麻醉小型猪 z-bo 2020-10-15 283

　　(1) Injection anesthesia

　　1. Fasting before anesthesia Miniature pigs should be observed for 5 to 7 days before anesthesia. During transportation, symptoms such as dehydration and weight loss may be caused. Standard care procedures should be established for newly introduced miniature pigs. Fasting for a period of time is to empty the food and liquid in the stomach during induction of anesthesia, and to prevent reflux and aspiration during anesthesia. Both reflux and aspiration are closely related to gastric emptying. The upper gastrointestinal tract of miniature pigs has a fast emptying rate and can empty the stomach in just a few hours. Therefore, it is sufficient to fast for solid food for 12 hours before surgery, but it should always be used before surgery. Provide drinking water. Miniature pigs can eat liquid and sweet food quickly, which can prevent hypoglycemia caused by long fasting after surgery. The litter for miniature pigs should be removed from the cage during the fasting process, because the miniature pigs may eat it as food during the fasting process. Prolonged fasting and drinking can also lead to a series of adverse performances, which should be paid attention to, including obvious thirst, hunger and anxiety; reduced tolerance and safety of anesthesia; due to general anesthesia or epidural anesthesia, either The blood vessels below the level of anesthesia are dilated, resulting in a drop in blood pressure, preoperative collapse, hypoglycemia, etc., which significantly reduces the tolerance of the miniature pigs to anesthesia; prone to sweating, palpitation, and blood pressure drop before surgery, and slight blood loss during surgery A drop in blood pressure or even shock can occur, which affects the smooth progress of the operation. At the same time, the blood pressure is low, the blood circulation around the surgical incision is poor, and the incidence of poor wound healing after surgery increases; stress reaction is aggravated.

　　2. Pre-anaesthetic medications. Anesthesia should be induced before mini-pigs are anesthetized. Different anesthesia inducers have an impact on the physiological indicators of mini-pigs and the type and dosage of anesthesia maintenance drugs. In the induction of anesthesia for small pigs, the animal’s stress response should be minimized, and personnel injury and equipment damage should be prevented during the operation.

　　Pre-anaesthesia medication can relieve the anxiety of mini-pigs, block the vagus nerve, reduce the dosage of drugs for maintaining anesthesia, and facilitate the holding and catching of mini-pigs. Such pre-narcotics include anticholinergics, tranquilizers, hypnotics and tranquilizers.

　　(1) Anticholinergic drugs: Atropine is a commonly used prodrug before surgery. This drug can reduce the production of bronchial secretions. Because the drug can block the vagus nerve, it can be used during tracheal intubation or endotracheal suction. Can reduce the reflex of small pigs. The drug has a certain effect on bradycardia caused by anesthesia. In our laboratory, 0.05 mg/kg of atropine was injected intramuscularly before anesthesia in miniature pigs, and 0.02 mg/kg was injected intravenously during the anesthesia process and achieved good results. In addition, atropine is not a necessary drug in the process of anesthesia for miniature pigs. In the process of anesthesia for miniature pigs, it should be considered that the drug will block the vagus nerve and cause tachycardia, which will affect the results of the experiment.

　　(2) Sedatives and sedatives: Phenothiazines and benzodiazepines sedatives are commonly used pre-anaesthetic drugs in miniature pig anesthesia, and these drugs can induce anesthesia. Large doses of drugs can cause peripheral vasodilation and adrenergic block, and the action time of such drugs is between 8 to 12 hours. Reports have shown that subcutaneous (0.5～10mkg/kg) or intravenous (0.44～2mg/kg) injection of fat-soluble diazepam injection can produce good hypnotic and sedative effects during miniature pig anesthesia, and its action time can be maintained 6 hour. Our laboratory combines diazepam injection (1～2mg/kg) with anesthetics for maintenance of anesthesia in miniature pigs, which can reduce the amount of anesthetics and reduce the risk of anesthesia; subcutaneous or intravenous injection (0.1～2mg/kg) is water-soluble Midazolam can produce good sedation, but high-dose midazolam can cause a significant decrease in cardiovascular index during anesthesia in miniature pigs.

