That is, advanced life support (ALS), is based on basic life support, the application of auxiliary equipment, special techniques, etc. to establish more effective ventilation and blood circulation, the main measures include tracheal intubation to establish ventilation, defibrillation to turn the rhythm into a hemodynamically stable rhythm, the establishment of intravenous access and the application of the necessary drugs to maintain the restored circulation. ECG, blood pressure, pulse oximetry, and end-expiratory carbon dioxide partial pressure measurement must be continuously monitored, and invasive hemodynamic monitoring, such as arterial blood gas analysis, arterial pressure, central arterial pressure, and pulmonary artery pressure, is required when necessary. 1. Ventilation and oxygen supply: If the patient’s spontaneous breathing is not restored, tracheal intubation should be performed as soon as possible. The purpose of adequate ventilation is to correct hypoxemia and give 100% oxygen concentration by inhalation. Out-of-hospital patients usually use face mask and simple balloon to maintain ventilation, while in-hospital patients are commonly ventilated with a tidal volume of 6-7 ml/kg or 500-600 ml, and then adjusted according to the results of blood gas analysis. 2.Electrical defibrillation, resuscitation and pacing therapy: The most common arrhythmia in cardiac arrest is ventricular fibrillation. Although timely chest compressions and artificial respiration can partially maintain cardiac and cerebral function, they can rarely convert ventricular fibrillation to normal rhythm, and rapid restoration of an effective rhythm is a crucial step for successful resuscitation. The most effective method to terminate ventricular fibrillation is electrical defibrillation, and time is of the essence in the treatment of ventricular fibrillation; for every minute of delayed defibrillation, the success rate of resuscitation decreases by 7% to 10%. Neither cardiac arrest nor pulseless electrical activity electrical defibrillation is beneficial. Position of defibrillation electrodes: placed on the anterolateral part of the patient’s bare chest at the outer sternal border. The right electrode plate is placed below the patient’s right clavicle, and the left electrode plate is placed flush with the left nipple in the lower lateral part of the left chest. Other locations are the lower chest wall at the left and right lateral collateral lines, or the left electrode is placed in the standard position and the other electrodes are placed above the left and right back. If bidirectional wave defibrillation is used 150-200 J can be selected, if single wave defibrillation is used 360 J should be selected. one shock without effect continue chest compressions and manual ventilation, after 5 cycles of CRP (about 2 minutes) analyze the rhythm again and defibrillate again if necessary. The timing of electrical defibrillation after cardiac arrest is the most important determinant of successful cardiopulmonary resuscitation. Although electrical defibrillation is classified as a means of advanced resuscitation, it should be performed as early as possible if available, and is not bound to the stage of resuscitation, and it is advocated to perform electrical cardioversion in primary cardiopulmonary resuscitation. Pacing therapy: Pacing therapy is not recommended for patients with cardiac arrest, while it is considered for patients with symptomatic bradycardia. Pacing should be performed immediately if the patient has severe symptoms, especially if a high degree of AV block occurs below the bundle of Hirschsprung. If the patient does not respond to transcutaneous pacing, then transvenous pacing is indicated. 3. Drug therapy: Patients in cardiac arrest should have intravenous access as soon as possible during cardiopulmonary resuscitation. Peripheral veins usually choose anterior elbow vein or external jugular vein, hand or lower extremity veins are less effective as possible. Internal jugular, subclavian and femoral veins can be used for central veins. If venipuncture cannot be completed, certain resuscitation drugs can be given via the trachea. Epinephrine is the drug of choice for CPR. It can be used for ventricular fibrillation and pulseless ventricular tachycardia, cardiac arrest, or pulseless electrophysiologic activity where electric shock is ineffective. Routine administration is by intravenous push of 1 mg, repeated every 3 to 5 minutes, and the dose can be gradually increased to 5 mg. vasopressin, which has the same effect as epinephrine, can also be used as a first-line drug, and only