Hello, everyone. We're going to talk about airway emergencies. My name is Dr. Sarah Kacoma, and I work at Rush University Medical Center in Chicago, Illinois. I am an anesthesiologist and intensivist there. I have no disclosures. The objectives today are listed here. We're going to identify signs and symptoms of an airway emergency, recognize a patient at risk for an airway emergency, and use accepted algorithms for team management of such emergencies. During the presentation, we'll review what constitutes a normal airway, talk about respiratory insufficiency in the airway, discuss emergent airway control, including medications and emergencies, talk about the difficult airway, and discuss special circumstances of a cannot-intubate, cannot-ventilate patient. Before we begin, let's take a moment to talk about airway management outside of the operating room. In this setting, intubation is often urgent. You have less time to organize all appropriate resources, so it's important to be well-prepared. You're often intubating for respiratory failure, where the desaturation time is faster. The airway will likely be more difficult, and there may be airway edema from prior intubations or intubation attempts. These patients are more likely to be at the extremes of age and have other issues that make airway management difficult. We often do not have the option to wake the patient up if we can't intubate them, and we may lack access to additional help. What are some of the indications for managing the airway, particularly for intubation? We can divide them into three groups, airway, respiratory, and circulatory. Airway protection includes patients with depressed levels of consciousness, patients who need deep sedation, and patients with compromised airway anatomy. Respiratory indications include inadequate oxygenation, inadequate alveolar ventilation, and excessive respiratory workload. And finally, circulatory issues include shock and cardiopulmonary arrest. Question number one, what should a clinician do if the first attempt to intubate an unstable critically ill patient fails? Option one, try three times before getting help. Option two, get help. Option three, change the type of laryngoscope blade being used. Option four, wake the patient up or try video laryngoscopy. The best answer here is number two, get help. Although you may be allowed three attempts, you don't want to wait until the third attempt to seek help. You should seek help immediately and then continue with the remaining attempts until help arrives. The cornerstone of airway philosophy are these, an awake airway is best. If the first attempt fails, get help. If you can't intubate, use bag mass ventilation plus alternative airways. And if you have a situation where you cannot intubate and cannot ventilate, call for help and begin the process of cricothyroidomy. Since the situation occurs outside of the operating room and circumstances tend to be urgent or emergent, you need to have a complete plan in place. You need to have a general medical assessment, including hemodynamics, comorbidities, and potassium level. You need to think about how to position the airway in order to maximize your success. That means using sniffing position to align the oral, pharyngeal, and laryngeal accesses. Are you going to use a ramp or manual inline stabilization for patients with spine issues? Are you going to use cricothyroid pressure? What agent will you use? Should you use a paralytic? What blade will you choose? Will you use direct laryngoscopy or a video laryngoscopy? Do you know what your cannot intubate, cannot ventilate strategy is? What is your institution's method of getting help if a surgical airway is required? Everyone in the ICU should take time to manage an airway, but you should also know how to bag mass ventilate patients while you're waiting to get help. Having this skill can save lives. That means being familiar with the risk factors for difficult airways, which we see on this slide. Most of these are anatomic, like the Malampati score, decreased thyromental distance, jaw protrusion, unstable spine or limited neck extension, thick neck, and high BMI. But you should be aware of non-anatomic factors as well. You may have patients who are edentulous, and in those patients, you may need a nasal trumpet or an oral airway to help facilitate mask ventilation. The Malampati score is routinely used when predicting intubation success via laryngoscopy, but you can also use it when bag mass ventilating in order to determine the potential for difficult ventilation. In class one, you can see the uvula and everything around it and beyond it. In class two, you can no longer see the tip of the uvula and the opening is not as wide. In class three, you can only see the base of the uvula, and in class four, you really can't see anything at all. Patients in class three and four will most likely pose the most difficulty. The airway will have more redundant tissue. It's even more difficult if the tongue is very large. While you're bag mass ventilating the patient, you should also think about the patient's risk factors for difficult intubation. We see many of the same risk factors that we just saw on the mask slide with a few additions, including decreased neck range of motion, history of difficult intubation, history of tracheal stenosis, oropharyngeal cancer, and pregnancy, which has special considerations like reflux and the potential for airway edema. Question number two, failure to use capnography or capnometry in ventilated patient contributes to what percentage of deaths from airway complications? Number one, 5%, number two, 10%, number three, 20%, number four, 