Overview of Unanticipated Difficult Intubation in an Adult Patient
Learning how to carry out a procedure called intubation is a critical skill for anesthesiologists and other medical professionals such as emergency and critical care doctors. Intubation involves inserting a tube through a person’s mouth and then into their airway. This is done to ensure the person can breathe properly, especially during emergencies or surgery.
Before the doctor performs the intubation, they should gather all the necessary medical equipment and review the patient’s medical history and current health condition. If the first attempt doesn’t work, the doctor should have backup plans ready.
Some medical professionals, however, do not prepare adequately or make mistakes that can lead to complications. For example, there can be instances where a patient’s intubation is more difficult than expected and can’t be identified beforehand.
A study from the Royal College of Anaesthetists found that some key mistakes included not properly assessing the patient’s airway, not having backup plans, or continuously trying to intubate despite the patient’s oxygen levels dropping. It also found that overweight patients often have more difficulties during intubation and that complications may arise from repeated failed intubation attempts – even leading to death in some cases.
The study also found that out of nearly three million general anesthetics given, one in every 22,000 led to significant complications, including death or brain damage due to lack of oxygen. These complications happened far more often in emergency departments and intensive care units.
Issues around intubation are also prominent in data from the American Society of Anesthesiologists. In some of these cases, otherwise healthy patients who were undergoing planned surgery experienced complications.
Therefore, it’s vital that doctors are specific in their reports about problems they had during an airway procedure. This means noting whether there were difficulties with the facemask ventilation, laryngoscopy (which allows doctors to see the voice box), delivering the tube to the windpipe, or placing a supraglottic airway (a device to keep the airway open). Having this detailed information can help other healthcare providers when they need to manage the patient’s airway in the future.
Anatomy and Physiology of Unanticipated Difficult Intubation in an Adult Patient
There are certain physical features which can make placing a breathing tube (also known as intubation) more challenging for doctors. These features include having a small mouth opening, a short distance from the thyroid to the chin, a full set of teeth with large front teeth, limited jaw movement, less softness under the jaw, a short neck, a thick neck, restricted neck movement, a throat shape classified as Mallampati 3 or 4, being overweight, and changes from surgery or radiation. Each of these features can slightly increase the chance of a difficult intubation if a visual tool is used.
Apart from physical differences, some other factors can also make airway management difficult. This includes conditions like low oxygen levels, low blood pressure, severe acid buildup in the body, or weakened right side of the heart. This is a new idea in the field of medical assessment and it refers to conditions where managing the patient’s airway is hard due to these physiological issues.
Putting even these aside, there could be other challenges that might make managing one’s airway difficult. These could include issues related to the person handling the situation, such as their skill level, the help they have, the equipment they have to use, or even if the patient has certain complications like being under the influence of drugs or has a disability.
Why do People Need Unanticipated Difficult Intubation in an Adult Patient
For certain groups of patients, intubation (a medical procedure where a tube is inserted into the windpipe to help with breathing) can be challenging or may fail. This includes pregnant patients needing emergency anesthesia, trauma victims with neck injuries, people who are severely overweight, and patients previously treated for head and neck cancer. These individuals tend to be at a higher risk of complications during intubation
Intubation is usually successful, but it fails in about 1 out of 390 patients. Pregnant women are at an even higher risk because changes during pregnancy can risk lower oxygen levels and a higher chance of inhaling food or liquid into the lungs. The Obstetric Anesthetists Association and the Difficult Airway Society have created guidelines to manage this process in high-risk pregnancies. The best way to manage this in pregnant patients, when possible, is to use regional anesthesia early in the process. Regional anesthesia involves numbing only a specific area of the body for a short period. This strategy needs coordination with the complete medical team.
For trauma patients with neck injuries, intubating them is difficult and risky as they are already wearing a neck brace for stability, and they have a high chance of inhaling liquid or solid food particles into their lungs. Intubation in these patients is typically done for ensuring airway protection or facilitating mechanical breathing or emergency surgery. Achieving intubation without moving the neck and without complications like low blood pressure or insufficient oxygen or excessive carbon dioxide in the blood is crucial. Taking off the front portion of the neck brace can make the process more manageable.
People who are morbidly obese face many challenges during the intubation process. They can quickly lose oxygen in their bodies during the procedure, which can be potentially dangerous. The approach for intubation in patients who are severely overweight may need to be adjusted.
