Why do you have to fast before surgery? Can’t drink a glass of water?

Many people do not understand why they should fast and ban water before surgery. According to the general understanding of the general public, Only when you have enough food and drink can you work hard. When the patient is lying on the operating table and is about to undergo surgery, when you have enough food and drink, you will have more energy to fight against the physical trauma caused by the surgery. Unfortunately, the doctor does not think so at all, and it is not the same thing in medicine. The doctor will clearly inform you that you must not eat or drink before the operation.

As for the truth, look down! Drink a glass of water and the operation was cancelled? I have seen many family members who secretly let patients eat in the ward. When you told them not to eat or drink the night before the operation, They promised. It was fine. But when we got to the operating table, The patient shyly told you: [Doctor, I drank a glass of milk in the morning]. When the doctor was ready to lose his temper, the patient would say: [You said you wouldn’t let me drink water, I listened to you. Therefore, I only drank a glass of milk…]. Other patients would say, [I did endure not eating or drinking all night, but I felt very hungry in the morning, so I quietly ate half of steamed bread. Is it not a big problem? ] To put it simply, If you don’t fast and ban water as required before surgery, The most direct consequence is the temporary cancellation or postponement of the operation. This is done for only one purpose. For the sake of medical safety. The most worrying thing for doctors is that Gastric content reflux causes respiratory tract obstruction and aspiration pneumonia by mistake, Even suffocated to death. There are reports in the literature, The incidence of anesthesia-related reflux aspiration in adults is 5 in 10,000, The incidence rate of children is twice that of adults, and that of newborns and infants is ten times that of children. In particular, it is worth mentioning that the incidence rate of reflux aspiration in pregnant women is much higher than that in ordinary adults. The main reasons are as follows: pregnancy will lead to a decrease in the tension of the lower esophageal sphincter; With the enlargement of the uterus and the upward movement of the stomach, vomiting is more likely to occur. What’s more, most pregnant women in labor are not restricted from eating in traditional Chinese habits, which may determine that pregnant women are still in a state of “full stomach” during surgery, undoubtedly increasing the difficulty of anesthesiologists’ treatment. How does aspiration occur during surgery? Normal people are very sensitive to cough and swallowing reflex. When drinking water or eating, food will obediently enter the stomach through the esophagus and will not go through the nostrils or enter the trachea by mistake. Do you want to experience this process? Try swallowing saliva, This action looks simple, In fact, it involves complex reflective activities. One of the important points is that Food stimulates the throat, It will close the glottis at the beginning of the trachea. At this time, Food has no possibility of entering the trachea, only obediently entering the esophagus. Even if foreign bodies accidentally enter the trachea, healthy and sober people will try their best to expel foreign bodies through choking cough reflex, which is a spontaneous protective action of the human body. Recall whether there has been a strong cough when drinking water or eating? The human body can effectively remove secretions or foreign bodies in the airway by coughing. This is an important basis for ensuring [one’s breath of life]. Many elderly people, stroke patients, As these reflex function diminish or even disappear, Dysphagia often leads to aspiration, It is a high risk group for aspiration pneumonia. However, when patients receive deep sedation or general anesthesia, Its protective cough reflex and swallowing reflex will also weaken or disappear, It is also prone to aspiration. We can give a living example. After many people drink too much, Will try to pick your fingers at your throat to induce vomiting, Although this tactic, which I do not recommend, works, But it is much weaker than normal awake state. The reason for this is that Excessive drinking is equivalent to moderate or deep sedation. You can also search the Internet for keywords [drunk suffocation], You will see many horrifying real examples of death from foreign bodies in the trachea caused by drunkenness. Of course, you can also watch [Pinkman] from the American TV series “Deadly Poison Master”. His girlfriend died of suffocation due to reflux aspiration after taking drugs. How can you live without food or drink? As the saying goes, [people are iron, rice is steel, and one meal is not hungry.] Does fasting and drinking have a bad effect on the body in what? For infants, children and some adults, Excessive fasting and drinking time, It will increase discomfort such as thirst and hunger, Even cause irritability and other bad emotions, In the 2014 edition of the Anesthesiology Branch of the Chinese Medical Association < Guidelines for Fasting Before Anesthesia for Adults and Children, anesthesia experts gave such suggestions and precautions: [Infants and newborns can be infused with sugary liquid in wards after fasting for 2 hours due to low glycogen reserves to prevent hypoglycemia and dehydration; Emergency surgery should also supplement liquid during fasting. The operation time for diabetic patients should be arranged at the first operation as far as possible. If not, polarized fluid can be infused intravenously in the ward.] In other words, although you cannot eat or drink, the doctor will replenish water and energy for you through other channels-intravenous infusion of corresponding fluid. How to properly fast and ban drinking? Obviously, Fasting and drinking is a gate to ensure the safety of surgery. According to the corresponding domestic and international guidelines, I have brought you the above table. A guide from China, Consistent with the requirements of the American Society of Anesthesiology. To put it simply, This is the [2-4-6-8] principle of fasting and drinking. Below, Let’s take a look at how to correctly avoid eating or drinking before the operation. 1. The drink that can be drunk two hours before the anesthesia operation is clear drink. However, the total amount should be controlled within 5 ml/kg body weight (or the total amount should be 300 ml). Clear drinks refer to clear water (such as plain boiled water), carbonated drinks, sugar water, clear tea and black coffee (without milk). It also includes juice without residue. It is worth noting that Alcoholic liquids, milk and formula milk, It is not a clear drink. 2. For infants, It is mainly breast milk, milk and formula milk that need to be fasted. Fortunately, breast milk is more easily emptied by the stomach than the latter two. Therefore, the last time infants eat breast milk is 4 hours before anesthesia, Milk and formula milk are 6 hours. 3. Digestible solids, Most of them refer to flour and cereals, Such as bread, noodles, steamed bread, rice, etc. Their main ingredients are carbohydrates. It is necessary to stop eating at least 6 hours before surgery. 4. Indigestible solids mainly refer to meat and fried foods, which contain high fat and protein and stay in the stomach for a long time. Therefore, it is necessary to stop eating at least 8 hours before surgery. How to operate in reality? 1. For elective surgery, Most doctors recommend that in the early morning of the night before the operation, Stop drinking and eating. This advice seems general but practical. It is also easy to get the patient’s execution. 2. For patients who need oral drugs (such as hypertension) before surgery, Doctors are allowed to take the tablets with a mouthful of clear water 1-2 hours before the operation. The maximum amount of this mouthful of water is 0.25-0.5 ml/kg body weight. Take a 60 kg patient as an example, This saliva should not exceed 30 milliliters. 3. If there is gastrointestinal disorder, Such as gastroparesis, gastrointestinal obstruction, gastroesophageal reflux disease, morbid obesity, A stricter ban on food and drink is needed, Please follow the doctor’s advice. The aforementioned fasting and drinking ban guidelines are only for patients with normal digestive tract function. 4. For patients who need digestive tract surgery, the preoperative fasting and drinking ban plan is much more complicated and needs to be implemented according to the advice of specialists. 5. If the preoperative polydipsia is too bad, you can wet your lips with cotton swabs and clear water. If the feeling has not improved, you can suck a moist cotton swab with your mouth. 2014 edition < < Guidelines for Fasting Before Anesthesia for Adult and Pediatric Surgery > >