Management of the Difficult Airway

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..

Difficult Airway Assessment Based on Multi-View Metric Learning

The preoperative assessment of difficult airways is of great significance in the practice of anesthesia intubation. In recent years, although a large number of difficult airway recognition algorithms have been investigated, defects such as low recognition accuracy and poor recognition reliability still exist. In this paper, we propose a Dual-Path Multi-View Fusion Network (DMF-Net) based on multi-view metric learning, which aims to predict difficult airways through multi-view facial images of patients. DMF-Net adopts a dual-path structure to extract features by grouping the frontal and lateral images of the patients. Meanwhile, a Multi-Scale Feature Fusion Module and a Hybrid Co-Attention Module are designed to improve the feature representation ability of the model. Consistency loss and complementarity loss are utilized fully for the complementarity and consistency of information between multi-view data. Combined with Focal Loss, information bias is effectively avoided. Experimental validation illustrates the effectiveness of the proposed method, with the accuracy, specificity, sensitivity, and F1 score reaching 77.92%, 75.62%, 82.50%, and 71.35%, respectively. Compared with methods such as clinical bedside screening tests and existing artificial intelligence-based methods, our method is more accurate and reliable and can provide a reliable auxiliary tool for clinical healthcare personnel to effectively improve the accuracy and reliability of preoperative difficult airway assessments. The proposed network can help to identify and assess the risk of difficult airways in patients before surgery and reduce the incidence of postoperative complications.

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.

Three Episodes of Postanesthesia Paradoxical Vocal Cord Motion Disorder in the Same Patient: A Case Report

Postanesthesia paradoxical vocal cord motion disorder (PVCMD) is often benign. However, if not recognized, PVCMD can lead to unnecessary treatments. Our patient had 3 different surgeries over a period of 20 months. The first episode of PVCMD occurred after a shoulder surgery, and the patient was reintubated. PVCMD was correctly diagnosed and treated successfully with reassurance after an ulnar nerve decompression. The third episode of PVCMD occurred after a cervical fusion surgery. Prevertebral edema from surgery further compromised the airways. Our case demonstrates the challenges of identifying and managing perioperative PVCMD, especially when surgical complications confound the airway management.

Observation of the validity of the upper lip bite test in predicting difficult intubation

The upper lip bite test (ULBT) is considered an effective method for predicting difficult airways, but data on the ULBT for predicting difficult tracheal intubation are lacking. This study aimed to examine the clinical utility of the ULBT in predicting difficult endotracheal intubation. We conducted an observational case-cohort study of adult patients undergoing elective surgery and requiring endotracheal intubation for general anesthesia. Difficult airway assessment was performed on the recruited patients before the operation, including the ULBT, mouth opening, thyromental distance, modified Mallampati test, and body mass index. The primary outcome was the incidence of difficult tracheal intubation. The receiver operating characteristic curve analysis was used to compare the performance of variables in predicting difficult tracheal intubation. We successfully recruited 2522 patients for analysis and observed 64 patients with difficult tracheal intubation. When predicting difficult tracheal intubation, grade 2 ULBT had a sensitivity of 0.75 and a specificity of 0.54, and grade 3 had a sensitivity of 0.28 and a specificity of 0.75. Compared with mouth opening, the area under the receiver operating characteristic curve of the ULBT was lower in predicting difficult tracheal intubation (0.69 [95% confidence interval: 0.67-0.71] vs. 0.84 [95% confidence interval: 0.82-0.87], P < 0.05).Clinical Trials Registry: ChiCTR-ROC-16009050, principal investigator: Weidong Yao.

Synergic Difficulties in an Anticipated Physiologically and Anatomically Difficult Airway in a Trauma Patient: A Case Report

The American Society of Anesthesiologists (ASA) defines a difficult airway as a clinical situation in which a physician who is trained in anesthesiology experiences difficulty or fails in either face mask ventilation, laryngoscopy, using a supraglottic airway, tracheal intubation, extubation, or front-of-neck airway. Classically, this has been defined in relation to anatomic factors, but the concept of a physiologically difficult airway has been growing in relevance, in which physiologic factors, such as hypoxemia and hypercapnia, act to reduce safe apnea times. The case reports on a trauma patient with an unstable thoracic vertebral fracture requiring correction via the posterior approach. Our patient had multiple anatomical difficult airway predictors, namely, a short neck, greatly limited neck mobility, and a Mallampati class IV airway, among others, and multiple physiological difficult airway predictors, such as a baseline hypoxemic respiratory failure and severe sleep apnea, in addition to the restrictions on mobility imposed by the fracture itself. We describe a successful perioxygenation strategy, using high-flow nasal oxygen (HFNO) during the preoxygenation, intubation, extubation, and post-anesthesia care phases, and with an awake fiberoptic intubation technique for securing the airway.

Hyperangulated blades or direct epiglottis lifting to optimize glottis visualization in difficult Macintosh videolaryngoscopy: a non-inferiority analysis of a prospective observational study

Purpose

It is unknown if direct epiglottis lifting or conversion to hyperangulated videolaryngoscopes, or even direct epiglottis lifting with hyperangulated videolaryngoscopes, may optimize glottis visualization in situations where Macintosh videolaryngoscopy turns out to be more difficult than expected. This study aims to determine if the percentage of glottic opening (POGO) improvement achieved by direct epiglottis lifting is non-inferior to the one accomplished by a conversion to hyperangulated videolaryngoscopy in these situations.

Methods

One or more optimization techniques were applied in 129 difficult Macintosh videolaryngoscopy cases in this secondary analysis of a prospective observational study. Stored videos were reviewed by at least three independent observers who assessed the POGO and six glottis view grades. A linear mixed regression and a linear regression model were fitted. Estimated marginal means were used to analyze differences between optimization maneuvers.

