Epinephrine is the oldest, most effective, and most widely used method of CPR. It has been the drug of choice for CPR in recent decades because its alpha-receptor effect is significantly greater than its beta-receptor effect, and it can increase aortic diastolic pressure and myocardial blood flow and prevent and correct arterial collapse caused by prolonged synchronized cardiac compressions and ventilation. However, in the last two decades, although single epinephrine has been the mainstream of CPR drugs, the dose of epinephrine has changed several times, from small doses in the 1980s to the rise of high-dose regimens in the 1990s, and then through the individualized regimen phase, and in recent years has returned to small-dose regimens, which happens to be a complete cycle, and is in line with the dialectical materialism of negation This is a complete cycle and is in line with the law of negation of negation in dialectical materialism, i.e., the development of things is spiraling and wave-like. Accordingly, this paper will explain the philosophical basis of epinephrine dose changes during CPR from the principle of dialectical materialism, and discuss the future direction of epinephrine dose research. 1. Small-dose regimen phase In the 1980s, the recognition that small doses (1 mg/dose) of epinephrine can agonize both α and β adrenergic receptors, resulting in peripheral vasoconstriction (α receptor effect) and increased heart rate and myocardial contractility (β receptor effect). It also causes constriction of the vascular bed outside the brain and heart, which increases aortic systolic and diastolic pressures without altering right atrial and cerebral pressures, thereby increasing perfusion pressure in the brain and heart and improving the success rate of resuscitation. Therefore, the traditional epinephrine usage during CPR is all low-dose therapy. That is, throughout the resuscitation process, generally at least 1 mg of epinephrine is administered sedately every 3 to 5 minutes. Because epinephrine is metabolized rapidly, it should be injected frequently. If intravenous access is not established, the drug can be administered intratracheally, i.e., a 1 mg dose of epinephrine dissolved in 10 ml of fluid is dropped into the trachea. 2. High-dose regimen phase In the early 1990s, there was controversy about the optimal dose of epinephrine. Some researchers tried to find out the optimal dose. Berkowitz study found that epinephrine at a dose of 1 μg/kg/min in an IV drip increased the perfusion pressure of the brain; when the dose was increased to more than 10 μg/kg/min, the myocardial blood flow also increased, but when it was increased to 100 μg/kg/min, there was no further improvement in resuscitation. It has also been shown that epinephrine at a dose of at least 200 μg/kg/min improves cerebral and myocardial blood flow. Some experimental animal studies have shown that a high dose (100 μg/kg/min) of epinephrine can surprisingly improve the recovery rate of cardiac autonomic circulation. Since then, some scholars at home and abroad began to apply larger doses of epinephrine for cardiopulmonary resuscitation (3-5 mg/dose), and individual scholars even used very large doses (more than 10 mg per dose) of epinephrine. As a result, the situation of high-dose epinephrine dominated. 3, individualized program stage In the late 1990s, some studies showed that although mega-dose epinephrine could improve the cardiac resuscitation rate, the final survival rate did not improve. This may be related to the fact that high-dose epinephrine application can lead to post-resuscitation syndromes such as intractable hypertension and rapid arrhythmias. Therefore, with the rise of opposition to the application of high-dose epinephrine, scholars in China and abroad at that time mostly believed that an individualized compromise plan was more reasonable. In other words, the dosage of epinephrine should be individualized, and the gradient of dosage should be decided flexibly according to the immediate response of the specific patient to the drug, rather than adhering to a rigid rule. For example, a standard small dose (1 mg) of epinephrine should be applied for the first time in patients with a short duration of cardiac arrest, while a larger dose (2-5 mg) should be applied for the first time in patients with a longer duration of cardiac arrest. For patients given standard small doses of epinephrine for the first time, the dose can be increased when reapplied, i.e., stepwise dosing; i.e., “1, 2, 3 mg” or “1, 3, 5 mg” in increments of dosing. However, the application of very large doses of epinephrine of more than 5 mg per dose is opposed, as the latter may do more harm than good. In the individualized epinephrine application protocol, it is also suggested that the sensitivity of the patient to the drug differs significantly before and after the recovery of the voluntary heart rhythm, which may be related to the adjustment of adrenergic receptors in the myocardium before and after the recovery of the heartbeat. In the absence of a voluntary heartbeat, the patient