Can you perform an emergency surgical cricothyroidotomy? In the dreaded Can't Intubate, Can't Oxygenate (CICO) scenario, if your patient has no airway, you must immediately establish a front of neck access (FONA) to save your patient's life.
This week I attended an outstanding Stanford Anesthesia Grand Rounds delivered by Drs. Jeremy Collins, Susan Galgay, and Tom Bradley. The lecture reviewed the literature regarding CICO events, and concluded that performing a surgical airway through the cricoid membrane is an essential skill for anesthesiologists.
Most anesthesia professionals have never cut into a patient's neck, but we must own this skill if the necessity arises. I've done thousands of cases over 34 years. I have never performed a surgical cricothyroidotomy, but I may need to do one tomorrow. It's essential expertise for myself and for every anesthesiologist.
As I've reviewed in previous columns, a lack of oxygen to the brain for five minutes can cause anoxic brain damage—a disaster all anesthesiology professionals must avoid. The specter that someday we will induce and paralyze a morbidly obese patient, and then be unable to intubate or oxygenate that patient, is in the back of the mind of every anesthesia professional. If and when this happens, we must be able to act without hesitation to oxygenate the patient via FONA.
CICO events are rare, but they do occur with a published incidence of 1 in 50,000 anesthetics, per the fourth national audit project in the United Kingdom (NAP4). Approaches to FONA include either cannula techniques or surgical techniques, with significant differences.
These involve inserting a large bore IV catheter through the cricothyroid membrane. Because the lumen of a 14-gauge IV catheter is small, ventilation requires a high- pressure jet oxygen delivery system. In Duggan's publication from 2016, the failure rate with cannula techniques was 42% in CICO emergencies. In addition, barotrauma occurred in 32% of CICO emergency procedures. Fifty-one percent of CICO emergency events managed with a FONA cannula had a complication. Several reports described trans-tracheal jet ventilation-related subcutaneous emphysema hampering subsequent attempts at surgical airway or tracheal intubation. Failure can also occur because of kinking, malposition, or displacement of the needle/cannula. The Stanford Anesthesia Grand Rounds concluded that these failure rates and complications with cannula FONA techniques were prohibitively high.
The cricothyroid membrane is divided by a surgical incision made with a wide scalpel (#10 scalpel). With the scalpel, bougie, tube (SBT) technique, a bougie is inserted into the trachea through the incision. A lubricated 6.0 mm cuffed endotracheal tube is advanced over the bougie into the trachea, and the bougie is removed.
There are contrasting difficult airway algorithms algorithms for different English-speaking countries around the globe. See this link for the algorithms from the United States, Australia, Canada, and United Kingdom. Each has unique recommendations for CICO emergencies.
The American Society of Anesthesiologists Difficult Airway Algorithm outlines an approach to airway management, but at the bottom right of the chart, the plan for the CICO situation is "Emergency Invasive Airway Access." A footnote reads "invasive airway access includes surgical or percutaneous airway, jet ventilation, and retrograde intubation." The algorithm gives no definitive choice of which technique to use. This is a shortcoming of the American algorithm. There are invasive airway options, and in an emergency there can be no wavering or doubts regarding what to do. Per the data above, percutaneous airway and jet ventilation carry high failure and complication rates. Per discussion at the Stanford Anesthesia Grand Rounds, retrograde intubation is too slow, too difficult, and should be eliminated from the recipe for emergency lifesaving treatment.
The Australian algorithm uses the Vortex approach to managing an unexpected difficult airway.
Three options (face mask, endotracheal intubation, and laryngeal mask airway) are all attempted, in any order, to establish a patent airway. If all three methods fail to establish a patent airway, this (not the occurrence of oxygen desaturation) is the trigger to establish an emergency surgical airway (ESA). ESA techniques include either cannula or scalpel cricothyroidotomy to provide a patent airway as rapidly as possible. Note that the Australian Vortex approach endorses either cannula or scalpel cricothyroidotomy, and recommends that anesthesiologists be familiar with both FONA techniques.
Author's addendum: Many or most patients who suffer CICO events will be obese and have thick or short necks. The cricothyroid membrane may not be easily palpable. Per the text above, the United Kingdom Difficult Airway Society guidelines recommend you make an 8-10 cm vertical skin incision, caudad to cephalad, over the cricothyroid area. This type of surgical maneuver is not a routine part of anesthetic practice, and it will require both skill and courage to commit to the incision. The guidelines next ask you to use blunt dissection with the fingers of both hands to separate tissues until you can identify the larynx and palpate the cricothyroid membrane. Once the cricothyroid membrane is identified, the scalpel incision is made through the cricothyroid membrane. This technique will no doubt create bleeding in the anterior neck, and will not be easy to perform. Enlisting the surgeon's help during the procedure is advisable. Remember that controlling bleeding is not the primary issue—the primary goal is to locate the cricothroid membrane deep to the adipose of the anterior neck.
When I was a resident I was trained to give cricothyroid injections of lidocaine or cocaine to anesthetize the lumen of the trachea prior to awake fiberoptic intubations. The anatomy of the cricothyroid membrane in most patients is easily palpable, and it can be penetrated with minimal effort or bleeding. In a morbidly obese patient, this approach will be more difficult.
This was the subject of discussion at the end of Grand Rounds. Because of the extreme rarity of CICO events, skills will be absent, lost, or dormant for many practitioners. Practice on simulators or plastic models at 6 months intervals was recommended. Dr. Bradley explained that in one approach in Britain, a two-person team traveled from operating room to operating room to teach the SBT method. One member of the teaching team relieved the anesthesiologist from the operating room, and the second member then took the anesthesiologist a room to enjoy a pot of tea and to learn from a plastic training model of the cricothyroid membrane. The final proposals for education and re-education to retain skills at Stanford and throughout the world are challenges for the future. Note that surgeons have almost no education at cricothyroid approaches. Head and neck surgeons are trained in tracheostomy, a different procedure that likely will take too much time to perform when compared to a cricothyroidotomy. Training of surgical colleagues also needs to be addressed in the future.
Familiarize yourself with the anatomy of the cricothyroid membrane on each of your patients.
Have an SBT kit containing a #10 scalpel, a bougie, and a #6 cuffed endotracheal tube included with each difficult airway cart at each facility you anesthetize at.
I now carry an SBT kit in my briefcase which I take with me every day at work. In the current model of private practice in California, where we work at multiple different freestanding surgery centers and surgeon offices, this is a reliable means to assure that I have FONA equipment with me wherever I anesthetize patients.
Be prepared. Review and rehearse the anatomy and skills necessary to perform front of neck surgical cricothyroidotomy in seconds.
Work to avoid CICO events. Evaluate each airway prior to surgery. If a significant concern exists regarding a difficult intubation, a difficult mask ventilation, or a difficult FONA, use your judgment and perform an awake intubation. Securing an airway prior to anesthesia induction is a reliable way to avoid CICO disasters.
Learn the specific the SBT recipe for front of neck access.
Don't hesitate and waste seconds—it will take courage to grab that scalpel, but that's your job and your duty to your patient.
For further discussion and advice on airway emergencies, see my columns on Avoiding Airway Lawsuits, Airway Disasters, and The Most Important Technical Skill For an Anesthesiologist.
Posted in CLINICAL CASES FOR ANESTHESIA PROFESSIONALS.Tagged anesthesia blog, ASA Difficult Airway Algorithm, cannula cricothyroidotomy, cricothyroidotomy, Difficult Airway Society algorithm, FONA, front of neck access, RIchard Novak MD, RIck Novak MD, SBT access to neck, Stanford Anesthesia Grand Rounds, Vortex approach.
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