Results

In this study, 163 optimization maneuvers (77 direct epiglottis lifting, 57 hyperangulated videolaryngoscopy and 29 direct epiglottis lifting with a hyperangulated videolaryngoscope) were applied exclusively or sequentially. Vocal cords were not visible in 91.5% of the cases with Macintosh videolaryngoscopy, 24.7% with direct epiglottis lifting, 36.8% with hyperangulated videolaryngoscopy and 0% with direct lifting with a hyperangulated videolaryngoscope. Conversion to direct epiglottis lifting improved POGO (mean + 49.7%; 95% confidence interval [CI] 41.4 to 58.0; p < 0.001) and glottis view (mean + 2.2 grades; 95% CI 1.9 to 2.5; p < 0.001). Conversion to hyperangulated videolaryngoscopy improved POGO (mean + 43.7%; 95% CI 34.1 to 53.3; p < 0.001) and glottis view (mean + 1.9 grades; 95% CI 1.6 to 2.2; p < 0.001). The difference in POGO improvement between conversion to direct epiglottis lifting and conversion to hyperangulated videolaryngoscopy is: mean 6.0%; 95% CI -6.5-18.5%; hence non-inferiority was confirmed.

Conclusion

When Macintosh videolaryngoscopy turned out to be difficult, glottis exposure with direct epiglottis lifting was non-inferior to the one gathered by conversion to hyperangulated videolaryngoscopy. A combination of both maneuvers yields the best result.

Clinical trial registration

ClinicalTrials.gov, NCT03950934.

Development and validation of a screening method for difficult tracheal intubation based on geometric simulation and computer technology

BACKGROUND

The anatomical characteristics of difficult airways can be analysed geometrically. This study aims to develop and validate a geometry-assisted difficult airway screening method (GADAS method) for difficult tracheal intubation.

METHODS

In the GADAS method, a geometric simulated model was established based on computer graphics. According to the law of deformation of the upper airway on laryngoscopy, the expected visibility of the glottis was calculated to simulate the real visibility on laryngoscopy. Validation of the new method: Approved by the Ethics Committee of Yijishan Hospital of Wannan Medical College. Adult patients who needed tracheal intubation under general anaesthesia for elective surgery were enrolled. The data of patients were input into the computer software to calculate the expected visibility of the glottis. The results of tracheal intubation were recorded by anaesthesiologists. The primary observation outcome was the screening performance of the expected visibility of the glottis for difficult tracheal intubation.

RESULTS

The geometric model and software of the GADAS method were successfully developed and are available for use. We successfully observed 2068 patients, of whom 56 patients had difficult intubation. The area under the receiver operating characteristic curve of low expected glottis visibility for predicting difficult laryngoscopy was 0.96 (95% confidence interval [CI]: 0.95-0.96). The sensitivity and specificity were 89.3% (95% CI: 78.1-96.0%) and 94.3% (95% CI: 93.2%-95.3), respectively.

CONCLUSIONS

It is feasible to screen difficult-airway patients by applying computer techniques to simulate geometric changes in the upper airway.

Learning curve for flexible bronchoscope-guided orotracheal intubation for anesthesiology residents: A cumulative sum analysis

BACKGROUND

Endotracheal intubation with a flexible bronchoscope is a well-recognized airway management technique that anesthesiologists must master. Skill acquisition and knowledge must reach an appropriate level before trainees perform independent practice on patients. There are a paucity of evidence-based outcome measures of trainee competence in performing flexible bronchoscopy. The objectives of this study were to 1) construct a learning curve for flexible bronchoscope-guided orotracheal intubation for anesthesiology residents using the CUSUM method and 2) determine the number of procedures required to achieve proficiency.

METHODS

This study included 12 first-year anesthesiology residents with no previous experience with flexible bronchoscopic intubation. Trainees attended theoretical and simulation training and performed flexible bronchoscope-guided orotracheal intubation in adult patients with normal airways under general anesthesia. Number of intubation attempts, intubation success rate, time to intubation, and incidence of dental and mucosal injuries were recorded. The cumulative sum (CUSUM) method was used to evaluate the learning curve of flexible bronchoscope-guided orotracheal intubation.

RESULTS

Trainees performed flexible bronchoscope-guided orotracheal intubation on 364 patients. First-attempt intubation success occurred in 317 (87.1%) patients. Second-attempt intubation success occurred in 23 (6.3%) patients. Overall, the flexible bronchoscope-guided orotracheal intubation success rate was 93.4% (range, 85.3% to 100%). The mean number of orotracheal intubation procedures per trainee was 31 ± 5 (range, 23 to 40). All trainees crossed the lower decision boundary (H0) after 15.1 ± 5.6 procedures (range, 8 to 25 procedures). There was a significant decrease in median intubation time [39s (IQR: 30, 50) vs. 76s (IQR: 54, 119)] (P < 0.001) after crossing the lower decision boundary (H0) compared to before. There were no dental, mucosa, arytenoid or vocal cord trauma events associated with intubation.

CONCLUSIONS

Learning curves constructed with CUSUM analysis showed that all trainees (anesthesiologist residents) included in this study achieved competence (intubation success rates ≥ 80%) in flexible bronchoscope-guided orotracheal intubation. Trainees needed to perform 15 (range, 8 to 25) procedures to achieve proficiency. There was wide variability between trainees.

TRIAL REGISTRATION

Trial registration: Chinese Clinical Trial Register, ChiCTR 2000032166.

Nasendoscopy to Predict Difficult Videolaryngoscopy: A Multivariable Model Development Study

BACKGROUND

Transnasal videoendoscopy (TVE) is the standard of care when staging pharyngolaryngeal lesions. This prospective study determined if preoperative TVE improves the prediction of difficult videolaryngoscopic intubation in adults with expected difficult airway management in addition to the Simplified Airway Risk Index (SARI).

METHODS

374 anesthetics were included (252 with preoperative TVE). The primary outcome was a difficult airway alert issued by the anesthetist after Macintosh videolaryngoscopy. SARI, clinical factors (dysphagia, dysphonia, cough, stridor, sex, age and height) and TVE findings were used to fit three multivariable mixed logistic regression models; least absolute shrinkage and selection operator (LASSO) regression was used to select co-variables.

