The elements of general anesthesia include sedation, analgesia and muscle relaxation, while the essence of intraoperative pain in patients under general anesthesia is the body's unconscious response to tissue damage, namely the stress response.Stress response is a series of hormonal and metabolic changes produced by the body in response to nociceptive stimuli. It is part of the systemic response to injury and includes a wide range of endocrine, immunological and hemodynamic effects.Operation as well as the modern medicine common disease treatment, as a harmful stimulation, can cause the body strong stress reaction, reaction and duration and the size of the surgery is often proportional to the damage degree, its mechanism mainly include the activation of the sympathetic nervous system, adrenocorticotropic hormone (ACTH), growth hormone, vasopressin (AVP), cortisol and aldosterone and a series of hypothalamus pituitary adrenal axis hormone changes, insulin resistance and stress hyperglycemia, IL - 1, IL - 6, TNF alpha, such as the change of cytokines,And the increase in acute phase reactions such as acute response phase protein (CRP).As a protective response, stress response can mobilize the energy stored in the body when the body is injured, and help the body survive in harsh environment.But now a good perioperative management environment means that patients can be adequately nourished even after surgery.In this case, excessive stress response leads to preoperative anxiety of patients, the occurrence of adverse events in the intraoperative central blood vessels, and the occurrence of postoperative complications.In surgical patients, many systems, including the brain, are negatively affected by stress hormones.Perioperative acute stress can lead to post-traumatic stress disorder, depression, postoperative fatigue, chronic pain, and cognitive decline in elderly patients.Perioperative hyperglycemia and insulin resistance are closely related to postoperative infection and cardiovascular events, and may prolong hospital stay.Perioperative stress response will also damage the immune function of patients, which is mainly manifested as inhibition of natural killer cell function and inhibition of innate immune function response, which brings concerns about postoperative infection and tumor recurrence of patients.Anesthesia can inhibit the intraoperative stress of patients to a certain extent. Different anesthesia drugs and anesthesia methods can be selected for the same operation.Dexmedetomidine has dose-dependent sedative, analgesic, anti-anxiety and hypnotic effects. It can reduce serum s-100 protein, lipid peroxidation product malondialdehyde (MDA), raise the level of hyper oxide dismutase (SOD), and reduce TNF-, il-1, il-6 and other pro-inflammatory mediators.Fentanyl, rui fentanyl, sufentanil opioids can inhibit the hypothalamus pituitary adrenal axis, decrease the plasma levels of stress hormones, but this does not mean that the investigators can in the art of unlimited increase the drug, also want to consider the stability of hemodynamics, respiratory depression caused by delayed awakening, postoperative nausea and vomiting, postoperative itching and postoperative recovery of gastrointestinal, etc.;Epidural anesthesia with segmental sympathetic nerve blocking effect, in the chest surgery, general anesthesia compound epidural block than all by intravenous anesthesia, the patient's heart rate, blood pressure, mean arterial pressure, such as index significantly more smoothly, catecholamine levels in peripheral blood, the incidence of postoperative adverse events also significantly reduced.Real-time monitoring of the intraoperative stress level of patients is helpful for the anesthesiologist to determine the depth of anesthesia and guide the intraoperative anesthesia medication.There are many ways to monitor the level of intraoperative stress in patients.Surgical volume index (SPI) is used to monitor the pain-analgesic balance during general anesthesia through heartbeat interval and pulse wave amplitude measured by light.Skin pain conductance meter (SCA) assesses the size and pain of nociceptive stimulation through sweating and skin conductance.The pupil pain index (PPI) monitors intraoperative pain by measuring changes in pupil size caused by nociceptive stimulation.All of these indicators were used to monitor the intraoperative stress level through sympathetic or parasympathetic nerve activity. However, the intraoperative acute stress response was related to the state of high adrenocorticotropin and high cortisol. Currently, there is no index to evaluate the intraoperative pain of patients based on the change of intraoperative stress hormone level.However, the changes of stress hormones must be detected by laboratory tests. Therefore, whether the changes of stress hormones can be estimated by the blood pressure and heart rate that the investigators routinely monitor during the operation, so as to provide a research direction for us to establish the intraoperative pain monitoring method with stress hormones as the evaluation standard.In summary, this clinical study analyzed the relationship between the changes of systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate under surgical curettage stimulation and the changes of plasma adrenocorticotrophin and cortisol through prospective observational studies, and found out the indexes that could reflect the changes of stress hormones during the operation.