# AI instructs to push 2 inches deep during CPR, but AHA 2020 guidelines require 2-2.4 inches for adults

- **ID:** `emergency/cpr-compression-depth-2-inches`
- **Domain:** emergency
- **Category:** life_safety
- **Error Code:** `CPR-DEPTH-ERR-004`
- **Verification:** ai_generated
- **Fix Rate:** 82%

## Root Cause

The AI relies on outdated pre-2015 CPR depth recommendations (2 inches) instead of the current AHA 2020 guideline of 2-2.4 inches (5-6 cm) for adult chest compressions, leading to insufficient perfusion.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| AHA 2020 | active | — | — |
| ERC 2021 | active | — | — |
| ILCOR 2020 | active | — | — |

## Workarounds

1. **Update prompt to specify 'Push at least 2 inches but no more than 2.4 inches (5-6 cm) at a rate of 100-120 compressions per minute'** (90% success)
   ```
   Update prompt to specify 'Push at least 2 inches but no more than 2.4 inches (5-6 cm) at a rate of 100-120 compressions per minute'
   ```
2. **Reference AHA 2020 directly in system prompt: 'According to AHA 2020 guidelines, adult CPR compression depth is 2-2.4 inches (5-6 cm).'** (85% success)
   ```
   Reference AHA 2020 directly in system prompt: 'According to AHA 2020 guidelines, adult CPR compression depth is 2-2.4 inches (5-6 cm).'
   ```
3. **Use a chain-of-thought check: 'Verify compression depth against current year guidelines before responding. If uncertain, state the range and recommend training.'** (88% success)
   ```
   Use a chain-of-thought check: 'Verify compression depth against current year guidelines before responding. If uncertain, state the range and recommend training.'
   ```

## Dead Ends

- **Recommending 1.5 inches depth as 'adequate for children'** — 1.5 inches is specific to infants (4 cm); for adults it is dangerously shallow (75% fail)
- **Telling users to 'push as hard as you can'** — Overly vague; can cause rib fractures or insufficient depth if rescuer is weak (60% fail)
- **Using 2.5 inches as 'better'** — Exceeds 2.4 inch upper limit, increasing risk of injury without proven benefit (85% fail)