Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults

Development of an Artificial Intelligence-Based Image Recognition System for Time-Sequence Analysis of Tracheal Intubation

BACKGROUND

Total intubation time (TIT) is an objective indicator of tracheal intubation (TI) difficulties. However, large variations in TIT because of diverse initial and end targets make it difficult to compare studies. A video laryngoscope (VLS) can capture images during the TI process. By using artificial intelligence (AI) to detect airway structures, the start and end points can be freely selected, thus eliminating the inconsistencies. Further deconstructing the process and establishing time-sequence analysis may aid in gaining further understanding of the TI process.

METHODS

We developed a time-sequencing system for analyzing TI performed using a #3 Macintosh VLS. This system was established and validated on 30 easy TIs performed by specialists and validated using TI videos performed by a postgraduate-year (PGY) physician. Thirty easy intubation videos were selected from a cohort approved by our institutional review board (B-ER-107-088), and 6 targets were labeled: the lip, epiglottis, laryngopharynx, glottic opening, tube tip, and a black line on the endotracheal tube. We used 887 captured images to develop an AI model trained using You Only Look Once, Version 3 (YOLOv3). Seven cut points were selected for phase division. Seven experts selected the cut points. The expert cut points were used to validate the AI-identified cut points and time-sequence data. After the removal of the tube tip and laryngopharynx images, the durations between 5 identical cut points and sequentially identified the durations of 4 intubation phases, as well as TIT.

RESULTS

The average and total losses approached 0 within 150 cycles of model training for target identification. The identification rate for all cut points was 92.4% (194 of 210), which increased to 99.4% (179 of 180) after the removal of the tube tip target. The 4 phase durations and TIT calculated by the AI model and those from the expert exhibited strong Pearson correlation (phase I, r = 0.914; phase II, r = 0.868; phase III, r = 0.964; and phase IV, r = 0.949; TIT, r = 0.99; all P < .001). Similar findings were obtained for the PGY's observations (r > 0.95; P < .01).

CONCLUSIONS

YOLOv3 is a powerful tool for analyzing images recorded by VLS. By using AI to detect the airway structures, the start and end points can be freely selected, resolving the heterogeneity resulting from the inconsistencies in the TIT cut points across studies. Time-sequence analysis involving the deconstruction of VLS-recorded TI images into several phases should be conducted in further TI research.

National survey on the current status of airway management in China

Apparently, understanding airway management status may help to reduce risk and improve clinical practice. Given these facts, our team conducted a second survey on the current status of airway management for mainland China following our 2016 national airway survey. The national survey was conducted from November 7 to November 28, 2022. An electronic survey was sent to the New Youth Anesthesia Forum, where Chinese anesthesiologists completed the questionnaire via WeChat. A total of 3783 respondents completed the survey, with a response rate of 72.14%. So far, in 2022, 34.84% of anesthesiologists canceled or delayed surgery at least once due to difficult airway. For the anticipated difficult airway management, 66.11% of physicians would choose awake intubation under sedation and topical anesthesia, while the percentage seeking help has decreased compared to the 2016 survey. When encountering an emergency, 74.20% of respondents prefer to use the needle cricothyrotomy, albeit less than a quarter have actually performed it. Anesthesiologists with difficult airway training experience reached 72.96%, with a significant difference in participation between participants in Tier 3 hospitals and those in other levels of hospitals (P < 0.001). The videolaryngoscope, laryngeal mask, and flexible intubation scope were equipped at 97.18%, 95.96%, and 62.89%, respectively. Additionally, the percentage of brain damage or death caused by difficult airways was significantly decreased. The study may be the best reference for understanding the current status of airway management in China, revealing the current advancements and deficiencies. The future focus of airway management remains on training and education.

Palpation Versus Ultrasonography for Identifying the Cricothyroid Membrane in Case of a Laterally Deviated Larynx: A Randomized Trial

BACKGROUND

Large neck circumference and displacement of the trachea due to pathology increase the risk of failed identification of the cricothyroid membrane and cricothyroidotomy. We investigated whether ultrasound aids in the successful identification of the cricothyroid membrane in a model of an obese neck with midline deviation of the trachea.

METHODS

We developed silicone neck models that were suitable for both palpation and ultrasonography and where the trachea deviated laterally from the midline to either side. After reading a book chapter and participating in a 25-minute lecture and a 15- to 23-minute hands-on demonstration and rehearsal of ultrasonography for identification of the cricothyroid membrane, anesthesiologists and anesthesiology residents randomly performed identification with either ultrasound or palpation on 1 of 2 neck models.

RESULTS

We included 57 participants, of whom 29 and 28 were randomized to palpation and ultrasound, respectively. Correct identification of the cricothyroid membrane was achieved by 21 (75.0%) vs 1 (3.5%) of participants in the ultrasound versus palpation groups (risk ratio [RR], 21.8 [95% confidence interval {CI}, 3.1-151.0]). The tracheal midline position in the sagittal plane was identified correctly by 24 (85.7%) vs 16 (55.2%) of participants in the ultrasound versus palpation groups (RR, 1.6 [95% CI, 1.1-2.2]).

CONCLUSIONS

Identification of the cricothyroid membrane in a model of an obese neck with midline deviation of the trachea was more often successful with ultrasound compared to palpation. Our study supports the potential use of ultrasound before induction of anesthesia and airway management in this group of patients, and it may even be applied in emergency situations when ultrasound is readily available. Further studies in human subjects should be conducted.

Effectiveness of preoxygenation strategies: a systematic review and network meta-analysis

BACKGROUND

Preoxygenation is universally recommended before induction of general anaesthesia to prolong safe apnoea time. The optimal technique for preoxygenation is unclear. We conducted a systematic review to determine the preoxygenation technique associated with the greatest effectiveness in adult patients having general anaesthesia.

METHODS

We searched six databases for randomised controlled trials of patients aged ≥16 yr, receiving general anaesthesia in any setting and comparing different preoxygenation techniques and methods. Our primary effectiveness outcome was safe apnoea time, and secondary outcomes included incidence of arterial oxygen desaturation; lowest SpO2 during airway management; time to end-tidal oxygen concentration of 90%; and [Formula: see text] and [Formula: see text] at the end of preoxygenation. We assessed the quality of evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) recommendations.

RESULTS

We included 52 studies of 3914 patients. High-flow nasal oxygen with patients in a head-up position was most likely to be associated with a prolonged safe apnoea time when compared with other strategies, with a mean difference (95% credible interval) of 291 (138-456) s and 203 (79-343) s compared with preoxygenation with a facemask in the supine and head-up positions, respectively. Subgroup analysis of studies without apnoeic oxygenation also showed high-flow nasal oxygen in the head-up position as the highest ranked technique, with a statistically significantly delayed mean difference (95% credible interval) safe apnoea time compared with facemask in supine and head-up positions of 222 (63-378) s and 139 (15-262) s, respectively. High-flow nasal oxygen was also the highest ranked technique for increased [Formula: see text] at the end of preoxygenation. However, the incidence of arterial desaturation was less likely to occur when a facemask with pressure support was used compared with other techniques, and [Formula: see text] was most likely to be lowest when preoxygenation took place with patients deep breathing in a supine position.

CONCLUSIONS

Preoxygenation of adults before induction of general anaesthesia was most effective in terms of safe apnoea time when performed with high-flow nasal oxygen with patients in the head-up position in comparison with facemask alone. Also, high-flow nasal oxygen in the head-up position is likely to be the most effective technique to prolong safe apnoea time among those evaluated. Clinicians should consider this technique and patient position in routine practice.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42022326046.

Impact of airway devices and emergency airway techniques characteristics on airway adverse events in mainland China: a cross-sectional study

BACKGROUND

Novel airway devices are becoming widely available, yet it is unclear whether the techniques or preferences of airway practitioners for airway management have been impacted. Given these facts, a cross-sectional study of the current status of airway management in mainland China was conducted and compared with previous survey findings.

METHODS

The national survey was conducted from November 7th to November 28th, 2022. An electronic survey was sent to the New Youth Anesthesia Forum to examine the availability of airway devices, preference for front-of-neck access (FONA) techniques, the incidence of adverse airway events, and the status of airway management training.