RESULTS

SARI predicted the primary outcome (odds ratio [OR] 1.33; 95% confidence interval [CI] 1.13-1.58). The Akaike information criterion for SARI (327.1) improved when TVE parameters were added (311.0). The Likelihood ratio test for SARI plus TVE parameters was better than for SARI plus clinical factors (p < 0.001). Vestibular fold lesions (OR 1.82; 95% CI 0.40-8.29), epiglottic lesions (OR 3.37; 0.73-15.54), pharyngeal secretion retention (OR 3.01; 1.05-8.63), restricted view on rima glottidis <50% (OR 2.13; 0.51-8.89) and ≥50% (OR 2.52; 0.44-14.56) were concerning.

CONCLUSION

TVE improved prediction of difficult videolaryngoscopy in addition to traditional bedside airway examinations.

A fully-automatic semi-supervised deep learning model for difficult airway assessment

Background

Difficult airway conditions represent a substantial challenge for clinicians. Predicting such conditions is essential for subsequent treatment planning, but the reported diagnostic accuracies are still quite low. To overcome these challenges, we developed a rapid, non-invasive, cost-effective, and highly-accurate deep-learning approach to identify difficult airway conditions through photographic image analysis.

Methods

For each of 1000 patients scheduled for elective surgery under general anesthesia, images were captured from 9 specific and different viewpoints. The collected image set was divided into training and testing subsets in the ratio of 8:2. We used a semi-supervised deep-learning method to train and test an AI model for difficult airway prediction.

Results

We trained our semi-supervised deep-learning model using only 30% of the labeled training samples (with the remaining 70% used without labels). We evaluated the model performance using metrics of accuracy, sensitivity, specificity, F1-score, and the area under the ROC curve (AUC). The numerical values of these four metrics were found to be 90.00%, 89.58%, 90.13%, 81.13%, and 0.9435, respectively. For a fully-supervised learning scheme (with 100% of the labeled training samples used for model training), the corresponding values were 90.50%, 91.67%, 90.13%, 82.25%, and 0.9457, respectively. When three professional anesthesiologists conducted comprehensive evaluation, the corresponding results were 91.00%, 91.67%, 90.79%, 83.26%, and 0.9497, respectively. It can be seen that the semi-supervised deep learning model trained by us with only 30% labeled samples can achieve a comparable effect with the fully supervised learning model, but the sample labeling cost is smaller. Our method can achieve a good balance between performance and cost. At the same time, the results of the semi-supervised model trained with only 30% labeled samples were very close to the performance of human experts.

Conclusions

To the best of our knowledge, our study is the first one to apply a semi-supervised deep-learning method in order to identify the difficulties of both mask ventilation and intubation. Our AI-based image analysis system can be used as an effective tool to identify patients with difficult airway conditions.

Clinical trial registration

ChiCTR2100049879 (URL: http://www.chictr.org.cn).

Cadaveric emergency cricothyrotomy training for non-surgeons using a bronchoscopy-enhanced curriculum

BACKGROUND

Emergency cricothyrotomy training for non-surgeons is important as rare "cannot intubate or oxygenate events" may occur multiple times in a provider's career when surgical expertise is not immediately available. However, such training is highly variable and often infrequent, therefore, enhancing these experiences is important.

RESEARCH QUESTION

Is bronchoscopy-enhanced cricothyrotomy training in cadavers feasible, and what are the potential benefits provided by this innovation for trainees?

METHODS

This study was performed during implementation of a new program to train non-surgeon providers on cadaveric donors on our campus. Standard training with an instructional video and live coaching was enhanced by bronchoscopic visualization of the trachea allowing participants to review their technique after performing scalpel and Seldinger-technique procedures, and to review their colleagues' technique on live video. Feasibility was measured through assessing helpfulness for trainees, cost, setup time, quality of images, and operator needs. Footage from the bronchoscopy recordings was analyzed to assess puncture-to-tube time, safety errors, and evidence for a training effect within groups. Participants submitted pre- and post-session surveys assessing their levels of experience and gauging their confidence and anxiety with cricothyrotomies.

RESULTS

The training program met feasibility criteria for low costs (<200 USD/donor), setup time (<30 minutes/donor), and operator needs (1/donor). Furthermore, all participants rated the cadaveric session as helpful. Participants demonstrated efficient technique, with a median puncture-to-tube time of 48.5 seconds. Bronchoscopy recordings from 24 analyzed videos revealed eight instances of sharp instruments puncturing the posterior tracheal wall (33% rate), and two instances of improper tube placement (8% rate). Sharp instruments reached potentially dangerous insertion depths beyond the midpoint of the anterior-posterior diameter of the trachea in 58.3% of videos. Bronchoscopic enhancement was rated as quite or extremely helpful for visualizing the trachea (83.3%) and to assess depth of instrumentation (91.7%). There was a significant average increase in confidence (64.4%, P<0.001) and average decrease in performance anxiety (-11.6%, P = 0.0328) after the session. A training effect was seem wherein the last trainee in each group had no posterior tracheal wall injuries.

INTERPRETATION

Supplementing cadaveric emergent cricothyrotomy training programs with tracheal bronchoscopy is feasible, helpful to trainees, and meets prior documented times for efficient technique. Furthermore, it was successful in detecting technical errors that would have been missed in a standard training program. Bronchoscopic enhancement is a valuable addition to cricothyrotomy cadaveric training programs and may help avoid real-life complications.

An Approach to Improve the Effectiveness of the Video-Assisted Intubating Stylet Technique for Tracheal Intubation: A Case Series Report

Direct laryngoscopy and videolaryngoscopy are currently the dominant tools for endotracheal intubation. However, the video-assisted intubating stylet, a type of videolaryngoscopy, has been shown to offer some advantages over these tools, such as rapid intubation time, high first-attempt success rates, less airway stimulation, and high subjective satisfaction. On the other hand, this optical intubating technique also has some technical limitations that need to be addressed, including camera lens fogging, airway path disorientation, and obscured visibility due to secretions. In this clinical report, we describe an approach that improves the visibility of the glottis by introducing a suctioning catheter into the nasopharyngeal airway to enhance the efficiency and accuracy of using the intubating stylet technique for tracheal intubation.