　　3. Intramuscular injection anesthesia: Intramuscular injection anesthesia is the most commonly used anesthesia technique in the experimental application of small pigs. Intravenous anesthesia and inhalation anesthesia usually require intramuscular anesthesia induction. There are usually three methods for intramuscular anesthesia of mini-pigs in our laboratory. The first is to fix the mini-pigs on one side of the rearing cage with a retractable cage and then perform intramuscular injection (Figure 3-16); Put the pig into the transport cage, lift the side of the transport cage where the pig’s head is about 450, use the pig’s own weight to fix the buttocks, the anesthetist grasps the pig’s tail with one hand to further fix the pig, and the other hand injects anesthetic into the buttocks muscle (Picture 3-17); The third method is mainly for small pigs that are docile or easy to touch after training. The anesthetist opens the breeding cage and gently strokes the small pigs to minimize their fear. After the small pigs are quiet, the syringe is pierced Injection into the hip or ear. In the implementation of the above three methods for anesthesia induction, the tip of the syringe should be connected to a scalp needle with a hose (butterfly wing needle). The advantage of this is that the hose of the scalp needle can be bent at will as the pig struggles. Prevent the needle from coming out due to the sudden struggle of the small pig.

　　Ketamine hydrochloride is the most commonly used anesthetic for small pigs, usually combined with other drugs. Ketamine hydrochloride belongs to the phencyclidine group of intravenous general anesthetics, and its basic chemical structure is cyclohexylamine, so it is also called cyclohexyl. The effect of the drug can be called "separation anesthesia", and its notable feature is complete analgesia accompanied by light sleep. Mini-pigs can produce chemical effects within 20 minutes of simple application of the drug (11～33mg/kg). The drug has a poor muscle relaxation effect, but has little effect on heart function. Ketamine hydrochloride alone cannot produce analgesic effects on the internal organs of mini-pigs. It must be combined with other drugs to produce better muscle relaxation and analgesia effects.

　　The plan of combined application of ketamine hydrochloride and other drugs is as follows: ketamine 33mg/kg, acepromazine injection 1.1mg/kg; ketamine 15mg/kg, diazepam injection 2mg/kg; ketamine 10mg/kg, flunazepam 0.2 mg/kg; ketamine 33mg/kg, midazolam 0.5mg/kg; ketamine 15mg/kg, azaperone 2mg/kg; ketamine 20mg/kg, xerazine 2mg/kg; ketamine 10mg/kg, meto Imididine 0.2mg/kg. Ketamine combined with midazolam can produce muscle relaxation, and its anesthesia is maintained at 45 to 60 minutes after a single administration, which is convenient for endotracheal intubation. Studies have shown that the drug application dose of ketamine combined with medetomidine has a relatively wide safety range. The medication range of ketamine is 1-10mg/kg, and the medication range of medetomidine is 0.08-0.2mg/kg. Generally speaking, increasing the dosage of ketamine should correspondingly reduce the dosage of medetomidine. Ketamine combined with xylazine can produce short-acting analgesia, but this combination is prone to heart block. Ketamine combined with acepromazine, diazepam and azaperone cannot produce enough muscle relaxation for endotracheal intubation, and they all have a certain effect on dilating peripheral blood vessels. Ketamine hydrochloride (20mg/kg) and xylazine hydrochloride (2mg/kg) have been recommended as general anesthesia regimens for pigs. However, because pigs are prone to fatal arrhythmia, this combination medication should be accompanied by atropine to prevent persistent heart block and hypotension associated with xylazine hydrochloride. Huang He et al. used 12 mg/kg of ketamine and 0.5 mg/kg of midazolam intramuscular injection for basic anesthesia during pancreaticoduodenal transplantation in miniature pigs, and intravenous infusion of 0.02% ketamine and 0.4% etomidate to maintain anesthesia Achieve good results.

　　This laboratory study found that small pigs injected intramuscularly with ketamine hydrochloride 10mg/kg alone have the characteristics of fast anesthesia, and can be used for short-term, minimally irritating surgical operations. However, due to the insufficient depth of anesthesia, the muscle relaxation effect of ketamine hydrochloride is poor, so it is difficult to perform tracheal intubation. Ketamine hydrochloride and Sumianxin II (volume ratio 2:1) intramuscular injection of 0.3-0.5ml/kg induces fast, muscle relaxation effect is good, and it is convenient for tracheal intubation. The disadvantage of this method is that Sumianxin has a significant effect on the cardiovascular system, which is manifested as a decrease in heart rate and blood oxygen content. For experiments on the cardiovascular system, it should be used with caution and its dosage should be controlled. In addition, Sumianxin II and midazolam injection (volume ratio 1:1) were used to establish intravenous access to miniature pigs after induction of anesthesia by intramuscular injection of 0.5ml/kg. The intravenous maintenance of pentobarbital sodium is also commonly used in our laboratory. Anesthesia method, this method has achieved good results in the anesthesia process of miniature pigs.

