The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient

Routine Use of Videolaryngoscopy in Airway Management

Tracheal intubation is a fundamental facet of airway management, for which the importance of achieving success at the first attempt is well recognized. Failure to do so can lead to significant morbidity and mortality if there is inadequate patient oxygenation by alternate means. The evidence supporting the benefits of a videolaryngoscope in attaining this objective is now overwhelming (in adults). This has led to its increasing recognition in international airway management guidelines and its promotion from an occasional airway rescue tool to the first-choice device during routine airway management. However, usage in clinical practice does not currently reflect the increased worldwide availability that followed the upsurge in videolaryngoscope purchasing during the coronavirus disease 2019 pandemic. There are a number of obstacles to widespread adoption, including lack of adequate training, fears over de-skilling at direct laryngoscopy, equipment and cleaning costs, and concerns over the environmental impact, among others. It is now clear that in order for patients to benefit maximally from the technology and for airway managers to fully appreciate its role in everyday practice, proper training and education are necessary. Recent research evidence has addressed some existing barriers to default usage, and the emergence of techniques such as awake videolaryngoscopy and video-assisted flexible (bronchoscopic) intubation has also increased the scope of clinical application. Future studies will likely further confirm the superiority of videolaryngoscopy over direct laryngoscopy, therefore, it is incumbent upon all airway managers (and their teams) to gain expertise in videolaryngoscopy and to use it routinely in their everyday practice..

Use of a Nasal Cannula as a Preoxygenation Adjunct: A Randomized Crossover Study

Background

Preoxygenation prior to induction of general anesthesia is intended to increase the oxygen reserve in the lungs. This technique delays the onset of hypoxemia during the placement of the tracheal tube.

Objective

To observe the benefits of oxygen through nasal cannula when used as an adjunct during preoxygenation.

Methods

We enrolled 30 healthy volunteers and conducted a sequence of six preoxygenation tests. These included 3-minute tidal volume breathing and 8 vital capacity breaths, with and without oxygen flowing through the nasal cannula as an adjunct. Subjects were kept at a supine position with a face mask on their faces. Their baseline vitals were measured and end-tidal O2 (ETO2) was recorded at the end of each test. The comfort of each technique was also assessed.

Results

When comparing the efficacy of the two preoxygenation methods, we found that the addition of oxygen through the nasal cannula improved the efficacy of preoxygenation with both the 3-minute tidal volume breathing method and the 8 vital capacity method (p < 0.001). The three-minute tidal volume breathing technique had higher end-tidal oxygen when compared to the eight vital capacity breaths.

Conclusions

The administration of oxygen through a nasal cannula during preoxygenation improves the efficacy of preoxygenation in healthy volunteers. Tidal volume breathing for three minutes achieves a higher end-tidal oxygen concentration compared to eight vital capacity breaths over one minute.

The nature of the response to airway management incident reports in high income countries: A scoping review

Adverse events associated with failed airway management may have catastrophic consequences, and despite many advances in knowledge, guidelines and equipment, airway incidents and patient harm continue to occur. Patient safety incident reporting systems have been established to facilitate a reduction in incidents. However, it has been found that corrective actions are inadequate and successful safety improvements scarce. The aim of this scoping review was to assess whether the same is true for airway incidents by exploring academic literature that describes system changes in airway management in high-income countries over the last 30 years, based on findings and recommendations from incident reports and closed claims studies. This review followed the most recent guidance from the Joanna Briggs Institute (JBI). PubMed, Ovid MEDLINE and Embase, the JBI database, SCOPUS, the Cochrane Library and websites for anaesthetic societies were searched for eligible articles. Included articles were analysed and data synthesised to address the review's aim. The initial search yielded 28,492 results, of which 111 articles proceeded to the analysis phase. These included 23 full-text articles, 78 conference abstracts and 10 national guidelines addressing a range of airway initiatives across anaesthesia, intensive care and emergency medicine. While findings and recommendations from airway incident analyses are commonly published, there is a gap in the literature regarding the resulting system changes to reduce the number and severity of adverse airway events. Airway safety management mainly focuses on Safety-I events and thereby does not consider Safety-II principles, potentially missing out on all the information available from situations where airway management went well.

Favour the best in case of emergency cricothyroidotomy-a randomized cross-over trial on manikin focused training and simulation of common devices

Background

Performing an emergency cricothyroidotomy (EC) is extremely challenging, the devices used should be easy to handle and the selected technique reliable. However, there is still an ongoing debate concerning the most superior technique.

Methods

Three different techniques were compared using a standardized, simulated scenario regarding handling, performing, training and decision making: The scalpel-bougie technique (SBT), the surgical anatomical preparation technique (SAPT) and the Seldinger technique (ST). First, anaesthesia residents and trainees, paramedics and medical students (each group n = 50) performed a cricothyroidotomy randomly assigned with each of the three devices on a simulator manikin. The time needed for successful cricothyroidotomy was the primary endpoint. Secondary endpoints included first-attempt success rate, number of attempts and user-satisfaction. The second part of the study investigated the impact of prior hands-on training on both material selection for EC and on time to decision-making in a simulated "cannot intubate cannot ventilate" situation.

Results

The simulated scenario revealed that SBT and SAPT were significantly faster than percutaneous EC with ST (p < 0.0001). Success rate was 100% for the first attempt with SBT and SAPT. Significant differences were found with regard to user-satisfaction between individual techniques (p < 0.0001). In terms of user-friendliness, SBT was predominantly assessed as easy (87%). Prior training had a large impact regarding choice of devises (p < 0.05), and time to decision making (p = 0.05; 180 s vs. 233 s).

Conclusion

This study supports the use of a surgical technique for EC and also a regular training to create familiarity with the materials and the process itself.The trial was registered before study start on 11.11.2018 at ClinicalTrials.gov (NCT: 2018-13819) with Nicole Didion as the principal investigator.

Diagnostic accuracy of airway ultrasound in confirming the endotracheal tube depth in critically ill children

BACKGROUND

Chest X-ray, the established standard of confirming endotracheal tube (ETT) position, has important drawbacks including radiation exposure. Point-of-care airway ultrasound, which has been insufficiently studied in children, can overcome these problems.

MATERIALS AND METHODS

This was a prospective cross-sectional study done on children aged 2 months to 17 years undergoing intubation with cuffed ETT in the PICU. The ETT cuff was filled with saline and three ultrasonographic techniques were used- 1) Suprasternal (SS) method 2) Cricoid (CC) metho and 3) Tracheal ring (TR) method. Position of the ETT as determined by ultrasound and X-ray were compared. The main outcomes were sensitivity, specificity, and area under curve (AUC) for ultrasound-based methods vs. X-ray. For the TR method, concordance between the X-ray and ultrasound categories were taken.

RESULTS

Total 62 patients were enrolled. The sensitivity and specificity of SS method were 71% (95% CI: 57-83%) and 100% (40-100%). The CC distance method had an AUC of 0.94 (95% CI: 0.86, 1.0). In the TR method, 98% of correct position on X-ray were correctly classified by USG. The agreement between X-ray and ultrasound categories with the cuff between the first and third tracheal rings, was very good [kappa (95% CI): 0.87 (0.70, 1.00), p ≤0.001)].

CONCLUSION

Bedside ultrasound is a good method to confirm ETT depth in children. The tracheal ring method had the best diagnostic accuracy and is easy to perform. The new method using cricoid cuff distance needs further validation in different ICU settings.

Pilot cadaveric study on the feasibility of cricothyroidotomy and the associated complications in 30 cats

Objectives

The study's primary goal was to assess the feasibility of the cricothyroidotomy technique (CTT) in cats and evaluate its success rate (i.e., secure airway access). Secondary outcomes were the assessment of the subjective difficulty of airway access based on body score condition and weight. Further secondary outcomes consisted of procedural time and scoring of associated complications. The current study hypothesized that the CTT procedure would provide secure airway access with a reasonable success rate.

Materials and methods

A prospective experimental study assessing the performance of CTT and associated complications was conducted on 30 feline cadavers. A procedural datasheet was completed to subjectively grade difficulty of landmark palpation, guide placement and tube placement and expected success of the procedure. A dissection was then performed post-procedure by a blinded observer to evaluate for any associated damages.