RESULTS

Questionnaires were completed by 3783 respondents, with a response rate of 72.14%. So far, the availability of optical airway devices has improved dramatically, with the availability of videolaryngoscopes reaching 97.18%. When encountering "cannot intubate, cannot ventilate" (CICV) scenarios, the majority of respondents would prefer needle cricothyrotomy to establish FONA. However, less than a quarter of respondents had actually performed it. Moreover, the incidence of airway adverse events from 2016 to 2022 was 11.48%, of which 5.13% were brain damage or death. Multivariate logistic regression analysis revealed that the ability to perform FONA techniques (odds ratio [OR] 0.23, 95% CI: 0.16, 0.32; P<0.001) and the availability of difficult airway management carts or kits (OR 0.59, 95% CI 0.41, 0.85; P=0.005) were associated with a lower incidence of airway adverse events.

CONCLUSIONS

Optical airway devices can overcome some of the challenges posed by difficult airways, yet the CICV scenario remains a major obstacle. The future focus of airway management should be training, particularly for complicated emergency airway techniques.

The effect of a dedicated intensivist staffing to a medical emergency team on airway management in general wards

Although medical emergency teams (METs) have been widely introduced, studies on the importance of a dedicated intensivist staffing to METs are lacking. A single-center retrospective before-and-after study was performed. Deteriorating patients who required emergency airway management in general wards by MET were included in this study. We divided the study period according to the presence of a dedicated intensivist staff in MET: (1) non-staffed period (from January 2016 to February 2018, n = 971) and (2) staffed period (from March 2018 to December 2019, n = 651), and compared emergency airway management-related variables and outcomes between the periods. Among 1622 patients included, mean age was 63.0 years and male patients were 64.2% (n = 1042). The first-pass success rate was significantly increased in the staffed period (85.9% in the non-staffed vs 89.2% in the staffed; P = .047). Compliance to rapid sequence intubation was increased (9.4% vs 34.4%; P < .001) and vocal cords were more clearly open (P < .001) in the staffed period. The SpO2/FiO2 ratio (median [interquartile range], 125 [113-218] vs 136 [116-234]; P = .007) and the ROX index (4.6 [3.4-7.6] vs 5.1 [3.6-8.5]; P = .013) at the time of intubation was higher in the staffed period, suggesting the decision on intubation was made earlier. The post-intubation hypoxemia was less commonly occurred in the staffed period (7.2% vs 4.2%, P = .018). In multivariate analysis, the rank of operator was a strong predictor of the first-pass success (adjusted OR [95% CI], 2.280 [1.639-3.172]; P < .001 for fellow and 5.066 [1.740-14.747]; P < .001 for staff, relative to resident). In our hospital, a dedicated intensivist staffing to MET was associated with improved emergency airway management in general wards. Staffing an intensivist to MET needs to be encouraged to improve the performance of MET and the patient safety.

The comparison of preoxygenation methods before endotracheal intubation: a network meta-analysis of randomized trials

Background

Preoxygenation before endotracheal intubation (ETI) maintains asphyxiated oxygenation and reduces the risk of hypoxia-induced adverse events. Previous studies have compared various preoxygenation methods. However, network meta-analyses (NMAs) of the combined comparison of preoxygenation methods is still lacking.

Methods

We searched for studies published in PubMed, Embase, Web of Science, Scopus, and the Cochrane Library. Review Manager version 5.3 was used to evaluate the risk of bias. The primary outcome of this meta-analysis was low oxygen saturation (SpO2) during ETI. The secondary outcomes included SpO2 <80%, SpO2 <90%, and apnea time during ETI. NMA was performed using R 4.1.2 software gemtc packages in RStudio.

Results

A total of 15 randomized controlled trials were included in this study. Regarding the lowest SpO2, the noninvasive ventilation (NIV) with high-flow nasal cannula (HFNC) group performed better than the other groups. For SpO2 <80%, the NIV group (0.8603467) performed better than the HFNC (0.1373533) and conventional oxygen therapy (COT, 0.0023) groups, according to the surface under the cumulative ranking curve results. For SpO2 <90%, the NIV group (0.60932667) performed better than the HFNC (0.37888667) and COT (0.01178667) groups. With regard to apnea time, the HFNC group was superior to the COT group (mean difference: -50.05; 95% confidence interval: -90.01, -10.09; P = 0.01).

Conclusion

Network analysis revealed that NIV for preoxygenation achieved higher SpO2 levels than HFNC and COT and offered a more significant advantage in maintaining patient oxygenation during ETI. Patients experienced a longer apnea time after HFNC preoxygenation. The combination of NIV with HFNC proved to be significantly superior to other methods. Given the scarcity of such studies, further research is needed to evaluate its effectiveness.

Systematic review registration

identifier CRD42022346013.

Institution of a difficult airway response team for emergency department patients with anticipated or encountered difficult airways: Descriptive analysis of a 5-year experience at an academic teaching hospital

Objectives

This study aimed to describe characteristics and outcomes associated with difficult airway response team (DART) encounters in the emergency department (ED).

Methods

We performed a descriptive analysis of a prospective, single-center database of DART encounters in the ED from April 1, 2016 to March 31, 2021 cross-referenced with retrospective chart review. Adult ED patients ≥18 years old for whom a DART was activated were eligible. We prospectively collected activation characteristics, intubation indications, operator characteristics, and intubation methods used for DART encounters. Retrospective chart review was conducted to obtain patient demographics and outcome variables. Descriptive analyses were computed for all outcomes.

Results

We analyzed 89 DART encounters. No intubation attempts were made prior to DART activation in 52 cases (58.4%). The most common indications for intubation were angioedema (n = 17, 19.1%) or other airway obstruction (n = 15, 16.9%). A definitive airway was established by anesthesiology (n = 46, 51.7%), emergency medicine (n = 25, 28.1%), trauma surgery (n = 9, 10.1%), and ENT (n = 5, 5.6%). The most common method of intubation used to establish a definitive airway was video laryngoscopy with a bougie or D-blade (n = 29, 32.6%) followed by flexible fiberoptic intubation (n = 19, 21.3%). A surgical airway was required in eight encounters (cricothyrotomy [n = 4, 4.5%]; tracheostomy [n = 4, 4.5%]). Cases were managed in the ED (n = 73, 82%), operating room (OR) (n = 10, 11.2%), and intensive care unit (ICU) (n = 1, 1.1%). All patients requiring intubation had an endotracheal or surgical airway established.

Conclusion

Our findings provide important insights regarding ED DART utilization and have implications when considering institution of a DART in the ED.

The Prevalence of Difficult Airway and Associated Risk Factors in Pediatric Patients: A Cross-sessional Observational Study

BACKGROUND

Difficult airway remains a great challenge in pediatric anesthesia practice. Previously published data show the prevalence of difficult airways in pediatric population varies in a wide range. However, there is a lack of studies in the Asian region.

METHODS

This cross-sectional single-center study was conducted in a tertiary pediatric hospital in China from October 2022 to October 2023. The patients who underwent elective surgery under general anesthesia with tracheal intubation were recruited consecutively. Data on patient characteristics, airway assessment, and airway management information were collected. Multivariable logistic regression analysis was performed to detect the independent variables of difficult airway in pediatric patients.

RESULTS

A total of 18,491 pediatric patients were included in this study. The overall incidence of difficult airways was 0.22%, 39% of whom were unanticipated. Very few previous airway management information was available in the patients presented with a known difficult airway. Patients with younger age, higher American Society of Anesthesiologists (ASA) physical status classification grade, and presented for craniofacial and thoracic surgery were associated with higher incidence of difficult airway. Further multivariable logistic regression analysis revealed that age ≤28 days (OR=50.48), age between 28days and 1 year (OR=6.053), craniofacial surgery (OR=1.81), and thoracic surgery (OR=0.2465) were independent risk factors of increased incidence of difficult airway.

CONCLUSIONS

Our study showed the prevalence of difficult airways in pediatric surgical patients. Patient characteristics, age, and type of surgery were identified as the independent factors associated with increased occurrence of difficult airways. Unanticipated difficult airway was not unusual in our study population, even for the patients with previous surgical history.

