Emergency cricothyroidotomy: an observational study to estimate optimal incision position and length

Cricothyroidotomy in extreme emergency: A case report of a real-life experience in three steps and less than 30 s using a single blade

INTRODUCTION AND IMPORTANCE

Cricothyroidotomy is often the last resort when conventional ventilation devices prove ineffective. The conventional procedure that involves several steps and requires the completion of a preoperative checklist. This report describes a novel approach to cricothyroidotomy, allowing quick access to the cricothyroid membrane in fewer steps.

CASE PRESENTATION

We present the case of a 26-year-old male with Schimmelpenning syndrome, exhibiting significant anatomical deformity. Following surgery for temporomandibular joint replacement, the patient developed a hematoma requiring urgent intervention. During nasotracheal intubation, the patient experienced a significant drop in oxygen saturation, which required prompt cricothyroidotomy. The procedure was performed in less than 30 s using a single blade for incising the tissues and the surgeon's hands for dissection and retraction. The procedure resulted in immediate recovery of the patient's oxygen saturation.

CLINICAL DISCUSSION

In contrast to previously reported multi-step procedures, this study reports a simpler three-step cricothyroidotomy. The technique involves a vertical skin incision, blunt dissection using the surgeon's fingers, and a horizontal incision on the cricothyroid membrane. The procedure was executed with the patient in a semi-reclined position, optimizing time efficiency.

CONCLUSION

This case highlights the efficacy of a rapid cricothyroidotomy technique in extreme emergencies. The presented technique requires minimal instrumentation and can be completed quickly in an emergency situation, even in the presence of anatomical variations.

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part II

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Point-of-care ultrasound for airway management in the emergency and critical care setting

Airway management is a common procedure within emergency and critical care medicine. Traditional techniques for predicting and managing a difficult airway each have important limitations. As the field has evolved, point-of-care ultrasound has been increasingly utilized for this application. Several measures can be used to sonographically predict a difficult airway, including skin to epiglottis, hyomental distance, and tongue thickness. Ultrasound can also be used to confirm endotracheal tube intubation and assess endotracheal tube depth. Ultrasound is superior to the landmark-based approach for locating the cricothyroid membrane, particularly in patients with difficult anatomy. Finally, we provide an algorithm for using ultrasound to manage the crashing patient on mechanical ventilation. After reading this article, readers will have an enhanced understanding of the role of ultrasound in airway management.

Anatomical morphometry for Cricothyrotomy puncture and incision

PURPOSE

Emergency surgical airway securing techniques include cricothyrotomy, puncture, and incision. While the instruments used for these methods vary in size, no index of laryngeal morphology exists to guide instrument selection. Therefore, we measured the morphology of the cricothyroid ligament in Japanese individuals and assessed its correlations with height.

METHODS

This retrospective study used 61 anatomical practice specimens. The cricothyroid ligament of the laryngeal area was dissected, and a frontal image was recorded. Next, images of the midsagittal sections of the larynx and trachea were recorded. The width and height of the cricothyroid ligament were measured from the frontal images, and the depth of the larynx and the angle to the lower edge of the cricothyroid plate were measured from the mid-sagittal cross-sectional images. The height was estimated from the tibial lengths of the specimens and statistically analyzed for correlations. 　 RESULTS: The width and depth were significantly greater in males. Overall, there was a slight correlation between the results of each laryngeal measurement and estimated height for all items.

CONCLUSION

The morphology of cricothyrotomy revealed that the width and depth of the laryngeal area varied according to sex. Moreover, the results also showed a correlation with the estimated height. Thus, it is important to predict the morphology of the laryngeal area and cricothyroid ligament by considering factors such as patient sex, weight, and height.