Results

CTT was successful in securing an airway in 100% of the cats. The time to completion of the CTT was rapid, with a median time of 49 s (ranging from 31 to 90 s) for securing an airway. Of importance, this procedure was judged to be overall easy (median "ease of procedure score" of 7/10; ranging from 3 to 10) by the experimenters. The post-procedural lesion rate was elevated (76.7%) in this population of cats, though based on the lesion scores, was deemed mild in 73.9% of the cases.

Clinical significance

CTT warrants consideration as the primary option for emergency front-of-neck airway access for cats although further studies are necessary.

Videolaryngoscopy use before and after the initial phases of the COVID-19 pandemic: The report of the VL-iCUE survey with responses from 96 countries

BACKGROUND

The potential benefit of videolaryngoscopy use in facilitating tracheal intubation has already been established, however its use was actively encouraged during the COVID-19 pandemic as it was likely to improve intubation success and increase the patient-operator distance.

OBJECTIVES

We sought to establish videolaryngoscopy use before and after the early phases of the pandemic, whether institutions had acquired new devices during the COVID-19 pandemic, and whether there had been teaching on the devices acquired.

DESIGN

We designed a survey with 27 questions made available via the Joint Information Scientific Committee JISC online survey platform in English, French, Spanish, Chinese, Japanese and Portuguese. This was distributed through 18 anaesthetic and airway management societies.

SETTING

The survey was open for 54 to 90 days in various countries. The first responses were logged on the databases on 28 October 2021, with all databases closed on 26 January 2022. Reminders to participate were sent at the discretion of the administering organisations.

PARTICIPANTS

All anaesthetists and airway managers who received the study were eligible to participate.

MAIN OUTCOME MEASURES

Videolaryngoscopy use before the COVID-19 pandemic and at the time of the survey.

RESULTS

We received 4392 responses from 96 countries: 944/4336 (21.7%) were from trainees. Of the 3394 consultants, 70.8% (2402/3394) indicated no change in videolaryngoscopy use, 19.9% (675/3394) increased use and 9.3% (315/3393) reduced use. Among trainees 65.5% (618/943) reported no change in videolaryngoscopy use, 27.7% (261/943) increased use and 6.8% (64/943) reduced use. Overall, videolaryngoscope use increased by 10 absolute percentage points following the pandemic.

CONCLUSIONS

Videolaryngoscopy use increased following the early phase of the COVID-19 pandemic but this was less than might have been expected.

Emergency airway management in resource limited setting

BACKGROUND

Emergency airway management in resource-limited settings presents multifaceted challenges due to shortages in essential medical resources, healthcare professionals, and infrastructure.

METHODS

We conducted a literature search using keywords "Emergency Airway Management" "Low Resource" "Africa" "Asia" from databases such as Pubmed, and Google Scholar, from where we extracted relevant literature for our study.

FINDINGS

These limitations resulted in delayed interventions, suboptimal care, and higher complication rates during intubation procedures. However, innovative solutions have emerged to address these challenges, including cost-effective airway management devices and training programs tailored for non-medical personnel. Capacity building and local empowerment are critical components of improving emergency airway management in these settings. Additionally, advocating for policy support and investment in healthcare infrastructure is essential to ensure access to essential equipment and adequate staffing. Collaboration and knowledge-sharing networks among healthcare professionals and organisations are pivotal in disseminating best practices and advancing healthcare delivery in resource-limited regions.

CONCLUSION

Future efforts should focus on tailored training programs, rigorous research, innovative device development, telemedicine solutions, sustainable capacity building, and advocacy to enhance emergency airway management in resource-limited settings.

Difficult intubation in ENT patient: Simultaneous videolaryngoscopy with flexible bronchoscopy. A combined approach. Case report

INTRODUCTION

Difficult intubation is the situation when a skilled anesthetist has difficulties to manage airway using face mask, laryngoscopy, supraglottic device, tracheal intubation, surgery. Videolaryngoscope and flexible fibroscope (FFS) represent valid alternatives for difficult airway management, with some limitations. However, literature lacks of studies about the efficacy of the combined use of videolaryngoscope and FFS.

CASE REPORT

We report a case of a man, with glottic lesion, who needs surgery under general anesthesia. Anesthesiologic pre-operative evaluation revealed that he's a difficult intubation case. So, in a supine position, intubation was performed on first attempt by videolaryngoscope combined with FFS. On post-op, no signs of injuries due to intubation have been found.

DISCUSSION

In 2022, the American Society of Anesthesiologists defined the guidelines to manage difficult intubation: based on patient' anatomical and clinical feature and anesthetist' skills, several intubation procedures could be used. Each procedure has pros and cons.

CONCLUSION

It's the first case of anticipated difficult intubation in adult man that was intubated under general anesthesia by using videolaryngoscope combined with FFS. We demonstrated that this procedure is safe and useful in case of difficult airway and recommended in case of laryngeal lesions that hinder the visualization of glottic plane.

Current Status of Difficult Airway Information Dissemination at a Tertiary Pediatric Hospital

OBJECTIVE

Difficult airway is one of the most common potential risk factors for increased fatality in craniofacial/plastic surgery patients. To date, there is no well-established and all-around difficult airway notification system in China, which has recently been recommended by existing guidelines to improve the care of patients with known difficult airways. This study aimed to investigate the current status of critical information communication concerning difficult airway management in our institute.

METHODS

Vital information required to establish a difficult airway registry and notification system was collected through a literature review and expert suggestions. After approval by the Research Ethics Board, 3 online questionnaires were developed and sent to surgeons, anesthesiologists, and proxies of the patients. Knowledge of difficult airways, the willingness to be involved in the difficult airway notification system, and the way to disseminate the information were investigated in the 3 groups. The specific information that was disseminated, required, and available was investigated in the anesthesiologist group.

RESULTS

Compared with the surgeons and anesthesiologists, significantly fewer patients knew the definition of a difficult airway and thought it was a potential risk factor. There were no significant differences in the willingness to be informed of the difficulty encountered during airway management. Significant differences were detected in the willingness and way to disseminate the airway information when the participants communicated with different groups. Significantly more patients would disseminate the information to the surgeon and significantly more surgeons would disseminate the information to the patient and the other surgeon. Significantly more anesthesiologists would disseminate the information to the patient and the other anesthesiologists. A significant difference was observed between what was expected and what was available for the anesthesiologist to retrieve the airway information of a patient with known airway difficulty. Significantly more anesthesiologists would notify only the patient of the diagnosis of a difficult airway both oral and written, whereas significantly more anesthesiologists would notify the other anesthesiologist of the specific difficulties in oral only. Most participants agreed to be involved in the difficult airway notification system despite the significantly lower percentage in the patient group (89%).

CONCLUSIONS

Difficult airway information dissemination is, at the time of this writing, ineffective, which leads to a large gap between the expectation and practice of the anesthesiologist when caring for a patient with a difficult airway. Thus, a difficult airway registry and notification system should be developed, that has a solid foundation in all the participants.

Capnography-An Essential Monitor, Everywhere: A Narrative Review

Capnography is now recognized as an indispensable patient safety monitor. Evidence suggests that its use improves outcomes in operating rooms, intensive care units, and emergency departments, as well as in sedation suites, in postanesthesia recovery units, and on general postsurgical wards. Capnography can accurately and rapidly detect respiratory, circulatory, and metabolic derangements. In addition to being useful for diagnosing and managing esophageal intubation, capnography provides crucial information when used for monitoring airway patency and hypoventilation in patients without instrumented airways. Despite its ubiquitous use in high-income-country operating rooms, deaths from esophageal intubations continue to occur in these contexts due to incorrect use or interpretation of capnography. National and international society guidelines on airway management mandate capnography's use during intubations across all hospital areas, and recommend it when ventilation may be impaired, such as during procedural sedation. Nevertheless, capnography's use across high-income-country intensive care units, emergency departments, and postanesthesia recovery units remains inconsistent. While capnography is universally used in high-income-country operating rooms, it remains largely unavailable to anesthesia providers in low- and middle-income countries. This lack of access to capnography likely contributes to more frequent and serious airway events and higher rates of perioperative mortality in low- and middle-income countries. New capnography equipment, which overcomes cost and context barriers, has recently been developed. Increasing access to capnography in low- and middle-income countries must occur to improve patient outcomes and expand universal health care. It is time to extend capnography's safety benefits to all patients, everywhere.