　　4. Intravenous anesthesia

　　(1) Barbiturates: Pentobarbital sodium is a commonly used injection anesthetic for anesthesia of small pigs. Its effect is mainly to suppress the central nervous system, with mild sedation, moderate hypnosis, deep anesthesia, and overdose, which will inhibit the respiratory and circulation. When anesthesia is too deep, it can inhibit the respiratory center of the brain and cause animal death. Common barbiturate intravenous general anesthetics include thiopental sodium, pentobarbital sodium, thiopental barbital sodium, methynebarbital sodium, sec-butylthiobarbital sodium, cyclohexylbarbital sodium , Butylthiobarbital sodium, methylthiobarbital sodium and thionebarbital sodium. In the laboratory, barbiturate has been widely used as an anesthetic. Because barbiturate needs to be injected intravenously, the recommended dose can only be used as a guide. For pig anesthesia, barbiturate depends on age The dosage varies greatly depending on the body weight. When barbiturate is used in combination with other drugs, the dosage can be reduced by 1/2 to 2/3. It has been reported that the application range of pentobarbital sodium is 20-40mg/kg, and thiopental sodium is 6.6-30mg /Kg. In the anesthesia of mini-pigs, pentobarbital sodium must be administered by intravenous injection after the induction of anesthesia. The inhibitory effect of the drug on the cardiopulmonary function is positively correlated with the dosage. It is usually manifested as inhibiting breathing, reducing myocardial contractility and cardiac output, increasing peripheral vascular resistance, and reducing cerebral blood flow. Thiobarbiturates are shown to reduce cardiopulmonary function, reduce cerebral blood flow and intracranial pressure, and have little effect on peripheral vascular resistance. Among the barbiturates, thiobarbiturates have the least effect on cardiopulmonary function. The dosage for clinical anesthesia guidance is thiopental sodium, thiopental barbital sodium 6.6-30mg/kg, 3-30mg/(kg·h), pentobarbital sodium 20-40mg/kg, 5-40mg/(kg · H). Grund et al. divided the pigs into a pentobarbital sodium anesthesia group and a ketamine hydrochloride-fentanyl citrate-medetomidine anesthesia group for a comparative experiment, and the results confirmed ketamine hydrochloride-fentanyl citrate-medetomidine Compared with the sodium pentobarbital group, the anesthesia group showed more significant decreases in heart rate, myocardial contractility, arterial blood pressure, left ventricular pressure, and aortic blood flow. Xu Yihu and others applied ketamine 10mg/kg, midazolam 0.25～0.5mg/kg intramuscular injection to induce anesthesia, and 3% pentobarbital sodium 0.2ml/kg was used for anesthesia maintenance. They have achieved good results in the experimental burn surgery of miniature pigs. effect. Wu Qinghong et al. injected 0.1 ml/kg Sumianxin II intramuscularly into Tibetan mini-pigs to induce anesthesia, and established intravenous channels to inject 3% pentobarbital sodium intravenously at a dose of 0.2 ml/kg for anesthesia maintenance. The result was that the combined medication was significantly better than the single Using Sumianxin, the author believes that the combination of Sumianxin II and pentobarbital sodium is an ideal method for the anesthesia of Tibetan miniature pigs. Yu Wen et al. applied ketamine 10mg/kg, atropine 0.02mg/kg and diazepam 0.4mg/kg intramuscular injection to Guizhou mini-pigs for basic anesthesia, followed by intravenous injection of fentanyl 5μg/kg and 1% pentobarbital sodium intravenously Note that maintaining anesthesia successfully completed the miniature pig artery restenosis model. Ruan Dinghong and others injected ketamine hydrochloride 12mg/kg and atropine 0.5mg intramuscularly, and maintained anesthesia for miniature pigs. Sufentanil citrate 3～4gμ/(kg·h) and midazepam 0.15mg/(kg·h) were injected intravenously. And ketamine hydrochloride 15～20mg/(kg·h), it has achieved good anesthesia effect in miniature pig percutaneous nephroscopy.

