Advanced Trauma Life Support Classification of Hemorrhagic Shock*
| Class I | Class II | Class III | Class IV | |
|---|---|---|---|---|
| Blood loss (mL) | ≤750 | 750–1,500 | 1,500–2,000 | ≥2,000 |
| Blood loss (% blood volume) | ≤15 | 15–30 | 30–40 | ≥40 |
| Pulse rate (beats/min) | <100 | >100 | >120 | ≥140 |
| Blood pressure | Normal | Normal | Decreased | Decreased |
| Pulse pressure | Normal or increased | Decreased | Decreased | Decreased |
| Respiratory rate (breaths/min) | 14–20 | 20–30 | 30–40 | >35 |
| Urine output (mL/hr) | ≥30 | 20–30 | 5–15 | Negligible |
| Mental status | Slightly anxious | Mildly anxious | Anxious and confused | Confused, lethargic |
| Fluid replacement (3:1 rule) | Crystalloid† | Crystalloid | Crystalloid + blood | Crystalloid + blood |
*For a 70-kg male patient based on initial presentation.
†The 3:1 rule is based on empiric observation that most patients require 300 mL of balanced electrolyte solution for each 100 mL of blood loss. Without other clinical and monitoring parameters, this guideline may result in excessive or inadequate fluid resuscitation.
Adapted with permission from American College of Surgeons, Committee on Trauma: Shock, Advanced Trauma Life Support Student Course Manual. Edited by the American College of Surgeons, 8th ed.Chicago: American College of Surgeons; 2008:55–71.