Expanding scope of Kirkpatrick model from training effectiveness review to evidence-informed prioritization management for cricothyroidotomy simulation

Modified Kirkpatrick model has been adopted to evaluate training effectiveness by 6 categories, including activity accounting (training objectives/success in organization change) at Level-0, reaction (satisfaction) at Level-1, learning (acquisition of surgical airway skills) at Level-2, behavior (post-training change in personal strengths) at Level-3, result (organizational or clinical outcomes) at Level-4, and Return on Investment (ROI) or Expectation (ROE) (monetary and societal values following training and other quality and safety related measures) at Level-5. The purpose of this hospital-based prospective observational study was twofold: i) To evaluate potential impacts on monetary and societal values and successful organization change following implementation of advanced Cricothyroidotomy simulator and standardized curriculum in healthcare simulation training, ii) To inform decisions of resource allocation by reviewing overall values and prioritization strategies for i) general surgeon/emergency physician ii) with seniority >5 years and iii) prior porcine training experience based on findings at Kirkpatrick Level-0, Level-4, and Level-5. Seventy doctors and 10 nurses completed Cricothyroidotomy training and follow-up questionnaires within 2021/22. All training usability scoring measured by Scales of Emergency Surgical Airway Simulator (SESAS-17) achieved over 4 out of 5 (Level-4) with effects in favor of emergency physicians or general surgeons (p < .5), regardless of seniority and prior training experience. Success in organization change (Level-0) and cost-effectiveness (Level-5) were hypothetically established using theoretical framework of Gleicher's formula and Roger's Diffusion of Innovation Theory. Overall training effectiveness, in terms of advantage in usability, cost-benefits and successful organizational changes, provided sound evidence to support continuous investment of new curriculum and innovative simulator and "Surgeon-and-emergency-physician-first" policy when it comes to resources allocation strategies for Cricothyroidotomy training. [ACGME competencies: Practice Based Learning and Improvement, Systems Based Practice.].

Efficacy and safety of Cook staged Extubation Set in patients with difficult airway: a systematic review and meta-analysis

BACKGROUND

Cook Stage extubation is a tool developed by Cook Medical for patients with difficult airways. Multiple clinical studies demonstrated the effectiveness and safety of Cook Stage extubation Set (CSES). Currently, no systematic review evidence has been published in this field. Therefore, this study aimed to review the clinical success rate, safety, and tolerability of CSES in patients with difficult airways.

METHOD

The inclusion criteria were based on the population, intervention, comparator, outcomes, and study designs. An electronic search was conducted, and the following databases were used: PubMed, EMBASE, Cochrane Library, and Web of Science. Search keywords included difficult airway and CSES. The primary outcome was the CSES clinical success rate.The Joanna Briggs Institute Critical Appraisal tools for Case Series were used to assess the risk of bias in the included studies. R studio, version 4.2.2. was used to perform the statistical analysis. The Cochrane Q and I2 statistics were used to test the heterogeneity among all studies. Details of the included case reports were summarized in the systematic review part.

RESULTS

Five studies were eligible for meta-analysis, and 7 case reports were included for systematic review. The pooled overall CSES clinical success rate was 93% (95% CI: 85%, 97%). The CSES intolerable and complication incidence rates were 9% (95% CI: 5%, 18%) and 5% (95% CI: 2%, 12%), respectively. CSES clinical success rate was influenced by the study center and study design. The success rate of CSES was higher in multicenter and prospective design studies. Seven case reports have documented the successful operation of CSES intubation in obese, tall, oncologist, and pediatric patients.

DISCUSSION

This meta-analysis suggested that CSES have achieved a high clinical success rate in adult and pediatric patients with different physical conditions and types of surgery. The results of all original studies and meta-analysis confirmed a remarkably high tolerance rate and low overall complication rate. However, regardless of the tools chosen, a personalized, safe intubation strategy and a highly qualified anesthesiologist should be considered as the fundamental guarantee of a high clinical success rate. Future studies should also focus on the success rate of reintubation using CSES in patients with airway difficulties.

Development and Internal Validation of a Prediction Model for Difficult Laryngoscopy Using Ultrasound-Derived Factor in Comatose Patients

OBJECTIVES

The distance from skin to the hyoid bone (DSHB) and skin to the anterior commissure of vocal cords (DSAC) are reliable parameters for pre-operative airway ultrasound assessment in awake patients and can be assessed in comatose patients. This study aimed to inspect its feasibility and accuracy in predicting difficult laryngoscopy for comatose patients.

METHODS

A prospective cohort study included patients with a Glasgow Coma Scale (GCS) of ≤8 who underwent emergency tracheal intubation between November 2019 and August 2020. The outcome was difficult laryngoscopy and classified according to the Cormack-Lehane grading.

RESULTS

A total of 151 patients were included in the study. Fifty-two (34.4%) patients were categorized as having difficult laryngoscopy. The DSHB add DSAC (hereinafter referred to as the "DSBAC") was superior to either parameter alone in the predictive performance, and the optimal cut-off value was 1.90. To optimize the predictive value, DSBAC (adjusted odds ratio [OR]: 7.76; 95% confidence interval [CI]: 2.88-20.94; P < .001), GCS (adjusted OR: 1.39; 95% CI: 3.93-26.28; P = .039), mandibular retraction (adjusted OR: 8.20; 95% CI: 1.92-35.09; P = .005) and edentulous (adjusted OR: 4.23; 95% CI: 1.40-12.80; P = .011) were included in a multivariable model and constructed a nomogram. Discrimination and calibration statistics were satisfactory, with C-index above 0.80 from both model development and internal validation.

CONCLUSIONS

Ultrasound-derived factor, DSBAC, can be easily assessed and help predict difficult laryngoscopy among comatose patients. A simple nomogram including only four clinical items exhibited excellent discrimination performance and was useful when comatose patients underwent emergency tracheal intubation.

Pre-operative ultrasound prediction of difficult airway management in adult patients: A systematic review of clinical evidence

BACKGROUND

Predicting a difficult airway, including difficult laryngoscopy, intubation or mask ventilation, is paramount in peri-operative management. As clinical predictors are only partially reliable, ultrasound-based measurements might be useful in evaluating anterior neck fat tissues depth.

OBJECTIVES

The aim of this systematic review is to report clinical evidence on pre-operative ultrasound as a predictor of difficult laryngoscopy, difficult intubation or difficult mask ventilation.

DESIGN

A systematic review of randomised controlled trials and observational studies.

DATA SOURCES

The MEDLINE, EMBASE and Google Scholar databases were queried from inception until 28 February 2022.

ELIGIBILITY CRITERIA

Studies involving adult patients who had undergone orotracheal intubation after evaluation with airways ultrasound were considered suitable. Exclusion criteria were a clinical history of difficult airways, cancer or trauma, pregnancy, supraglottic airway devices, video-laryngoscopy. Parameters were classified by reporting their accuracy in discriminating 'difficult' vs. 'not difficult' laryngoscopy, intubation or mask ventilation.

RESULTS

Thirty-one observational studies were included and a total of 41 single parameters and 12 different combinations of clinical and ultrasound parameters were reported. The distance from skin to epiglottis midway with neutral position of head and neck, the distance from hyoid bone to skin surface with a neutral position of head and neck and the hyomental distance extended/neutral ratio are the most associated with difficult laryngoscopy or difficult intubation. A combination of clinical and ultrasound parameters (a modified Mallampati score, the distance from the skin to the epiglottis midway with neutral position of the head and neck, and the USED-MSH score) showed high accuracy. Only two studies reported the role of ultrasound in predicting difficult mask ventilation: the distance from hyoid bone to skin surface with neutral position of head and neck, the thickness of the base of the tongue with hyperextension of the head, and the hyomental distance with hyperextension of the head and active subluxation of the mandible are the parameters with the highest correlation.