Emergency front-of-neck access in pediatric anesthesia: A narrative review

BACKGROUND AND OBJECTIVES

Children undergoing airway management during general anesthesia may experience airway complications resulting in a rare but life-threatening situation known as "Can't Intubate, Can't Oxygenate". This situation requires immediate recognition, advanced airway management, and ultimately emergency front-of-neck access. The absence of standardized procedures, lack of readily available equipment, inadequate knowledge, and training often lead to failed emergency front-of-neck access, resulting in catastrophic outcomes. In this narrative review, we examined the latest evidence on emergency front-of-neck access in children.

METHODS

A comprehensive literature was performed the use of emergency front-of-neck access (eFONA) in infants and children.

RESULTS

Eighty-six papers were deemed relevant by abstract. Finally, eight studies regarding the eFONA technique and simulations in animal models were included. For all articles, their primary and secondary outcomes, their specific animal model, the experimental design, the target participants, and the equipment were reported.

CONCLUSION

Based on the available evidence, we propose a general approach to the eFONA technique and a guide for implementing local protocols and training. Additionally, we introduce the application of innovative tools such as 3D models, ultrasound, and artificial intelligence, which can improve the precision, safety, and training of this rare but critical procedure.

Comparison of the success rate of tracheal intubation between stylet and bougie with a hyperangulated videolaryngoscope: a randomised controlled trial

Hyperangulated videolaryngoscopes are known to increase the success rate of tracheal intubation in the setting of difficult airway management when used with a stylet or bougie. However, there is controversy over which adjunct is more useful. This randomised study aimed to compare first attempt tracheal intubation success rate between a stylet and bougie when using a hyperangulated videolaryngoscope. We recruited patients aged > 20 years who were scheduled for elective surgery under general anaesthesia and required tracheal intubation. We only included patients with factors predicting difficult tracheal intubation based on pre-anaesthesia airway evaluation. Tracheal intubation was attempted using a Glidescope® with either a stylet or bougie as an adjunct according to group assignment. Primary outcome was the success rate of the first tracheal intubation attempt, and secondary outcomes were success of second and third attempts; tracheal intubation time; and occurrence of sore throat, dysphagia or hoarseness. A total of 166 patients were included. The success rate of the first tracheal intubation attempt was significantly higher in patients allocated to the bougie group compared with those allocated to the stylet group (81/83 (98%) vs. 73/83 (88%), respectively; p = 0.032). The number of patients who needed two attempts was significantly lower in those allocated to the bougie group compared with those allocated to the stylet group (1/83 (1%) vs. 9/83 (11%), respectively; p = 0.018). Each group had one patient (1%) where tracheal intubation was achieved after a third attempt. There was no significant difference in the occurrence of sore throat, dysphagia and hoarseness between the two groups. When difficult tracheal intubation is anticipated and a hyperangulated videolaryngoscope is used, the success rate of the first attempt is higher when a bougie is used compared with a stylet.

Comparison of Macintosh Laryngoscope, King Vision®, VividTrac®, AirAngel Blade®, and a Custom-Made 3D-Printed Video Laryngoscope for Difficult and Normal Airways in Mannequins by Novices-A Non-Inferiority Trial

Background: Endotracheal intubation (ETI) is a cornerstone of airway management. The gold standard device for ETI is still the direct laryngoscope (DL). However, video laryngoscopes (VLs) are now also widely available and have several proven advantages. The VL technique has been included in the major airway management guidelines. During the COVID-19 pandemic, supply chain disruption has raised demand for 3D-printed medical equipment, including 3D-printed VLs. However, studies on performance are only sparsely available; thus, we aimed to compare 3D-printed VLs to the DL and other VLs made with conventional manufacturing technology. Methods: Forty-eight medical students were recruited to serve as novice users. Following brief, standardized training, students executed ETI with the DL, the King Vision® (KV), the VividTrac® (VT), the AirAngel Blade® (AAB), and a custom-made 3D-printed VL (3DVL) on the Laerdal® airway management trainer in normal and difficult airway scenarios. We evaluated the time to and proportion of successful intubation, the best view of the glottis, esophageal intubation, dental trauma, and user satisfaction. Results: The KV and VT are proved to be superior (p < 0.05) to the DL in both scenarios. The 3DVL's performance was similar (p > 0.05) or significantly better than that of the DL and mainly non-inferior (p > 0.05) compared to the KV and VT in both scenarios. Regardless of the scenario, the AAB proved to be inferior (p < 0.05) even to the DL in the majority of the variables. The differences between the devices were more pronounced in the difficult airway scenario. The user satisfaction scores were in concordance with the aforementioned performance of the scopes. Conclusions: Based upon our results, we cannot recommend the AAB over the DL, KV, or VT. However, as the 3DVL showed, 3D printing indeed can provide useful or even superior VLs, but prior to clinical use, meticulous evaluation might be recommended.

The anesthesiologist's guide to swine trauma physiology research: a report of two decades of experience from the experimental traumatology laboratory

PURPOSE

Swine are one of the major animal species used in translational research, with unique advantages given the similar anatomic and physiologic characteristics as man, but the investigator needs to be familiar with important differences. This article targets clinical anesthesiologists who are proficient in human monitoring. We summarize our experience during the last two decades, with the aim to facilitate for clinical and non-clinical researchers to improve in porcine research.

METHODS

This was a retrospective review of 337 swine with a mean (SD) weight 60 (4.2) kg at the Experimental Traumatology laboratory at Södersjukhuset (Stockholm south general hospital) between 2003 and 2023, including laboratory parameters and six CT-angiography examinations.

RESULTS

Swine may be ventilated through the snout using a size 2 neonatal mask. Intubate using a 35 cm miller laryngoscope and an intubating introducer. Swine are prone to alveolar atelectasis and often require alveolar recruitment. Insert PA-catheters through a cut-down technique in the internal jugular vein, and catheters in arteries and veins using combined cut-down and Seldinger techniques. Cardiopulmonary resuscitation is possible and lateral chest compressions are most effective. Swine are prone to lethal ventricular arrhythmias, which may be reversed by defibrillation. Most vital parameters are similar to man, with the exception of a higher core temperature, higher buffer bases and increased coagulation. Anesthesia methods are similar to man, but swine require five times the dose of ketamine.

CONCLUSION

Swine share anatomical and physiological features with man, which allows for seamless utilization of clinical monitoring equipment, medication, and physiological considerations.

Efficacy of bougie first approach for endotracheal intubation with video laryngoscopy during continuous chest compression: a randomized crossover manikin trial

BACKGROUND

Endotracheal intubation is challenging during cardiopulmonary resuscitation, and video laryngoscopy has showed benefits for this procedure. The aim of this study was to compare the effectiveness of various intubation approaches, including the bougie first, preloaded bougie, endotracheal tube (ETT) with stylet, and ETT without stylet, on first-attempt success using video laryngoscopy during chest compression.

METHODS

This was a randomized crossover trial conducted in a general tertiary teaching hospital. We included anesthesia residents in postgraduate year one to three who passed the screening test. Each resident performed intubation with video laryngoscopy using the four approaches in a randomized sequence on an adult manikin during continuous chest compression. The primary outcome was the first-attempt success defined as starting ventilation within a one minute.

RESULTS

A total of 260 endotracheal intubations conducted by 65 residents were randomized and analyzed with 65 procedures in each group. First-attempt success occurred in 64 (98.5%), 57 (87.7%), 56 (86.2%), and 46 (70.8%) intubations in the bougie-first, preloaded bougie, ETT with stylet, and ETT without stylet approaches, respectively. The bougie-first approach had a significantly higher possibility of first-attempt success than the preloaded bougie approach [risk ratio (RR) 8.00, 95% confidence interval (CI) 1.03 to 62.16, P = 0.047], the ETT with stylet approach (RR 9.00, 95% CI 1.17 to 69.02, P = 0.035), and the ETT without stylet approach (RR 19.00, 95% CI 2.62 to 137.79, P = 0.004) in the generalized estimating equation logistic model accounting for clustering of intubations operated by the same resident. In addition, the bougie first approach did not result in prolonged intubation or increased self-reported difficulty among the study participants.

CONCLUSIONS

The bougie first approach with video laryngoscopy had the highest possibility of first-attempt success during chest compression. These results helped inform the intubation approach during CPR. However, further studies in an actual clinical environment are warranted to validate these findings.

TRIAL REGISTRATION

Clinicaltrials.gov; identifier: NCT05689125; date: January 18, 2023.

