- Emergency cricothyroidotomy can be a lifesaving intervention in the cannot intubate-cannot ventilate scenario. Identification of the cricothyroid membrane is a crucial step before any intervention can be initiated. The traditional method was to identify the cricothyroid membrane was by palpation. However, this may be difficult or impossible in an obese patient, especially with a deviated trachea. Previous studies of the ability to palpate the cricothyroid membrane in obese patients had a success rate of 0-39%. This study examined whether the use of ultrasonography could improve the successful identification of the cricothyroid membrane in a model of an obese neck with a deviated trachea.
- The authors developed a silicon neck model that could be used for both palpation and ultrasonography. Fifty-seven participants, consisting of anesthesiologists and anesthesia trainees, were randomly assigned to either the palpation group or the ultrasound group.
- Prior to the actual study, the participants were given a training session in identifying the trachea and cricothyroid membrane using ultrasound. The training session consisted of reading materials, a 25-minute lecture, a 10-minute live demonstration, and a practice session.
- Both the palpation and ultrasound groups were given 60 seconds to identify the midpoint of the cricothyroid membrane on the model. They were also video-recorded for later analysis of their success in finding the midpoint of the membrane.
- In the ultrasound group, 21 (75%) of the participants were able to correctly identify the cricothyroid membrane. Whereas, in the palpation group, only 1 (3.5%) individual was successful in identifying the cricothyroid membrane.
- A secondary goal was to correctly identify the trachea. In the ultrasound group 86% of the participants were able to achieve this goal. However, in the palpation group, only 55% of participants were successful.
- The implications for patient safety are clear. Ultrasound guidance improved the successful identification of the cricothyroid membrane from 3.5% to 75%. Clinicians were able to learn the technique with only a brief focused training session.
- When the clinician is faced with a possible difficult or impossible airway, it would be prudent to have the ultrasound readily available in the OR prior to induction of anesthesia. In this scenario, the anesthesiologist could also use the ultrasound to identify the cricothyroid membrane and mark the patient’s neck before starting the case.
Summary of "Palpation Versus Ultrasonography for Identifying the Cricothyroid Membrane in Case of a Laterally Deviated Larynx: A Randomized Trial"
Summary published August 23, 2024