CONCLUSIONS

The use of ultrasound parameters might be useful in predicting difficult laryngoscopy or difficult intubation. Several ultrasound parameters and combinations have been associated with difficult laryngoscopy or difficult intubation prediction. The use of scores combining clinical predictors and ultrasound measures are very promising. Data on difficult mask ventilation are scarce and the role of ultrasound is still controversial. Future studies are needed.

CLINICAL TRIAL REGISTRATION

CRD42021250574.

An interactive and realistic phantom for cricothyroidotomy simulation of a patient with obesity through a reusable design using 3D-printing and Arduino

BACKGROUND AND OBJECTIVES

Proper airway management during emergencies can prevent serious complications. However, cricothyroidotomy is challenging in patients with obesity. Since this technique is not performed frequently but at a critical time, the opportunity for trainees is rare. Simulators for these procedures are also lacking. Therefore, we proposed a realistic and interactive cricothyroidotomy simulator.

METHODS

All anatomical structures were modeled based on computed tomography images of a patient with obesity. To mimic the feeling of incision during cricothyroidotomy, the incision site was modeled to distinguish between the skin and fat. To reinforce the educational purpose, capacitive touch sensors were attached to the artery, vein, and thyroid to generate audio feedback. The tensile strength of the silicone-cast skin was measured to verify the similarity of the mechanical properties between humans and our model. The fabrication and assembly accuracies of the phantom between the Standard Tessellation Language and the fabricated model were evaluated. Audio feedback through sensing the anatomy parts and utilization was evaluated.

RESULTS

The body, skull, clavicle, artery, vein, and thyroid were fabricated using fused deposition modeling (FDM) with polylactic acid. A skin mold was fabricated using FDM with thermoplastic polyurethane. A fat mold was fabricated using stereolithography apparatus (SLA) with a clear resin. The airway and tongue were fabricated using SLA with an elastic resin. The tensile strength of the skin using silicone with and without polyester mesh was 2.63 ± 0.68 and 2.46 ± 0.21 MPa. The measurement errors for fabricating and assembling parts of the phantom between the STL and the fabricated models were -0.08 ± 0.19 mm and 0.13 ± 0.64 mm. The measurement errors internal anatomy embodied surfaces in fat part were 0.41 ± 0.89 mm. Audio feedback was generated 100% in all the areas tested. The realism, understanding of clinical skills, and intention to retrain were 7.1, 8.8, and 8.3 average points.

CONCLUSIONS

Our simulator can provide a realistic simulation experience for trainees through a realistic feeling of incision and audio feedback, which can be used for actual clinical education.

Scalpel cricothyrotomy versus punctured cricothyrotomy in the context of the CICO crisis. A systematic review and Meta-analysis

IMPORTANCE

The preferential use of a scalpel (SCT) or puncture techniques (PCT) for cricothyrotomy remains a controversial topic.

OBJECTIVE

We performed a systematic review and meta-analysis comparing puncture cricothyrotomy with scalpel cricothyrotomy using overall success rate, first-time success rate, and time taken to perform the procedure as the primary outcome together with complications as a secondary outcome.

EVIDENCE REVIEW

Pubmed databases, EMBASE databases, MEDLINE, Google Scholar, and Cochrane Central Register of Controlled Trials, from 1980 to October 2022.

FINDINGS

A total of 32 studies were included in the systematic review and meta-analysis. It also showed that PCT was close to SCT in terms of overall success rate (82.2% vs. 82.6%, Odd Ratios OR = 0.91, [95%CI: 0.52-1.58], p = 0.74) as well as first-performance success rate (62.9% vs. 65.3%, OR = 0.52, [0.22-1.25], p = 0.15). PCT does not compare favorably with SCT in terms of required time for the procedure (the mean time required for PCT versus SCT incision in the intervention groups was 0.34 standard deviations higher (Mean Difference MD = 17.12, [3.37-30.87], p = 0.01) as well as complications (21.4% vs. 15.1%, Relative Risk RR = 1.49, [0.80-2.77], p = 0.21).

CONCLUSIONS AND RELEVANCE

The results show that SCT has an advantage over PCT in terms of time required for the procedure, while there is no difference in overall success rate, first-time success rate after training, and complications. The superiority of SCT may be the result of fewer and more reliable procedural steps. However, the level of evidence is low (GRADE).

Airways management in SARS-COV-2 acute respiratory failure: A prospective observational multi-center study

OBJECTIVE

Few studies have reported the implications and adverse events of performing endotracheal intubation for critically ill COVID-19 patients admitted to intensive care units. The aim of the present study was to determine the adverse events related to tracheal intubation in COVID-19 patients, defined as the onset of hemodynamic instability, severe hypoxemia, and cardiac arrest.

SETTING

Tertiary care medical hospitals, dual-centre study performed in Northern Italy from November 2020 to May 2021.

PATIENTS

Adult patients with positive SARS-CoV-2 PCR test, admitted for respiratory failure and need of advanced invasive airways management.

INTERVENTIONS

Endotracheal Intubation Adverse Events.

MAIN VARIABLES OF INTERESTS

The primary endpoint was to determine the occurrence of at least 1 of the following events within 30 minutes from the start of the intubation procedure and to describe the types of major adverse peri-intubation events: severe hypoxemia defined as an oxygen saturation as measured by pulse-oximetry <80%; hemodynamic instability defined as a SBP 65 mmHg recoded at least once or SBP < 90 mmHg for 30 minutes, a new requirement or increase of vasopressors, fluid bolus >15 mL/kg to maintain the target blood pressure; cardiac arrest.

RESULTS

Among 142 patients, 73.94% experienced at least one major adverse peri-intubation event. The predominant event was cardiovascular instability, observed in 65.49% of all patients undergoing emergency intubation, followed by severe hypoxemia (43.54%). 2.82% of the patients had a cardiac arrest.

CONCLUSION

In this study of intubation practices in critically ill patients with COVID-19, major adverse peri-intubation events were frequent.

CLINICAL TRIAL REGISTRATION

www.

CLINICALTRIALS

gov identifier: NCT04909476.

Airways management in SARS-COV-2 acute respiratory failure: A prospective observational multi-center study

Objective

Few studies have reported the implications and adverse events of performing endotracheal intubation for critically ill COVID-19 patients admitted to intensive care units. The aim of the present study was to determine the adverse events related to tracheal intubation in COVID-19 patients, defined as the onset of hemodynamic instability, severe hypoxemia, and cardiac arrest.

Setting

Tertiary care medical hospitals, dual-centre study performed in Northern Italy from November 2020 to May 2021.

Patients

Adult patients with positive SARS-CoV-2 PCR test, admitted for respiratory failure and need of advanced invasive airways management.

Interventions

Endotracheal Intubation Adverse Events.

Main variables of interests

The primary endpoint was to determine the occurrence of at least 1 of the following events within 30 minutes from the start of the intubation procedure and to describe the types of major adverse peri-intubation events: severe hypoxemia defined as an oxygen saturation as measured by pulse-oximetry <80%; hemodynamic instability defined as a SBP 65 mmHg recoded at least once or SBP < 90 mmHg for 30 minutes, a new requirement or increase of vasopressors, fluid bolus >15 mL/kg to maintain the target blood pressure; cardiac arrest.

Results

Among 142 patients, 73.94% experienced at least one major adverse peri-intubation event. The predominant event was cardiovascular instability, observed in 65.49% of all patients undergoing emergency intubation, followed by severe hypoxemia (43.54%). 2.82% of the patients had a cardiac arrest.

Conclusion

In this study of intubation practices in critically ill patients with COVID-19, major adverse peri-intubation events were frequent.

Clinical Trial registration

www.clinicaltrials.gov identifier: NCT04909476.

Implementation of video laryngoscopes and the development in airway management strategy and prevalence of difficult tracheal intubation: A national cohort study

BACKGROUND

We aimed to determine the development in the use of video laryngoscopy over a 9-year period, and its possible impact on airway planning and management.

