According to the ATLS 10th edition protocol, in a patient with Class III hemorrhagic shock (30–40% blood volume loss), which clinical finding best differentiates Class III from Class II shock?
- A Heart rate >100 bpm
- B Decreased systolic blood pressure and altered mental status (confusion/anxiousness) ✓
- C Urine output 20–30 mL/hr
- D Respiratory rate 20–30 breaths/min
Correct answer: B. Decreased systolic blood pressure and altered mental status (confusion/anxiousness)
Explanation
ATLS 10th edition simplified hemorrhagic shock to non-hypotensive (Class I/II) and hypotensive (Class III/IV). Class II: HR elevated, BP maintained, urine output 20–30 mL/hr, patient anxious. Class III (30–40% loss): hypotension (SBP <90), HR >120, urine output 5–15 mL/hr, and — most importantly — mental status changes (confusion, anxiety). The development of hypotension and mental status changes is the key distinguishing feature between Class II and III. ATLS 10 removed specific numerical thresholds and emphasizes clinical assessment.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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