Comparison of ultrasonography and surface landmarks in detecting the localization for cricothyroidotomy

doi:10.1016/j.ajem.2015.10.054

The American Journal of Emergency Medicine

Volume 34, Issue 2, February 2016, Pages 254-256

https://doi.org/10.1016/j.ajem.2015.10.054 Get rights and content

Abstract

Objective

The aim of the study was to compare ultrasonography (US) and surface landmark techniques for detecting the cricothyroid membrane (CTM) to perform a cricothyroidotomy on healthy volunteers.

Methods

In this prospective observational study, 5 operators and 24 models were included. The borders of the CTM were marked with an invisible pen. The operators were asked to point the CTM either with the palpation method or the US-guided fashion.

Results

The CTM was detected accurately in 80 (66.7%) attempts with palpation and 83 (69.2%) attempts with US. There was no statistically significant difference in the accuracy of detection of the CTM with palpation and US. The mean time for detecting the CTM with palpation was 8.25 ± 4.8 seconds (95% confidence interval, 7.3-9.1). The mean time for detecting CTM with US was 17 ± 9.2 seconds (95% confidence interval, 15.3-18.7). The duration for detecting the localization of the CTM was longer with US.

Conclusion

According to the results of this study, the accuracy of US and palpation was similar in detecting the localization of the CTM. However, the duration for detecting the CTM was longer with US when compared with the palpation technique.

Introduction

The incidence of difficult airways in the emergency medicine literature ranges from 2% to 14.8%; the incidence of surgical airways is much lower than that, at 0.06% [1].

The surgical airway is an infrequently needed yet important procedure, as complications during this procedure may result in morbidity and mortality. Although the cricothyroid membrane (CTM) is superficial and surface landmarks are easily palpated, patients suffering from obesity, patients with short necks, as well as those with secondary conditions affecting the neck region, such as subcutaneous emphysema or previous surgery, may all complicate the situation and may also increase the complication rates of the surgical airway procedure. In those cases where an emergency airway is needed, multiple attempts may not only prolong the hypoxia time but also lead to complications.

Ultrasonography (US) is being used for a variety of purposes in the practice of emergency medicine. Ultrasonography has gained popularity in the evaluation of airways, with a previous study demonstrating that emergency physicians can obtain the CTM 100% of the time [2]. Real-time screening of the related landmarks during surgical airway may be useful, particularly in patients with obscure neck anatomy [3].

In this study, the aim was to compare US and surface landmark techniques for detecting the CTM to perform a cricothyroidotomy on healthy volunteers.

Section snippets

Materials and methods

This prospective observational study was performed in a tertiary care facility with 90,000 annual ED patient visits. The study has been approved by the institutional review board (09.04.2013/75). All operators and participants gave their informed consent before the study.

Results

Five operators (3 PGY4 and 2 PGY2) and 24 participants (8 female and 16 male) were included in this study. The mean age of the models was 24.4 ± 5.1 years. The mean BMI was 23.8 (20.8-26.1), and the median neck circumference was 37.1 ± 3.8 cm. Seventeen of the participants were of normal weight, 6 participants were overweight, and only 1 of them was categorized as obese according to their BMI calculation. The CTM was detected accurately in 80 (66.7%) attempts with palpation and 83 (69.2%)

Discussion

According to the results of this study, the accuracy of the US and palpation was similar for detecting the localization of the CTM. The duration for detecting the CTM was, however, longer with the US when compared with the palpation technique.