[The correct way to deal with the definitive surgical airway]

Dealing with a difficult airway is familiar to emergency care providers in both the prehospital and clinical settings. In anesthesiology and emergency medical care different algorithms almost equal in their wording have been introduced, indicating that an emergency front of neck airway access (eFONA) has to be established in the case of a cannot ventilate-cannot oxygenate situation. In a survey (Surveymonkey®) data concerning the level of experience with eFONA, devices required, previous training and complications were allocated among acute and emergency care providers of different backgrounds (doctors and paramedics). Furthermore, we asked about individual attitudes to and frequency of previous situations, in which an eFONA was not established despite strong indications. Of the respondents 15% (n = 63) answered that they had experienced this type of situation. eFONA had been performed by 28% of the interviewed (n = 117), reflecting the high number of military and EMT (emergency medical team) physicians participating in the survey. The number of experiences are rarely representative for the civilian setting. Different adjuncts may be helpful to detect the cricothyroid ligament. To use ultrasound seems obvious but it doubles the time for the detection of the cricothyroid ligament. Laryngeal masks can be employed as a supraglottic airway device (SAD) during "plan B". Stabilizing the airway with a SAD almost doubles the success of identifying laryngeal landmarks in females. The crew resource management (CRM) guidelines are more than essential in threatening situations demanding measures like eFONA. Providers should anticipate emerging problems and whenever feasible call for help and finally speak up. Naming a failed airway should be avoided as it implies a failure of the provider or of the entire airway team. In fact, the term non-accessible airway should be introduced. This might help to avoid the implication of a major failure. So far, an ideal simulator to train eFONA has not been introduced but it is mandatory to train procedures and algorithms on different types of simulators and manikins to achieve mastery.

Equivalence of the top-down manoeuvre and bottom-up manoeuvre in speed and accuracy of identifying the cricothyroid membrane: a prospective randomised cross-over study

BACKGROUND

Accurate identification of the cricothyroid membrane is crucial for successful cricothyrotomy; however, a manoeuvre that helps identify it both accurately and quickly remains unclear. The effectiveness of the so-called 'bottom-up manoeuvre' has never been investigated. This study aimed to examine whether the bottom-up manoeuvre is as rapid and accurate as the conventional 'top-down manoeuvre' at identifying the cricothyroid membrane.

METHODS

This study was a prospective randomised cross-over trial conducted at an academic medical centre between 2018 and 2019. Fifth-year medical students participated. The students were trained in the use of either the top-down manoeuvre or the bottom-up manoeuvre first. Each student subsequently performed the technique once on a volunteer. The students were then taught and practiced the other manoeuvre as well. The accuracy of cricothyroid membrane identification and the time taken by successful participants only were measured and compared between the manoeuvres using equivalence tests with two one-sided tests.

RESULTS

A total of 102 medical students participated in this study and there was no missing data. The accuracy of identification and time required for success were similar between the top-down manoeuvre and the bottom-up manoeuvre (65.7% vs. 70.6%, taking 13.8 s [interquartile range (IQR): 9.4-17.5] vs. 15.5 s [IQR: 11.5-19.9], respectively). The success rate was statistically equivalent (rate difference, 4.9%; 90% confidence interval [CI], -5.8 to 15.6; equivalence margin, -20.0 to 20.0). The time required for success was also statistically equivalent (median difference, 1.7 s; 90% CI, -0.2 to 3.3; equivalence margin, -4.0 to 4.0).

CONCLUSION

Among students first trained in both manoeuvres for identifying the cricothyroid membrane, the speed and accuracy of identification were similar between those using the bottom-up manoeuvre and those using the top-down manoeuvre.

Evaluation of a novel emergency front of neck access device in a benchtop model of obesity

BACKGROUND

Emergency front of neck access (eFONA) is a critical step in oxygenation in cases of unrelieved airway obstruction. Multiple techniques are used in clinical practice without agreement regarding the optimal approach. We evaluated a novel device, the Cric-Guide (CG), a channelled bougie introducer that enters the airway in a single action and compared it with a scalpel-bougie-tube (SBT) technique in laboratory benchtop model.

