | Confused, lethargic |
| Urine output (mL/h) | >30 | 20–30 | 5–15 | Negligible |
| Fluid replacement | Crystalloid | Crystalloid | Crystalloid and blood | Crystalloid and blood |