　　This laboratory uses ketamine hydrochloride and Sumianxin II (volume ratio 2:1) 0.3ml/kg intramuscular injection to induce anesthesia, establish an intravenous channel, intravenous injection of pentobarbital sodium 3mg/kg for anesthesia maintenance, received more Good anesthesia effect. Some researchers believe that pentobarbital should be avoided during anesthesia procedures longer than 2 hours. For anesthesia procedures of 2 to 6 hours, it is more suitable to repeatedly apply ultra-short-acting low-dose thiopental sodium. In addition, continuous intravenous drip of these drugs can provide smoother anesthesia. When pentobarbital sodium is used for anesthesia, because experimental pigs are prone to respiratory depression, a ventilator should be provided.

　　(2) Separate anesthetics: Separate anesthetics can expand the bronchus, increase heart rate, increase cardiac output, and raise blood pressure. Ketamine hydrochloride is a commonly used separation anesthetic, which can prolong the refractory period of the myocardium and make the coronary Pulse dilation increases pulmonary artery vascular resistance and increases cerebral blood flow. Miniature pigs are anesthetized by intravenous infusion of ketamine hydrochloride and other drugs, which can provide internal organs analgesia for miniature pigs during surgery. Ketamine hydrochloride 1mg/ml, xerazine 1mg/ml and 5% guaiacol glycerol ether mixed with 5% glucose will provide stable cardiovascular function. The method of administration is 1ml/kg intravenously first, and then 1ml/(kg·h) infusion. Midazolam 0.5～1.5mg/(kg·h), ketamine hydrochloride 5mg/(kg·h), medetomidine 10mg/(kg·h) can be used for intravenous infusion anesthesia. Nowadays, low-dose intravenous injection of ketamine hydrochloride-azaperone is gradually being used as a sedative for miniature pigs. However, the above anesthesia methods should be accompanied by monitoring measures such as heart rate and blood pressure of miniature pigs.

　　Zhang Fan et al. combined ketamine hydrochloride with pentobarbital sodium and propofol to anesthetize Pama miniature pigs. The results showed that both anesthesia methods can achieve good anesthesia effects. Propofol combined with ketamine anesthesia is better than pentobarbital anesthesia. It is an ideal anesthesia method because it has a strong anesthesia effect and quick recovery from the postoperative period. When applying pentobarbital sodium to anesthetize mini-pigs, intramuscular injection of ketamine hydrochloride (5-10 mg/kg) according to the length of the operation can play the role of analgesia and prolong the anesthesia time, and recover the mini-pigs after surgery. On the one hand, the recovery time is significantly shorter than repeated addition of pentobarbital sodium.

　　(3) Opioid anesthetics: Opioids were first used intravenously in cardiac surgery to provide analgesic effects. Such drugs are often used in combination with drugs such as inhalation anesthesia in the anesthesia of small pigs. In inhalation anesthesia, the dosage of 0.5% can meet the demand. Opioids do not reduce cardiac contractility and coronary blood flow, and have little effect on peripheral vascular resistance, but they have a respiratory inhibitory effect. In the research of cardiovascular surgery in miniature pigs, intravenous administration of 0.03～0.05mg/kg [30～100mg/(kg·h)] fentanyl combined with anesthetics has been successfully used. Sufentanil is more effective than fentanyl. In cardiovascular surgery studies, sufentanil was injected intravenously at 5-10 mg/kg and then infused at a dose of 10-30 mg/(kg·h). The guiding dosage of these drugs in the anesthesia process of miniature pigs is: fentanyl 30～100mg/(kg·h), sufentanil 7～30mg/(kg·h), alfentanil 6mg/(kg ·H), Remifentanil 30～60mg/(kg·h). The application of such drugs can effectively prevent bradycardia and muscle tension during anesthesia.

　　5. Intraperitoneal injection of anesthesia The use of intraperitoneal injection of sodium pentobarbital for anesthesia in small pigs is also occasionally reported. Zhou Zhongxin et al. injected 5 mg/kg of ketamine into 37 cases of miniature pigs by intramuscular injection, followed by intraperitoneal injection of 25 mg/kg for induction of anesthesia. For anesthesia maintenance, intraperitoneal injection of sodium pentobarbital was used. During the operation of miniature pigs, the anesthesia was stable and the muscle relaxation was effective. Good, stable vital signs, good results have been achieved; Zuo Yanfang and others used intravenous injection of 30mg/kg pentobarbital sodium to 108 small pigs. To sodium, the author believes that this program is an ideal anesthesia method in miniature pig anesthesia. However, Wu Hongqing et al. through anesthesia experiments on Tibetan mini-pigs, believed that the effect of intraperitoneal or intramuscular injection of sodium pentobarbital alone was not satisfactory. After intraperitoneal injection, the drug was slowly absorbed after being diluted by ascites in the abdominal cavity. It takes a long time to reach the effective blood concentration, and intramuscular injection has more adipose tissue in miniature pigs, and the stable blood concentration of pentobarbital sodium can only be achieved after the adipose tissue is saturated. Although intraperitoneal injection of anesthesia has the characteristics of simple injection operation, the depth of anesthesia is not easy to control, and the dosage of drugs used is large, and there will often be cases of too shallow or too deep anesthesia.