METHODS

Seven anaesthesiologists attempted eFONA on both obese and non-obese models using both techniques in randomized order on an excised porcine trachea with an intact larynx with variable subcutaneous tissue depth. The primary outcome was successful tracheal cannulation. Secondary outcomes included false passage rate, time and tissue injury.

RESULTS

Anaesthesiologists performed 4 cricothyroidotomies on each model with each device. The CG was more successful in airway cannulation (47/56 [89.4%] vs. 33/56 [58.9%], P = 0.007). This difference was observed in the obese model only. The CG was associated with fewer false passages than the standard technique in the obese model (8/56 [14.3%] vs. 23/56 [41.1%], P = 0.006). There were no significant differences in time to completion or injury patterns between the techniques in the obese model, but the SBT was faster in the non-obese model. There was no difference in the proportion of specimens injured.

CONCLUSION

The Cric-Guide device was more successful than the standard SBT technique in airway cannulation in an obese neck model and with equivalent frequency and distribution of injury but performed equivalently in the non-obese model.

Emergency Front-of-Neck Airway Rescue Via the Cricothyroid Membrane: A High-Resolution Computed Tomography Study of Airway Anatomy in Adults

BACKGROUND

Emergency front-of-neck airway rescue is recommended in a can't intubate, can't oxygenate clinical scenario. Cannula cricothyroidotomy has been reported as having a high failure rate. Our primary aim was to estimate the angle of the trachea in relation to the horizontal axis in a simulated emergency front-of-neck airway rescue position. Our secondary aims were to estimate the optimal cannula angle of approach and evaluate the anatomical relationship of the cricothyroid membrane (CTM) to adjacent structures. We also assessed whether the CTM lies above or below the neck midpoint, a point equidistant from the suprasternal notch (SSN), and the chin surface landmarks. All measurements were compared between the male and female subjects.

METHODS

Subjects having elective computed tomography of their thorax were consented to have extension of the computed tomography to include their neck. A preliminary radiation dose and risk assessment deemed the additional radiation to be of very low risk (level IIa). Subjects were positioned supinely on the computed tomography table. Standard neck extension was achieved by placing a pillow under the scapulae and a rolled towel under the neck to simulate emergency front-of-neck airway rescue positioning.

RESULTS

Fifty-two subjects were included in this study: 31 men and 21 women. The mean angle of the trachea in relation to the horizontal axis was 25.5° (95% confidence interval [CI], 21.8-29.1) in men and 14.0° (95% CI, 11.5-16.5) in women. The mean minimum angles required for hypothetical cannula cricothyroidotomy for men and women were 55.2° (95% CI, 51.8-58.7) and 50.5° (95% CI, 45.4-55.6), respectively. The CTM was located lower in the neck in men compared to women. The CTM was located below the neck midpoint in 30 of 30 (100%) male subjects and 11 of 20 (55%) female subjects (P < .001).

CONCLUSIONS

The trachea angulates posteriorly in a simulated emergency front-of-neck airway rescue position in supine subjects and to a greater degree in men compared to women (P < .001). The minimum angle required for hypothetical cannula cricothyroidotomy was >45° in the majority (75%) of subjects studied. A steeper cannula angle of approach may be more reliable and warrants further clinical study. If airway anatomy is indistinct and performing a vertical scalpel cricothyroidotomy, consideration should be given to performing this incision lower in the neck in men compared to women.

The effect of patient positioning on ultrasound landmarking for cricothyrotomy

PURPOSE

Our primary objective was to assess the difference in position of the ultrasound-guided landmark of the cricothyroid membrane (CTM) when performed with the supine patient positioned at different head of bed (HOB) elevations.

