|It’s important when using advanced airway equipment to maintain basic airway and ventilation. Training to be proficient in the use of the bag-valve-mask (BVM) is essential.|
|Intubation requires visualization of the vocal cords using laryngoscopes. It’s an important tool and should be checked daily to ensure the batteries are charged and the light works. (Fire Apparatus Photo by Will Chapleau)|
To establish and manage patients’ airways, it sometimes requires more invasive procedures and equipment. Last month we looked at the basics. This month we’ll look at advanced airway management, devices that are inserted into or isolate the airway by sealing it off from the esophagus.
Often referred to as the gold standard, endotracheal intubation is considered by most to be optimal airway control. Insertion of these devices is considered an advanced skill, for the most part performed by paramedics, EMT-Intermediates and some EMT Basics.
Numerous studies look at intubation success rates and patient outcomes. What comes out of those studies is that training is essential, both primary and in continuing education review to maintain this skill. Training and skill honing is of particular importance as many prehospital care providers don’t get many opportunities to perform intubations.
Endotracheal tubes work by insertion into the airway beyond the vocal cords but above main stem bronchi. A balloon is inflated which closes the system, isolating the airway from the esophagus.
The advantage of intubation is that it provides a patent-protected airway. The airway is protected from emesis [vomit] and air directed into the tube goes only into the lungs. If ventilations are managed appropriately in intubated patients, this is the best possible airway/ventilation scenario.
There are some disadvantages to intubation, however. They are basically related to access and opportunity and dependent on the proficiency of the provider attempting intubation and monitoring the patient after intubation.
It is a sophisticated skill and requires significant training to initially master and maintain.
The biggest danger is in not recognizing the need for alternate airways when intubation is unsuccessful and in not recognizing poorly placed tubes.
Esophageal obturators were once a standard back-up device in most EMS units, but are rarely found today. They were presented as a foolproof option for basic life support (BLS) units to establish a patent airway.
The proponents described a blind insertion that would isolate the airway by sealing off the esophagus. The insertion does require some training and it is possible that the tube could mistakenly be inserted into the trachea, which would be disastrous.
Inserted properly into the esophagus, once the balloon is inserted, the esophagus is sealed off. Air delivered into the device is forced into the lungs as long as an adequate seal is maintained on the mask attached to the tube’s top.
The advantages of esophageal obturators are the ease of the insertion and relatively short learning curve to train technicians to use them. Once in place, and with the seal of the mask to the face maintained, the patient can be ventilated well without the risk of aspiration.
There are some distinct disadvantages including size restrictions. The device cannot be use in kids or very tall patients. The device also requires maintaining a seal, which is harder than it sounds.
Studies have shown that single rescuers have a hard time maintaining a seal. Also, an esophageal obturator can be lethal if mistakenly inserted into the trachea instead of the esophagus. Technicians need to be trained to recognize the difference and double check to make sure it’s inserted and used properly.
Another option available is the multiple lumen airways (MLAs). They are sometimes called by their trademarked name Combitube. An MLA can be a reasonable choice for BLS, or as a back-up airway for advanced life support (ALS) airway control.
These devices have a single insertion tube with two lumens which divide into two separate ports for ventilating. The tube also has two balloons, which are inflated to isolate the esophagus from the trachea further minimizing the potential for aspiration and protecting the airway. Once the tube is inserted, the rescuer attempts to ventilate through one tube then the other, listening to lung sounds. The tube that allows the lungs to inflate is the one that is used.
The design of the tube allows for its use whether it is inserted into the trachea or the esophagus because of the design of the multiple lumens, ventilation ports and balloons.
The advantages of these airways include relative ease of insertion and short learning curve for training. The ability of the tube to be used regardless of whether it’s in the trachea or esophagus is another advantage. The fact that it does not require the use of a mask is also a plus.
The biggest disadvantage is, that like the obturators, MLAs should not be used in patients less than 5 feet tall.
Yet another alternative for advanced airway management is the laryngeal-mask airways. They have long been used by anesthesiologists in-hospital but historically have not been in wide use in prehospital care in the U.S.
In Europe, however, LMAs are widely used. This is probably influenced by the fact that emergency medicine and prehospital care in Europe is largely driven by anesthesiologists.
Designed specifically to seat over the larynx, the LMA is another device that does not require visualization to insert. Some versions of the LMA facilitate endotracheal intubation through the LMA once placed.
Short Learning Curve
The main advantage of the LMA is the relative ease of insertion and short learning curve to train technicians in its use. Another advantage again is that it does not require visualization of the larynx to insert. It is also a less traumatic airway insertion than more invasive airways.
The biggest disadvantage is possible gastric aspiration as the seal is not absolute.
To sum it up, emergency medical service personnel have options. The point of this column is not to identify one over the other, but to describe them.
Personally, I think we are better at airway management with multiple options. For instance, my intubation program would be enhanced by the availability of a multi-lumen airway (MLA) as a back-up.
However, we would all perform better at airway and ventilation management if we focus on the areas where we are historically under-performing.
Improving Mask Seals
As an example, every EMS provider should be working on improving mask to face seals when using bag-valve masks (BVMs) and doing a better job at measuring the rates we are breathing for our patients to ensure the best possible outcomes.
For the last two months, we’ve been talking about airway management and ventilation. Clearly, we have options dependent on training, availability of devices and patient need.
We need to ensure that in attempting advanced airway management we don’t lose sight of the patients’ needs. If it’s taking too long to get the tube in, we need to stop and ventilate the patient.
Secondly, studies have shown that we need to be better at using masks for ventilation, focusing on maintaining an adequate seal and getting an adequate volume of ventilation.
Third, watch your rate. As a rule we ventilate way too fast. In the past while you may have thought more is better, the science tells us that ventilating too quickly (more than 20 bpm) can worsen patient outcomes.
The bottom line is the best airway is the one you are good at.
Once again, thanks for your time and stay safe.
Editor’s Note: Will Chapleau, who has 30 years of EMS experience, is chief of the Chicago Heights (Ill.) Fire Department. He has served as the chairperson for the Prehospital Trauma Life Support (PHTLS) program since 1996 and has been a member of its international faculty since 1984 and is a board member of the National Association of EMS Educators.