Reliable prediction of difficult airway for tracheal intubation from patient preoperative photographs by machine learning methods

BACKGROUND

Estimating the risk of a difficult tracheal intubation should help clinicians in better anaesthesia planning, to maximize patient safety. Routine bedside screenings suffer from low sensitivity.

OBJECTIVE

To develop and evaluate machine learning (ML) and deep learning (DL) algorithms for the reliable prediction of intubation risk, using information about airway morphology.

METHODS

Observational, prospective cohort study enrolling n=623 patients who underwent tracheal intubation: 53/623 difficult cases (prevalence 8.51%). First, we used our previously validated deep convolutional neural network (DCNN) to extract 2D image coordinates for 27 + 13 relevant anatomical landmarks in two preoperative photos (frontal and lateral views). Here we propose a method to determine the 3D pose of the camera with respect to the patient and to obtain the 3D world coordinates of these landmarks. Then we compute a novel set of dM=59 morphological features (distances, areas, angles and ratios), engineered with our anaesthesiologists to characterize each individual's airway anatomy towards prediction. Subsequently, here we propose four ad hoc ML pipelines for difficult intubation prognosis, each with four stages: feature scaling, imputation, resampling for imbalanced learning, and binary classification (Logistic Regression, Support Vector Machines, Random Forests and eXtreme Gradient Boosting). These compound ML pipelines were fed with the dM=59 morphological features, alongside dD=7 demographic variables. Here we trained them with automatic hyperparameter tuning (Bayesian search) and probability calibration (Platt scaling). In addition, we developed an ad hoc multi-input DCNN to estimate the intubation risk directly from each pair of photographs, i.e. without any intermediate morphological description. Performance was evaluated using optimal Bayesian decision theory. It was compared against experts' judgement and against state-of-the-art methods (three clinical formulae, four ML, four DL models).

RESULTS

Our four ad hoc ML pipelines with engineered morphological features achieved similar discrimination capabilities: median AUCs between 0.746 and 0.766. They significantly outperformed both expert judgement and all state-of-the-art methods (highest AUC at 0.716). Conversely, our multi-input DCNN yielded low performance due to overfitting. This same behaviour occurred for the state-of-the-art DL algorithms. Overall, the best method was our XGB pipeline, with the fewest false negatives at the optimal Bayesian decision threshold.

CONCLUSIONS

We proposed and validated ML models to assist clinicians in anaesthesia planning, providing a reliable calibrated estimate of airway intubation risk, which outperformed expert assessments and state-of-the-art methods. Our novel set of engineered features succeeded in providing informative descriptions for prognosis.

Evaluation of a novel, low-cost, 3D printed video laryngoscope with borescope in anesthetized Beagle dogs

OBJECTIVE

To develop and evaluate a low-cost three-dimensional (3D)-printed video laryngoscope (VLVET) for use with a commercial borescope.

STUDY DESIGN

Instrument development and pilot study.

ANIMALS

A total of six adult male Beagle dogs.

METHODS

The VLVET consisted of a laryngoscope handle and a Miller-type blade, and a detachable camera holder that attached to various locations along the blade. The laryngoscope and camera holder were 3D-printed using black polylactic acid filament. Dogs were premedicated with intravenous (IV) medetomidine (15 μg kg-1) and anesthesia induced with IV alfaxalone (1.5 mg kg-1). The VLVET, combined with a borescope, was used for laryngeal visualization and intubation. Performance was evaluated by comparing direct and video-assisted views in sternal recumbency. The borescope camera was sequentially positioned at 2, 4, 6, 8 and 10 cm from the blade tip (distanceLARYNX-CAM), which was placed on the epiglottis during intubation or laryngoscopy. At the 10 cm distanceLARYNX-CAM, laryngeal visualization was sequentially scored at inter-incisor gaps of 10, 8, 6, 4 and 2 cm. Laryngeal visualization scores (0-3 range, with 0 = obstructed and 3 = unobstructed views) were statistically analyzed using the Friedman's test.

RESULTS

Under direct visualization, the 2 cm distanceLARYNX-CAM had a significantly lower score compared with all other distanceLARYNX-CAM (all p = 0.014) because the view was obstructed by the camera holder and borescope camera. With both direct and camera-assisted views, visualization scores were higher at inter-incisor gaps ≥ 4 cm compared with 2 cm (all p < 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

During laryngoscopy and intubation, the VLVET and borescope facilitated both direct and video laryngoscopy at distanceLARYNX-CAM in Beagle dogs when inter-incisor gaps were ≥ 4 cm.

A case series of the Royal Perth Hospital cannula-first approach in the 'can't intubate, can't oxygenate' scenario

At the Royal Perth Hospital, we have been developing and teaching a can't intubate, can't oxygenate (CICO) rescue algorithm for over 19 years, based on live animal simulation. The algorithm involves a 'cannula-first' approach, with jet oxygenation and progression to scalpel techniques if required in a stepwise fashion. There is little reported experience of this approach to the CICO scenario in humans. We present eight cases in which a cannula-first Royal Perth Hospital approach was successfully implemented during an airway crisis. We recommend that institutions teach and practice this approach; we believe it is effective, safe and minimally invasive when undertaken by clinicians who have been trained in it and have immediate access to the requisite equipment. The equipment is low cost, comprising a 14G Insyte cannula, saline, 5 ml syringe and a Rapid-O2. Training can be provided using low-fidelity manikins or part-task trainers.

Obesity at term: What to consider? How to deliver?

Obesity presents significant challenges during pregnancy, increasing the risk of complications and adverse outcomes for both mother and baby. With the rising prevalence of obesity among pregnant women, questions arise regarding optimal management, including timing of delivery and choice of delivery mode. Labour induction in obese women may require a combination of mechanical and pharmacological methods due to increased risk of failed induction. Caesarean section in obese women presents unique challenges, requiring comprehensive perioperative planning and specialized care to optimize outcomes. However, specific guidelines tailored to obese patients undergoing caesarean sections are lacking. Postpartum care should include vigilant monitoring for complications. Addressing obesity in pregnancy necessitates a multidisciplinary approach and specialized care to ensure the best outcomes.

Comparison of Force Distribution during Laryngoscopy with the C-MAC D-BLADE and Macintosh-Style Blades: A Randomised Controlled Clinical Trial

Background: The geometry of a laryngoscope's blade determines the forces acting on the pharyngeal structures to a relevant degree. Knowledge about the force distribution along the blade may prospectively allow for the development of less traumatic blades. Therefore, we examined the forces along the blades experienced during laryngoscopy with the C-MAC D-BLADE and blades of the Macintosh style. We hypothesised that lower peak forces are applied to the patient's pharyngeal tissue during videolaryngoscopy with a C-MAC D-BLADE compared to videolaryngoscopy with a C-MAC Macintosh-style blade and direct laryngoscopy with a Macintosh-style blade. Beyond that, we assumed that the distribution of forces along the blade differs depending on the respective blade's geometry. Methods: After ethical approval, videolaryngoscopy with the D-BLADE or the Macintosh blade, or direct laryngoscopy with the Macintosh blade (all KARL STORZ, Tuttlingen, Germany), was performed on 164 randomly assigned patients. Forces were measured at six positions along each blade and compared with regard to mean force, peak force and spatial distribution. Furthermore, the duration of the laryngoscopy was measured. Results: Mean forces (all p < 0.011) and peak forces at each sensor position (all p < 0.019) were the lowest with the D-BLADE, whereas there were no differences between videolaryngoscopy and direct laryngoscopy with the Macintosh blades (all p > 0.128). With the D-BLADE, the forces were highest at the blade's tip. In contrast, the forces were more evenly distributed along the Macintosh blades. Videolaryngoscopy took the longest with the D-BLADE (p = 0.007). Conclusions: Laryngoscopy with the D-BLADE resulted in significantly lower forces acting on pharyngeal and laryngeal tissue compared to Macintosh-style blades. Interestingly, with the Macintosh blades, we found no advantage for videolaryngoscopy in terms of force application.