In the case of patients previously treated for head and neck cancer, intubation can be more complex. The changes to the throat anatomy following surgery or radiation treatment make the process of tube insertion more challenging. Anesthesiologists need to be aware of this potential difficulty. Using a special instrument called a fiberoptic scope provides better navigation inside the throat, even when the anatomy has been changed due to surgery or radiation.
Equipment used for Unanticipated Difficult Intubation in an Adult Patient
Make sure there is a cart equipped with all the necessary tools for managing a difficult airway, and it should always be within reach. Everyone working in the area should know what the cart contains and where it’s kept.
A video laryngoscopy should also be easily accessible. Ideally, this tool, which allows doctors to see the vocal cords and larynx on a video screen, should be in every operating room.
Also, it’s important to have more than one type of supraglottic airway tool on the cart. These are devices placed in the throat to keep the airway open if you have difficulty breathing.
In case of emergencies, there should be a scalpel, a bougie, and a small tube for the windpipe available. A bougie is a slender and flexible instrument that helps the doctor insert the breathing tube into the windpipe during an emergency.
Lastly, cognitive aids like the vortex and algorithms should be attached to the cart. These are tools that provide a step-by-step guide to managing breathing emergencies, helping staff to make better decisions under pressure.
Who is needed to perform Unanticipated Difficult Intubation in an Adult Patient?
This article is meant for doctors who specialize in areas such as anesthesia, emergency medicine, and lung and critical care. Plus, it’s also helpful for any other healthcare professionals who are in charge of managing emergency airway situations and performing intubation – a procedure where a tube is inserted into your windpipe to help you breathe in emergency situations.
Preparing for Unanticipated Difficult Intubation in an Adult Patient
There are several ways and techniques to help doctors prepare for dealing with high-risk patients or situations where placing a breathing tube is more difficult than usual.
A simple thing that doctors can do is to place a device that delivers low or high-flow oxygen to the patient. This is especially useful for patients who are overweight, as it can lengthen the safe time that the patient can be without active breathing (apnea).
Dr. Richard Levitan developed a helpful acronym, NO DESAT, which stands for Nasal Oxygen During Efforts Securing A Tube. It’s basically suggesting using oxygen through the nose while trying to insert the breathing tube.
The Vortex cognitive aid is a visual tool that helps doctors assess the success of different breathing assistance methods like using a mask, placing a tube above the vocal cords (supraglottic airway), or placing a tube through the windpipe (endotracheal placement). If any of these methods are successful, the situation improves (moving to the green zone). If none of these methods works, it signifies a critical situation called “cannot intubate and cannot oxygenate” (CICO) which requires performing an emergency procedure to establish a surgical airway. The priority is always to ensure the patient gets enough oxygen, rather than just securing the tube.
Doctors also have various techniques which they could use to help them. These include changing the patient’s head or neck position, applying an external pressure to the voice box (larynx), changing the blade of the laryngoscope (device used to visualize the windpipe), or using a video laryngoscope.
The Difficult Airway Society (DAS) provides a set of steps (algorithms) for managing unforeseen difficult tube placements. These steps progress from ensuring effective mask ventilation and successful tube placement (Plan A) to maintaining oxygenation with a supraglottic airway (Plan B). If unsuccessful, they suggest attempting mask ventilation again with the help of muscle-relaxing drugs and two people (Plan C). If all else fails, the last resort would be to create an emergency airway in the front of the neck (Plan D).
The guidelines also recommend limiting attempts at tube placement to a maximum of three times. Continued attempts without changing the approach are not advisable. Use of a second-generation supraglottic airway device is also suggested as it separates the air and food pathways and is better at preventing complications like accidental inhalation of stomach contents.
Emergency surgical airway (called emergency front of neck access or eFONA) is now the preferred method if needed. This method has shown better success rates with fewer complications than the traditional needle method.
Other guidelines are available for managing failed tube placements in pregnant patients under general anesthesia, managing breathing tubes in the intensive care unit, awake tube placements, and extubation (removal of the tube). All these guidelines are based on extensive research and are freely available.