Management of the Difficult Airway

ABSTRACT

Airway management is a fundamental component of care during resuscitation of critically ill and injured children. In addition to predicted anatomic and physiologic differences in children compared with adults, certain conditions can predict potential difficulty during pediatric airway management. This review presents approaches to identifying pediatric patients in whom airway management is more likely to be difficult, and discusses strategies to address such challenges. These strategies include optimization of effective bag-mask ventilation, alternative approaches to laryngoscopy, use of adjunct airway devices, modifications to rapid sequence intubation, and performance of surgical airways in children. The importance of considering systems of care in preparing for potentially difficult pediatric airways is also discussed.

Evaluation and Management of Airway Foreign Bodies in the Emergency Department Setting

BACKGROUND

Airway foreign body can be a life-threatening issue in pediatric and adult patients, and the majority of these patients will first present to the emergency department.

OBJECTIVE

This article provides a narrative review of the diagnosis and management of airway foreign bodies for the emergency clinician.

DISCUSSION

Foreign bodies in the upper and lower airways are potentially life threatening. This affects all age groups but is more common in pediatric patients. A history of a witnessed ingestion or aspiration event should raise the clinical suspicion for an aspirated foreign body. Patients with upper-airway foreign bodies are more likely to present in respiratory distress when compared with lower-airway foreign bodies, which often present with more subtle signs. Stridor, drooling, and wheezing suggest respiratory distress, but the presenting clinical picture is often unclear and may only include a cough. Immediate intervention is required in the patient with hemodynamic instability or respiratory distress. Airway management including laryngoscopy, fiberoptic bronchoscopy, and cricothyrotomy may be needed in these patients, with the emphasis on removing the obstructing foreign body and securing the airway. Specialist consultation can assist in retrieving the foreign body and managing the airway. If the patient is stable, imaging and specialist consultation for potential operating room intervention should be considered.

CONCLUSIONS

An understanding of the presentation, evaluation, and management of the patient with an airway foreign body is essential for emergency clinicians.

Anaesthetic considerations in Shrinking Man syndrome: two case reports

BACKGROUND

Shrinking Man syndrome (SMS) is a rare but often serious complication of dialysis-dependent end-stage renal disease, characterized by significant loss of height, bone pain, bone deformity, and skin itching. Patients with SMS always have abnormal facial changes and cardiovascular system damage (manifested by hypertension, hypotension, cardiovascular calcification, and valvular heart disease), which pose a great challenge to anaesthesiologists. The purpose of this report is to describe our anaesthetic experience regarding two patients with SMS combined with alterations of the airway and cardiovascular system.

CASE PRESENTATION

We describe two cases of SMS treated at West China Hospital, a tertiary care centre in Chengdu, China. All cases met the diagnostic criteria, which comprised 1) dialysis-dependent end-stage renal disease, 2) loss of height, and 3) bone pain and bone deformity. One patient had an anticipated difficult airway and moderate-to-severe mitral stenosis. The other patient presented with significant hypotension. Anaesthetic considerations included awake fibreoptic bronchoscopy-assisted tracheal intubation, real-time transoesophageal echocardiogram monitoring and individualized blood pressure management strategies.

CONCLUSION

This case series highlights the importance of adequate preoperative assessment and preparation, as well as individualized anaesthetic management, in patients with SMS.

Comparison of a polyvinyl chloride tube with a wire-reinforced tube for tracheal intubation through the SaCoVLM video laryngeal mask airway: protocol for a randomised controlled study

INTRODUCTION

The SaCoVLM is a new type of video intubating laryngeal mask airway (LMA), and it is the first LMA to realise continuous visual monitoring. There is a lack of studies on intubation using the SaCoVLM. The aim of this study is to compare the success rate of intubation with polyvinyl chloride (PVC) tubes and wire-reinforced (WR) tubes using the SaCoVLM.

METHODS AND ANALYSIS

This prospective, single-centre, single-blind, parallel-arm, randomised controlled study will be conducted in a tertiary university hospital in China. We will include 104 patients undergoing elective laparoscopic surgery under general anaesthesia. Patients will be randomly assigned to the PVC tracheal tube group (n=52, PVC group) or the WR tracheal tube group (n=52, WR group). The primary outcome is the total success rate of intubation. The secondary outcomes are the first success rate of intubation, the time of tracheal intubation, the site of the first contact, the adjustment action for tracheal intubation, haemodynamic fluctuation during intubation and extubation, incidence of trauma as evidenced by blood, and the incidence rates of postoperative sore throat, hoarseness, and dysphagia.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of the First Affiliated Hospital of Shandong First Medical University (YXLL-KY-2022 (008)). All participants will provide written informed consent. The results will be disseminated through peer-reviewed publications and at conferences or congresses.

TRIAL REGISTRATION NUMBER

NCT05338827.

Potential Fatal Complication of Neurofibromatosis Type 1: Acute Upper Airway Obstruction Due to Ruptured Transverse Cervical Artery Aneurysm

Neurofibromatosis type 1 (NF1) can cause vascular complications even in undiagnosed NF1 patients. A ruptured aneurysm of the branches of the subclavian artery is a rare but life-threatening event, and the hemorrhage can cause upper airway obstruction. We present a case of NF1 patient with a ruptured transverse cervical artery aneurysm, which led to a nearly obstructed airway. A 52-year-old man who was not previously diagnosed with NF1 presented with sudden pain from the left shoulder to the neck. Since childhood, he has had multiple cutaneous neurofibromas and café-au-lait macules, and freckling in the bilateral axillae. His swollen left side of the neck and left shoulder suggested a hematoma, which compressed the upper airway. Contrast-enhanced computed tomography revealed a cervical hematoma caused by a ruptured aneurysm of the transverse cervical artery. We performed awake fiberoptic intubation because a difficult airway was predicted and surgical airway management may have been impossible due to the anterior cervical hematoma. His airway was secured, and his aneurysm was successfully treated by coil embolization. Based on his cutaneous findings, he was finally diagnosed with NF1. Those who have café-au-lait macules and cutaneous neurofibromas may present with acute cervical hematoma, and it is important to consider the possibility of ruptured aneurysms in the neck region. When patients develop an acute cervical hematoma that causes an acute upper airway obstruction, emergency physicians should consider awake fiberoptic intubation to secure the airway.