Previous studies reported that the complication rate for surgical cricothyroidotomy is between 6.1% and 54.5% [6]. Misplacement of the tube due to misidentification of the anatomical landmarks of the CTM is an important complication. In the study by

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Cited by (26)

Evaluation of a Low-Cost Hybrid Airway Model to Train Nurse Anesthesiology Students in the Performance of Ultrasound-Guided Cricothyrotomy
2024, Clinical Simulation in Nursing
The specific aim of this study is to evaluate the use of a hybrid airway model as a safe and cost-effective instruction method to train novice student nurse anesthetists in ultrasound-guided cricothyroidotomy procedural performance.
A convenience sampling of 26 novice nurse anesthesia students, enrolled in an advanced anesthesia course, evaluated first impression, realistic tactile experience, echogenic appearance, representation of the human anatomy, comfort utilizing the model, improvement in psychomotor skills, and value in teaching the percutaneous cricothyrotomy procedure.
Overall, 95.8% of the students felt the hybrid airway model was a valuable tool in teaching ultrasound-guided percutaneous needle cricothyrotomies. Students universally found the hybrid airway model provided a realistic representation of the human anatomy that helped improve their psychomotor skills.
There is a critical requirement for developing simulators that can effectively teach students the necessary skills needed for clinical practice. The hybrid airway model provides a feasible solution in addressing the current reduction in training opportunities.
Comparison between ultrasound-guided and digital palpation techniques for identification of the cricothyroid membrane: a meta-analysis
2021, British Journal of Anaesthesia
The role of ultrasound in front-of-neck access for cricothyroid membrane identification: A systematic review
2020, Journal of Critical Care
Citation Excerpt :
Furthermore, 3 studies demonstrated a mean time of less than 30 s (24.32 ± 20.18 s, 17 ± 9.2 s, 24.0 ± 2.4 s [transverse technique]) for CTM visualization on patients with varying BMI and neck circumference [22,26,27]. The operators in these studies either used ultrasonography in their daily practice [26,27], attended monthly didactic US sessions [26], or were US-fellowship trained physicians [22]. Therefore, effective training with regular practice and routinely assessing the location of the CTM whenever US is employed should be implemented to reduce CTM identification times and fully capitalize on the short learning curve associated with ultrasonography of airway anatomy.
Conventional palpation techniques for cricothyroid membrane (CTM) identification are inaccurate and unreliable. Ultrasound plays a multi-faceted role in airway management, however there is limited literature around its use for CTM identification prior to cricothyrotomies. This review sought to compare ultrasound to palpation in the general population, identify its indications in subjects with ill-defined neck anatomy, and determine its role in defining neck anatomy.
Two reviewers independently assessed titles, abstracts and full-text English articles through the Ovid Medline and EMBASE databases. Studies related to ultrasound for CTM assessment and/or cricothyrotomy in subjects older than 12 years were included.
Fourteen studies were selected. Compared to palpation, ultrasound has greater accuracy, but longer CTM identification times in those with normal airway anatomy. Interestingly, ultrasound offers comparable times to palpation in patients with difficult airways. Ultrasound also helps define anatomical parameters in the neutral and extended neck positions thereby underscoring the importance of neck positioning during cricothyrotomies and confirming consensus-based incision recommendations set by the Difficult Airway Society.
Ultrasound appears to be superior to palpation for CTM localization especially in those with difficult airway anatomy and objectively defines neck anatomy. Its pre-emptive use should be incorporated during difficult airway management.
Anterior neck and airway ultrasound procedures with emphasis on resuscitation plus video clips
2020, Trends in Anaesthesia and Critical Care
What can anterior neck and airway ultrasound add to the established methods in emergency airway management, including capnography?