may be insensitive to larger doses of epinephrine; once the voluntary heartbeat is restored, a very small dose of epinephrine can trigger tachyarrhythmia or ventricular fibrillation, so it is important to adjust the dosage of epinephrine in time. Once the patient’s voluntary heartbeat is restored, a small dose of epinephrine can be administered intravenously to prevent re-arrest. The American Heart Association (AHA) recommends giving 10 μg/Kg/min. In clinical practice, 10 mg of epinephrine is often added to 250 or 500 ml of saline and the rate is adjusted according to the desired value of heart rate and blood pressure as determined by the patient’s electrocardiographic monitoring. In addition, epinephrine should also be avoided with sodium bicarbonate, which can reduce its potency or increase the possibility of causing tachyarrhythmias and ventricular fibrillation. These are the key points for individualized application of epinephrine at that time. In the last few years, most scholars no longer advocate the initial high-dose intravenous infusion of epinephrine in the early stages of cardiopulmonary resuscitation. The reason for this is mainly due to its main pharmacological effects of stimulating α receptors, causing vasoconstriction and increasing coronary perfusion pressure; and stimulating cardiac? receptors, producing positive chronotropic and force-changing effects, so the application of epinephrine after cardiac arrest may lead to excessive cardiac contraction, resulting in impaired myocardial diastole and stone heart phenomenon. In particular, numerous recent studies on epinephrine have shown that increasing the dose of epinephrine does not improve the success rate of cardiopulmonary resuscitation and the neurological function of survivors [2], so the latest version of the American Heart Association’s 2005 guidelines for cardiopulmonary resuscitation recommends a small dose of epinephrine (1 mg/dose), and only slightly increases the dose to 2 -In recent decades, the dose regimen of epinephrine in CPR has gone from small to large doses and back to small doses in exactly one cycle. However, after this cycle, the disadvantages of excessive application of epinephrine, such as causing stone heart, leading to post-resuscitation syndromes such as intractable hypertension and rapid arrhythmias, have been fully recognized. This is fully consistent with the law of negation of negation of dialectical materialism, where things develop in an upward spiral. Secondly, according to the law of negation of dialectical materialism, the dose of epinephrine will be developed to high dose again in the future, the premise is to find ways to counteract the disadvantages of high dose of epinephrine, so as to maximize the beneficial effects of epinephrine, and start a new round of “spiral up”. Regarding the dose of epinephrine for CPR, it is recognized that increasing the dose of epinephrine during CPR is a “double-edged sword”. Therefore, the application of epinephrine program, from small doses to large doses, and then to small doses, is the result of people’s understanding of the contradiction between the beneficial and harmful effects of epinephrine, but also the full embodiment of the principle of dialectical materialism law of unity of opposites. Secondly, because of the harmful effects of epinephrine, such as can cause stone heart, there is no good solution, so at present can only emphasize the harmful effects of epinephrine, so the recommended small dose of epinephrine program, which is the embodiment of the main contradiction. In addition, solving the contradiction between the beneficial and harmful effects of epinephrine, i.e., finding ways to counteract the disadvantages of high-dose epinephrine, so that the two can reach unity, will be one of the priorities of future research. The variation of epinephrine dose in CPR is also a full manifestation of the law of mutual change of quality in materialistic dialectics. Small doses of epinephrine are beneficial to CPR, but after increasing to a certain dose, the effect on the heart becomes harmful, which is a process of quantitative to qualitative change. At present, it is believed that the single dose of epinephrine should be 1 mg, often clinically known as the standard dose, which is the philosophical “degree”. However, it must be recognized that this standard dose is only the result of the current understanding; with the progress of the pathophysiology of cardiopulmonary resuscitation and changes in the method of resuscitation, a so-called standard dose under new conditions will be needed, that is, people will determine a new “degree”. Therefore, finding a new “degree” and determining the standard dose of epinephrine under new conditions is one of the directions of future CPR research. In conclusion, epinephrine is the first-line drug for CPR in clinical practice, and the change of its dose application scheme is a full manifestation of materialistic dialectics; applying the principle of dialectical materialism to determine the direction of development will help the theory and practice of CPR research.