Case of laryngeal venous malformations requiring repeated advanced airway management in the perioperative course

Laryngeal venous malformations rarely but do cause airway obstruction resulting in life-threatening events. The perioperative airway management for the patients with them has not been well established. We suggest a strategy for laryngeal venous malformations management in the patients who undergo surgery in addition to planning for airway management.

Airway Management in Adult Intensive Care Units: A Survey of Two Regions in China

The critical medicine residency training in China started in 2020, but no investigation on the practice of tracheal intubation in ICUs in China has been conducted. A survey was sent to the adult ICUs in public hospitals in Shenzhen (SZ) city and Xinjiang (XJ) province using a WeChat miniprogram to be completed by intensive care physicians. It included questions on training on intubation, intubation procedures, and changes in the use of personal protective equipment due to COVID-19. We analyzed 301 valid questionnaires which were from 72 hospitals. A total of 37% of respondents had completed training in RSI (SZ, 40% vs. XJ, 30%; $p=0.066$ ), and 50% had participated in a course on the emergency front of the neck airway (SZ, 47% vs. XJ, 54%; $p=0.256$ ). Video laryngoscopy was preferred by 75% of respondents. Manual ventilation (56%) and noninvasive positive pressure ventilation (34%) were the first-line options for preoxygenation. For patients with a high risk of aspiration, nasogastric decompression (47%) and cricoid pressure (37%) were administered. Propofol (82%) and midazolam (70%) were the most commonly used induction agents. Only 19% of respondents routinely used neuromuscular blocking agents. For patients with difficult airways, a flexible endoscope was the most commonly used device by 76% of respondents. Most participants (77%) believed that the COVID-19 pandemic had significantly increased their awareness of the need for personal protective equipment during tracheal intubation. Our survey demonstrated that the ICU doctors in these areas lack adequate training in airway management.

Ultrasound measurements for evaluation of changes in upper airway during anaesthesia induction and prediction difficult laryngoscopy: a prospective observational study

Upper airway collapsibility after anaesthesia induction may be associated with unpredictable difficult airway. However, most works on airway anatomy are tended to morphological description before anaesthesia. This study aimed to evaluate the changes of upper airway after anaesthesia induction and using pre-anesthetic ultrasound measurements to predict Difficult Laryngoscopy (DL). We included 104 eligible subjects with complete data, who were performed tracheal intubations under general anaesthesia in the study. The upper airway changes before and after anaesthesia induction were determined by seven neck ultrasound measurements, included as follow: (1) Distance from skin to under surface of Tongue (DT), (2) Thickness of the thickest part of Tongue body (TT), (3) Hyoid Mental Distance (HMD), (4) Depth of Hyoid (DH), (5) Width of Hyoid (WH), (6) Distance from Skin to Epiglottis (DSE), (7) Depth of the anterior combination of the Vocal Cords (DVC). DL was evaluated with Cormack-Lehane (CL). Data regarding HMD [from 45.3 (42.4-48.5) to 41.1 (38.5-44.9) mm], DH [from 8.7 (6.6-10.9) to 7.0 (5.3-9.1) mm], DSE [from 20.1 (16.6-22.5) to 19.5 (16.5-21.6) mm] and the DVC [from 7.1 (5.7-8.3) to 6.8 (5.7-7.9) mm] were decreased (P < 0.05), while the DT [from 15.9 (13.1-18.4) to 17.4 (14.5-19.8) mm] was increased (P > 0.05) after anaesthesia induction. Additionally, when cut-off value of DSE was 21.25 mm before anaesthesia, it may be better predicted to DL [sensitivity 80.0% (95% CI: 60.7-91.6%) and specificity 83.8% (95% CI: 73.0-91.0%)]. The upper airway after induction showed the propensity of collapsibility by ultrasound measurements. Compared with other indicators, the DSE assessed by ultrasound might be considered to a valuable predictor of DL.Trial registration: The study was registered in ClinicalTrials.gov on 23th Jan 2019, ChiCTR1900021123.

Multidisciplinary Difficult Airway Team Characteristics, Airway Securement Success, and Clinical Outcomes: A Systematic Review

Objective:

To investigate whether implementation of a multidisciplinary airway team was associated with improvement in (1) rate of successful airway securement at first attempt; (2) time to secure airway; and (3) overall complication rate in patients with a difficult airway, as compared with usual care.

Data Sources:

Ovid Medline, Embase, Scopus, Cochrane Central, and CINAHL databases.

Review Methods:

Systematic review of literature on inpatient multidisciplinary team management of difficult airways, including all studies performed in inpatient settings, excluding studies of ventilator weaning, flight/military medicine, EXIT procedures, and simulation or educational studies. DistillerSR was used for article screening and risk of a bias assessment to evaluate article quality. Data was extracted on study design, airway team composition, patient characteristics, and clinical outcomes including airway securement, complications, and mortality.

Results:

From 5323 studies screened, 19 studies met inclusion criteria with 4675 patients. Study designs included 12 quality improvement projects, 6 cohort studies, and 1 randomized controlled trial. Four studies evaluated effect of multidisciplinary difficult airway teams on airway securement; all reported higher first attempt success rate with team approach. Three studies reported time to secure the difficult airways, all reporting swifter airway securement with team approach. The most common difficult airway complications were hypoxia, esophageal intubation, hemodynamic instability, and aspiration. Team composition varied, including otolaryngologists, anesthesiologists, intensivists, nurses, and respiratory care practitioners.