METHODS

In this prospective observational study of patients presenting to the emergency department with non-life-threatening complaints, subjects underwent ultrasound-guided landmarking of the CTM with HOB elevation at 0°, 30°, and 90°. A linear mixed effects regression model was used to assess the change in the CTM landmark associated with head position. We used a second adjusted linear mixed effects model to assess possible confounding patient factors associated with these changes.

RESULTS

One-hundred and ten patients were enrolled, with a median [interquartile range] age of 39 [29-59] yr and 51:49 female:male ratio. Head of bed elevation at 30° and 90° resulted in a cephalad change in the CTM landmark of 2.7 mm (99% confidence interval [CI], 1.7 to 3.8; P < 0.001) and 4.2 mm (99% CI, 3.2 to 5.3; P < 0.001) respectively compared with the landmark at 0°. Body mass index (BMI) was associated with a change of 4.6 mm (99% CI, 0.5 to 8.7; P = 0.004) for BMI ≥ 30 compared with < 18.5 kg·m^-2 The impact of patient age on distance depended on HOB elevation, where patients > 70 yr had a change of 2.6 mm (99% CI, 0.01 to 5.1; P = 0.009) at 90° HOB elevation compared with 30°.

CONCLUSION

The location of the ultrasound-identified surface landmark of the CTM moves in a cephalad direction by changing the position of the HOB from supine 0° to elevation at 30° and 90°. This may be clinically important when attempting cricothyrotomy using a percutaneous (blind) technique, particularly when CTM identification and cricothyrotomy are performed at different head elevations.

The role of ultrasound in front-of-neck access for cricothyroid membrane identification: A systematic review

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Perceived versus actual cricothyroid membrane landmarking accuracy by emergency medicine residents and staff physicians

OBJECTIVES

Cricothyrotomy is an intervention performed to salvage "can't intubate, can't ventilate" situations. Studies have shown poor accuracy with landmarking the cricothyroid membrane, particularly in female patients by surgeons and anesthesiologists. This study examines the perceived versus actual success rate of landmarking the cricothyroid membrane by resident and staff emergency physicians using obese and non-obese models.

METHODS

Five male and female volunteers were models. Each model was placed supine, and a point-of-care ultrasound expert landmarked the borders of each cricothyroid membrane; 20 residents and 15 staff emergency physicians were given one attempt to landmark five models. Overall accuracy and accuracy stratified by sex and obesity status were calculated.

RESULTS

Overall landmarking accuracy amongst all participants was 58% (SD 18%). A difference in accuracy was found for obese males (88%) versus obese females (40%) (difference = 48%, 95% CI = 30-65%, p < 0.0001), and non-obese males (77%) versus non-obese females (46%) (difference = 31%, 95% CI = 12-51%, p = 0.004). There was no association between perceived difficulty and success (correlation = 0.07, 95% CI = -0.081-0.214, p = 0.37). Confidence levels overall were higher amongst staff physicians (3.0) than residents (2.7) (difference = 0.3, 95% CI = 0.1-0.6, p = 0.02), but there was no correlation between confidence in an attempt and its success (p = 0.33).

CONCLUSION

We found that physicians demonstrate significantly lower accuracy when landmarking cricothyroid membranes of females. Emergency physicians were unable to predict their own accuracy while landmarking, which can potentially lead to increased failed attempts and a longer time to secure the airway. Improved training techniques may reduce failed attempts and improve the time to secure the airway.

Accuracy of pediatric cricothyroid membrane identification by digital palpation and implications for emergency front of neck access

BACKGROUND

Emergency front of neck access in a "can't intubate can't oxygenate" scenario in pediatrics is rare. Ideally airway rescue would involve the presence of an ear, nose, and throat surgeon. If unavailable however, responsibility lies with the anesthesiologist and accurate identification of anterior neck structures is essential for success.

AIM

We assessed anesthesiologists' accuracy in identification of the pediatric cricothyroid membrane by digital palpation in three predefined age groups (37 weeks to <1 year old, 1-8 years old, and 9-16 years old) and whether accuracy improved with repetition. We also investigated a novel hypothetical vertical skin incision strategy to successfully expose the cricothyroid membrane.