one 40 U intravenous dose is recommended. Norepinephrine, dopamine, and dobutamine can be given for severe hypotension. Metabolic acidosis produced during resuscitation can often be improved by improved ventilation and should not be corrected by overly aggressive bicarbonate supplementation. Patients with cardiac arrest or prolonged resuscitation, or those with long-standing metabolic acidosis or hyperkalemia may be appropriately supplemented with sodium bicarbonate at an initial dose of 1 mmol/kg, with 1/2 amount repeated every 15 minutes during continuous cardiopulmonary resuscitation, preferably adjusted according to the results of arterial blood gas analysis to prevent the development of alkalosis. If ventricular fibrillation/pulseless ventricular tachycardia persists after 2 to 3 doses of defibrillation plus CPR and epinephrine, consider giving an antiarrhythmic agent (Table 3-4-1). The commonly used drug, amiodarone, may be considered with lidocaine. For lidocaine, give 1 to 1.5 mg/kg intravenously and repeat every 3 to 5 minutes if ineffective. If the total dose reaches 3 mg/kg and still no successful defibrillation, amiodarone or brodifacoum may be given as the next step. Amiodarone can be given slowly (>10 min) for the first 150 mg intravenously, and if ineffective, the total dose can be repeated up to 500 mg, followed by 10 mg/(kg・d) maintenance intravenous drip; or the drip can be continued at 1 mg/min for 6 hours, and then 0.5 mg/min for up to 2 g total daily, which can be maintained for several days as needed. For some refractory polymorphic ventricular tachycardia, tip-twisting ventricular tachycardia, rapid monomorphic ventricular tachycardia or ventricular flutter (frequency >260 beats/min) and refractory ventricular fibrillation, intravenous β-blockers can be tried. Metoprolol 5 mg IV every 5 min until a total dose of 15 mg; esmolol 0.5 mg/kg IV (1 min), followed by 50-300 μg/min IV maintenance. Patients with refractory ventricular fibrillation triggered by acute hyperkalemia may be given 5 to 20 ml of 10% calcium gluconate at an injection rate of 2 to 4 ml/min. isoproterenol or ventricular pacing may be effective in terminating bradycardia and drug-induced TDP. when VF/pulseless VT cardiac arrest is associated with tip-twisting ventricular tachycardia (TDP) with a long QT interval, 1 to 2 g of magnesium sulfate, diluted push for 5 to 20 minutes, or 1 to 2 g of magnesium sulfate in 50 to 100 ml of fluid drip. The management of slow arrhythmias and ventricular arrest is different from ventricular fibrillation. After giving basic life support, every effort should be made to try to stabilize the autonomic rhythm or to try to pace the heart. Commonly used drugs are epinephrine 1 mg every 3 to 5 minutes and atropine 1 to 2 mg intravenously. When intravenous access is not established, endotracheal administration of 2 mg in 10 ml of saline is an option. In patients with cardiac arrest or chronic pulseless electrical activity, consider atropine at a dosage of 1mg iv, which may be repeated every 3-5 minutes (maximum total of 3 doses or 3mg). If available, temporary artificial cardiac pacing, such as extracorporeal cardiac pacing or bedside transvenous endocardial pacing, is performed for slow arrhythmias. The above treatment should be accompanied by active search for possible reversible causes, such as hypovolemia, hypoxemia, cardiac tamponade, tension pneumothorax, drug overdose, hypothermia, and hyperkalemia, and treated accordingly. After cardiopulmonary resuscitation to restore the cardiac rhythm, emphasis should be placed on maintaining a stable cardiac and hemodynamic state. Catecholamines are not only good at stabilizing the electrical activity of the heart, but also have good positive inotropic and peripheral vascular effects. Among them, epinephrine is the drug of choice, with an initial dose of 1 μg/min for boosting, adjusted according to hemodynamics, with a dose range of 1-10 μg/min. norepinephrine significantly reduces renal and mesenteric blood flow and is now less commonly used. When the time-varying effect of epinephrine is not needed, dopamine or dobutamine can be considered. The recommended dose range of dopamine is 5-20 μg/(kg/min), and vasoconstriction of the body circulation and abdominal organs can occur at doses greater than 10 μg/(kg/min); dobutamine is a stronger drug to enhance myocardial contractility, without obvious vasoconstrictive effects, and the dose range is 5-20 μg/(kg/min). (kg/min). The role of fibrinolytic therapy in cardiac arrest is uncertain, but it may be considered in patients with suspected pulmonary embolism.