Noninvasive respiratory support in the perioperative setting: a narrative review

The application of preoperative noninvasive respiratory support (NRS) has been expanding with increasing recognition of its potential role in this setting as a physiological optimization for patients with a high risk of developing atelectasis and postoperative pulmonary complications (PPC). The increased availability of high-performance anesthesia ventilator machines providing an easy way for NRS support in patients with reduced lung function should not be under-evaluated. This support can reduce hypoxia, restore lung volumes and theoretically reduce atelectasis formation after general anesthesia. Therapeutic purposes should also be considered in the perioperative setting, such as preoperative NRS to optimize treatment of patients' pre-existing diseases, e.g., sleep-disordered breathing. Finally, the recent guidelines for airway management suggest preoperative NRS application before anesthesia induction in difficult airway management to prolong the time needed to secure the airway with an orotracheal tube. This narrative review aims to revise all these aspects and to provide some practical notes to maximize the efficacy of perioperative noninvasive respiratory support.

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.

Airway and respiratory complications during anaesthesia and associated with peri-operative cardiac arrest as reported to the 7th National Audit Project of the Royal College of Anaesthetists

The 7th National Audit Project (NAP7) of the Royal College of Anaesthetists studied complications of the airway and respiratory system during anaesthesia care including peri-operative cardiac arrest. Among 24,721 surveyed cases, airway and respiratory complications occurred commonly (n = 421 and n = 264, respectively). The most common airway complications were: laryngospasm (157, 37%); airway failure (125, 30%); and aspiration (27, 6%). Emergency front of neck airway was rare (1 in 8370, 95%CI 1 in 2296-30,519). The most common respiratory complications were: severe ventilation difficulty (97, 37%); hyper/hypocapnia (63, 24%); and hypoxaemia (62, 23%). Among 881 reports to NAP7 and 358 deaths, airway and respiratory complications accounted for 113 (13%) peri-operative cardiac arrests and 32 (9%) deaths, with hypoxaemia as the most common primary cause. Airway and respiratory cases had higher and lower survival rates than other causes of cardiac arrest, respectively. Patients with obesity, young children (particularly infants) and out-of-hours care were overrepresented in reports. There were six cases of unrecognised oesophageal intubation with three resulting in cardiac arrest. Of these cases, failure to correctly interpret capnography was a recurrent theme. Cases of emergency front of neck airway (6, approximately 1 in 450,000) and pulmonary aspiration (11, approximately 1 in 25,000) leading to cardiac arrest were rare. Overall, these data, while distinct from the 4th National Audit Project, suggest that airway management is likely to have become safer in the last decade, despite the surgical population having become more challenging for anaesthetists.

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.

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.

Comparison of Laryngeal Mask Airway Seal Between Anesthesiologists and Individuals Without Previous Airway Experience

BACKGROUND

Tracheal intubation is the gold standard for airway management in emergency medicine, but more difficult to apply for inexperienced individuals than laryngeal mask airway (LMA).

OBJECTIVE

The aim of our study was to investigate if inexperienced individuals are able to secure the airway with the help of LMA after a short introduction. A second aim was to evaluate Thiel-fixed specimens against unfixed ones.

METHODS

In a body donor model, LMA application was evaluated between medical students without previous airway experience and anesthesiologists by comparing the sealing of the larynx using a water column applied to the esophagus.

RESULTS

LMAs were successfully applied in 46 out of 55 (83.6%) attempts by medical students and in 30 out of 39 (76.9%) attempts by anesthesiologists. Among medical students, 14.1% of all LMA applications were primarily leaky, compared with 18.8% in anesthesiologists. Esophageal sealing was better in Thiel-fixed specimens (leakage 10.9%) compared with unfixed specimens (leakage 22.9%). Our data showed no significant difference between anesthesiologists and medical students in terms of sealing of LMA. Therefore, we conclude that medical students without previous airway experience can quickly learn to apply LMA sufficiently and thus, achieve aspiration protection similar to anesthesiologists.

CONCLUSION

Medical students without previous airway experience can successfully insert LMAs after a short introduction. Thiel-fixed specimens are suitable for studies as well as for training in LMA application.

Determination of the Cricothyroid Membrane Height by Age and Sex and Optimal Tracheal Tube Size

OBJECTIVES

The primary aim of this study was to determine the average cricothyroid membrane (CTM) height in healthy volunteers, and the secondary aim was to determine the hypothetical success rate for emergency cricothyrotomy with a tracheal tube with an 8.0 mm outer diameter.

METHODS

This study included healthy volunteers aged 18 years and older. The participants' clinical characteristics were recorded, and their CTM height was measured using ultrasound, with their necks placed sequentially in the neutral and extension positions. The relationship between the CTM height and sex, age, height, weight, body mass index, and sternomental distance was evaluated using linear regression analysis. An equation that could estimate the height of the CTM was obtained with the parameters found significant in this analysis.

RESULTS

Of the 340 participants, 208 (61.2%) were male. The mean (SD) height of the CTM in the extension position was 9.60 (1.54) mm, and it was significantly shorter in the women than in the men (8.72 [1.19] mm vs. 10.16 [1.48] mm, p < 0.001). Among the participants of short stature, the CTM was significantly shorter, regardless of sex. The hypothetical success rate for emergency cricothyrotomy was 93.3% for the males and 73.5% for the females. The equation for estimating the height of the CTM in the extension position was determined as -4.36 + 5.27 × height (m) + 0.32 × sternomental distance (cm).

CONCLUSIONS

Since the CTM height may differ according to age, sex, and height, cricothyrotomy sets should be available in various outer diameters.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1825-1830, 2024.

Teaching Airway Management Using Virtual Reality: A Scoping Review

Airway management, a defined procedural and cognitive skillset embracing routine tracheal intubation and emergency airway rescue, is most often acquired through an apprenticeship model of opportunistic learning during anesthesia or acute care residency training. This training engages a host of modalities to teach and embed skill sets but is generally time- and location-constrained. Virtual reality (VR)-based simulation training offers the potential for reproducible and asynchronous skill acquisition and maintenance, an advantage that may be important with restricted trainee work hours and low frequency but high-risk events. In the absence of a formal curriculum from training bodies-or expert guidance from medical professional societies-local initiatives have filled the VR training void in an unstructured fashion. We undertook a scoping review to explore current VR-based airway management training programs to assess their approach, outcomes, and technologies to discover programming gaps. English-language publications addressing any aspect of VR simulation training for airway management were identified across PubMed, Embase, and Scopus. Relevant articles were used to craft a scoping review conforming to the Scale for quality Assessment of Narrative Review Articles (SANRA) best-practice guidance. Fifteen studies described VR simulation programs to teach airway management skills, including flexible fibreoptic bronchoscopic intubation (n = 10), direct laryngoscopy (n = 2), and emergency cricothyroidotomy (n = 1). All studies were single institution initiatives and all reported different protocols and end points using bespoke applications of commercial technology or homegrown technologic solutions. VR-based simulation for airway management currently occurs outside of a formal curriculum structure, only for specific skill sets, and without a training pathway for educators. Medical educators with simulation training and medical professional societies with content expertise have the opportunity to develop consensus guidelines that inform training curricula as well as specialty technology use.

A comparative evaluation of fibreoptic bronchoscopy versus C-MAC® D-BLADE-guided videolaryngoscopy for nasotracheal intubation under general anesthesia in oropharyngeal carcinoma surgery patients

PURPOSE

Nasotracheal intubation (NTI) is required for surgery in oropharyngeal (OP) carcinoma patients, but it may be challenging because of distorted anatomy, mucosal congestion, and increased risk of bleeding. Flexible bronchoscopy (FB)-guided NTI is preferred in these cases but has limitations. In this randomized controlled study, we sought to compare C-MAC® D-BLADE-guided videolaryngoscopy (VL) (Karl Storz SE & Co. KG, Tuttlingen, Germany) with FB for NTI under general anesthesia in patients with OP carcinomas.

METHODS

We randomized a total of 100 patients with OP carcinoma and El-Ganzouri's risk index (EGRI) < 7 to undergo NTI under general anesthesia with FB (n = 50) or C-MAC D-BLADE-guided VL (n = 50). The primary outcome was the total intubation time. We also recorded the time to glottis view, nasal intubation difficulty scale (NIDS) score, best percentage of glottis opening score, and complications.

