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Airway Algorithms

Airway Management AlgorithmIn my last EMS Airway Clinic article, “How to Make the Difficult Airway Less Difficult,” we looked at situations that can make airway management difficult; one of those situations was not having a strategy. Today, I’ll share with you the airway algorithm that has helped me over the years, and I want to give you some tips for building your own algorithm.

As professionals, we should know our protocols. We should be able to deliver quality patient care without looking up the details. I believe these ambitions, but folks, I’m just not one of those medics who remembers every nook and cranny of the protocol book. My worst example is the Glasgow Coma Scale. What a great tool to objectively record the conscious state of a patient. Let’s see, I know that if I’m dead for two weeks, I get a three, and I’m a 13 or a 14 when I get up in the morning. Otherwise, I’ve got to either look it up or use a memory aid, such as an algorithm.

An algorithm is “a step by step procedure for solving a problem.”(1) Medical algorithms help us deliver better patient care. They standardize treatment therapies, so we collectively deliver similar care in similar situations. They help us successfully navigate low-incidence, high-consequence incidents. They reduce medical errors. In EMS, we typically use two types of algorithms: flowcharts and checklists.

Flow charts guide us through a series of “if-then” situations that help us respond quickly and effectively in critical situations; if the patient is in ventricular fibrillation, then defibrillate them. A checklist is a memory aid to make sure we don’t forget something, especially in a situation that we don’t face regularly. A checklist for rapid sequence intubation (RSI) helps us remember to check patients for all contraindications.

I’ve found several characteristics that are commonly found in good emergency airway management algorithms. First and foremost, the algorithm must be based on your world—your patient population, distance to hospitals, available equipment and staff, as well as your own training, experience and confidence. It’s convenient to borrow an algorithm, but it won’t work if it doesn’t fit your operational environment. Using a hospital-based airway algorithm just doesn’t work in the parking lot of the Piggly Wiggly. A second feature of a good algorithm is comfort. If it’s awkward and unfamiliar, then you won’t use it well if at all. You make it comfortable by practicing and making adjustments. Finally, a good algorithm has to be systematic. It must logically and easily flow from one step to the next.

My Algorithm
I’ve used my current airway algorithm for about 15 years. Now, I didn’t just sit down at the kitchen table one morning and put it on paper. I started out using someone else’s algorithm, and then I gradually changed it to fit my needs. My algorithm will always be a work in progress. When I started, I didn’t consider video laryngoscopy or a bougie. Now, they both sit in a place of prominence.

Every patient receives oxygen at every possible moment. Do everything you can to wash out all of the nitrogen in the patient’s lungs and replace it with oxygen. A hyper-oxygenated patient will tolerate short periods of apnea better than a patient with low oxygenation.

Every EMS provider must be proficient at bag-valve-mask (BVM) ventilation. I think BVM ventilation is so important that it’s mentioned six times in my algorithm. I start with BVM to get a feel for compliance and how well the patient responds. Some folks do quite well with a little oxygen, an oral airway and gentle BVM ventilation. If my attempts at laryngoscopy or an alternative airway are unsuccessful, I reach right for the BVM.

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I’ve found that more than two attempts at laryngoscopy is usually a waste of a patient’s precious time because chances of success decrease with each attempt. I prepare to successfully place an endotracheal tube on my first attempt. I do everything to make my first attempt my best attempt. I have a second laryngoscopy attempt in the algorithm as an opportunity to make a course correction if I encounter an unanticipated condition, a technique or equipment failure, or I fail to prepare well enough.

I used to have supra-glottic airway placement as steps five and six in the algorithm until a colleague pointed out his success with nasal-tracheal intubation and digital intubation. Out of respect for Steve, I’ve changed these steps to use of an alternative airway. Similar to my experiences with multiple attempts at laryngoscopy, I’ve found that more than two attempts with an alternative airway become futile and detrimental to the patient. If you displace the tongue sufficiently and use adequate lubricant, first-pass success is likely. I’ve included a second attempt in the algorithm to give myself the opportunity to address an unexpected condition or a misstep in my preparation.

Step seven is our familiar friend, BVM ventilation and a quick ride to the hospital.

How long should you spend on each intubation attempt? Wow, that’s a loaded question. I wish I could give you a solid number backed up with a stack of studies, but I can’t. The time spent depends on the patient’s physiological condition, the level of difficulty you experience and your skill level. Many of us were taught to spend no more than 30seconds on an intubation attempt, and I think that’s a pretty safe number. From the moment you insert the blade into the patient’s mouth, it should take you about 10 seconds to locate the glottic structures, and then no more than another 10 seconds or so to place the tube, inflate the cuff and withdraw the stylette. The remaining 10 seconds are a pad for handling any surprises you might find.

I’d like to hear your thoughts on this. How much time do you think we should spend securing an airway?

Your Turn
Feel free to use this algorithm as template from which you build your own. A word of caution; an algorithm is one tool. It isn’t a replacement for sound clinical judgment. Please let me know how you fare in creating your own airway algorithm. In my next EMS Airway Clinic article, I’ll talk about some of the things you can do to improve your first pass success rate.

Be safe my friends.

1. Merriam-Webster. www.m-m.com/dictionary/algorithm.

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