First Pass Intubation: When You Can’t See The Cords

Failure of first pass intubation occurs about 10% of the time. The most common reasons, as I’ve described in a previous article (Avoiding Difficult Intubation Of The Easy Airway), is failure to pre-position the patient or optimally use our intubation tools.

I recently got an email from a first year resident who had elected to turn some intubations over to her instructors when she couldn’t see the cords. The instructors then had the same problems that she had had visualizing the larynx in those particular patients. Her instructors were successful in intubating despite not being able to see well and she was wondering how common it was to have poor visualization of the cords. She was also wondering if she was stepping aside too soon when she couldn’t see the cords. Maybe she should be trying a little longer.

Those were excellent questions. I thought it might be helpful to describe some of the thought process that goes behind the steps I take when I look but can’t see the cords —or when my student can’t see the cords.

Incidence Of First Pass Intubation Failure

Difficult intubation is defined by the American  Society of Anesthesiologists as “the need for more than 3 intubation attempts by a trained provider or attempts at intubation that last longer than 10 minutes”. In 2010, there were an estimated 25 million intubations in the United States and more than 50 million worldwide (1). The incidence of difficult intubation has been reported as 0.15% . That sounds like a small number, but it calculates to 1.5 in 1,000 intubations, or multiplied by 25 million, would theoretically predict 37,500 occurrences per year in the United States alone. (2)

For intubations in Emergency Departments, some studies have shown that more than two thirds (68%) of the intubations were successful on the first attempt, and about 10% of cases required three or more intubation attempts. Less experienced providers tended to require more intubation attempts. In one study of 2,833 patients (3), CA-1 residents had a 14.5% incidence vs 6% incidence for their staff attendings. More than 99% of these intubations were completed orally.

As you can see from those statistics, it’s not just novice intubators who fail to see the larynx on their first intubation pass. When we can’t see the cords during laryngoscopy,  our heart rate and blood pressure instantaneously rises as our level of anxiety soars. We know that first pass success is associated with a relatively small incidence of complications. As the number of intubation attempts increases, the incidence of complications increases substantially.  One Emergency Department study of 1,828 intubations showed that the incidence of adverse events such as hypoxia or physical injury during intubation was about 14% for one attempt, 47% for two attempts,  64% for three attempts, and 71% for four or more attempts (4).

Failure to see the cords on the first pass is scary. When we can’t see the larynx, we don’t know at that moment whether we will be able to see the larynx on the next pass, or if indeed we are starting down the terrifying road to can’t intubate/can’t ventilate.

The 4Ps of Preparation

You can read a more detailed approach to avoiding difficult intubation in my clinical review article in Airway Management (Always Prepare for Failure: 10 Rules for Approaching Difficult Intubation).(5) But it is worthwhile at least mentioning that the  best way to minimize the risk of getting into a situation where you can’t see the cords  is to optimize intubating conditions before you start. Perform the 4 Ps of preparation. For myself, I often find that I am much more likely to encounter difficulty if I have skipped these steps — which is unfortunately tempting to do in today’s fast paced turnover environment.

  • Past medical history:
    • ask the patient for history of any anesthetic problems
    • look at their old anesthesia records when you can
  • Perform an exam: look for potential anatomical problems
  • Position: place the head and neck in the best sniffing position
  • Preoxygenate well: because you never know when you will have problems

However, there is no question that you can do all of these steps and still fail to see the cords on your first try. Assuming you cannot see enough anatomical landmarks to make a reasonable attempt, what should you do next? Note that some of these steps are occurring simultaneously or in rapid succession.

Stop and Ventilate The Patient

Ventilating the patient gives you a moment to think about next steps. This is a big decision point. Most likely your next attempt will succeed, but if not, then you need to be prepared. If intubation attempts continue to fail,  you will need to decide to either:

  • keep trying – and if so what additional tools or helpers might you need
  • wake the patient up,
  • use a supraglottic airway to either proceed with the case or as an adjunct to intubation
  • consider an emergency airway

Now is the time to optimize oxygenation because further attempts at intubation may take time depending on the circumstances. You also need to ensure that your patient’s medical condition, vital signs, and lack of awareness are optimized.