Conclusion:

Multidisciplinary difficult airway teams are associated with improved clinical outcomes compared to unstructured emergency airway management; however, studies have significant heterogeneity in team composition, algorithms for airway securement, and outcomes reported. Further evidence is necessary to define the clinical efficacy, cost-effectiveness, and best practices relating to implementing difficult airway teams in inpatient settings.

Endotracheal Tube Size in Critically Ill Patients

Importance

Many patients who survive critical illness are left with laryngeal functional impairment from endotracheal intubation that permanently limits their recovery and quality of life. Although the risk for laryngeal injury increases with larger endotracheal tube sizes, there are no data delineating the association of smaller endotracheal tube sizes with survival or acute recovery from critical illness.

Objective

To determine if smaller endotracheal tubes are noninferior to larger endotracheal tubes with respect to critical illness outcomes.

Design, Setting, and Participants

This propensity score-matched retrospective cohort study included all adult patients who underwent endotracheal intubation in the emergency department or intensive care unit and received mechanical ventilation for at least 12 hours from June 2020 to November 2020 at a single tertiary referral academic medical center.

Exposures

Endotracheal intubation.

Main Outcomes and Measures

Propensity score-matched analyses were performed with respect to the primary end point of 30-day all-cause in-hospital survival as well as the secondary end points of duration of invasive mechanical ventilation, length of hospital stay, mean peak inspiratory pressure, 30-day readmission, need for reintubation, and need for tracheostomy or gastrostomy tube placement.

Results

Overall, 523 participants (64%) were men and 291 (36%) were women. Of these, 814 patients were categorized into 3 endotracheal tube groups: small for height (n = 182), appropriate for height (n = 408), and large for height (n = 224). There was not a significant difference in 30-day all-cause in-hospital survival between groups ([HR, 1.1; 95% CI, 0.7-1.7] for small vs appropriate; [HR, 1.1; 95% CI, 0.7-1.6] for large vs appropriate). Patients with small-for-height endotracheal tubes had longer intubation durations (mean difference, 32.5 hrs [95% CI, 6.4-58.6 hrs]) compared with patients with appropriate-for-height tubes.

Conclusions and Relevance

Despite differences in intubation duration, the results of this cohort study suggest that smaller endotracheal tube sizes are not associated with impaired survival or recovery from critical illness. They support future prospective exploration of the association of smaller endotracheal tube sizes with recovery from critical illness.

A model to predict difficult airway alerts after videolaryngoscopy in adults with anticipated difficult airways - the VIDIAC score

A model to classify the difficulty of videolaryngoscopic tracheal intubation has yet to be established. The videolaryngoscopic intubation and difficult airway classification (VIDIAC) study aimed to develop one based on variables associated with difficult videolaryngoscopic tracheal intubation. We studied 374 videolaryngoscopic tracheal intubations in 320 adults scheduled for ear, nose and throat or oral and maxillofacial surgery, for whom airway management was expected to be difficult. The primary outcome was whether an anaesthetist issued a 'difficult airway alert' after videolaryngoscopy. An alert was issued after 183 (49%) intubations. Random forest and lasso regression analysis selected six intubation-related variables associated with issuing an alert: impaired epiglottic movement; increased lifting force; direct epiglottic lifting; vocal cords clearly visible; vocal cords not visible; and enlarged arytenoids. Internal validation was performed by a 10-fold cross-validation, repeated 20 times. The mean (SD or 95%CI) area under the receiver operating characteristic curve was 0.92 (0.05) for the cross validated coefficient model and 0.92 (0.89-0.95) for a simplified unitary score (VIDIAC score with component values of -1 or 1 only). The calibration belt for the coefficient model was consistent with observed alert probabilities, from 0% to 100%, while the unitary VIDIAC score overestimated probabilities < 20% and underestimated probabilities > 70%. Discrimination of the VIDIAC score for patients more or less likely to be issued an alert was better than discrimination by the Cormack-Lehane classification, with mean (95%CI) areas under the receiver operating characteristic curve of 0.92 (0.89-0.95) vs. 0.75 (0.70-0.80), respectively, p < 0.001. Our model and score can be used to calculate the probabilities of difficult airway alerts after videolaryngoscopy.

Assessment of predictors for difficult intubation and laryngoscopy in adult elective surgical patients at Tikur Anbessa Specialized Hospital, Ethiopia: A cross-sectional study

Background

General anesthesia is not without morbidity. One of the well-known life-threatening events associated with general anesthesia is difficult airway which can happen during induction of anesthesia while attempting to insert the endotracheal tube with the aid of a laryngoscope. Difficult intubation, inadequate ventilation, and esophageal intubation are the principal causes of death or brain damage related to airway manipulation.

Objective

The main objective of this study was to assess the magnitude and predictors for difficult laryngoscopy and intubation among surgical patients who underwent elective surgery under general anesthesia with endotracheal intubation at Tikur Anbessa Specialized Hospital from February 1 to March 30, 2019.

Materials &method

An institutional based cross sectional study was conducted from February 1 to March 30, 2019 on patients who underwent elective surgery under general anesthesia with endotracheal intubation. Data on socio-demographic characteristics, preanesthetic airway assessment and laryngoscopic view were collected. Data were analyzed by SPSS Version 20.0. Chi- square test, binary logistic regression and multivariate analysis were performed. Tables and texts were used to present data. A p value less than 0.05 was considered as statistically significant.

Results

The magnitude of difficult laryngoscopy, difficult intubation, and failed intubation were 12.2%, 6.1%, and 0.67%, respectively. Upper Lip Bite Test (ULBT) had a higher sensitivity (90.2%) and negative predictive value of 85.3%. Mallampati had a sensitivity of 45.8% and negative predictive value of 86% in predicting difficult laryngoscopy. Mallampati grade, thyromental distance and ratio of height to thyromental distance (HRTMD) have also showed greater sensitivity (69.6%, 58.3% and 47.8%, respectively) when compared to other tests in predicting difficult intubation. Mallampati class, upper lip bite test (ULBT) and inter-incisor distance (IID) are independent predictors for difficult laryngoscopy (p < 0.05). Furthermore, Mallampati class, Thyromental distance and ratio of height to thyromental distance (HRTMD) are identified as independent predictors of difficult intubation (p < 0.001).