The aim of this narrative review is to review relevant methods. We describe three major categories of anterior neck and airway ultrasound exam methods in order to distinguish its applicability within a defined clinical context. We particularly describe two types of focused anterior neck ultrasound exam styles depending on the clinical scenario, post-intubation (type #1 style) and during intubation (type #2 style). Regarding both exam styles, the key message is to identify or rule out a double tract immediately, indicating an esophageal misplacement. For this finding no ventilation trial is mandatory. In case of clinical emergency scenarios, this is the major advantage in comparison to capnometry. Exam type #1 style is a very brief sonoscopy-like exam and can be performed within 10 s in an ALS-conformed way. As these stethoscope-like examinations can be integrated into the advanced life support algorithm, it is suggested that anterior neck and airway ultrasound should be part of the collection of methods of “Resuscitation Ultrasound” and training. To make it available to a wider audience, the exam techniques are visualized in video clips and available at www.yumpu.com/en/SonoABCD.
Considering the evidence and limitations of anterior neck and airway ultrasound procedures in emergencies, training within scenarios or a defined clinical context is recommended. These point-of-care ultrasound methods should be readily accessible for emergency and critical care practitioners.
Ultrasound for identifying the cricothyroid membrane prior to the anticipated difficult airway
2018, American Journal of Emergency Medicine
Prior to the anticipated difficult airway, the emergency physician commonly palpates the neck to identify the presumed location of the cricothyroid membrane (CTM). In the event of a “cannot-intubate, cannot‑oxygenate” airway, precise CTM localization is vital to the success of a cricothyrotomy and hence, the patient's survival.
This narrative review will summarize the prospective studies evaluating CTM identification. It will demonstrate the inaccuracy of the classically used landmark palpation technique. It will then describe the use of ultrasound (US) as a superior tool for CTM identification, illustrate the technique itself, and propose its implementation in the pre-intubation checklist for the anticipated difficult airway.
Evidence demonstrates that physicians are not sufficiently accurate in palpating the CTM in both cadavers and volunteers in a stable non-emergent setting. In preparing for a real-time intubation, this fine motor task would be more difficult to achieve. Moreover, this particular patient group may often exhibit difficult airway features. US has been demonstrated to be superior for locating the CTM than landmark palpation across body habitus, gender, and failed airway simulations. This technique carries a short learning curve even without prior airway US experience, along with a high retention rate. An illustrative tutorial is provided.
Emergency physicians may apply this US technique for CTM localization in preparation for an anticipated difficult airway. However, since this technique takes longer than landmark palpation, using US is not recommended once already in the midst of a failed airway situation.
Ultrasonographic identification of the cricothyroid membrane: Best evidence, techniques, and clinical impact
2016, British Journal of Anaesthesia
Citation Excerpt :
In females, success rates were 24,12 25 (neutral position),10 29 (hyperextended neck),10 and 71% in the non-obese,13 whereas they were found to be 0 (neutral position),10 6 (hyperextended neck),10 35,12 37,11 and 39%32 in obese females. In heterogeneous populations including a mixed population of both sexes and with various BMI, a wide range of success rates was found, as follows: 19,29 30,16 39 (cadaver),32 46,21 62,33 66.7,34 and 70%.29 Identification of the cricothyroid membrane by visual inspection of the overlying skin creases was successful in 50%.33
Inability to identify the cricothyroid membrane by inspection and palpation contributes substantially to the high failure rate of cricothyrotomy. This narrative review summarizes the current evidence for application of airway ultrasonography for identification of the cricothyroid membrane compared with the clinical techniques. We identified the best-documented techniques for bedside use, their success rates, and the necessary training for airway-ultrasound-naïve clinicians. After a short but structured training, the cricothyroid membrane can be identified using ultrasound in difficult patients by previously airway-ultrasound naïve anaesthetists with double the success rate of palpation. Based on the literature, we recommend identifying the cricothyroid membrane before induction of anaesthesia in all patients. Although inspection and palpation may suffice in most patients, the remaining patients will need ultrasonographic identification; a service that we should aim at making available in all locations where anaesthesia is undertaken and where patients with difficult airways could be encountered.

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Original ContributionComparison of ultrasonography and surface landmarks in detecting the localization for cricothyroidotomy

Abstract

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Materials and methods

Results

Discussion

J Emerg Med

Am J Emerg Med

Am J Emerg Med

J Emerg Med

Original Contribution
Comparison of ultrasonography and surface landmarks in detecting the localization for cricothyroidotomy