A major task of the anesthesiologist is to ensure effective ventilation and intrapulmonary gas exchange of the patient. Endotracheal intubation is one of the important techniques in clinical anesthesia, emergency resuscitation and critical care treatment, and it is a prerequisite and an important guarantee for successful and effective airway management. In clinical practice, there are always some patients who have difficulties or failures in endotracheal intubation due to poor exposure of the vocal folds for different reasons, and there are also always some patients who have a difficult airway due to their medical conditions or medical factors, which may even threaten the patient’s life safety. Therefore, it is important to maintain a clear understanding of the difficult airway and pay high attention to it. When encountering emergency difficult airway situation how to make the best judgment in the shortest time and choose the most simple, safe and effective way to deal with it, to maximize the avoidance and reduction of the patient’s risk is the knowledge and skills that every clinician must have. I. Common emergency difficult airway situations 1, repeated intubation caused by the inability to ventilate, can not be intubated 2, various reasons such as trauma, arteriovenous vascular malformation, Buga syndrome, etc. intubation of the oral cavity, nasal hemorrhage caused by 3, a large number of upper respiratory tract hemorrhage 4, patients with a large number of reflux 5, the maxillofacial region, head and neck of the serious trauma 6, laryngeal tumors 7, serious edema of the airway 8, airway foreign body 9, airway stenosis or trauma leading to airway disruption 10, the larynx of a large tumor 7, serious edema 8, airway foreign body 9, the airway narrowing or Trauma resulting in airway interruption 10, pharyngeal cellulitis 11, cervical hematoma, abscess, tumor or cerebrospinal fluid leakage resulting in airway compression II. Emergency Difficulty Airway Process Ideas come first, the more urgent the difficult airway, the more we should be in accordance with a simple and fast process for treatment. Usually, the ABS process for difficult airway management can be divided into three steps. A: Ask for help (Ask for help) Ask for help should always be at the top of the list. Whether you are a junior or senior physician, day or night, asking for help immediately is the most responsible thing you can do for your patient. B: Breathing ventilation (breathing) While seeking help, if ventilation with supraglottic tools is still possible (e.g., after repeated intubation resulting in an unventilated, unintubated condition), immediately give supraglottic tools such as a laryngeal mask-type, combined esophageal-tracheal catheter, laryngeal tubing, oropharyngeal airway, oropharyngeal ventilator tube with a sleeve, and a face mask for breathing ventilation (B). Then go to the next step. S: This S contains three meanings. After good ventilation, wait for the patient to resume spontaneous breathing (S1, spontaneous) or proceed to the next step, if ventilation with supraglottic tools is not possible (e.g., huge tumor of the larynx, etc.) or ventilation is ineffective (e.g., severe edema of the larynx), then immediately proceed to S2: (Stick cricothyroid membrane) puncture of the cricothyroid membrane to ventilate, if the cricothyroid membrane is not available due to the sleeve If the cricothyroid membrane is punctured for ventilation because the trocar is too small or a cricothyroid puncture kit is not available, then an S3 (surgical airway) cricothyrotomy or tracheotomy is immediately performed. If necessary, immediate cricothyrotomy or tracheotomy can be performed while puncturing the cricothyroid membrane for oxygenation, or direct cricothyrotomy or tracheotomy can be performed. Emergency difficult airway management can be categorized into non-invasive, minimally invasive and invasive methods, all of which can be handled with B and S in the procedure. (A) Non-invasive 1, laryngeal mask (B) The United States from 1993, the laryngeal mask added to the difficult airway management process, 10 years later in 2003 again revised the difficult airway management process still added the laryngeal mask. The failed airway management process designed by Walls also incorporated the laryngeal mask, as did the difficult airway management process published by France in 1996, the unforeseen difficult airway process published by Canada in 1998, by the United Kingdom in 2004, and the failure to ventilate process published by Mulcahy AJ, Yentis SM in 2005. The German difficult airway procedure published in 2004 did not specifically mention the laryngeal mask but included supraglottic ventilation tools, which naturally included the laryngeal mask, and the Italian difficult airway procedure published in 2005 also included the laryngeal mask, thus demonstrating the importance of the laryngeal mask in difficult airway resuscitation. We also put the laryngeal mask at the top of the list in the design of the ABS procedure for difficult airway management in 2008. The reason why the mask was not put at the top of the list is that the difficulty of mask ventilation is one of the emergency difficult airways. Therefore, whenever possible, the laryngeal mask is used as the ventilation tool of choice in emergency treatment, and the role of the laryngeal mask in emergency treatment has been confirmed by a large amount of literature. 2. Combined esophageal-tracheal tube (B) The combined esophageal-tracheal tube is another type of emergency airway device and is the most important extramural airway ventilation device after the laryngeal mask. The combined tube consists of a double-lumen tube with the esophageal and airway lumens arranged in parallel. The esophageal lumen is blind, but there are many openings in the middle of the tube at the level of the laryngopharynx; the airway lumen is open at the distal end; the two lumens do not communicate with each other. To use the combined tube, feed it directly down through the mouth. Until the tube reaches the incisors at a predetermined scale, the oropharyngeal sleeve is then inflated by about 80 ml, and the distal sleeve by 5-15 ml. The unforeseen difficult airway procedure published by the United Kingdom in 2004 included the combined tube, and the difficult airway procedure published by Germany in 2004 included supraglottic ventilatory tools, which naturally included the combined esophageal-tracheal tube. The combined esophageal-tracheal tube has become the ventilation tool of choice in national EMS centers in all countries, with the ability to be manipulated and ventilated under all conditions, and can be used quickly by anesthesiologists and emergency physicians, paramedics, and field medics. A large body of literature reports the use of the combined tube in emergency situations such as upper respiratory bleeding, persistent vomiting, cervical hematoma, failed intubation, and oral hemorrhage. The combined tube can be equally useful in patients who fail laryngeal mask ventilation. 