Conclusion

and recommendation: Mallampati class, Thyromental distance and Ratio of height to Thyromental distance (HRTMD) can predict the probability of difficult endotracheal intubation in adult patients. Whereas, Mallampati class and upper lip bite test (ULBT) predicts higher probability for difficult laryngoscopy.

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The magnitude of difficult laryngoscopy and intubation were 12.2% and 6.1%, respectively.

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Mallampati class, TMD and HRTMD were predictors of difficult intubation.

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Upper Lip Bite Test had a higher sensitivity to predict difficult laryngoscopy.

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Mallampati class, Upper Lip Bite Test and IID predicts difficult laryngoscopy.

Factores clínicos asociados a extubación fallida y a estridor laríngeo post-extubación en pacientes adultos con ventilación mecánica invasiva

Introducción. La intubación orotraqueal es un procedimiento que conlleva riesgos como la extubación fallida y el estridor laríngeo, los cuales aumentan el riesgo de morbilidad. Objetivo. Identificar los factores asociados a extubación fallida temprana (≤24 horas) y al desarrollo de estridor laríngeo post-extubación en pacientes adultos con ventilación mecánica invasiva (VMI). Materiales y métodos. Estudio de casos y controles con recolección prospectiva de información realizado en la unidad de cuidados intensivos (UCI) de un hospital de IV nivel de Bogotá, Colombia, entre abril de 2019 y febrero de 2020. Se incluyeron 180 pacientes con VMI ≥24 horas y al menos ≥1 intento de extubación: 30 casos, definidos como pacientes con extubación fallida temprana (≤24 horas a la extubación) y 150 controles. Las diferencias en las variables consideradas entre casos y controles se determinaron mediante las pruebas t de Student y Chi 2 o exacta de Fisher. Además, se realizó un análisis multivariado (modelo de regresión logística no condicional) para determinar los factores asociados con extubación fallida y estridor laríngeo post-extubación, calculando los Odds ratio (OR) con sus respectivos intervalos de confianza al 95% (IC95%). Se consideró un nivel de significancia de p<0.05. Resultados. La extubación fallida temprana y el estridor laríngeo tuvieron una prevalencia de 16.66% (n=30) y 3.89% (n=7), respectivamente. En el análisis multivariado, el antecedente de intubación (OR=4.27, IC95%=1.44-12.66), la presencia de cáncer activo (OR= 2.92, IC95%=1.08-7.90) y ser diagnosticado con neumonía (OR=2.84, IC95%=1.15-6.99) se asociaron significativamente con extubación fallida, mientras que la duración de la VMI (OR=1.53, IC95%=1.18-1.99) y el antecedente de intubación (OR=37.9, IC95%=2.22-650.8), con estridor laríngeo post-extubación. Conclusiones. Con base en los resultados aquí obtenidos, se sugiere considerar factores como antecedente de intubación previa, comorbilidad con cáncer y diagnóstico de neumonía en la estratificación de estos pacientes críticos para aumentar la probabilidad de una extubación exitosa.

Anesthesiology trainees performing flexible scope intubation in spontaneously breathing patients in the left lateral position and the supine position: a prospective randomized trial

Background

Flexible scope intubation is an important airway management skill that requires hands-on training in a real airway. We compared flexible scope intubation by trainees between patients in the left lateral and supine positions.

Methods

Forty patients aged 20 to 80 years with American Society of Anesthesiologists physical status class I to III were scheduled for elective surgery under general endotracheal anesthesia in Ramathibodi Hospital from February 2020 to June 2020. Patients were randomly assigned to be intubated in one of two positions: supine (Group S) or left lateral (Group L). Trainees performed flexible scope intubation in sedated patients under the supervision of an attending anesthesiologist. Intubation success, time to successful intubation, number of attempts, airway adjustment maneuvers, and hemodynamic changes were compared between groups.

Results

Patient characteristics did not differ between groups except for Mallampati airway classification. The rate of successful intubation on the first attempt and intubation time did not significantly differ between groups. The proportion of patients who required a jaw thrust during intubation was significantly lower in Group L (10.5% vs. 85%; P < 0.01). Blood pressure and oxygen saturation declined in both groups after intubation. The relative risk of desaturation in patients in the left lateral position compared with the supine position was 0.44 (0.1649–1.1978).

Conclusion

The rate of successful flexible scope intubation on the first attempt and intubation time did not differ between the groups. The proportion of patients who required a jaw thrust maneuver was significantly lower in patients in the left lateral position.

Trial registration

https://www.thaiclinicaltrials.org/ (TCTR20200208001) on 08/02/2020.

Nomograms for predicting difficult airway based on ultrasound assessment

Background

Accurate prediction of the difficult airway (DA) could help to prevent catastrophic consequences in emergency resuscitation, intensive care, and general anesthesia. Until now, there is no nomogram prediction model for DA based on ultrasound assessment. In this study, we aimed to develop a predictive model for difficult tracheal intubation (DTI) and difficult laryngoscopy (DL) using nomogram based on ultrasound measurement. We hypothesized that nomogram could utilize multivariate data to predict DTI and DL.

Methods

A prospective observational DA study was designed. This study included 2254 patients underwent tracheal intubation. Common and airway ultrasound indicators were used for the prediction, including thyromental distance (TMD), modified Mallampati test (MMT) score, upper lip bite test (ULBT) score temporomandibular joint (TMJ) mobility and tongue thickness (TT). Univariate and the Akaike information criterion (AIC) stepwise logistic regression were used to identify independent predictors of DTI and DL. Nomograms were constructed to predict DL and DTL based on the AIC stepwise analysis results. Receiver operating characteristic (ROC) curves were used to evaluate the accuracy of the nomograms.