METHODS

We retrieved 822,259 records of tracheal intubations recorded from 2008 to 2016 in the Danish Anaesthesia Database. The circumstances regarding pre-operative airway assessment, the scheduled airway management plan and the actual airway management concerning video laryngoscopy were reported for each year of observation. Further, the association between year of observation and various airway management related outcomes was evaluated by multivariate logistic regression.

RESULTS

There was a significant increase in airway management with 'advanced technique successfully used within two attempts' from 2.7% in 2008 to 15.5% in 2016 (p < .0001). This predominantly reflects use of video laryngoscopy. The prevalence of tracheal intubations 'scheduled for video laryngoscopy' increased from 3.5% in 2008 to 10.6% in 2016 (p < .0001). We found a significant increase in the prevalence of anticipated difficulties with intubations by direct laryngoscopy from 1.8% in 2008 to 5.2% in 2016 (p < .0001). The prevalence of failed tracheal intubations decreased from 0.14% in 2008 to 0.05% in 2016 (p < .0001).

CONCLUSION

From 2008 to 2016, a period of massive implementation of video laryngoscopes, a significant change in airway management behaviour was recorded. Increasingly, video laryngoscopy is becoming a first-choice device for both acute and routine airway management. Most importantly, the data showed a noticeable reduction in failed intubation over the time of observation.

Ultrasound Guided Measurement of Anterior Neck Tissue for the Prediction of Difficult Airway: A Prospective Observational Study

Objectives

To determine that ultrasound (US) measurements of anterior neck soft tissue thickness at hyoid bone, thyrohyoid membrane, and anterior commissure levels can be used to predict difficult laryngoscopy.

Materials & Methods

The present study included 100 patients of age group 18-60 years undergoing elective surgery under general anaesthesia. It was a prospective observational study which included patients with ASA physical status I and II. Excluded patients were with facial and neck deformities, neck trauma, or those undergoing surgery of the larynx, epiglottis and pharynx. Comparison analysis was performed using t-test for continuous variables and chi-square or Fisher exact test for non-continuous variables. Correlation analysis performed using Pearson test.

Results

There were 39 out of 100 patients categorised as difficult laryngoscopy. Thickness at hyoid bone (DSHB), thyrohyoid membrane (DSEM) and anterior commissure (DSAC), MMS (modified Mallampati score), and BMI (body mass index) were greater in the difficult laryngoscopy group (p < 0.001). TMD (thyromental distance) was less in the difficult laryngoscopy group (p < 0.001). There was a strong positive correlation between DSEM and DSAC (r = 0.784). Moderate positive correlation was between DSEM and DSHB (r = 0.559), DSEM and MMS(r=0.437). The area under curve (AUC) of DSHB, DSEM, DSAC, TMD and MMS is >0.7. The optimal cut-off values for DSEM, DSHB, DSAC and TMD were 1.34 cm, 0.98 cm, 1.68 cm and 6.59 cm, respectively, in predicting difficult airway.

Conclusion

Ultrasound measurement of soft tissue thickness at hyoid bone, thyrohyoid membrane, and anterior commissure of vocal cord are good independent predictors for difficult laryngoscopy. When combined with traditional screening tests it improves the ability to predict difficult laryngoscopy.

Comparison of emergency surgical cricothyroidotomy and percutaneous cricothyroidotomy by experienced airway providers in an obese, in vivo porcine hemorrhage airway model

BACKGROUND

Emergency front-of-neck airway (eFONA) is a life-saving procedure in "cannot intubate, cannot oxygenate" (CICO). The fastest and most reliable method of eFONA has not been determined. We compared two of the most advocated approaches: surgical cricothyroidotomy and percutaneous cricothyroidotomy, in an obese, in vivo porcine hemorrhage model, designed to introduce real-time physiological feedback, relevant and high provider stress. The primary aim was to determine the fastest method to secure airway. Secondary aims were arterial saturation and partial pressure of oxygen, proxy survival and influence of experience.

METHODS

Twelve pigs, mean weight (standard deviation, SD) (60.3 ± 4.1) kg, were anesthetized and exposed to 25-35% total blood volume hemorrhage before extubation and randomization to Seldinger technique "percutaneous cricothyroidotomy" (n = 6) or scalpel-bougie-tube technique "surgical cricothyroidotomy" (n = 6). Specialists in anesthesia and intensive care in a tertiary referral hospital performed the eFONA, simulating an actual CICO-situation.

RESULTS

In surgical cricothyroidotomy vs. percutaneous cricothyroidotomy, the median (interquartile range, IQR) times to secure airway were 109 (IQR 71-130) s and 298 (IQR 128-360) s (P = 0.0152), arterial blood saturation (SaO₂) were 74.7 (IQR 46.6-84.2) % and 7.9 (IQR 4.1-15.6) % (P = 0.0167), pO₂ were 7.0 (IQR 4.7-7.7) kPa and 2.0 (IQR 1.1-2.9) kPa (P = 0.0667), and times of cardiac arrest (proxy survival) were 137-233 s, 190 (IQR 143-229), from CICO. All six animals survived surgical cricothyroidotomy, and two of six (33%) animals survived percutaneous cricothyroidotomy. Years in anesthesia, 13.5 (IQR 7.5-21.3), did not influence time to secure airway.

CONCLUSION

eFONA by surgical cricothyroidotomy was faster and had increased oxygenation and survival, when performed under stress by board certified anesthesiologists, and may be an indication of preferred method in situations with hemorrhage and CICO, in obese patients.

Performance time of anesthesiology trainees for cricothyroid membrane identification and characteristics of cricothyroid membrane in pediatric patients using ultrasonography

BACKGROUND

Identifying the cricothyroid membrane is an essential technical skill for front-of-neck access procedures.

AIMS

This study evaluated the usefulness of cricothyroid membrane identification in pediatric patients using ultrasonography by anesthesiology trainees without experience in airway ultrasound and collected anatomical data on the cricothyroid membrane and its surrounding airway structures in children.

METHODS

This prospective observational study included children aged <18 years scheduled to undergo general anesthesia and anesthesiology trainees who identified the cricothyroid membrane in five sequential anesthetized patients using ultrasonography. A pediatric anesthesiologist confirmed the accuracy of the identified cricothyroid membrane and recorded the performance time. The primary aims were the cricothyroid membrane identification success rate and performance time. The secondary aims were the characterization of the cricothyroid membrane and its surrounding structures.

RESULTS

Overall, 150 pediatric patients and 30 anesthesiology trainees were analyzed. The cricothyroid membrane identification success rate using ultrasonography was 100% in all the attempts using a transverse approach. The mean (standard deviation) performance time was 27.2 (18.6) s and 31.0 (23.8) s using the transverse and longitudinal approaches, respectively. The performance time decreased by 3.1 (p = .003, 95% confidence interval [CI] = -5.1--1.0) and 5.2 (p = .007, 95% CI = -8.9--1.4) seconds per increase in number of attempts with the transverse and longitudinal approaches, respectively. The cricothyroid membrane length was mostly correlated with the patients' height (r = .75, p < .001), and the blood vessels surrounding the cricothyroid membrane were observed in 95.9% of the patients.

CONCLUSIONS

Anesthesiology trainees without experience in airway ultrasound successfully identified the cricothyroid membrane in pediatric patients using ultrasonography after a brief training period. Further research is required as the identification of a structure does not predict the success of the actual procedure, particularly if done in an emergency situation.

Updated guideline on equipment to manage difficult airways: Australian and New Zealand College of Anaesthetists

The Australian and New Zealand College of Anaesthetists (ANZCA) recently reviewed and updated the guideline on equipment to manage a difficult airway. An ANZCA-established document development group, which included representatives from the Australasian College for Emergency Medicine and the College of Intensive Care Medicine of Australia and New Zealand, performed the review, which is based on expert consensus, an extensive literature review, and bi-nationwide consultation. The guideline (PG56(A) 2021, https://www.anzca.edu.au/getattachment/02fe1a4c-14f0-4ad1-8337-c281d26bfa17/PS56-Guideline-on-equipment-to-manage-difficult-airways) is accompanied by a detailed background paper (PG56(A)BP 2021, https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PG56(A)BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper), from which the current recommendations are reproduced on behalf of, and with the permission of, ANZCA. The updated 2021 guideline replaces the 2012 version and aims to provide an updated, objective, informed, transparent, and evidence-based review of equipment to manage difficult airways.