RESULTS

The median [interquartile range (IQR)] total intubation time was shorter with VL than with FB (total intubation time, 38 [26-43] sec vs 60 [52-65] sec; difference, -20 sec [95% confidence interval (CI), -27 to -11]; P < 0.001). Similarly, the median [IQR] time to glottis view was shorter with VL compared to FB (8 [6-9] sec vs 22 [14-25] sec; difference, -13 sec [95% CI, -17 to -10]; P < 0.001). The median NIDS score was higher with VL (difference, 2 [95% CI, 2 to 3]; P < 0.001). The incidences of airway trauma (two cases with FB vs seven with VL; P = 0.30) and postoperative sore throat (ten cases in both groups; P = 0.56) were similar.

CONCLUSION

Compared to FB, C-MAC D-BLADE-based VL reduced the total time for nasal intubation oropharyngeal carcinoma patients, potentially representing an acceptable alternative in selected cases.

TRIAL REGISTRATION

CTRI.nic.in (2018/11/0162830); first submitted 8 November 2018.

Impact of simulation-based training on bougie-assisted cricothyrotomy technique: a quasi-experimental study

BACKGROUND

Cricothyrotomy is a lifesaving surgical technique in critical airway events. However, a large proportion of anesthesiologists have little experience with cricothyrotomy due to its low incidence. This study aimed to develop a multisensory, readily available training curriculum for learning cricothyrotomy and evaluate its training effectiveness.

METHODS

Seventy board-certificated anesthesiologists were recruited into the study. Participants first viewed an instructional video and observed an expert performing the bougie-assisted cricothyrotomy on a self-made simulator. They were tested before and after a one-hour practice on their cricothyrotomy skills and evaluated by a checklist and a global rating scale (GRS). Additionally, a questionnaire survey regarding participants' confidence in performing cricothyrotomy was conducted during the training session.

RESULTS

The duration to complete cricothyrotomy was decreased from the pretest (median = 85.0 s, IQR = 72.5-103.0 s) to the posttest (median = 59.0 s, IQR = 49.0-69.0 s). Furthermore, the median checklist score was increased significantly from the pretest (median = 30.0, IQR = 27.0-33.5) to the posttest (median = 37.0, IQR = 35.5-39.0), as well as the GRS score (pretest median = 22.5, IQR = 18.0-25.0, posttest median = 32.0, IQR = 31.0-33.5). Participants' confidence levels in performing cricothyrotomy also improved after the curriculum.

CONCLUSION

The simulation-based training with a self-made simulator is effective for teaching anesthesiologists to perform cricothyrotomy.

Comparison of the effects of paratracheal pressure and cricoid pressure on placement of the i-gel® supraglottic airway: a randomized clinical trial

PURPOSE

Anesthesiologists can use supraglottic airway devices as a rescue technique for failed intubation even in patients with an increased risk of gastric regurgitation. In this randomized study, we aimed to evaluate the effects of cricoid pressure and paratracheal pressure on placement of the i-gel® (Intersurgical Ltd., Wokingham, Berkshire, UK).

METHODS

After induction of anesthesia in 76 adult patients, we inserted the i-gel under paratracheal or cricoid pressure, and assessed the success rate of i-gel insertion, resistance during insertion, time required for insertion, accuracy of the insertion location, tidal volumes, and peak inspiratory pressure with or without each maneuver after i-gel insertion.

RESULTS

The overall success rate of insertion was significantly higher under paratracheal pressure than under cricoid pressure (36/38 [95%] vs 27/38 [71%], respectively; difference, 24%; 95% confidence interval [CI], 8 to 40; P = 0.006]. Resistance during insertion was significantly lower under paratracheal pressure than under cricoid pressure (P < 0.001). The time required for insertion was significantly shorter under paratracheal pressure than under cricoid pressure (median [interquartile range], 18 [15-23] sec vs 28 [22-38] sec, respectively; difference in medians, -10; 95% CI, -18 to -4; P < 0.001). Fibreoptic examination of the anatomical alignment of the i-gel in the larynx revealed no significant difference in the accuracy of the insertion location between the two maneuvers (P = 0.31). The differences in tidal volume and peak inspiratory pressure with or without the maneuvers were significantly lower with paratracheal pressure than with cricoid pressure (P = 0.003, respectively).

CONCLUSIONS

Insertion of the i-gel supraglottic airway was significantly more successful, easier, and faster while applying paratracheal pressure than cricoid pressure.

STUDY REGISTRATION

ClinicalTrials.gov (NCT05377346); first submitted 11 May 2022.

High-flow nasal oxygenation versus face mask oxygenation for preoxygenation in patients undergoing double-lumen endobronchial intubation: protocol of a randomised controlled trial

INTRODUCTION

With the growing emphasis on swift recovery, minimally invasive thoracic surgery has advanced significantly. Video-assisted thoracoscopic surgery (VATS) has seen rapid development, and the double-lumen tube (DLT) remains the most dependable method for tracheal intubation in VATS. However, hypoxaemia during DLT intubation poses a threat to the perioperative safety of thoracic surgery patients. Recently, transnasal high-flow nasal oxygen (HFNO) has shown promise in anaesthesia, particularly in handling short-duration hypoxic airway emergencies. Yet, its application in the perioperative period for patients undergoing pulmonary surgery with compromised cardiopulmonary function lacks evidence, and there are limited reliable clinical data.

METHODS AND ANALYSIS

A prospective, randomised, controlled, single-blind design will be employed in this study. 112 patients aged 18-60 years undergoing elective VATS-assisted pulmonary surgery will be enrolled and randomly divided into two groups: the nasal high-flow oxygen group (H group) and the traditional mask transnasal oxygen group (M group) in a 1:1 ratio. HFNO will be used during DLT intubation for the prevention of asphyxia in group H, while conventional intubation procedures will be followed by group M. Comparison will be made between the two groups in terms of minimum oxygen saturation during intubation, hypoxaemia incidence during intubation, perioperative complications and postoperative hospital days.

ETHICS AND DISSEMINATION

Approval for this study has been granted by the local ethics committee at Shenzhen Second People's Hospital. The trial results will be disseminated through peer-reviewed journals and scientific conferences.

TRIAL REGISTRATION NUMBER

NCT05666908.

A Convenient and Effective Preoxygenation Technique for Prolonging Deep Inspiration Breath-Hold Duration With a Venturi Mask With a 50% Oxygen Concentration

PURPOSE

Voluntary deep inspiration breath-hold (DIBH) is commonly used in radiation therapy (RT), but the short duration of a single breath-hold, estimated to be around 20 to 40 seconds, is a limitation. This prospective study aimed to assess the feasibility and safety of using a simple preoxygenation technique with a Venturi mask to prolong voluntary DIBH.

METHODS AND MATERIALS

The study included 33 healthy volunteers and 21 RT patients. Preoxygenation was performed using a Venturi mask with a 50% oxygen concentration. Paired t tests compared the duration of a single DIBH in room air and after 5, 15, and 30 minutes of preoxygenation in healthy volunteers. Sustainability of breath-hold and tolerability of heart rate and blood pressure were assessed for multiple DIBH durations in both volunteers and patients.

RESULTS

In healthy volunteers, a 15-minute preoxygenation significantly prolonged the duration of a single DIBH by 24.95 seconds compared with 5-minute preoxygenation (89 ± 27.76 vs 113.95 ± 30.63 seconds; P < .001); although there was a statistically significant increase in DIBH duration after 30-minute preoxygenation, it was only extended by 4.95 seconds compared with 15-minute preoxygenation (113.95 ± 30.63 vs 118.9 ± 29.77 seconds; P < .01). After 15-minute preoxygenation, a single DIBH lasted over 100 seconds in healthy volunteers and over 80 seconds in RT patients, with no significant differences among 6 consecutive cycles of DIBH. Furthermore, there were no significant differences in heart rate or blood pressure after DIBHs, including DIBH in room air and 6 consecutive DIBHs after 15-minute preoxygenation (all P > .05).

CONCLUSIONS

Preoxygenation with a 50% oxygen concentration for 15 minutes effectively prolongs the duration of 6 cycles of DIBH both in healthy volunteers and RT patients. The utilization of a Venturi mask to deliver 50% oxygen concentration provides a solution characterized by its convenience, good tolerability, and effectiveness.

