Ever since I have been on-staff at a tertiary care academic hospital, I have made it a point to teach all the students and residents I work with about the ‘laryngospasm notch’. Specifically, since it is my standard care for every patient I extubate, I make sure trainees are applying firm pressure in the laryngospasm notch after they extubate every patient. Usually, the first residents have ever heard of the ‘notch’ is from me! This is disappointing since this manoeuvre is extremely important in clinical anesthesia, and every anesthesia practitioner should know about it. I therefore thought I would write a blog post about it.
What is the laryngospasm notch, and why haven’t you heard of it before?
I’ll get to the first question in a bit. The answer to the second question is I have no idea, because this technique is so super-important I am amazed everyone doesn’t already know about it! As its name implies, the notch is used to treat (and prevent) laryngospasm. Before we get into the details about the ‘notch’, though, let’s first consider what post-extubation laryngospasm is and why it’s important.
Once in a while, due to secretions sitting on the vocal cords, stimulation of the vocal cords as the tracheal tube is being removed, mid-plane depth of anesthesia, or other reasons, a patient’s vocal cords will seize shut after the tracheal tube is removed at the end of an anesthetic. This means no gas can enter or leave the lungs despite the fact that the patient may be making respiratory efforts! Becuase it is difficult to predict which patients may develop this serious complication, until you can verify the movement of gas in and out of the patient’s mouth and/or nose after extubation of the trachea, you should assume the patient has laryngospasm. To do otherwise is foolhardy and potentially risky for the patient.
I have witnessed many occasions where someone has extubated the patient and held a mask over the patient’s face, but without seeing the bag on the anesthetic machine move. These patients might have been breathing (i.e. the respiratory muscles were being activated by the brain), but they were not ventilating (i.e. no gas was moving in and out of their lungs because the patient was breathing against a closed glottis).
Post-extubation laryngospasm is a serious problem, becasuse unless it is treated successfully, it is quickly followed by “bad things”, including:
- hypercarbia / respiratory acidosis, and eventually,
- negative pressure pulmonary edema (since, as the patient is still breathing and generating negative intrathoracic pressure, fluid can literally be “sucked” out of the intravascular fluid into the alveoli).
Negative pressure pulmonary edema can occur surprisingly quickly. In a young healthy patient breathing actively against a closed glottis, it can develop within a few breaths.
So, after tracheal extubation, it makes a lot of sense to be proactive in ensuring the patient actually has a patent airway before you relax after extubating someone.
Typical treatment of laryngospasm
Over the years, many potential treatments for laryngospasm have emerged, including:
- trying to “break” it with positive pressure mask ventilation and 100% oxygen
- aggressive chin-lift/jaw thrust
- applying CPAP via a face mask
- low- or high-dose succinylcholine (IV or IM)
- propofol bolus
The problem with all of the above techniques is that they have variable success rates. Additionally, in the case of succinylcholine or propofol, one must ensure the drug is drawn-up and ready to use. In contrast to the above techniques, applying pressure in the laryngospasm notch treats laryngospasm with almost complete success and can be applied in all patients immediately.
So, where is this awesome laryngospasm notch?
It is easiest to describe where the notch is by landmarking on yourself. So, just behind your earlobe, point your middle (or index) finger towards your skull base and place the tip of your finger on the mastoid process. Next, bring your finger anteriorly until you feel the ascending ramus of the mandible (you may need to bring your finger down — caudad — a little bit). In between the mastoid and the ascending ramus of the mandible, when you apply cephalad pressure, you will feel a ‘notch’. This is the laryngospasm notch. See the drawing below for a nice graphical representation of the notch. (This Figure is from a seminal paper by Larson, published in Anesthesiology — Larson CP. Laryngospasm–the best treatment. Anesthesiology 1998; 89(5): 1293-94.)
The technique is very simple: apply firm cephalad and medial pressure in the laryngospasm notch (either one side or both sides). That’s it! This manoeuvre will almost always break laryngospasm without any drugs, and it will do it very quickly in the majority of cases. An additional benefit is that, even if the patient does not have laryngospasm, applying pressure in the notch will:
- prevent laryngospasm from occurring
- increase the respiratory rate
- increase tidal volume at a time when many patients need a bit of stimulation.
NB: You should be aware that applying pressure to the laryngospasm notch is quite distinct from the typical grasp an anesthesiologist uses to hold a mask on a patient, which is at the angle of the mandible and the chin. The laryngospasm notch is quite a bit further cephalad, and the ‘mask grasp’ is inadequate to break most cases of laryngospasm. See the photo below where the left hand holds the mask in the usual fashion whilst the right hand applies pressure in the laryngospasm notch.
The History of “the Notch’
As far as I’m aware, nobody has claimed the ‘discovery’ of the notch. However, the first time it received significant attention in an anesthesia journal was in 1988 in Anesthesiology when an Emeritus Professor of Anesthesia at Stanford, Philip Larson, wrote an article entitled ‘Laryngospasm–the best treatment.‘ In this article, he described the conventional means of treating laryngospasm, what the laryngospasm notch was, and how it should be properly stimulated. The fact that this paper was published so long ago and that all anesthesia practitioners don’t already know about it is, quite frankly, incredible to me.
Summary and Recommendations
When you extubate your next patient, and all patients who follow, make a point to press firmly on the laryngospasm notch, at least with one hand. I do it by pressing with my right middle finger as I am concurrently applying a mask with high-flow oxygen with my left hand (in the usual ‘mask grasp’ fashion). Applying the pressure prevents and/or treats laryngospasm post-extubation, and it also stimulates ventilation, which makes it easier for me to assess whether or not the patient has a patent airway.
The only contraindication to pressing on the laryngospasm notch is if you might be able to harm a patient by doing so. In patients who have just had neurosurgery or a mastoidectomy, I ensure I press on the non-operative side.
Any pain felt by the patient will not be remembered, as you are only pressing in the most early stages of emergence from anesthesia. Bluntly, the gain is a lot more than the pain. I encourage everyone to adopt this practice. As always, I encourage your feedback, either in the comments below, or via Twitter.
Here’s to eliminating post-extubation laryngospasm!
Addendum: I was alerted to a video showing the Larson manoeuvre. Thanks to @TheButterdog !