Results

Among the 2254 patients enrolled in this study, 142 (6.30%) patients had DL and 51 (2.26%) patients had DTI. After AIC stepwise analysis, ULBT, MMT, sex, TMJ, age, BMI, TMD, IID, and TT were integrated for DL nomogram; ULBT, TMJ, age, IID, TT were integrated for DTI nomogram. The areas under the ROC curves were 0.933 [95% confidence interval (CI), 0.912–0.954] and 0.974 (95% CI, 0.954–0.995) for DL and DTI, respectively.

Conclusion

Nomograms based on airway ultrasonography could be a reliable tool in predicting DA.

Trial registration

Chinese Clinical Trial Registry (No. ChiCTR-RCS-14004539), registered on 13th April 2014.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01567-y.

Tracheal Tube-Mounted Camera Assisted Intubation vs. Videolaryngoscopy in Expected Difficult Airway: A Prospective, Randomized Trial (VivaOP Trial)

Background: Tracheal intubation in patients with an expected difficult airway may be facilitated by videolaryngoscopy (VL). The VL viewing axis angle is specified by the blade shape and visualization of the larynx may fail if the angle does not meet anatomy of the patient. A tube with an integrated camera at its tip (VST, VivaSight-SL) may be advantageous due to its adjustable viewing axis by means of angulating an included stylet.

Methods: With ethics approval, we studied the VST vs. VL in a prospective non-inferiority trial using end-tidal oxygen fractions (etO₂) after intubation, first-attempt success rates (FAS), visualization assessed by the percentage of glottis opening (POGO) scale, and time to intubation (TTI) as outcome parameters.

Results: In this study, 48 patients with a predicted difficult airway were randomized 1:1 to intubation with VST or VL. Concerning oxygenation, the VST was non-inferior to VL with etO₂ of 0.79 ± 0.08 (95% CIs: 0.75–0.82) vs. 0.81 ± 0.06 (0.79–0.84) for the VL group, mean difference 0.02 (−0.07 to 0.02), p = 0.234. FAS was 79% for VST and 88% for VL (p = 0.449). POGO was 89 ± 21% in the VST-group and 60 ± 36% in the VL group, p = 0.002. TTI was 100 ± 57 s in the VST group and 68 ± 65 s in the VL group (p = 0.079). TTI with one attempt was 84 ± 31 s vs. 49 ± 14 s, p < 0.001.

Conclusion: In patients with difficult airways, tracheal intubation with the VST is feasible without negative impact on oxygenation, improves visualization but prolongs intubation. The VST deserves further study to identify patients that might benefit from intubation with VST.

Extracorporeal membrane oxygenation for thyroid surgery in patients with severe tracheal stenosis

Venovenous extracorporeal membrane oxygenation is effective for maintaining gas exchange in patients with respiratory failure or severe tracheal stenosis. Perioperative anesthetic management of severe airway obstruction can be associated with ventilation or intubation difficulties. Consequently, venovenous extracorporeal membrane oxygenation could be an option for treating such patients to avoid potential risks. However, only a limited number of similar cases have been reported. Therefore, we have summarized two cases to provide theoretical and practical references for treating patients with respiratory failure or severe tracheal stenosis using extracorporeal membrane oxygenation.

Effect of Use of a Bougie vs Endotracheal Tube With Stylet on Successful Intubation on the First Attempt Among Critically Ill Patients Undergoing Tracheal Intubation: A Randomized Clinical Trial

IMPORTANCE

For critically ill adults undergoing emergency tracheal intubation, failure to intubate the trachea on the first attempt occurs in up to 20% of cases and is associated with severe hypoxemia and cardiac arrest. Whether using a tracheal tube introducer ("bougie") increases the likelihood of successful intubation compared with using an endotracheal tube with stylet remains uncertain.

OBJECTIVE

To determine the effect of use of a bougie vs an endotracheal tube with stylet on successful intubation on the first attempt.

DESIGN, SETTING, AND PARTICIPANTS

The Bougie or Stylet in Patients Undergoing Intubation Emergently (BOUGIE) trial was a multicenter, randomized clinical trial among 1102 critically ill adults undergoing tracheal intubation in 7 emergency departments and 8 intensive care units in the US between April 29, 2019, and February 14, 2021; the date of final follow-up was March 14, 2021.

INTERVENTIONS

Patients were randomly assigned to use of a bougie (n = 556) or use of an endotracheal tube with stylet (n = 546).

MAIN OUTCOMES AND MEASURES

The primary outcome was successful intubation on the first attempt. The secondary outcome was the incidence of severe hypoxemia, defined as a peripheral oxygen saturation less than 80%.

RESULTS

Among 1106 patients randomized, 1102 (99.6%) completed the trial and were included in the primary analysis (median age, 58 years; 41.0% women). Successful intubation on the first attempt occurred in 447 patients (80.4%) in the bougie group and 453 patients (83.0%) in the stylet group (absolute risk difference, -2.6 percentage points [95% CI, -7.3 to 2.2]; P = .27). A total of 58 patients (11.0%) in the bougie group experienced severe hypoxemia, compared with 46 patients (8.8%) in the stylet group (absolute risk difference, 2.2 percentage points [95% CI, -1.6 to 6.0]). Esophageal intubation occurred in 4 patients (0.7%) in the bougie group and 5 patients (0.9%) in the stylet group, pneumothorax was present after intubation in 14 patients (2.5%) in the bougie group and 15 patients (2.7%) in the stylet group, and injury to oral, glottic, or thoracic structures occurred in 0 patients in the bougie group and 3 patients (0.5%) in the stylet group.

CONCLUSIONS AND RELEVANCE

Among critically ill adults undergoing tracheal intubation, use of a bougie did not significantly increase the incidence of successful intubation on the first attempt compared with use of an endotracheal tube with stylet.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03928925