围手术期护理 z-bo 2020-10-15 297

　　(1) Intravenous injection

　　1. Purpose of intravenous infusion The purpose of hydration during anesthesia is to maintain open venous access, provide circulatory support for oxygen supply, replenish perceivable fluid loss, replenish imperceptible fluid loss, and perform infusion. Including supplementary losses. In emergency situations, intravenous access facilitates drug delivery and can ensure rapid and effective drugs. Delivering oxygen to the tissues is very important for maintaining aerobic metabolism, but not only does it require sufficient cardiac output to effectively deliver oxygen to the tissues. You also need enough hemoglobin to combine with oxygen. Therefore, it is not enough to provide sufficient hemoglobin concentration and sufficient circulating blood volume. Anesthetized and awake animals have the same fluid requirements, depending on their physiology and morbidity (such as heart disease). Therefore, different hydrating therapies should be prescribed for animals with different conditions.

　　2. Commonly used infusion (1) 0.9% sodium chloride solution (normal saline): Normal saline is an isotonic and imbalanced electrolyte solution containing Na +, Cl- and water. Yes, it is the most commonly used body fluid supplement in veterinary clinics. Isotonic dehydration is very effective without loss of water and electrolytes. (2) 5% glucose solution: the crystalline solution is an isotonic solution of glucose in water. After injection, the glucose in the solution is quickly absorbed by the cells and participates in metabolism. A 5% sugar solution is not suitable for volume expansion, because glucose molecules only play a temporary osmotic effect, and the released free water is evenly distributed throughout the body.

　　(3) Ringer's solution: Ringer's solution is an isotonic balanced electrolyte solution. In addition to water, Ringer's solution also contains sodium, potassium, chlorine and calcium. Because the composition of Ringer's solution is similar to that of extracellular fluid, it is the most commonly used sodium-containing crystal solution, which can restore the amount of extracellular fluid and maintain normal cell function during injection. Help. At the same time, it has the functions of thinning blood, reducing viscosity, improving microcirculation, replenishing electrolytes and correcting acidosis.

　　(4) Hermann's solution (lactated Ringer's solution): Hermann's solution is an isotonic electrolyte balance solution, similar to plasma electrolyte concentration. In addition to water, Hermann's solution also contains sodium, potassium, chlorine, calcium and lactic acid. Lactic acid can be metabolized by the liver to form bicarbonate. If the liver's ability to metabolize lactic acid is low, it will cause acidosis. Therefore, similar electrolyte balancing solutions containing other buffer salts (such as acetate) can be metabolized to bicarbonate independently of liver function, so it can be used in animals with abnormal liver function. can do. In addition, Hermann's solution contains calcium and should not be mixed with blood products for injection. A blood clot will quickly form after mixing. (5) 0.18% sodium chloride-4% glucose (glucose normal saline): If adding glucose normal saline for a long time, potassium must be added. Glucose saline does not promote vasodilation, because the free water released is evenly distributed throughout the body. (6) 7.2% sodium chloride solution (hypertonic salt solution): 7.2% sodium chloride solution is a hypertonic electrolyte non-equilibrium solution, and the hypertonic salt solution contains Na +, Cl- and water. It is mainly used to quickly replenish blood volume, and has the effect of increasing the contractility and output of the heart.

　　3. Many anesthetics are metabolized in the liver and excreted in the kidneys. With enough body fluids, these processes can proceed smoothly. Therefore, it is very important to provide circulatory support for animals during the anesthesia and recovery phases. For animals under general anesthesia, the injection rate of conventional balanced isotonic crystals should be 5-10 ml/(kg·H). In anesthetized animals, this "maintenance rate" is higher than that of unanaesthetized healthy animals [1-2 ml /(kg·H)], which not only compensates or increases the perceptible or unperceptible fluid loss. When anesthetics produce hemodynamic effects, it can also provide circulatory support. Some experts recommend using normal liquid retention [2 ml/(kg?H)] at the beginning of anesthesia. During the operation, the severity of the operation (mild, moderate, severe surgical trauma) should be increased according to the feeling. It has increased by 5 ml/(kg·H), 10 ml/(kg·H) and 15 ml/(kg·H). Regardless of the dose, the animal's response to the adjuvant should be continuously monitored to adjust the rate of infusion. In the process of clinical anesthesia, the maintenance rate of anesthesia can be appropriately increased for animals with very large original loss and/or animals that have not been corrected before anesthesia and continue to lose. However, in animals with a slower fluid loss, it can cause rapid hydration of hydrated plasma proteins and electrolytes. Therefore, it is recommended to choose this rehydration method at least 4-6 hours after anesthesia.