Ventilating the patient immediately verifies, (and reassures), that you are not (yet) in a “can’t intubate/can’t ventilate” scenario. If you can’t ventilate, then you need to immediately jump further down the algorithm of options.

The ease with which you can ventilate should be factored into how long you will continue further attempts and indeed which steps you might take. If my patient is easy to ventilate, and I saw a fair amount of recognizable anatomy, then I will feel more comfortable trying a simple change in head position and a change in laryngoscope blades. If ventilation is difficult, then I’m much more likely to ask immediately for a videolaryngoscope, ask for another intubator to be called as a back up, or consider waking the patient up.

Communicate With Your Team

As you remove the laryngoscope from the patient’s mouth and begin to ventilate the patient, alert your team to what’s going on. If those team members are doing other tasks in the operating room, call them back to the bedside. Now is not the time to be the strong silent type and solve this problem heroically on your own. You want their attention and help before the patient potentially desaturates.

Quickly Assess What Went Wrong

As soon as you abort an intubation attempt you should be asking yourself: “What went wrong?” What could you see? What couldn’t you see? What can you do to make the next time successful? Start planning ahead.

Change Something On The Next Attempt!

The definition of insanity is to do the same thing that just failed again. Unless you had a perfect view of the cords and the light went out on your laryngoscope right before passing the tube, you must change at least one thing on your next attempt.

What Can You Change?

There are many things that you can change on your next pass, and depending on what you saw the first time you may want to change more than one thing.

  • Type or size of laryngoscope blade
  • Use of, or shape of a stylet
  • Position of the patient
  • Sniffing position improved
  • Addition of cricoid pressure
  • Head tilt
  • How high you’ve lifted the head off the bed
  • Height of the bed
  • The technique of how you’re using the blade
    • e.g. positioning of the tip of a curved blade on the hyoepiglottic ligament

Remember you have helpers who cannot read your mind. Talk to them, tell them what you’re doing and how you need them to help.

What If You Can’t See On The Second or Third Pass?

The recommendation of the ASA Task Force on the Management of the Difficult Airway is to limit laryngoscopic attempts to three before switching to an alternative method in order to avoid the risk of considerable patient injury that may occur. The slippery slope that is sometimes encountered is: Is that three attempts by one provider? Does it matter if the first provider is a novice — e.g. does the count start over when the attending steps in? How many times do you then attempt with the alternate method?

Alternate Intubation Methods

Perhaps as soon as a first pass intubation fails, and certainly when a second pass intubation fails, you should at least start running through the back of your mind what alternate methods you have and what you need to do to use them. What equipment might you need? Where is that equipment? When should you send for the equipment? Should I ask for the difficult airway cart? Is there another skilled intubation who might be called?

Get The VideoLaryngoscope

If your facility has a video laryngoscope, think about asking for it to be brought early. Having it in the room, even if you end up not needing it, saves precious moments if you patient does desaturate. The risk of complications rises with each attempt. Being able to switch quickly to the videolaryngoscope decreases the potential for a truly prolonged intubation attempt. You can read more on the techniques of successfully using one type of videolaryngoscope, the Glidescope here (Glidescope: Tricks For Successful Intubation)

Videolaryngoscopy is quickly becoming the tool of choice for when you can’t see the cords. As costs of videolaryngsocopes come down and their availability increases, I predict that they will eventually become the primary tool for first pass intubation. However, at present they are expensive and not everyone has easy access to one.

Use A Bougie

When you don’t have a videolaryngoscope immediately available, the bougie is a wonderful tool for intubation. It must be used carefully to avoid complication, but if you can’t see the cords it offers you a quick solution. You can read more about the bougie and precautions in its use here (The Bougie: Use Wisely To Avoid Rare But Serious Complications)

Supraglottic Airway Assisted Intubation

Using an LMA to assist with intubation is a nice option. A device such as the Fastrach gives you the ability to ventilate during the intubation process. Details on use of the Fastrach intubating Airway can be found here (Tips for Mastering the LMA Fastrach)

Fiberoptic

Intubation with the fiberoptic bronchoscope is best done electively before one starts so that the airway can be optimized with topical anesthesia, and a drying agent. In an unanticipated intubation, consider using the Fiberoptic early rather than later, before the airway is traumatized and excessive secretions stimulated. Blood and saliva in the airway make visualization very difficult.