Emergency front-of-neck access in infants: A pragmatic crossover randomized control trial comparing two approaches on a simulated rabbit model

BACKGROUND

Rapid-sequence tracheotomy and scalpel-bougie tracheotomy are two published approaches for establishing emergency front-of-neck access in infants. It is unknown whether there is a difference in performance times and success rates between the two approaches.

AIMS

The aim of this cross-over randomized control trial study was to investigate whether the two approaches were equivalent for establishing tracheal access in rabbit cadavers. The underlying hypothesis was that the time to achieve the tracheal access is the same with both techniques.

METHODS

Between May and September 2022, thirty physicians (pediatric anesthesiologists and intensivists) were randomized to perform front-of-neck access using one and then the other technique: rapid-sequence tracheotomy and scalpel-bougie tracheotomy. After watching training videos, each technique was practiced four times followed by a final tracheotomy during which study measurements were obtained. Based on existing data, an equivalence margin was set at ∆ = ±10 s for the duration of the procedure. The primary outcome was defined as the duration until tracheal tube placement was achieved successfully. Secondary outcomes included success rate, structural injuries, and subjective participant self-evaluation.

RESULTS

The median duration of the scalpel-bougie tracheotomy was 48 s (95% CI: 37-57), while the duration of the rapid-sequence tracheotomy was 59 s (95% CI: 49-66, p = .07). The difference in the median duration between the two approaches was 11 s (95% CI: -4.9 to 29). The overall success rate was 93.3% (95% CI: 83.8%-98.2%). The scalpel-bougie tracheotomy resulted in significantly fewer damaged tracheal rings and was preferred among participants.

CONCLUSIONS

The scalpel-bougie tracheotomy was slightly faster than the rapid-sequence tracheotomy and favored by participants, with fewer tracheal injuries. Therefore, we propose the scalpel-bougie tracheostomy as a rescue approach favoring the similarity to the adult approach for small children. The use of a comparable equipment kit for both children and adults facilitates standardization, performance, and logistics.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05499273.

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 I

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.

Airway management of adult epiglottitis: a systematic review and meta-analysis

Background

Adult epiglottitis is a life-threatening airway emergency where airway protection is the immediate priority. Despite its importance, the optimal approach to airway management remains unclear. We performed a systematic review of the airway management for adult epiglottitis, including meta-analysis of trends over time.

Methods

We systematically searched PubMed, Ovid MEDLINE®, and Embase® for adult epiglottitis studies that described the airway management between 1980 and 2020. The primary outcome was the prevalence of airway intervention. Secondary outcomes were prevalence of tracheal intubation, tracheostomy, and failed intubation. A random-effects model meta-analysis was performed with subgroups defined by decade of study publication. Cases that described the specific method of airway intervention and severity of epiglottitis were included in a separate technique summary.

Results

Fifty-six studies with 10 630 patients were included in the meta-analysis. The overall rate of airway intervention was 15.6% (95% confidence interval [CI] 12.9-18.8%) but the rate decreased from 20% to 10% between 1980 and 2020. The overall rate of tracheal intubation was 10.2% (95% CI 7.1-13.6%) and that of failed intubation was 4.2% (95% CI 1.4-8.0%). The airway technique summary included 128 cases, of which 75 (58.6%) were performed awake and 53 (41.4%) involved general anaesthesia. We identified 32 cases of primary technique failure.

Conclusion

The rate of airway intervention for adult epiglottitis has decreased over four decades to a current level of 10%. Tracheal intubation is a high-risk scenario with a 1 in 25 failure rate. Specific technique selection is most likely influenced by contextual factors including the severity of epiglottitis.

Narrative Review and Consensus Recommendations for the Use of Transnasal Humidified Rapid-Insufflation Ventilatory Exchange in Modified Electroconvulsive Therapy

Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) is a safe, effective, and novel technique that is currently being used in electroconvulsive therapy (ECT). This study aimed to summarize the clinical practices of THRIVE use in ECT to aid physicians and institutions in implementing the best practice guidelines for ECT. Thus, we reviewed the current literature and presented our consensus on the application of THRIVE in ECT in daily clinical practice. This consensus provides information regarding THRIVE use in ECT, including its safety, effectiveness, procedures, precautions, special case management, and application in special populations. Moreover, it guides the standardized use of THRIVE in ECT.

Airway and Anaesthetic Management of Adult Patients with Mucopolysaccharidoses Undergoing Cardiac Surgery

Background: Mucopolysaccharidoses (MPSs) are rare congenital lysosomal storage disorders due to a deficiency of enzymes metabolising glycosaminoglycans, leading to their accumulation in tissues. This multisystem disease often requires surgical intervention, including valvular cardiac surgery. Adult MPSs have complex airways making anaesthesia risky. Methods: We report novel three-dimensional (3D) modelling airway assessments and multidisciplinary peri-operative airway management. Results: Five MPS adults underwent cardiac surgery at the national MPS cardiac centre (type I = 4, type II = 1; ages 20, 24, 33, 35, 37 years; two males, three females). All had complex airway abnormalities. Assessments involved examination, nasendoscopy, imaging, functional studies, 3D reconstruction, virtual endoscopy, virtual reality and simulation using computerised, physical modelling. Awake oral fibre-optic intubation was achieved via airway conduit. Staged extubation was performed on the first post-operative day under laryngo-tracheoscopic guidance. The post-operative period involved chest physiotherapy and occupational therapy. All patients had safe intubation, ventilation and extubation. Four had good cardiac surgical outcomes, one (MPS type I; age 35 years) was inoperable due to endocarditis. None had post-operative airway complications. Conclusions: Expertise from cardiovascular-heart team, multidisciplinary airway management, use of novel techniques is vital. Traditional airway assessments are insufficient, so ENT input, radiology and computerised methods to assess and simulate the airway in 3D by collaboration with clinical engineering is essential.

Cardiorespiratory consequences of attenuated fentanyl and augmented rocuronium dosing during protocolised prehospital emergency anaesthesia at a regional air ambulance service: a retrospective study

BACKGROUND

Pre-Hospital Emergency Anaesthesia (PHEA) has undergone significant developments since its inception. However, optimal drug dosing remains a challenge for both medical and trauma patients. Many prehospital teams have adopted a drug regimen of 3 mcg/kg fentanyl, 2 mg/kg ketamine and 1 mg/kg rocuronium ('3:2:1'). At Essex and Herts Air Ambulance Trust (EHAAT) a new standard dosing regimen was introduced in August 2021: 1 mcg/kg fentanyl, 2 mg/kg ketamine and 2 mg/kg rocuronium (up to a maximum dose of 150 mg) ('1:2:2'). The aim of this study was to evaluate the cardiorespiratory consequences of a new attenuated fentanyl and augmented rocuronium dosing regimen.

METHODS

A retrospective study was conducted at EHAAT as a service evaluation. Anonymized records were reviewed from an electronic database to compare the original ('3:2:1') drug dosing regimen (December 2019-July 2021) and the new ('1:2:2') dosing regimen (September 2021-May 2023). The primary outcome was the incidence of absolute hypotension within ten minutes of induction. Secondary outcomes included immediate hypertension, immediate hypoxia and first pass success (FPS) rates.

RESULTS

Following exclusions (n = 121), 720 PHEA cases were analysed (360 new vs. 360 original, no statistically significant difference in demographics). There was no difference in the rate of absolute hypotension (24.4% '1:2:2' v 23.8% '3:2:1', p = 0.93). In trauma patients, there was an increased first pass success (FPS) rate with the new regimen (95.1% v 86.5%, p = 0.01) and a reduced incidence of immediate hypoxia (7.9% v 14.8%, p = 0.05). There was no increase in immediate hypertensive episodes (22.7% vs. 24.2%, p = 0.73). No safety concerns were identified.

CONCLUSION

An attenuated fentanyl and augmented rocuronium dosing regimen showed no difference in absolute hypotensive episodes in a mixed cohort of medical and trauma patients. In trauma patients, the new regimen was associated with an increased FPS rate and reduced episodes of immediate hypoxia. Further research is required to understand the impact of such drug dosing in the most critically ill and injured subpopulation.

Training approaches and devices utilization during endotracheal intubation in French Emergency Departments: a nationwide survey

BACKGROUND AND IMPORTANCE

Endotracheal intubation is a lifesaving procedure that is reportedly associated to a significant risk of adverse events. Recent trials have reported that the use of videolaryngoscope and of a stylet might limit this risk during emergency intubation.

