There are many causes of cardiac arrest. For adult patients, the common cause of cardiac arrest is heart disease, and for infants and children, the common causes are asphyxia and infection, trauma, and other factors. When a patient experiences cardiac arrest, first make sure the environment is safe and move the patient to a safe environment, lying flat on a hard surface. Assess the patient’s consciousness, if the patient is not conscious, activate the emergency response system, at the same time touch the carotid artery pulsation, when the patient’s consciousness is lost and the arterial pulsation disappeared, start the cardiopulmonary resuscitation operation. The position of the operator’s compression is the midpoint of the line between the two nipples, with the root of the palm as the focus point, the elbow joint is straightened, and the pressure is exerted to the vertical angle of the ground, with a compression depth of 5-6 cm, a frequency of 100-120 times/min, avoiding interruption of the compression for more than 10 seconds, avoiding hyperventilation, and ensuring the chest is fully rebound, with 30 times of compression, and 2 artificial respirations are given. Every 5 cycles of operation, assess the patient’s consciousness and arterial pulsation.