40%, number five, 70%. The answer is number five, 70%. Notice this question is not about pulse oximetry, since that's well established. Capnography or capnometry is relatively new in the clinical environment outside of the operating room. How important is it to know what the CO2 exhalation is? Very important. You also want to think about your induction plan. Obviously, the goal is to facilitate safe intubating conditions. You need to think about the medical assessment of the patient's comorbidities, their mental status, their cardiopulmonary status, drug elimination, and so forth. This is very important. You also need to think about what induction may involve. It could be sedative or hypnotic agents, paralytics, or local anesthetics, or you may decide to do an awake intubation on the patient. Frequently in emergency circumstances, we don't know when the patient last ate or drank, whether they have diabetes with some degree of gastroparesis, and so on. As a result, we often find ourselves in a position where we need to consider a rapid sequence induction. The goal here is to minimize the time that the airway is unprotected from induction until tracheal intubation is confirmed. Rapid sequence induction is indicated for all patients with aspiration risk. The secondary benefits include minimizing the time of apnea and therefore also minimizing the risk of desaturation. Rapid sequence induction should be the rule more than the exception in the ICU because so many variables can be in play. Historically, students were taught to apply cricoid pressure as part of a rapid sequence induction. The pros are that the movement of the esophagus is irrelevant to your efficiency and effectiveness, and cricoid pressure also reduces the diameter of the hypopharynx by 35%. The reasons against using cricothyroid pressure include esophagus displacement lateral to the cricoid ring in up to 90% of the patients during cricoid pressure, which can actually make the airway more difficult. Plus, cricoid pressure may increase the time to intubation. If cricoid pressure is used, the person performing it must be very skilled and must know how to apply pressure properly to minimize the risks. Conclusion is unclear, so institutional standardization is suggested. We saw earlier on the airway philosophy slide that awake intubation proceeds better when the patient can tolerate it. There are some things to consider with an awake intubation. Before beginning, you can give a drying agent such as glycopyrrolate. You need to think about topicalization of the airway and whether you have an atomizer or lidocaine on hand. Do you have a bite block handy? Glossopharyngeal, superior laryngeal, and transtracheal nerve blocks can be considered in patients where coagulopathy is not an issue. If you have equipment for fibrooptic intubation, you should obtain it ahead of time. And finally, how are you going to secure the endotracheal tube? This is all part of the process of being prepared. These are the most common agents for induction, propofol, etomidate, ketamine, and midazolam. You can see the dosages on this chart along with the effects on arterial pressure and respiration and the most common side effects. Note that one of the side effects of etomidate is adrenal cortical suppression. Ketamine causes less respiratory depression and actually entails some bronchodilation, which can be useful in patients who have reactive airway disease. It's also thought to have less hemodynamic lability. However, ketamine can cause hypotension in critically ill patients with depleted ketocholamine reserves and it also increases salivation, which can make intubation more difficult. Giving a drying agent early is especially important when ketamine is used. Etomidate is associated with minimal cardiovascular suppression, so it can be useful in patients with cardiovascular instability. Etomidate does cause adrenal cortical suppression, regardless of whether it's administered as a single dose or in a continuous infusion. From a medication standpoint, the next thing to consider is whether you'll use a neuromuscular blockade agent. Blockades were introduced into clinical practice in 1942 and they interrupt nerve impulse transmission at the neuromuscular junction. They are primarily used by anesthesiologists and the use of neuromuscular blockade does improve your first attempt success with intubation in the intensive care unit. Question number four, which of the following is not a non-depolarizing agent? Number one, rocuronium. Number two, atricurium. Number three, succinylcholine. Number four, curare. Number five, echeronium. The answer is number three, succinylcholine. Succinylcholine is an important agent for airway management in the intensive care unit. It's depolarizing, so it fires the muscle and you can see the patient having fasciculations about 30 seconds or so after administration of the agent. Succinylcholine is associated with rapid onset and short duration of action and it's hydrolyzed by plasma, butyrocolline esterases. Succinylcholine can be dangerous to use in patients with renal failure or burns and other causes of hyperkalemia. It should also be used in caution in those who have been bed bound for 48 hours or more. Non-depolarizing agents fall into a couple of different classes. The first class is the benzyl isoquinolinium compounds, which include atricurium and cistatricurium. This slide offers a brief overview of these two agents, including their intubation dosages and their infusion rates. Atricurium has a faster onset of action than cistatricurium and it uses both Hoffman elimination and ester hydrolysis, so there's really no accumulation. With cyst