OBJECTIVES

The objective of this study was to provide a national description of intubation practices in French Emergency Departments (EDs).

SETTINGS AND PARTICIPANTS

We conducted an online nationwide survey by sending an anonymous 37-item questionnaire via e-mail to 629 physicians in French EDs between 2020 and 2022.

INTERVENTION

A single questionnaire was sent to a sole referent physician in each ED.

OUTCOME MEASURES AND ANALYSIS

The primary endpoint was to assess the proportion of French EDs in which videolaryngoscopy was available for emergency intubation and its use in routine practice. Secondary endpoints included the presence of local protocol or standard of procedure for intubation, availability of capnography, and routine use of a stylet.

MAIN RESULTS

Of the surveyed EDs, 342 (54.4%) returned the completed questionnaire. A videolaryngoscope was available in 193 (56%) EDs, and direct laryngoscopy without a stylet was majorly used as the primary approach in 280 (82%) EDs. Among the participating EDs, 74% had an established protocol for intubation and 92% provided a capnography device for routine verification of tube position. In cases of difficult intubation, the use of a bougie was recommended in 227 (81%) EDs, and a switch to a videolaryngoscope in 16 (6%) EDs. The most frequently used videolaryngoscope models were McGrath Mac Airtraq (51%), followed by Airtraq (41%), and Glidescope (14%).

CONCLUSION

In this large French survey, the majority of EDs recommended direct laryngoscopy without stylet, with seldom use of videolaryngoscopy.

Application of Machine Learning to Ultrasonography in Identifying Anatomical Landmarks for Cricothyroidotomy Among Female Adults: A Multi-center Prospective Observational Study

We aimed to develop machine learning (ML)-based algorithms to assist physicians in ultrasound-guided localization of cricoid cartilage (CC) and thyroid cartilage (TC) in cricothyroidotomy. Adult female volunteers were prospectively recruited from two hospitals between September and December, 2020. Ultrasonographic images were collected via a modified longitudinal technique. You Only Look Once (YOLOv5s), Faster Regions with Convolutional Neural Network features (Faster R-CNN), and Single Shot Detector (SSD) were selected as the model architectures. A total of 488 women (mean age: 36.0 years) participated in the study, contributing to a total of 292,053 frames of ultrasonographic images. The derived ML-based algorithms demonstrated excellent discriminative performance for the presence of CC (area under the receiver operating characteristic curve [AUC]: YOLOv5s, 0.989, 95% confidence interval [CI]: 0.982-0.994; Faster R-CNN, 0.986, 95% CI: 0.980-0.991; SSD, 0.968, 95% CI: 0.956-0.977) and TC (AUC: YOLOv5s, 0.989, 95% CI: 0.977-0.997; Faster R-CNN, 0.981, 95% CI: 0.965-0.991; SSD, 0.982, 95% CI: 0.973-0.990). Furthermore, in the frames where the model could correctly indicate the presence of CC or TC, it also accurately localized CC (intersection-over-union: YOLOv5s, 0.753, 95% CI: 0.739-0.765; Faster R-CNN, 0.720, 95% CI: 0.709-0.732; SSD, 0.739, 95% CI: 0.726-0.751) or TC (intersection-over-union: YOLOv5s, 0.739, 95% CI: 0.722-0.755; Faster R-CNN, 0.709, 95% CI: 0.687-0.730; SSD, 0.713, 95% CI: 0.695-0.730). The ML-based algorithms could identify anatomical landmarks for cricothyroidotomy in adult females with favorable discriminative and localization performance. Further studies are warranted to transfer this algorithm to hand-held portable ultrasound devices for clinical use.

The utilization of video laryngoscopy in nasotracheal intubation for oral and maxillofacial surgical procedures: a narrative review

The video laryngoscope is a novel instrument for intubation that enables indirect visualization of the upper airway. It is recognized for its ability to enhance Cormack-Lehane grades in the management of difficult airways. Notably, video laryngoscopy is associated with equal or higher rates of intubation success within a shorter time frame than direct laryngoscopy. Video laryngoscopy facilitates faster and easier visualization of the glottis and reduces the need for Magill forceps, thereby shortening the intubation time. Despite the advanced glottic visualization afforded by video laryngoscopy, nasotracheal tube insertion and advancement occasionally fail. This is particularly evident during nasotracheal intubation, where oropharyngeal blood or secretions may obstruct the visual field on the monitor, thereby complicating video laryngoscopy. Moreover, the use of Magill forceps is markedly challenging or nearly unfeasible in this context, especially in pediatric cases. Furthermore, the substantial blade size of video laryngoscopes may restrict their applicability in individuals with limited oral apertures. This study aimed to review the literature on video laryngoscopy, discuss its clinical role in nasotracheal intubation, and address the challenges that anesthesiologists may encounter during the intubation process.

Oropharyngeal Hemorrhage and Difficult Airway Management: A Decision Not to Intubate

BACKGROUND

Bleeding in the upper airways is an important cause of airway-related death. A higher incidence of airway management failure and complications after intubation attempts in the emergency department (ED) had been suggested. Airway management of patients with active oropharyngeal hemorrhage may be challenging, leading the clinician to modify the approach.

CASE REPORT

A 57-year-old woman presented to the ED with oropharyngeal hemorrhage after an extensive invasive dental procedure. She was on long-term warfarin therapy due to aortic and mitral valve replacement, which she suspended 5 days prior and restarted the day after the procedure. Besides the active bleeding, swelling, and hematoma of the face, the patient had other signs of "difficult airway," so there were serious questions on when and how to manage the airway. Several strategies to address the airway were considered, the main point being an early versus later intubation. As the patient remained clinically stable, she was conservatively managed with local hemostasis and coagulopathy reversal. The patient was transferred to the intensive care unit, where she remained stable and was successfully discharged after restart on warfarin. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: When faced with an oropharyngeal hemorrhage, emergency physicians may be compelled to secure and protect the airway. This could be achieved by planning several strategies. Nevertheless, in selected patients, and considering the circumstances, not addressing the airway is a reasonable and justifiable alternative.

Video-stylet vs. channeled hyperangulated videolaryngoscope: Efficacy in simulated Ludwig's angina randomized cadaver trial

INTRODUCTION

Ludwig's angina (LA) is a life-threatening infection that can affect the floor of the mouth and neck, potentially causing serious airway obstruction. In such cases, rescue airway management and oxygenation can be challenging due to swelling of the mouth floor, trismus, and limited mouth opening. The aim of this study was to assess the efficacy of the Trachway video-stylet (VS) and Pentax AWS hyperangulated videolaryngoscope with channel (HAVL-C) compared to the standard geometric video-laryngoscope (SGVL, Macintosh 3, Trachway) in simulating Ludwig's angina with cadavers.

METHODS

Three fresh frozen cadavers were prepared with varying degrees of difficulty to simulate the airway conditions of patients with LA, including mouth floor swelling, restricted mouth opening, and trismus. Fifty-five second-year resident physicians from various specialties participated in the study and received training in airway management using SGVL, VS, and HAVL-C devices. Participants were randomly assigned to intubate simulated LA with cadavers using the three devices in a random order, and intubation times and success rates were recorded. Participants also rated the difficulty of intubation using a visual analogue scale (VAS) score. The primary outcome assessed the first-pass intubation success or failure, while the secondary outcomes measured the intubation time and subjective difficulty using a visual analogue scale with different laryngoscopes.

RESULTS

The success rates for intubation within 90 s were 40% for SGVL, 82% for VS, and 76% for HAVL-C. VS and HAVL-C had significantly higher success rates than SGVL, with hazard ratios of 3.4 and 2.7, and 95% confidence intervals (CI) of 2.0-5.7 and 1.6-4.6, p < 0.001, respectively. The odds ratios of successful intubation for VS and HAVL-C were 8.1 and 6.3, respectively, with a 95% CI of 3.7-17.8 and 2.4-16.7, p < 0.001, compared to SGVL. The VAS score was significantly correlated with intubation success rate and time.

CONCLUSIONS

In cases of LA, the use of VS and HAVL-C is preferable over SGVL. These findings suggest that using VS and HAVL-C can improve intubation success rates and reduce intubation time in patients with LA.