　　(2) Inhalation anesthesia

　　1. Overview of Inhalation Anesthesia Inhalation anesthesia uses gas or volatilized gas to enter the body through the respiratory tract to play an anesthetic effect. Inhalation anesthesia is divided into gas inhalation anesthesia and endotracheal intubation anesthesia. Intratracheal intubation anesthesia is to place a special catheter into the trachea of an animal to establish an artificial ventilation tube. The anesthesia is carried out through this endotracheal catheter. The endotracheal intubation anesthesia can keep the airway unobstructed and facilitate the removal of secretions in the airway. Oxygen inhalation and assisted breathing, the inhalation anesthesia process has the characteristics of reversibility, no accumulation, low metabolic rate in the body, non-toxic metabolites, high safety, stable anesthesia, and quick recovery.

　　When performing inhalation anesthesia, the inhalation anesthetic must be inhaled through the anesthesia machine to produce anesthesia. The anesthesia machine can be used for anesthesia, oxygen supply and assisted or controlled breathing. The required concentration of oxygen and inhaled anesthetics should be precise, stable and easy to control. In addition to the basic components of the air circuit, modern anesthesia machines are also equipped with electronic, computer control and monitoring equipment, so they have higher requirements for operation and management. The combination of high-level anesthesiologists and multi-functional modern anesthesia machines is the development trend of today's anesthesia, which will greatly reduce accidents caused by mechanical failures. Anesthesia machine includes air supply device, flow meter, vaporizer, ventilation system, anesthesia ventilator, monitoring and alarm device, anesthesia residual gas removal system and various accessories and connectors.

　　In inhalation anesthesia, a very important concept must be clarified, that is, the minimum alveolar concentration (MAC), which is defined as 50% of patients at one atmosphere without moving during skin incision stimulation. At this time, the alveoli The concentration of the anesthetic is 1 MAC. MAC is a measure of the potency of inhaled anesthetics and the basis for monitoring the depth of anesthesia in animals. Approximately 1.5 to 2 times the MAC is required for surgery, but there are differences due to animal species, body conditions, and combination drugs. The higher the minimum effective concentration of alveolar gas, the weaker the effect of the anesthetic. In addition, MAC can also be used as a means to explore the mechanism of anesthesia. The factors that affect the minimum effective concentration of alveolar gas mainly include: ①The difference between animal species and species; ②Physiological rhythm, in the same animal, due to different measurement times, the minimum effective concentration of alveolar gas will also change; ③Hypocapnia And hypercapnia, hypocapnia has a slight effect on the minimum effective concentration of alveolar gas. Hypercapnia above 12.6kPa (95mmHg) will become an anesthetic. Therefore, the minimum effective concentration of alveolar gas should be reduced; ④ Compensatory acid Poisoning, little or no effect; ⑤The age of animals, old animals should reduce the dosage; ⑥The synergistic application of other drugs, opioids and analgesics will reduce the minimum effective concentration of alveolar gas.