Cannula cricothyroidotomy in the impalpable neck: An observational study of simulated 'can't intubate, can't oxygenate' scenarios by teams following a cannula-first algorithm in live anaesthetised pigs

Live animal models can be used to train anaesthetists to perform emergency front-of-neck-access. Cannula cricothyroidotomy success reported in previous wet lab studies contradicts human clinical data. This prospective, observational study reports success of a cannula-first 'can't intubate, can't oxygenate' algorithm for impalpable anatomy during high fidelity team simulations using live, anaesthetised pigs.Forty-two trained anaesthesia teams were instructed to follow the Royal Perth Hospital can't intubate, can't oxygenate algorithm to re-oxygenate a desaturating pig with impalpable neck anatomy (mean (standard deviation, SD) 16.2 (3.5) kg); mean (SD) tracheal internal diameter 11 (1.4) mm. Teams were informed that failure would prompt veterinary-led euthanasia.All teams performed percutaneous cannula cricothyroidotomy as the initial technique, with a median (interquartile range, IQR (range)) start time of 42 (35-50 (24-93)) s. First-pass percutaneous cannula success was 29% to both insufflate tracheal oxygen and re-oxygenate. Insufflation success improved with repeated percutaneous attempts (up to three), but prolonged hypoxia time increasingly necessitated euthanasia (insufflation 57%; re-oxygenation 48%). First, second and third percutaneous attempts achieved insufflation at median (IQR (range)) 74 (64-91 (46-110)) s, 111 (95-136 (79-150)) s and 141 (127-159 (122-179)) s, respectively. Eighteen teams failed with percutaneous cannulae and performed scalpel techniques, predominantly dissection cannulation (n = 17) which achieved insufflation in all cases (insufflation 100%; re-oxygenation 47%). Scalpel attempts were started at median (IQR (range)) 142 (133-218 (97-293)) s and achieved insufflation at 232 (205-303 (152-344)) s.While percutaneous cannula cricothyroidotomy could rapidly re-oxygenate, the success rate was low and teams repeated attempts beyond the recommended 60 s time frame, delaying transition to the more successful dissection cannula technique. We recommend this 'cannula-first' can't intubate, can't oxygenate algorithm adopts a 'single best effort' strategy for percutaneous cannula, with failure prompting a scalpel technique.

Comparison of Hemodynamic Response to Laryngoscopy Using Miller and McCoy Blade

Background: The most commonly used equipment to aid endotracheal intubation is a laryngoscope, and the procedure performed is known as laryngoscopy, which leads to profound cardiovascular effects. The process of laryngoscopy causes the release of catecholamines, thereby leading to marked pressor responses and tachycardia. The process of laryngoscopy can be made easier by the use of various types of laryngoscopic blades. The McCoy blade is a modification of the standard Macintosh blade that incorporates a hinged tip blade. It allows elevation of the epiglottis while decreasing overall laryngeal movement. A Miller blade is a straight blade with a slight upward curve near the tip. It is found that the force exerted, head extension, and cervical spine movement are less with the Miller blade. This study was undertaken to compare changes in haemodynamic parameters before, during, and after laryngoscopy using these two blades.

Materials and methods: Following institutional ethical committee approval and obtaining informed written consent, 100 patients of American Society of Anesthesiologists (ASA) grades I and II in the age group of 18-45 years of either sex undergoing elective surgeries under general anaesthesia were included in the study. The patients were randomly allocated into two groups of 50 patients each. Group Mc - laryngoscopy was performed using a no. 3 McCoy blade. Group Ml - laryngoscopy was performed using a no. 2 Miller blade. The laryngoscopic view was compared using Cormack and Lehane grading. Haemodynamic parameters before, during, and after laryngoscopy were recorded.

Results: Hemodynamic parameters including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were increased in both the groups but were statistically and clinically significant in the Miller group with p≤0.001.

Conclusion: McCoy blade is associated with a significantly more stable hemodynamic response to laryngoscopy in comparison with the Miller blade.

Prehospital Manual Ventilation: An NAEMSP Position Statement and Resource Document

Manual ventilation using a self-inflating bag device paired with a facemask (bag-valve-mask, or BVM ventilation) or invasive airway (bag-valve-device, or BVD ventilation) is a fundamental airway management skill for all Emergency Medical Services (EMS) clinicians. Delivery of manual ventilations is challenging. Several strategies and adjunct technologies can increase the effectiveness of manual ventilation. NAEMSP recommends:All EMS clinicians must be proficient in bag-valve-mask ventilation.BVM ventilation should be performed using a two-person technique whenever feasible.EMS clinicians should use available techniques and adjuncts to achieve optimal mask seal, improve airway patency, optimize delivery of the correct rate, tidal volume, and pressure during manual ventilation, and allow continual assessment of manual ventilation effectiveness.

Anaesthesia protocol evaluation of the videolaryngoscopy with the McGrath MAC and direct laryngoscopy for tracheal intubation in 1000 patients undergoing rapid sequence induction: the randomised multicentre LARA trial study protocol

INTRODUCTION

Rapid sequence induction of anaesthesia is indicated in patients with an increased risk of pulmonary aspiration. The main objective of the technique is to reduce the critical time period between loss of airway protective reflexes and rapid inflation of the cuff of the endotracheal tube to minimise the chance of aspiration of gastric contents. The COVID-19 pandemic has reinforced the importance of first-pass intubation success to ensure patient and healthcare worker safety. The aim of this study is to compare the first-pass intubation success rate (FPS) using the videolaryngoscopy compared with conventional direct laryngoscopy in surgical patients with a high risk of pulmonary aspiration.

METHODS AND ANALYSIS

The LARA trial is a multicentre, patient-blinded, randomised controlled trial. Consecutive patients requiring tracheal intubation are randomly allocated to either the McGrath MAC videolaryngoscope or direct laryngoscopy using the Macintosh laryngoscope. The expected rate of FPS is 92% in the McGrath group and 82% in the Macintosh group. Each group must include a total of 500 patients to achieve 90% power for detecting a difference at the 5% significance level. Successful intubation with the FPS is the primary endpoint. The secondary endpoints are the time to intubation, the number of intubation attempts, the necessity of airway management alternatives, the visualisation of the glottis using the Cormack and Lehane Score and the Percentage Of Glottic Opening Score and definite adverse events.

ETHICS AND DISSEMINATION

The project is approved by the local ethics committee of the Medical Association of the Rhineland Palatine state (registration number: 2020-15502) and medical ethics committee of the University of Freiburg (registration number: 21-1303). The results of this study will be made available in form of manuscripts for publication and presentations at national and international meetings.

TRIAL REGISTRATION

NCT04794764.

Management of haematoma after thyroid surgery: systematic review and multidisciplinary consensus guidelines from the Difficult Airway Society, the British Association of Endocrine and Thyroid Surgeons and the British Association of Otorhinolaryngology, Head and Neck Surgery

Haematoma after thyroid surgery can lead to airway obstruction and death. We therefore developed guidelines to improve the safety of peri‐operative care of patients undergoing thyroid surgery. We conducted a systematic review to inform recommendations, with expert consensus used in the absence of high‐quality evidence, and a Delphi study was used to ratify recommendations. We highlight the importance of multidisciplinary team management and make recommendations in key areas including: monitoring; recognition; post‐thyroid surgery emergency box; management of suspected haematoma following thyroid surgery; cognitive aids; post‐haematoma evacuation care; day‐case thyroid surgery; training; consent and pre‐operative communication; postoperative communication; and institutional policies. The guidelines support a multidisciplinary approach to the management of suspected haematoma following thyroid surgery through oxygenation and evaluation; haematoma evacuation; and tracheal intubation. They have been produced with materials to support implementation. While these guidelines are specific to thyroid surgery, the principles may apply to other forms of neck surgery. These guidelines and recommendations provided are the first in this area and it is hoped they will support multidisciplinary team working, improving care and outcomes for patients having thyroid surgery.