　　（2）Insulation

　　The skin preparation of miniature pigs, the disinfection of surgical operation, the expansion of surrounding blood vessels by chemicals, the effect of fluid exchange during the operation, and the large amount of cleansing fluid are all the reasons for the reduction of miniature pig’s body temperature. The rectal temperature should be continuously monitored during all operations. For miniature pigs, the body temperature should be higher than 36°C (normal body temperature range: 38-39°C). Perioperative body temperature care is mainly carried out from the following viewpoints. First, adjust the temperature of the operating room. During the operation, the temperature in the operating room should not be too high. Otherwise, the surgeon will not only cause discomfort, but also bacterial growth. Risk of contamination of surgical wounds. It is best to control the temperature of the operating room at about 24°C, and the relative humidity should be kept between 40% and 60%. Second, reduce animal contact before and after surgery. Animals should be kept warm enough when entering and leaving the operating room to isolate them from the surrounding cold air. Third, the operating table must have a heating function or use an electric blanket to heat the animal. Fourth, during anesthesia or surgery, exposing the surgical site and covering the surgical site (especially the limbs and injection site) with a warm bedding or surgical towel can reduce the heat dissipation of the skin. Fifth, infusion of liquid or blood products preheated to 36-37°C is safe and comfortable, and will not affect the composition of the drug solution. It can effectively prevent the body temperature from falling, but it should be noted that certain drugs cannot be heated. Sixth, if you need to clean the body cavity or wound during the operation, heat the cleaning solution to about 37°C to prevent the animal's body surface from being immersed in the cleaning solution and prevent excessive heat loss in the body. , You need to keep calm to avoid a drop in body temperature during the operation.

　　(3) Anesthesia monitoring

　　Anesthesia is monitored by monitoring heart rate and blood pressure. This method is more accurate than observing the reflexes of muscles and eyelids. ECG monitoring should be carried out during the entire operation, because the anesthesia of small pigs is very easy to cause arrhythmia during anesthesia. During the induction of anesthesia, the action of anesthetics can cause respiratory depression, and then hypoxia and hypercarboemia. During this period, the monitor should check the pulse, observe the color of the mucous membrane, the pressure of the finger on the gums, to observe the replenishment time of capillaries, and the depth and frequency of breathing.

　　1. The depth of anesthesia is a common method to determine the depth of anesthesia through the eyelid reflex, eye position and muscle tension of the massager. It is not easy for miniature pigs to observe eyelid reflexes under anesthesia. This is mainly due to the deep eye sockets of the miniature pigs. The eyeballs of miniature pigs are located in the middle, rather than bend, do not move the line of sight, expand the pupils, and weaken or even eliminate light reflection. This indicates that the deep suppression is too deep and the anesthesia is too deep. Press down on the crown, tail and ear tip of the miniature pig and observe its muscle reflex. Similarly, mandibular muscle contraction is considered to be a relatively accurate monitoring point for anesthesia. If the mandibular muscle is tense and stiff, it usually indicates a shallow depth of anesthesia.