Prepare Alternate Equipment Before you Start

When I begin an elective intubation, I always have Plan B and C. I try to have at least some of the equipment close by. I will have still in their sterile wrappers:

  • a second type of blade out on my station
  • a laryngeal mask airway of he correct size
  • a bougie in the room

I (and my team) will know where the glide scope is kept for emergencies. If I’m worried about the airway I often have the GlideScope outside the door ready to grab. It saves a lot of time and anxiety to know that I have alternate methods of intubation and ventilation immediately to hand and ready to go.

If I am running to an emergency intubation on the ward, my intubation box contains alternate methods such as a bougie and an LMA. I will often bring the portable GlideScope with me. Especially when dealing with critically ill and deteriorating patients, first pass i intubation success is especially important.

When To Stop Intubation Attempts

It is difficult to know when to change to a different technique, to ask someone else to try, or to stop the attempt. Failure to recognize the potential point of no return on the way to loss of the airway can be very hard. The temptation is strong to protect your ego by proving to yourself, and your audience of staff members, that you are skilled at performing that technique. “This should work, I’ve done it before; I will make it work now.” I’ve watched colleagues repeat spinal attempts at the same interspace over and over without changing anything, yet expecting success with each new needle pass. As has been said, “The definition of insanity is doing the same thing over and over again, expecting different results.”

Another confounding factor in deciding to abandon a technique, or even the entire intubation attempt, is the fact that one simply is not aware of time passing in the middle of an emergency. What seems like 1 to 2 minutes can really be 10 to 15. Force yourself to keep track of the clock. the longer an intubation attempt persists, the risk of complications increases and indeed the risk of of a “can’t intubate/can’t ventilate” scenario increase as well.

flowchart Difficult Airway Society Guideline for Unanticipated Difficult Intubation 2015

Difficult Airway Society Guideline for Unanticipated Difficult Intubation 2015

Working With A Student Who Misses The First Pass Intubation

The resident who emailed me was wondering what criteria should be used for when the student’s first pass intubation fails and when the next intubation attempt should be turned over to the attending. When I’m working with a student, the timing of when I take over will depend on:

  • my assessment as to how much stimulation the patient will tolerate
  • the experience of the student (and their past success rate)
  • the student’s intubation technique
  • how gentle he or she is being with the patient
  • how well she or he is communicating with me

Patient safety comes first. If I have a high risk patient and an inexperienced student, I will do the intubation and demonstrate the techniques with a running commentary. If my student has more experience and has demonstrated previous success, then I will often try to talk them through the changes I think they need to make on the second ad perhaps third attempt.

One important factor, apart from their technique and how gentle they are, that often gives me more patience in giving them another pass is how well they are communicating with me. I am much more likely to approve another pass from a student who tells me what she sees, explains what she thinks she needs to change, and then describes her proposed next steps.

May The Force Be With You!

Christine E Whitten MD, author

Anyone Can Intubate: A Step by Step Guide
and
Pediatric Airway Management: A Step By Step Guide

To Preview Books On Amazon.com Click Below

  Button link to see inside or buy the book Anyone Can Intubate, A Step By Step Guide to Intubation and Airway Management, 5th edition on amazon    Button to see inside or buy the book Pediatric Airway Management: A Step-by-Step Guide by Christine Whitten

References

  1. American Society of Anesthesiologists: Presentation by Chunyuan Qui, MD, CEO of Qscope. Presented at: Elsevier Business Intelligence IN3 West Conference; March 4-5, 2010; Las Vegas, NV. www.velosal.com/?page_id=15.
  2. Cook TM, MacDougall-Davis SR. Complications and failure of airway management. Br J Anaesth.2012;109 suppl 1:i68-i85.
  3. Mort TC. Emergency Tracheal Intubation: Complications Associated with Repeated Laryngoscopic Attempts. Anesth Analg 2004;99:607–13
  4. Sakles JC, Chiu S, Mosier J, Walker C, Stolz U. The importance of first pass success when performing orotracheal intubation in the emergency department. Acad Emerg Med. 2013;20(1):71–78. doi:10.1111/acem.12055
  5. Whitten CE. Prepare For Failure: 10 Rules forApproaching Difficult Intubation. Airway Management. Suppler to Anesthesiology News 2019-2020

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