1. Rapid confirmation of cardiac arrest: loss of consciousness, carotid femoral artery pulsation disappeared intermittent or stop, skin bun, heart sound disappeared, blood pressure can not be measured pupil dilated, ECG straight line.
2. Defibrillation is decisive, rapid, and race against time.
3. Defibrillation in cardiopulmonary resuscitation, because each defibrillation to stop the extracardiac compression time should be as short as possible, to discharge defibrillation at the end of expiration, in order to reduce cross-thorac electrical impedance.
4. Weight and heart size: determine the choice of electrical energy size, children's energy choice: the first 2J / kg, the second 2 ~ 4J / kg, the third 4J / kg.
5. Electrode plate and local impedance: the electrode plate is small, the chest wall is not tightly contacted, the electrode plate is too close, and short circuit is formed between the electrode plates. The current cannot pass through the heart. Keep the electrode plates clean and spaced at intervals of more than 10 cm.
6. Defibrillation at the same time, medication to correct acid-base imbalance and electrolyte imbalance, which is conducive to successful defibrillation.