atricarium, the clinical duration is unchanged with both renal and hepatic disease, so it's becoming a very common agent in a small population of patients who require neuromuscular blockade after induction. The second group of non-depolarizing neuromuscular blockade agents are the aminosteroidal compounds, which include vecuronium and rocuronium. Again, this slide shows information about both of these agents, including their intubation dosages and their infusion rates. For vecuronium, elimination is unchanged in liver and kidney disease because of a dual pathway. If liver elimination is decreased, then the kidneys pick up its role in elimination to counterbalance it, and vice versa. Vecuronium also has an active metabolite. Rocuronium has a faster onset, making an attractive alternative to succinylcholine, which also has a rapid onset. Rocuronium isn't associated with any significant metabolism, and it's primarily eliminated through the liver. Neuromuscular blockade agents have problematic side effects. These agents can cause the patient to appear to be asleep, but the patient can actually still have awareness, which is obviously a significant consideration. Given continuously or for long periods of time, neuromuscular blockade agents can lead to muscular weakness, which can be multifactorial. Neuromuscular blockade agents should always be monitored, and you need to know how to use a peripheral nerve stimulator to evaluate a train of four. When you do use neuromuscular blockade agents outside of intubation, then your goal is to usually have a small number of twitches so the patient can be reversed at any given time. Twitches are also useful for monitoring for accumulation. Because awake intubation is better, according to the airway philosophy we talked about earlier, a common question is whether to paralyze the airway. You will get good or excellent intubating conditions 35% of the time without atriocurium and 95% of the time with atriocurium. There's also a lower prevalence of hypoxemia when a neuromuscular blockade agent is used during intubation, so it can be easier to bag mask, ventilate, or intubate, and there's also a lower complication rate in the non-OR setting. All of this means that you're going to lean towards getting these agents unless there's an absolute contraindication. As we mentioned earlier, learning mask ventilation is essential because it absolutely can and does save lives. However, mask ventilation does not protect the airway, so it's only a temporizing measure. It also requires minimal equipment and can be readily performed, but it does need to be practiced potentially in a simulation setting. Now we'll look at some of the tools we use for intubation. We have lots of options including direct laryngoscopy, video laryngoscopy, blind nasal intubation, intubating through a supraglottic airway device, fiber optic intubation, and other tools like light wands and COMBA tubes. On this slide, we'll talk about the McIntosh blade and the Miller blade used in direct laryngoscopy. The McIntosh blade or MAC blade is a larger curved blade that yields a wider view and is helpful in patients with excessive soft tissue, placement of bulky endotracheal tubes, and suctioning of debris, blood, or gastric contents while intubating. The Miller blade is a smaller straight blade that yields a narrower view but is especially useful in patients who have a large floppy epiglottis because you can slide the blade under that large epiglottis and lift it out of the way. It can also be useful in patients with a decreased siremental distance because the airway tends to be anterior. I'd like to highlight this study from the New England Journal of Medicine in 2023. It's a multi-center randomized trial conducted at 17 emergency departments and ICUs throughout the country. 1,417 patients were included in the study and the patients were assigned to the video laryngoscopy group or the direct laryngoscopy group. The primary outcome was successful intubation on first attempt and the secondary outcome was the occurrence of severe complications during intubation. The severe complications were defined as severe hypoxemia, severe hypotension, new or increased vasopressor use, cardiac arrest, or death. The results of this large study were successful intubation on the first attempt was achieved in 600 of the 705 patients in the video laryngoscopy group. That's about an 85% success rate and in 504 of the 712 patients in the direct laryngoscopy group. That's about a 70% success rate. Video laryngoscopy is becoming more and more common. Some of the advantages are listed here. It does not require a straight line of sight to see the vocal cords. Novices will likely have a higher success rate using this technique and everyone can share the same view unless you're using a portable device where the monitor is small and it's mounted on the device. However, there are some disadvantages. It does take a bit longer to set up and intubate with. Blood and debris in the airway can obstruct the lens, can fail in patients with altered head and neck anatomy, and it does not replace the fibro-optic intubation. Video laryngoscopy shows the larynx but not the pharynx. If the pharynx is making it difficult to pass an endotracheal tube, then direct laryngoscopy may be a more useful approach than a video. At times, you may need to consider a blind nasal intubation. Blind nasal intubation should be absolutely avoided in patients presenting with signs or a history suggesting a basilar skull fracture. The hallmark of these fractures are the so-called raccoon eyes or the battle sign that we see here, a hematoma behind the ear. You also should not use this