Ultrasound Is Superior to Palpation in Identifying the Cricothyroid Membrane in Subjects with Poorly Defined Neck Landmarks

Abstract

Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Success of a cricothyrotomy is dependent on accurate identification of the cricothyroid membrane. The objective of this study was to compare the accuracy of ultrasonography versus external palpation in localizing the cricothyroid membrane. Methods In total, 223 subjects with abnormal neck anatomy who were scheduled for neck computed-tomography scan at University Health Network hospitals in Toronto, Canada, were randomized into two groups: external palpation and ultrasound. The localization points of the cricothyroid membrane determined by ultrasonography or external palpation were compared to the reference midpoint (computed-tomography point) of the cricothyroid membrane by a radiologist who was blinded to group allocation. Primary outcome was the accuracy in identification of the cricothyroid membrane, which was measured by digital ruler in millimeters from the computed-tomography point to the ultrasound point or external-palpation point. Success was defined as the proportion of accurate attempts within a 5-mm distance from the computed-tomography point to the ultrasound point or external-palpation point. Results The percentage of accurate attempts was 10-fold greater in the ultrasound than external-palpation group (81% vs. 8%; 95% CI, 63.6 to 81.3%; P < 0.0001). The mean (SD) distance measured from the external-palpation to computed-tomography point was five-fold greater than the ultrasound to the computed-tomography point (16.6 ± 7.5 vs. 3.4 ± 3.3 mm; 95% CI, 11.67 to 14.70; P < 0.0001). Analysis demonstrated that the risk ratio of inaccurate localization of the cricothyroid membrane was 9.14-fold greater with the external palpation than with the ultrasound (P < 0.0001). There were no adverse events observed. Conclusions In subjects with poorly defined neck landmarks, ultrasonography is more accurate than external palpation in localizing the cricothyroid membrane.

The effect of i-gel® insertion on the accuracy of cricothyroid membrane identification in adult females: a prospective observational study

“…[21][22][23] A lateral accuracy definition of 5 mm from the midpoint of the cricothyroid membrane is common to a number of studies from other groups researching in this area. 3,5,6,13,14 Assessments in this study were conducted by participants naive of the laryngeal handshake technique for cricothyroid membrane palpation. 8,24 Although the study designs are different, the accuracy rates reported with the i-gel ® in place are similar to that with the laryngeal handshake technique (66% vs 62%).…”

The role of ultrasonography in the determination of cricothyroid membrane localization in the predicted difficult airway

“…US has been shown as a reliable, noninvasive method in the evaluation of the airway and determination of the CTM, and several studies have investigated the accuracy of the USguided localization of the CTM over classic landmark techniques. [6,14,15,[18][19][20] The ease of US use is significantly correlated more strongly with a higher BMI, the male gender, an increased neck circumference, thyro-mental distance, and sterno-mental distance. However, the multivariate analysis results show that only a higher BMI reached statistical significance.…”

Ultrasonographic identification of the cricothyroid membrane in a patient with a difficult airway as a result of cervical hematoma caused by hemophilia: a case report

“…It is difficult to conduct high-quality clinical research on the success rate of cricothyroidotomy under ultrasonographic guidance, so the efficacy of identification of the CMT using this modality is still a matter of debate. However, it was recently found that ultrasound-guided identification of the cricothyroid membrane [6, 13] is highly effective and is comparable to a CT-scan as the accepted standard [14] in patients with abnormal neck anatomy. This strongly indicates that this technique can be applied for patients such as the one described in this report.…”