Seven years on from the Canadian Airway Focus Group Difficult Airway Guidelines: an observational survey

PURPOSE

Numerous clinical guidelines are available for management of the unanticipated difficult airway. It is unclear if practice recommendations are endorsed on regional, local, or individual levels. The objective of this observational study was to examine local and regional use of airway guidelines by anesthesiologists within a hospital partnership in Southwestern Ontario.

METHODS

Using a paper survey, distributed locally to consultant and trainee anesthesiologists in a tertiary hospital, we examined individual clinical and educational practices regarding guideline use in airway management. Respondents were asked to report which published guideline they used for unanticipated airway difficulty. The effectiveness of dissemination of the national Canadian airway guidelines-the Canadian Airway Focus Group (CAFG) Difficult Airway Guidelines-was examined. We invited anesthesia department heads within the regional hospital partnership to complete an electronic survey investigating departmental adoption of guidelines.

RESULTS

The response rate was 70% locally (79/112 anesthesiologists) and 52% regionally (11/21 department heads). Approximately 80% (64/79) of respondents reported using a formal clinical guideline if unanticipated difficulty with airway management was encountered. Seventy-two per cent of respondents (57/79) were aware of the published CAFG guidelines. Approximately 30% (16/51) of consultant anesthesiologists reported using the CAFG guidelines in clinical practice. Within the hospital partnership, 36% (4/11) of departments formally endorsed use of a specific airway management guideline.

CONCLUSIONS

Despite widespread awareness of the national CAFG Difficult Airway Guidelines, they are not widely adopted in clinical practice. Further research is warranted to explore barriers to adoption of airway management guidelines for both individual anesthesiologists and anesthesia departments.

Comparison of the strength of various disposable videolaryngoscope blades

PURPOSE

Breaking of disposable blades during emergency endotracheal intubation has been reported. Breakage can cause serious injury and foreign body ingestion. We aimed to measure and analyze the strength characteristics of different disposable videolaryngoscope blades with the application of an upward-lifting force.

METHODS

We measured the strength of four disposable videolaryngoscope blades (C-Mac® S Video laryngoscope MAC #3, Glidescope GVL® 3 stat, Pentax AWS® PBlade TL type, and King Vision® aBlade #3) using the fracture test. The strength of 12 samples of each type of disposable videolaryngoscope blade was measured using an Instron 5,966 tensile tester by applying an upward-lifting force.

RESULTS

After the fracture test using C-Mac, Glidescope GVL, Pentax AWS, and King Vision, the number of deformed blades were 0, 12, 3, and 7, respectively, and the number of broken blades were 12, 0, 9, and 5, respectively. The mean (standard deviation) maximum force strengths of Pentax AWS, C-Mac, King Vision, and Glidescope GVL blades were 408.4 (27.4) N, 325.8 (26.5) N, 291.8 (39.3) N, and 262.7 (3.8) N, respectively (P < 0.001).

CONCLUSION

Clinicians should be aware of the varied strength characteristics of the four types of disposable videolaryngoscope blades when they are used in endotracheal intubation.

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.

Cuff Leak Test and Airway Obstruction in Mechanically Ventilated ICU Patients: A Pilot Randomised Controlled Trial

RATIONALE

Laryngeal edema is a known complication of endotracheal intubation that may cause airway obstruction upon extubation. The only test available to predict this complication is the cuff leak test (CLT).

OBJECTIVE

Given the uncertainty of the CLT's clinical utility, we conducted the Cuff Leak Test and Airway Obstruction in Mechanically Ventilated ICU Patients (COMIC) pilot study to examine the feasibility of undertaking a larger trial.

METHODS

COMIC is a multicentred, parallel-group randomised trial performed in Canada, Saudi Arabia, and Poland. We enrolled mechanically ventilated adults admitted to the intensive care unit (ICU) who were deemed ready for extubation. Those allocated to the intervention arm had the results of their CLT communicated to the healthcare team, who then decided to proceed with extubation or not. In those randomised to the control arm, the CLT results were not communicated to the healthcare team and patients were extubated, regardless of the CLT result. The primary outcomes focused on feasibility.

RESULTS

One hundred patients (56 in the intervention and 44 in the control arm) were enrolled. All feasibility criteria were met including: 1) Recruitment rate of 7.6 patients/month; 2) Consent rate of 88.3% (95% confidence interval [CI] 82.1-94.5%); and 3) Protocol adherence of 98% (95% CI 95-100%). There were two episodes of clinically significant stridor in the intervention group, and four patients that required reintubation in each group.

CONCLUSION

The results of the COMIC pilot trial support the feasibility of a larger trial to determine the effect of the CLT on reintubation and clinically important stridor. Clinical trial registered with ClinicalTrials.gov (NCT03372707). Registered December 14th, 2017, https://clinicaltrials.gov/ct2/show/NCT03372707.

Ultrasonography relative to Cormack-Lehane in predicting difficult laryngoscopy: a systematic review of diagnostic test accuracy

OBJECTIVE

The objective of this review is to determine the diagnostic test accuracy of point-of-care ultrasound anterior soft tissue quantification techniques for predicting difficult laryngoscopy in relation to Cormack-Lehane scores.

INTRODUCTION

Difficult airway management is a critical challenge for anesthesia providers, and a non-invasive test to confidently predict difficult airway is lacking. When difficult airway is not anticipated, the provider's management of the event deteriorates, resulting in significant morbidity or mortality. This systematic review of the diagnostic efficacy of newer ultrasound techniques has potential to advance difficult airway prediction and patient safety.

INCLUSION CRITERIA

This review will consider adults 18 years and older presenting for elective surgery, who undergo a preoperative point-of-care ultrasound anterior soft tissue airway examination that is referenced to an intraoperative Cormack-Lehane airway examination, obtained using direct laryngoscopy under general anesthesia.

METHODS

Data sources will include Ovid MEDLINE, Trip Database, Embase, CINAHL Complete, Clinicaltrials.gov, Google Scholar, MedNar, Grey Literature Report, and ProQuest Dissertations and Theses. Only studies published in English after the advent of the Cormack-Lehane reference test (1984) will be included. Studies will be critically appraised using a checklist for studies of diagnostic test accuracy. Details about the index tests, populations, study methods, and outcomes of significance to the review will be extracted. Where possible, sensitivity and specificity will be pooled in statistical bivariate meta-analysis. Diagnostic thresholds will be displayed on a paired forest plot or summary receiver operator characteristic curve, depending on the degree of variability.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020205974.

Case series and review of emergency front-of-neck surgical airways from The Australian and New Zealand Emergency Department Airway Registry

BACKGROUND

An emergency front-of-neck access (eFONA), also called can't intubate, can't oxygenate (CICO) rescue, is a rare event. Little is known about the performance of surgical or percutaneous airways in EDs across Australia and New Zealand.

OBJECTIVE

To describe the management of cases resulting in an eFONA, and recorded in The Australian and New Zealand Emergency Department Airway Registry (ANZEDAR).

METHODS

A retrospective case series and review of ED patients undergoing surgical or percutaneous airways. Data were collected prospectively over 60 months between 2010 and 2015 from 44 participating EDs.

RESULTS

An eFONA/CICO rescue airway was performed on 15 adult patients: 14 cricothyroidotomies (0.3% of registry intubations) and one tracheostomy. The indication for intubation was 60% trauma and 40% medical aetiologies. The intubator specialty was emergency medicine in eight (53.3%) episodes. Thirteen (86.7%) cricothyroidotomies and the sole tracheostomy (6.7%) were performed at major referral hospitals with 12 (80%) surgical airways out of hours. In four (26.7%) cases, cricothyroidotomy was performed as the primary intubation method. Pre-oxygenation techniques were used in 14 (93.3%) episodes; apnoeic oxygenation in four (26.7%).

CONCLUSIONS

Most cases demonstrated deviations from standard difficult airway practice, which may have increased the likelihood of performance of a surgical airway, and its increased likelihood out of hours. Our findings may inform training strategies to improve care for ED patients requiring this critical intervention. We recommend further discussion of proposed standard terminology for emergency surgical or percutaneous airways, to facilitate clear crisis communication.

