1, open the airway Keeping the airway open is an important step to successful resuscitation, can be used to open the airway by tilting the head and lifting the chin method. The method is: the operator will place one hand on the patient’s forehead with forceful pressure, so that the head is tilted back, and the other hand’s show and middle fingers lift the chin, so that the line between the tip of the jaw, earlobe and the ground is vertical, in order to open the airway. Foreign bodies and vomit in the patient’s mouth should be removed, and the patient’s loose denture should be removed. 2, artificial respiration After opening the airway, first put your ear close to the patient’s mouth and nose to feel whether there is breath, then observe whether there is heaving action in the chest, and finally listen carefully to the sound of airflow exhalation. If no respiration can be determined without the above signs, artificial ventilation should be implemented immediately, and the judgment and evaluation time should not exceed 10 seconds. Firstly, two artificial respirations should be performed, each with a continuous blowing time of more than 1 second, to ensure sufficient tidal volume to make the thorax heave. Chest compressions should be performed immediately after the two artificial ventilations, regardless of whether there is thoracic heave. Endotracheal intubation is the best method to establish artificial ventilation. When intermittent or conditions do not allow, mouth-to-mouth, mouth-to-nose, or mouth-to ventilatory protection devices can be used for breathing. Mouth-to-mouth breathing is a fast and effective method of ventilation, and the oxygen in the exhaled gas of the operator is sufficient to meet the patient’s needs, but it is important to ensure a patent airway first. The operator pinches the patient’s nostrils with the thumb and index finger of the hand placed on the patient’s forehead, takes a breath, covers the patient’s mouth fully with the mouth and lips, and then blows slowly, each blow should last for more than 1 second to ensure that there is a chest rise and fall when breathing. Before the rescuer performs artificial respiration, normal inhalation is sufficient, without deep inhalation. Whether single or double CPR, the ratio of compressions to ventilation is 30:2, alternating. The above ventilation is only a temporary resuscitation measure, should strive to immediately endotracheal intubation, with artificial airbag extrusion or artificial ventilator for assisted breathing and oxygen delivery to correct hypoxemia. 3, chest compressions is the main method to establish artificial circulation, the principle of blood flow generation during chest compressions is relatively complex, mainly based on the chest pump mechanism and heart pump mechanism. Through chest compressions can make the intrathoracic pressure rise and direct pressure on the heart and maintain a certain blood flow, with artificial respiration can provide certain oxygenated blood flow to the heart and brain and other important organs, creating conditions for further resuscitation. When manual chest compressions are performed, the patient should lie on his back on a rigid surface, with the rescuer kneeling beside him. If chest compressions are performed in bed, the patient’s back should be padded with a hard board. The site of external chest compressions is the lower part of the sternum, between the nipples. Place the root of the palm of one hand on the sternum between the double nipples in the middle of the chest, and press the other hand parallel and overlapping on the back of the hand to ensure that the transverse axis of the root of the palm is in the same direction as the long axis of the sternum, and ensure that the palm of the hand exerts force on the sternum to avoid rib fractures, and do not press on the saber process. When pressing, straighten the elbow joint, rely on the strength of the shoulder and back to press vertically downward, press the sternum with an amplitude of about 3-5 cm, press to restore the thorax to its original position, press and relax for roughly the same amount of time do not leave the chest wall when relaxing, and press at a frequency of 100 times/min. Efforts should be made to minimize interruptions during chest compressions, with a minimum of 10 seconds, except for special operations such as establishing an artificial airway or performing defibrillation. Complications of chest compressions include rib fractures, pericardial hemorrhage or cardiac compressions, pneumothorax, hemothorax, pulmonary contusions, liver and spleen lacerations, and fat embolism. Proper handling should be followed to avoid complications as much as possible. Chest tapping is not recommended and has the potential to worsen the heart rhythm, such as accelerating VT, converting VT to VF, or converting to complete heart block, or causing cardiac arrest. 4. Defibrillation External cardiac electrical defibrillation is the use of a defibrillator to release a high-voltage electrical current through the chest wall to the heart in an instant, causing simultaneous depolarization of cardiomyocytes in an instant, terminating abnormal folds or ectopic foci of excitation that cause arrhythmias, thus restoring sinus rhythm. Since ventricular fibrillation is the most common arrhythmia in nontraumatic cardiac arrest patients, it can be performed after a period of CPR (e.g., 5 cycles or approximately 2 minutes) before EMS arrives. If an AED automatic electric defibrillator is available, CPR and AED should be applied in combination. because the AED is portable and easy to operate, it automatically recognizes the ECG and prompts defibrillation, and can be operated by nonspecialists.