　　2. Commonly used inhalation anesthetics for miniature pigs The most commonly used inhalation anesthetics for miniature pigs are mainly isoflurane, desflurane and sevoflurane. On the one hand, these three anesthetics do not have too many side effects on animals, and on the other hand, they are less harmful to humans than other inhalation anesthetics. Therefore, they are ideal drugs for small pigs. In terms of drug cost, isoflurane has a greater advantage than desflurane and sevoflurane. Now isoflurane has been widely used in the anesthesia process of miniature pigs. Holmstrom et al. used isoflurane, desflurane, and sevoflurane to anesthetize pigs, and calculated cerebral blood flow (CBF) by intra-arterial injection of 133Xe and the clearance curve of 133Xe; the mean arterial pressure (the mean Arterial pressure (MAP) and cerebral blood flow are used to calculate cerebrovascular resistance (CVRe). Studies have confirmed that these three inhalation anesthetics act on miniature pigs, and their CBF size is desflurane> isoflurane> sevoflurane; MAP and The size of CVRe is sevoflurane>isoflurane>desflurane. Isoflurane has no obvious effect on cerebral vasodilation at low inhalation doses, but sevoflurane and desflurane have effects on cerebral vasculature at high inhalation doses. The expansion effect is higher than that of isoflurane. In a dose-dependent manner, all inhaled anesthetics cause increased cerebral blood flow, decreased coronary blood flow, lower oxygen consumption, and are prone to hypercapnia and cause bronchiectasis. In contrast, these effects of isoflurane are minimal. Yes, isoflurane can also increase coronary blood flow at a certain dose. In terms of inhibition of myocardial contractility, isoflurane, desflurane and sevoflurane are much less damaging to the myocardium than other inhaled anesthetics. Aagaard et al. studies have confirmed that sevoflurane has the ability to enhance myocardial contractility in the initial stage of anesthesia. effect.

　　It is reported that desflurane can reduce the oxygen capacity of the liver and small intestine, but it will not cause hypoxia in the tissues. A1-laouchiche et al. used propofol [8mg/(kg·h)], sevoflurane (1MAc) and desflurane (1MAc) to anesthetize small pigs. After anesthesia, the blood serum and lung perfusion fluid of small pigs Malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx) and other indicators of oxidative stress were measured. The results confirmed that mechanical ventilation inhalation of desflurane can easily cause local And systemic oxidative stress. Although the application of nitrous oxide in the anesthesia process of mini-pigs is gradually reduced, the application of nitrous oxide alone cannot produce analgesic effect on visceral surgery in mini-pigs. However, studies have confirmed that the combination of nitrous oxide and oxygen (1:1 or 2 : 1) Mixing, then combined with other anesthetics can produce very good results. For example, mixing nitrous oxide with oxygen (2:1) and combined with isoflurane for anesthesia of miniature pigs can greatly reduce the myocardial depression caused by anesthesia, and the concentration of isoflurane required during anesthesia is reduced. Nearly 50%, its MAC concentration is 195, pure isoflurane is 1.2 to 2.04, desflurane is 8.28 to 10, halothane is 0.91 to 1.25, sevoflurane is 2.53, and enflurane is 1.66. However, nitrous oxide is potentially harmful to the human body, and exhaust gas treatment should be done when using it.

　　For other inhaled anesthetics, such as: Methoflurane has a relatively low anesthetic effect, which reduces blood pressure, cardiac output and peripheral vascular resistance, and it can be used for humans. The kidneys cause damage; halothane can sensitize the myocardium to catecholamines to induce arrhythmia. It has a strong inhibitory effect on the myocardium, reduces cardiac output, and can also cause certain harm to human health; Enflurane is sensitive to some When applied to animals, it is easy to induce epilepsy, and it can also reduce blood pressure, cardiac output and peripheral vascular resistance. Therefore, it is not recommended to use these drugs during anesthesia in miniature pigs.

　　3. Inhalation anesthesia for mini-pigs Inhalation anesthesia is the main anesthesia method for mini-pigs. This anesthesia method provides a good anesthesia and analgesic effect for the miniature pigs and greatly shortens the recovery time of the postoperative miniature pigs. Before inhalation anesthesia for small pigs, check whether the CO2 absorption device of the anesthesia machine, the exhaust gas absorption device of the anesthetic agent and various instruments are working properly and whether there is any air leakage. The fasting, pre-anaesthesia administration, induction of anesthesia and tracheal intubation for minipigs are the same as those of injection anesthesia.

　　Before performing inhalation anesthesia, the parameters of the anesthesia machine should be completely set, including tidal volume, number of breaths, oxygen flow rate, etc. The lung tissues of miniature pigs are very sensitive to hyperventilation. When hyperventilation occurs, pneumothorax and pneumoperitoneum can easily occur. In severely symptomatic miniature pigs, intestinal wall cyst-like pneumatosis can occur, and inhalational anesthesia of miniature pigs can easily cause lung bulging Carvalho et al. studied the mechanism of reducing the positive end-expiratory pressure of the lungs in young pigs. The air pressure for miniature pigs should be between 18-22cmH2O, tidal volume should be 5-10ml/kg, end tidal CO2 is usually 40-50mmHg, end expiratory pressure (PEEP) can be adjusted by a ventilator to ensure proper Lung pressure.

