Table 1 Inclusion and exclusion criteria

A. Inclusion criteria for observational part

 1. Cardiac arrest is caused by respiratory failure or hypovolemic shock;

 2. In-hospital cardiac arrest;

 3. Aged 18–85 years old;

 4. Patients with return of spontaneous circulation (ROSC) that is sustained for ≥ 20 min;

 5. Glasgow coma score ≤ 8 after ROSC, and before sedation (if any) ;

 6. The legal representative signed the informed consent;

 7. Advanced cardiovascular life support is conducted.

B. Exclusion criteria

 1. No-flow time > 10 min (time from collapse to initiation of external cardiac massage);

 2. Low-flow time > 60 min (time from initiation of external cardiac massage to ROSC);

 3. Major hemodynamic instability (defined as a continuous epinephrine or norepinephrine infusion at a flow rate > 1 μg/kg/min);

 4. Cardiac arrest caused by advanced tumor and other end-of-state diseases;

 5. Cardiac arrest caused by an irreversible cause (such as severe trauma and poisoning);

 6. Cardiogenic cardiac arrest (acute infarction, malignant arrhythmia, heart failure, etc.);

 7. Acupoint with lesions, wounds, or skin diseases affects acupuncture;

 8. Allergic persons, or known to be allergic to treatment, such as metal;

 9. Pregnant or lactating women.