3.Laryngeal tube (B) consists of an oropharyngeal sleeve, an esophageal sleeve, a ventilation tube and a gastric drainage tube. The ventilator tube between the two cuffs has multiple ventilation holes and is located at the vocal folds. It is designed to allow airway creation and prehospital resuscitation in case of emergency. Some authors have reported successful ventilation with a laryngeal tube after failed intubation during cardiopulmonary resuscitation of a patient. In prehospital emergency care, supraglottic ventilation tools have been used in 18.8% of patients, which of course includes the laryngeal tube. In addition to this, other options such as perilaryngeal ventilation tubes, oro-nasopharyngeal ventilation tubes and face masks are available when necessary. (Minimally invasive transtracheal jet ventilation (S2) If the placement of a laryngeal mask, a combined esophageal-tracheal tube, or other supraglottic ventilators does not rapidly and effectively improve gas exchange, an invasive approach must be taken immediately, and transtracheal jet ventilation (TTJY) is undoubtedly the invasive method that anesthesiologists are most adept at and familiar with (most anesthesiologists are familiar with this method). method (most anesthesiologists have practiced surface anesthesia via cricothyroid puncture). It is a transitional technique that buys valuable time, is simple to perform, can be done with a needle or trocar, and is a faster technique than emergency cricothyrotomy and tracheotomy, and allows for adequate oxygenation, but is associated with CO2 buildup and acidosis, which can be helped by a hyperbaric source of oxygen (50 PSI), with attention to catheter kinking and pneumothorax. If a hyperbaric jet ventilation device is not available, the following simple methods of resuscitation can be used both inside and outside the operating room. 1. 10-20ml syringe first aid method(S2) Use 10-20ml syringe with a large needle to pierce the cricothyroid membrane and then pump back to confirm the position, then pull out the inner core of the syringe, insert a 4.5-7.5 endotracheal tube, inflate and seal the syringe, and then connect to the respiratory bladder for ventilation. 2. 3ml syringe first aid method(S2) Insert a large cannula needle or a large needle through the cricothyroid membrane, pull out the needle core to connect the 3ml syringe, pump back the air to confirm the position, pull out the inner core of the syringe, connect the standard endotracheal tube connector to connect the respiratory balloon for rapid ventilation. The larger the cannula needle and needle, the better the effect. 3.No.3.5 tracheal catheter connector directly connected to the first aid method (S2) with a catheter connector below No. 3.5 directly and a variety of cannula needles or large needles connected, and then directly ventilated. In order to put the displacement and facilitate the ventilation operation, you can connect the blood tube between the catheter connector and the cannula needle. Of course, the Emergency Transtracheal Airway Catheter ( Cook Emergency Transtracheal Ventilation Cannula 6F) with steel wires to prevent folding and twisting is more effective. (C) Invasive 1. Emergency cricothyrotomy kit (S2) The minimally invasive tools mentioned above can supply oxygen, but the ventilation effect is not good. The emergency cricothyroid puncture kit can solve the role of oxygenation and ventilation, which can be called the “fire extinguisher” of anesthesiology, convenient and quick. The study suggests that the median time for successful puncture with Tracheo Quick is 20.2 s, (11.4-44.7 s), the median time for successful puncture with Airfree is 22.8 s, (14.3-33.2 s), and the median time for successful puncture with Quicktrach I is 21.1 s, (14.5-32.4 s). 2. Keyed Emergency Cricothyrotomy Kit (S2) A portable keyed emergency cricothyrotomy kit that can be carried around for rapid airway creation both in and out of hospital. 3. Melker cricothyrotomy kit(S2) This device consists of a scalpel blade, trocar needle, syringe, guidewire, extender and airway tube. The procedure is similar to central venous puncture catheterization. The advantages of this kit are as follows: 1) it is readily accepted by anesthesiologists inexperienced in cricothyrotomy, 2) the learning curve is short, with 96% of anesthesiologists trained on the model in 5 sessions being able to perform it successfully in less than 40 seconds, 3) the usual time is 40-100 seconds, and 4) there is relatively little bleeding. It is important to note that every effort should be made to ensure the patient’s oxygen supply and ventilation during surgery. 4, surgical cricothyrotomy (S3) American Society of Anesthesiologists this as a last resort after the failure of other methods, suitable for: (1) through the mouth and nose or ciliopathic intubation failure of conventional emergency methods, (2) for maxillofacial, cervical medulla injuries, head and neck injuries, head and neck injury, massive upper respiratory bleeding, upper respiratory obstruction of the airway control in an emergency. Advantage is and tracheotomy compared to more simple and fast, but children under 10 years old laryngeal cartilage and cricoid cartilage is relatively small, so not applicable. 5, surgical tracheotomy (S3) in the absence of conditions are directly surgical tracheotomy, which is an effective means of emergency, especially in the operating room field emergency intubation, surgical tracheotomy ratio of about 2.5%.