　　The respiratory rate of miniature pigs varies according to the depth of anesthesia. For miniature pigs weighing 20 to 40 kg, the respiratory rate is set at 12 to 15 breaths/min during inhalation anesthesia. Blood oxygen, arterial blood gas, and tidal end CO2 should be monitored during anesthesia to ensure correct ventilation.

　　Mini-pigs should be ventilated with pure oxygen for 5 minutes before inhalation anesthesia to expel the nitrogen in their bodies as much as possible. When turning on the inhalation anesthesia machine, first take a high concentration of inhalation (2% to 4%), and gradually reduce the inhalation of anesthetic (0.6% to 2.5%) as needed when a relatively stable state of anesthesia is reached. The combined application of static-suction combined anesthesia in surgery can greatly reduce the risk of surgery and increase the success rate of mini-pig surgery. After induction of anesthesia for miniature pigs (volume ratio of ketamine hydrochloride and Sumianxin II, 0.3ml/kg intramuscular injection), intravenous injection of sodium pentobarbital (2～4mg/kg) combined inhalation Isoflurane anesthetize mini-pigs and has achieved good results in thoracotomy and laparotomy. The inhalation of inhaled anesthetics can be reduced according to the increase in intravenous administration. The method can reduce the cost of anesthesia, is easy to control the depth of anesthesia, has the characteristics of good safety, stable anesthesia, and quick recovery.

　　Niu Jiyuan et al. applied 1% to 1.7% isoflurane inhalation anesthesia in the combined pancreas and kidney transplantation of Guizhou mini-pigs, and intravenously administered vancorson and fentanyl during the operation. This combined anesthesia achieved good results. Wang Yang et al. used 2mg/kg propofol intramuscular injection to induce anesthesia during Da Vinci robotic surgery, inhaled 1.5% to 2.0% isoflurane for anesthesia maintenance, and continued to give 1ml/(kg·kg· h) Propofol, because repeated administration of propofol does not accumulate in the body, it will not delay the recovery time of miniature pigs. Isoflurane has a fast metabolism rate and is easy to control the depth of anesthesia. It is considered an ideal miniature pig anesthesia. method. Bauer et al. used isoflurane and propofol to anesthetize the animals during the orthotopic xenotransplantation between minipigs and baboons. The results confirmed that the two anesthesia methods had no significant difference in the effects of the two methods on animal physiological indicators, but the application Isoflurane anesthesia. After the completion of the operation of cardiopulmonary bypass, the animal's dependence on drugs (epinephrine, norepinephrine) is significantly lower than that of the propofol group. The author suggests that the application of heterotopic xenotransplantation is recommended. Halothane anesthetize the animals. Baumert et al. used xenon gas to anesthetize pigs in the acute hemorrhagic shock experiment of pigs. During the experiment, they monitored the mean arterial pressure (MAP), heart rate and cardiac output (CO) of pigs. The results showed that xenon gas was used for anesthesia. Compared with isoflurane anesthesia in pigs, xenon anesthesia can observe the hemodynamic changes of acute blood loss faster than isoflurane, and monitor the transient recovery of mean arterial pressure (MAP) after blood loss. In the study of combined application of sevoflurane and xenon for pig anesthesia, hecker et al. confirmed that the minimum alveolar concentration (MAC) required for anesthesia of pigs by sevoflurane has a certain linear correlation with the concentration of xenon incorporated. Gerritzen et al. monitored piglet electroencephalogram (EEG) and electrocardiogram (ECG) during piglet castration, and believed that the application of 70% CO2 + 30% O2 to anesthetize pigs is suitable for piglet castration. Wang Yang et al. compared intravenous propofol (2mg/kg) with inhaled isoflurane (2%) to anesthetize small pigs. The results confirmed that isoflurane inhalation anesthesia is stable and the anesthetic effect is better than propofol. NO can selectively expand the blood vessels of the lung tissue, so it has a certain effect on the treatment of acute lung injury. However, because of the certain toxicity of NO, its clinical application is limited. Ashley et al. applied 10ppm, 40ppm and 80ppm NO to pigs for inhalation anesthesia, and the results confirmed that inhalation of 10ppm NO has no obvious damage to normal lung tissue, and this dose can effectively treat acute lung injury.