Cardiac arrest
Echo only during the pulse check, never longer than 10 seconds — looking for the reversible causes.
Echo approach, step by step
The ERC 2021 guidelines accept point-of-care ultrasound during CPR by skilled operators to identify reversible causes, provided it does not prolong pauses in compressions [198]. In practice, using ultrasound was associated with longer pauses [211]. The FEEL protocol integrates focused echo into ALS [200].
- Prepare during compressionsProbe on the subxiphoid window. The assistant counts the seconds aloud.
- Pulse check: 10 seconds onlyRecord a clip; do not interpret during the pause. Resume compressions and review the clip [198,200].
- Question 1: Is there a large effusion?→ Pericardiocentesis [198].
- Question 2: Is there cardiac motion?Coordinated activity without a pulse = pseudo-PEA (profound shock). No activity (standstill) = worse prognosis [214].
- Question 3: Is the RV severely dilated?Suggests massive PE, but RV dilatation develops in any prolonged arrest. Do not use it alone to diagnose PE [198].
- Question 4: Is the heart empty?Hypovolaemia.
- LungsAbsent sliding → pneumothorax.
- After ROSCLV function and regional wall motion (ACS), RV, aorta, effusion [138].
- Clip recorded during pulse check ≤10 s
- Effusion
- Cardiac activity
- RV size (with caution)
- Volume
- Pneumothorax
- Post-ROSC echo
Causes & echo clues
| Reversible cause (4 Hs, 4 Ts) | Echo clue | Action [198] |
|---|---|---|
| Hypovolaemia | Empty, collapsed ventricles | Volume, stop bleeding |
| Hypoxia | — | Airway and oxygenation |
| Hyper/hypokalaemia, metabolic | — | Blood gas, correct |
| Hypothermia | — | Rewarming, ECMO |
| Tamponade | Effusion with collapse | Pericardiocentesis |
| Thrombosis — pulmonary | Dilated RV (cautious), thrombus in transit | Thrombolysis; continue CPR 60–90 min |
| Thrombosis — coronary | Regional akinesis after ROSC | Angiography |
| Tension pneumothorax | No lung sliding | Decompression |
| Toxins | — | Specific antidote |
Clinical pathway to the diagnosis
- High-quality CPR, early defibrillation for VF or pVT[198].
- Rhythm checks every 2 minutes; adrenaline and amiodarone as per ALS [198].
- Treat reversible causesusing history, blood gas and ultrasound [198,200].
- After ROSC12-lead ECG; coronary angiography if ST elevation; CT head and chest if no obvious cause; temperature control [198].
Clinical pearls & pitfalls
PitfallStandstill on echo is not by itself a reason to stop CPR. Combine it with the whole clinical picture. In REASON, survival without cardiac activity was very low, but not zero [214].
- "Asystole" on the monitor can be fine VF. Echo shows fibrillating myocardium; defibrillate.
- Pseudo-PEA (organised contraction, no palpable pulse) has a better prognosis. Consider adrenaline infusion, volume and the cause [214].
- The subxiphoid window keeps you away from the compressor and the defibrillator pads.
Red flags
- Pauses in compressions must stay under 10 seconds [198,211]
- Effusion with collapse → pericardiocentesis [198]
- Organised cardiac activity without a pulse (pseudo-PEA) → treat as profound shock