How is Unanticipated Difficult Intubation in an Adult Patient performed
Video laryngoscopy is a game-changer in managing breathing pathways. The idea is to use a small camera known as a laryngoscope to easily view the area at the back of the throat bypassing the tongue. This allows for better visibility and accuracy. The method turns out to be more successful at first attempt, which is crucial for patients at high risk of choking, such as those with Achalasia, a condition that makes it hard to swallow food. A laryngoscope was a key tool during the COVID-19 pandemic.
When using a laryngoscope, if there’s a problem, it’s usually not due to not being able to see the opening to your windpipe (glottic opening). The challenge is often maneuvering the breathing tube (endotracheal tube) into the trachea. For the best result, the patient’s head should be straight with a limited view of the glottic opening. Traditional positioning might make this process harder.
Laryngoscopes come in two types – non-channeled (the more common type) and channeled ones. Channeled scopes have a sharper angle and a path that guides a breathing tube towards the glottic opening, causing the least neck movement. This is beneficial for patients with unstable neck injuries. It’s important to know the type of laryngoscope discussed in any literature or comparisons, as they work differently.
There’s a rare chance laryngoscopes might not work correctly or fail. Hence, it’s important to know any possible signs of such issues and plan alternatives.
There are also several methods to use supraglottic airways (tubes placed in the throat to allow air to pass through) to help with successful intubation. One of these is using a laryngeal mask airway specially designed for intubation. This type of device is particularly helpful for obese patients or patients with overly large and inflamed tonsils – a common cause for unexpected complications during intubation. This supraglottic airway pushes aside the extra tissue obstructing the airway and helps with intubation. It should be noted on the patient’s medical record for future reference.
Another method includes driving a flexible scope through a supraglottic airway device with a breathing tube loaded on it, allowing either the breathing tube or an airway exchange catheter (tube used to exchange breathing tubes) to be placed in the trachea.
Possible Complications of Unanticipated Difficult Intubation in an Adult Patient
Problems linked with difficulty or failure in managing a person’s airway could consist of several things. These include low oxygen levels in the body (hypoxia), inhaling food or liquid into the lungs (aspiration), accidental insertion of a tube into the food pipe instead of the windpipe (esophageal intubation), and an unplanned surgical procedure to open up an airway. Additionally, complications may lead to instability in heart function (cardiovascular instability), irregular heartbeats (cardiac arrhythmias), brain damage due to lack of oxygen (ischemic encephalopathy), and in worst-case scenarios, it could result in death.
What Else Should I Know About Unanticipated Difficult Intubation in an Adult Patient?
It’s important to note that medics can’t always predict when they might have a challenging time inserting a breathing tube, a process known as intubation. That’s why they need to have various backup plans and understand what might cause these methods to fail. When a patient’s oxygen levels drop, and the healthcare provider’s fine motor skills worsen, they have four possibilities: make the patient breathe through a mask, apply a supraglottic airway over the windpipe, insert an endotracheal tube into the windpipe, or perform an emergency surgical airway.
Knowing what factors can cause each of these methods to fail can help the practitioner decide which approach to take.
The predictors of a mask not working properly were discussed in the Airway Assessment article by StatPearls.
Some factors that make using a video laryngoscope more challenging include being overweight, the healthcare provider lacking experience with this tool, having blood or other fluids hindering the view inside the throat, having a direct view of the patient’s windpipe obscured by the vocal cords, and not being able to open the mouth widely.
Certain issues can make it more complicated to place a supraglottic airway – being overweight again, having a small mouth, having a pathological condition in the upper airway, a neck that can’t extend fully, and applying pressure to the cricoid cartilage in the neck.
In case of an emergency, when the only option left is to access the windpipe through a surgical cut in the front of the neck (eFONA), few factors might make this difficult, such as being obese, having hardened skin changes due to surgery and/or radiation, having a flexed neck deformity, a displaced windpipe, and being female.
In particular, being obese can complicate all airway management and contribute to a failed rescue. This situation might require the tube to be inserted when the patient is awake.
If it’s challenging to intubate due to physiological reasons, the management strategies can include providing additional oxygen, treating low blood pressure with fluids or medications, delaying the tube insertion until severe acidosis (a condition that makes your body fluids contain too much acid) improves, using an ultrasound of the heart to assess the severity of right heart failure, choosing drugs based on the patient’s blood flow and pressure, or possibly placing the tube while the patient is awake and able to breathe on their own.