METHODS

We asked anesthesiologists to identify the location of the cricothyroid membrane of anesthetized children in the extended neck position. Accuracy was defined as a mark made within the margins of the cricothyroid membrane using ultrasound as a reference standard. The position of the cricothyroid membrane relative to the neck midpoint, between the suprasternal notch and mentum, was defined for each child. Using this neck midpoint, we determined the hypothetical vertical skin incision lengths required to successfully expose the cricothyroid membrane ("midpoint incision").

RESULTS

Ninety-seven patients were included in this study. There were 14, 58, and 25 patients recruited across the three predefined groups. Accurate anesthesiologist identification of the location of the cricothyroid membrane occurred in 29.4%, 28.6%, and 38.2% of attempts, respectively. The majority of inaccurate assessments (64.1%) were below the cricothyroid membrane. There was no improvement in accuracy with repetition. Hypothetical "midpoint incision" lengths of 20, 30, and 35 mm were required.

CONCLUSION

Significant anesthesiologist inaccuracy exists in locating the cricothyroid membrane in children of all ages. This has implications for the technical approach to emergency front of neck access and how we teach the management of "can't intubate can't oxygenate" in pediatric practice.

Role of Ultrasound in Emergency Front of Neck Access: A Case Report and Review of Literature

Emergency front of neck access (eFONA) is a lifesaving procedure in a cannot intubate cannot oxygenate (CICO) situation. We report a case of a patient who presented to the emergency department (ED) in extremis with a difficult airway. A history of multiple neck surgeries and permanent tracheostomy from birth until the age of 17 years complicated his airway management. Altered neck anatomy led to failed intubation and oxygenation. EFONA was established with the use of rapid ultrasound imaging and using the scalpel-bougie-tube technique. We present a review of literature relating to the use of ultrasound during emergency airway management.

Comparison of Manikin Versus Porcine Trachea Models When Teaching Emergent Cricothyroidotomy Among Emergency Medicine Residents

OBJECTIVES

Emergent cricothyroidotomy (EC) is a rarely used yet lifesaving procedure that is important for an emergency physician to master throughout his or her training. We evaluated the difference in utilization of a manikin or porcine model among emergency medicine (EM) residents when teaching EC. We also evaluated the difference in the models using two different commonly utilized and taught techniques: "scalpel-finger-bougie" (SFB) technique and the Melker technique (MT).

METHODS

This was a prospective crossover design. Instructions about the procedure were provided; study participants were randomly assigned to one of two groups and performed cricothyrotomy on both manikin and porcine simulators using both the Melker and the SFB techniques. Each group was started with the technique on the second simulator opposite what they started with on the first simulator. After the procedures, study participants completed a questionnaire that used the same format for both groups. All survey questions required a 7-point Likert scale response. Confidence, difficulty, reality of the anatomy, and landmarks were compared.

RESULTS

Fifteen EM residents participated in the study. Compared to the porcine-first group, the manikin-first group rated the anatomy more realistic (question 5) after their first attempt (6.29 vs. 5.87) than their second attempt (using the porcine model; 4.29 vs. 5.62; main effect for attempts [first vs. second] p = 0.027; interaction p = 0.074). Interestingly, the porcine model-first group rated the landmarks (question 6) significantly easier to find in both attempts (6.87 vs. 5.86 on the first attempt and 6.50 vs. 5.57 on the second attempt; p = 0.012). Twelve participants (80%) chose SFB as their preferred technique to use in real-life scenario.

CONCLUSION

The Manikin model tends to be more realistic in cricothyrotomy simulation than the porcine model. The influence of fresh pig skin overlying the porcine model may require further research. Landmark identification during the procedure was easier on both models when participants start with the porcine model. Participants prefer the SFB over MT if faced with a real-life scenario.