　　2. Respiration focuses on observing the patency of breathing, breathing rate and breathing range. Poor airway opening can cause animals to have difficulty breathing, increase breathing activity in the chest, enlarge the nostrils and make the mucous membranes blue. During inhalation anesthesia, the tidal volume can be measured with a tidal meter. Deeper, shallower, and faster breathing are all signs of respiratory failure. If the tidal volume decreases sharply, hypoxia will soon occur. Decreased tidal volume is a symptom of severe respiratory depression during anesthesia. The visible color of the mucosa reflects the current oxygen supply and peripheral circulation function. Observe the color of the mucous membranes of the gums and tongue to roughly determine the degree of hypoxia in the animal. However, anemic animals may also show mucosal cyan due to their very low oxygen saturation. You can measure the partial pressure of oxygen and carbon dioxide in the arterial blood to determine whether the animal meets the needs of oxygen inhalation and carbon dioxide excretion.

　　3. The circulatory system mainly uses non-invasive methods, such as pulse check, hearing, blood pressure measurement, and ECG monitoring. During the operation, pulse, sprinting heartbeat, pale conjunctivitis and poor vascular filling are symptoms of shock. The slow pulse is mainly caused by excessive deep anesthesia and reflex blood pressure.

　　4. In general, it is mainly to pay attention to changes in consciousness, response to pain and other reflections, such as corneal reflex and eye position. When animals are shocked, their psychological reactions will become cold and even lose consciousness.

　　5. Body temperature anesthesia usually lowers the animal's body temperature by 1-2°C or 3-4°C. If the animal shows a strong stress response or does not adapt to certain drugs, it may cause a high fever.

　　6. Posture changes will adversely affect breathing and circulation due to posture changes. Compression or stretching of the limbs may cause paralysis of the limbs.

　　(4) Commonly used first aid methods for small pigs

　　Due to individual differences in animals and the existence of potential diseases, miniature pigs are often in danger during surgery and anesthesia. Timely and appropriate rescue measures will be taken to treat the accident during the operation. It is very important to save the lives of animals and retain the experimental data and materials of the animals. The following are some first-aid measures in dangerous situations:

　　1. If a mini-pig operation is performed during the operation or the respiratory dysfunction is caused by over-anaesthesia, the mini-pig should be infused immediately (for instructions, please see endotracheal intubation). After intubation, the catheter must be connected to the artificial respiration balloon. It is one person’s responsibility to pinch the artificial respiration airbag (about 15 times/min). Another person immediately turned on the ventilator and external oxygen, set the parameters of the ventilator, quickly separated the artificial respiration balloon from the catheter, and then connected the catheter to the ventilator to help the animal breathe. .. After turning on the ventilator, you can inject 10 mg/kg of Nixon injection into the animal experiment muscle to stimulate the respiratory center, and intravenous injection of Flosid injection of 1-2 mg/kg can accelerate the metabolism and excretion of the drug. And supplemented by sodium bicarbonate injection to relieve acidosis, appropriate intravenous drip.

　　2. Reduce blood volume During the operation of mini-pigs, excessive blood loss caused by the operation will reduce the heart rate. If blood pressure drops, different first aid measures should be taken according to blood loss. When the blood loss is small, the fluid flow in the venous channel can be accelerated, thereby increasing the body's blood volume. If you lose too much blood, you can inject hydroxyethyl starch to increase blood volume and increase blood pressure. If blood loss causes a sharp drop in blood pressure, blood pressure can be increased intravenously. Pressurized drugs (dopamine 1-5μg/min, Philippine hydrochloride, etc.).

　　3. During heart failure minipig surgery, if the operation causes heart failure, different rescue measures should be taken for the experimental animals according to different conditions. If a large amount of blood loss causes heart failure, it can be rescued by the following measures to reduce blood volume. If the heart develops ventricular fibrillation, it should be defibrillated with an ECG defibrillator. In the case of cardiac arrest, resurrect the chest with both hands, either intravenously or inject 1 mg of adrenaline hydrochloride into the heart.

　　The dangerous situations that occur in minipig surgery are complex and diverse. The above are some common situations. During mini-pig surgery, it is necessary to use collaborative applications to save endangered animals according to actual conditions.