approach in patients who are coagulopathic because bleeding can make the airway more difficult. Fibro-optic intubation is the gold standard for the difficult airway. It also requires the least amount of neck movement in patients with an unstable cervical spine. There are some disadvantages. However, blood and debris can obstruct the lens. The equipment is expensive and in many circumstances it can take a lot of time to locate and set up the equipment. Again, planning and organizing are essential if you intend to use this approach. The supraglottic airway device is another tool that you can use for intubation or as a temporary rescue modality for a cannot intubate, cannot ventilate situation. There are a variety of these masks in the marketplace, some of which are more useful in helping with intubation than others. Some examples of brands of supraglottic airway devices are LMA, iGel, and AirQ. The supraglottic airway device does not protect the airway from aspiration, but it does make it easier for you to ventilate many patients with whom you might not be able to ventilate or intubate otherwise. Practicing this skill and simulation is essential for potentially safety. The American Society of Anesthesiologists offers a very useful algorithm for dealing with the difficult airway, which you can find online simply by searching. Some patients are more likely to pose difficulty intubating and ventilating. This group includes patients who have facial trauma, a bloody airway, head or neck radiation, or burns. This also includes patients who've had multiple laryngoscopy attempts. In these patients, you may want to attempt to place a supraglottic airway device as a bridge to a definitive airway while you're waiting for help. It's also important to note that there's no absolute contraindication to a cricothyroidomy in an adult who is dying and whom you can't ventilate or intubate. Obtaining a surgical airway, even if that means a needle cricothyroidomy, is much better than losing the patient. There are several reasons why we use the cricothyroid. It has a superficial location. In most patients, there's an absence of critical structures like thyroid, nerves, or vessels. There's less risk of esophageal perforation because of circumferential cricoid cartilage, and it's faster and easier to do than a tracheostomy. It may be associated with a higher incidence of airway stenosis compared with tracheostomy, particularly in kids, but this is controversial. If you need to perform a needle cricothyroidomy, these are the steps. You need to ensure adequate neck extension, being aware of any cervical issues. Locate the cricothyroid membrane. Use a syringe half filled with saline attached to a large bore needle, 14 gauges recommended. Advance the needle in a caudal direction while aspirating until bubbles appear, indicating you're in an air-filled structure, which should be the trachea. Then advance the catheter off the needle and into the trachea. Complications of this include catheter kinking, inadequate ventilation, barotrauma from air trapping, and sub-q emphysema. If you can't do a needle cricothyroidomy or you have the ability or skilled assistance, you can perform a surgical cricothyroidomy. For a surgical cricothyroidomy, you need to ensure adequate neck extension, being aware of any cervical issues. Locate the cricothyroid membrane. Make a vertical or horizontal skin incision followed by a horizontal cricothyroid membrane incision below the skin incision. Use mayo scissors or a scalpel handle to dilate the incision and widen it slightly. Then be sure to insert something, a 6-0 endotracheal tube, a Shiley, or something similar. Even though the tube may go into the hole, the tip may not track into the trachea. You could wind up tracking into the mediastinum, so you need to be sure to confirm that you have an adequate airway. Complications that can happen with a surgical cricothyroidomy include bleeding, passage of the tube through a false track, infection, and subglottic stenosis. The fourth national audit project from the Royal College of Anesthetists and Difficult Airway Society offers these recommendations. Limit the number of intubation attempts to three. If a cannot intubate, cannot ventilate situation occurs and waking the patient up is not an option, give paralytics to facilitate attempts at subsequent airway management. Supraglottic airway devices such as an LMA should be attempted, and both surgical and needle cricothyroidomy should be taught and practiced. When you get into this cannot intubate, cannot ventilate situation, remember these stage words. It's not the cricothyroidomy that kills patients, but rather delaying or not doing the procedure that causes harm. After intubation, the most common complication is hypotension. This occurs because the loss of sympathetic drive, which can happen because you've taken away the work of breathing, or because medications that were used. Myocardial infarction at the time of airway management, tension pneumothorax, and auto-peep depending on the device that's used. The key points of this presentation go back to a slide that we saw earlier and the importance of having a complete plan. Think everything through in advance and be prepared with equipment and medications so that you can quickly gain airway control and don't be too proud or stubborn to seek help early if you're having trouble. In the meanwhile, consider a supraglottic airway device to buy time. Thank you.

airway emergencies

recognize

manage

signs and symptoms

airway control

medications

surgical airway

intubation

awake airway management

difficult airways

neuromuscular blockade agents

cricothyroidotomy