The Difficult Airway Navigator: Development and Implementation of a Health Care System's Approach to Difficult Airway Documentation Utilizing the Electronic Health Record

Careful airway risk assessment and procedural planning are vital to ensure patients' safety during airway management. Patients with known procedural difficulty during previous airway management or new anatomical changes pose challenges and risks. To improve communication and the value of documented information regarding difficult airway management for future clinical encounters, we utilized existing electronic health record functions to develop a "difficult airway Navigator." We describe this tool's creation and implementation, which allows clinicians to readily review past airway information and efficiently create difficult airway notes, bedside signs, flags, and orders.

Economic analysis of the use of video laryngoscopy versus direct laryngoscopy in the surgical setting

Aim: Compared with direct laryngoscopy (DL), video laryngoscopy (VL) offers clinical benefits in routine and difficult airways. The health economic benefit of VL versus DL for routine tracheal intubation remains unknown. Materials & methods: This analysis compared VL and DL health economic outcomes, including total inpatient costs, length of hospital stay (LOS), postoperative intensive care unit (ICU) admission and incidence of procedurally associated complications. Results: Patients with VL had decreased inpatient cost (US$1144-5891 across eight major diagnostic categories [MDC]); >1-day LOS reduction in five MDC; reduced odds for postoperative ICU admission (0.04-0.68) and reduced odds of respiratory complications in three MDC (0.43-0.90). Conclusion: Video laryngoscopy may lower total costs, reduce LOS and decrease the likelihood of postoperative ICU admission.

Simulation of Adult Surgical Cricothyrotomy for Anesthesiology and Emergency Medicine Residents: Adapted for COVID-19

INTRODUCTION

In a CICO (cannot intubate, cannot oxygenate) situation, anesthesiologists and acute care physicians must be able to perform an emergency surgical cricothyrotomy (front-of-neck airway procedure). CICOs are high-acuity situations with rare opportunities for safe practice. In COVID-19 airway management guidelines, bougie-assisted surgical cricothyrotomy is the recommended emergency strategy for CICO situations.

METHODS

We designed a 4-hour procedural simulation workshop on surgical cricothyrotomy to train 16 medical residents. We provided prerequisite readings, a lecture, and a videotaped demonstration. Two clinical scenarios introduced deliberate practice on partial-task neck simulators and fresh human cadavers. We segmented an evidence-based procedure and asked participants to verbalize the five steps of the procedure on multiple occasions.

RESULTS

Thirty-two residents who participated in the workshops were surveyed, with a 97% response rate (16 of 16 from anesthesiology, 15 of 16 from emergency medicine). Participants commented positively on the workshop's authenticity, its structure, the quality of the feedback provided, and its perceived impact on improving skills in surgical cricothyrotomy. We analyzed narrative comments related to three domains: preparation for the procedure, performing the procedure, and maintaining the skills. Participants highlighted the importance of performing the procedure many times and mentioned the representativeness of fresh cadavers.

DISCUSSION

We developed a surgical cricothyrotomy simulation workshop for anesthesiology and emergency medicine residents. Residents in the two specialities uniformly appreciated its format and content. We identified common pitfalls when executing the procedure and provided practical tips and material to facilitate implementation, in particular to face the COVID-19 pandemic.

Utilization of apnea-hypopnea index as a novel predictive factor for difficult mask ventilation in the Chinese population under general anesthesia

Purpose

Difficult mask ventilation (DMV) is a potentially life-threatening situation that can arise during anesthesia. However, most clinical predictors of DMV are based on European and US populations. On the other hand, most predictive models consist of multiple factors and complicated assessments. Since obstructive sleep apnea (OSA) is among the most important risk factors associated with DMV, the apnea-hypopnea index (AHI) may play an important role in determining patient risk.The purpose of this study was to investigate the relationship between DMV and AHI, and to determine preoperative risk factors for DMV in Chinese patients.

Methods

A prospective cohort trial enrolled patients scheduled for elective surgery. After obtaining informed consent, patient demographic information was collected, and patients were tested with pre-operative polysomnography. The anesthesiologist who managed the airway graded the mask ventilation. The difficult mask ventilation was defined as the mask ventilation provided by an unassisted anesthesiologist without oral airway or other adjuvant. A logistic regression model was used to analyze the association between AHI and DMV.

Results

A total of 159 patients were analyzed. For both primary and secondary outcomes, the unadjusted and adjusted odds ratio for DMV showed significant increases by 5 AHI units. AHI, age, and the Mallampati classification were found to be independent predictive factors for DMV.

Conclusions

AHI is associated with DMV as a novel independent risk factor in Chinese patients. Along with age and Mallampati classification, AHI should be included in establishing a superior predictive strategy for DMV screening.

Trial registration

Chinese Clinical Trial Registry ChiCTR-DDD-17013076

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 1. Difficult airway management encountered in an unconscious patient

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the literature on airway management has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This first of two articles addresses difficulty encountered with airway management in an unconscious patient.

SOURCE

Canadian Airway Focus Group members, including anesthesia, emergency medicine, and critical care physicians, were assigned topics to search. Searches were run in the Medline, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL databases. Results were presented to the group and discussed during video conferences every two weeks from April 2018 to July 2020. These CAFG recommendations are based on the best available published evidence. Where high-quality evidence was lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Most studies comparing video laryngoscopy (VL) with direct laryngoscopy indicate a higher first attempt and overall success rate with VL, and lower complication rates. Thus, resources allowing, the CAFG now recommends use of VL with appropriately selected blade type to facilitate all tracheal intubations. If a first attempt at tracheal intubation or supraglottic airway (SGA) placement is unsuccessful, further attempts can be made as long as patient ventilation and oxygenation is maintained. Nevertheless, total attempts should be limited (to three or fewer) before declaring failure and pausing to consider "exit strategy" options. For failed intubation, exit strategy options in the still-oxygenated patient include awakening (if feasible), temporizing with an SGA, a single further attempt at tracheal intubation using a different technique, or front-of-neck airway access (FONA). Failure of tracheal intubation, face-mask ventilation, and SGA ventilation together with current or imminent hypoxemia defines a "cannot ventilate, cannot oxygenate" emergency. Neuromuscular blockade should be confirmed or established, and a single final attempt at face-mask ventilation, SGA placement, or tracheal intubation with hyper-angulated blade VL can be made, if it had not already been attempted. If ventilation remains impossible, emergency FONA should occur without delay using a scalpel-bougie-tube technique (in the adult patient). The CAFG recommends all institutions designate an individual as "airway lead" to help institute difficult airway protocols, ensure adequate training and equipment, and help with airway-related quality reviews.

Anesthesiologists' airway management expertise: Identifying subjective and objective knowledge gaps

BACKGROUND

Failure in airway management continues to cause preventable patient harm, and the recommended continuing education is challenged by anesthesiologists' unknown knowledge gaps. This study aimed to identify anesthesiologists' subjective and objective knowledge gaps as well as areas where anesthesiologists are incorrect and unaware.

METHODS

An adaptive E-learning program with 103 questions on adult airway management was used for subjective and objective assessment of anesthesiologists' knowledge. All anesthesiologists in the Capital Region of Denmark were invited to participate.

RESULTS

The response rate was 67% (191/285). For preoperative planning, participants stated low confidence (subjective assessment) regarding predictors of difficult airway management in particular (69.1%-79.1%). Test scores (objective assessment) were lowest for obstructive sleep apnea as a predictor of difficult airway management (28.8% correct), with participants being incorrect and unaware in 33.5% of the answers. For optimization of basic techniques, the lowest confidence ratings related to patient positioning and prediction of difficulties (57.4%-83.2%), which agreed with the lowest test scores. Concerning advanced techniques, videolaryngoscopy prompted the lowest confidence (72.4%-85.9%), while emergency cricothyrotomy resulted in the lowest test scores (47.4%-67.8%). Subjective and objective assessments correlated and lower confidence was associated with lower test scores: preoperative planning [r = -.58, P < .001], optimization of basic techniques [r = -.58, P = .002], and advanced techniques [r = -.71, P < .001].

CONCLUSION

We identified knowledge gaps in important areas of adult airway management with differing findings from the subjective and objective assessments. This underlines the importance of objective assessment to guide continuing education.