ATLS 10th edition classifies haemorrhagic shock based on physiological parameters. Class III haemorrhagic shock is characterised by blood loss of approximately:
- A 30–40% of blood volume; tachycardia >120, decreased blood pressure, decreased pulse pressure, change in mental status ✓
- B Up to 15% of blood volume; normal BP, mild tachycardia
- C 15–30% of blood volume; tachycardia 100–120, mild decrease in pulse pressure
- D >40% of blood volume; profound hypotension, HR >140, altered consciousness
Correct answer: A. 30–40% of blood volume; tachycardia >120, decreased blood pressure, decreased pulse pressure, change in mental status
Explanation
ATLS 10th edition classification: Class I — up to 15% (<750 mL); Class II — 15–30% (750–1500 mL), tachycardia but BP maintained; Class III — 30–40% (1500–2000 mL), BP falls, HR >120, reduced urine output, altered mental status; Class IV — >40% (>2000 mL), immediately life-threatening. ATLS 10th ed streamlined to two classes (I/II as non-haemorrhagic shock and III/IV as haemorrhagic) in some references, but the four-class system remains the classic framework for examinations.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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