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Chest Compression Depth in CPR: Why 5 cm Matters for Survival

Current guidelines (AHA/ERC) recommend ≥5 cm (2 inches) depth for adults at 100–120 compressions/min. Rationale:

  1. Hemodynamic efficacy: Adequate depth generates sufficient intrathoracic pressure to produce forward blood flow (cardiac output ~20–30% of normal).
  2. Coronary perfusion pressure (CPP): CPP = aortic diastolic pressure – right atrial diastolic pressure; depth directly correlates with CPP, the strongest predictor of ROSC.
  3. Survival data: Observational studies show each 5 mm decrease below 5 cm reduces ROSC odds.
  4. Complete recoil equally critical—allows ventricular refilling.
  5. Minimize interruptions: Compression fraction >80%.

Feedback Devices

Real-time depth/rate feedback (accelerometer-based) improves compliance during training and actual resuscitation.

Pediatric Depths

  • Children: 5 cm (or 1/3 AP chest diameter).
  • Infants: 4 cm (1.5 inches).

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