The difficult airway with recommendations for management--part 2--the anticipated difficult airway

Improving difficult direct laryngoscopy prediction using deep learning and minimal image analysis: a single-center prospective study

Accurate prediction of difficult direct laryngoscopy (DDL) is essential to ensure optimal airway management and patient safety. The present study proposed an AI model that would accurately predict DDL using a small number of bedside pictures of the patient's face and neck taken simply with a smartphone. In this prospective single-center study, adult patients scheduled for endotracheal intubation under general anesthesia were included. Patient pictures were obtained in frontal, lateral, frontal-neck extension, and open mouth views. DDL prediction was performed using a deep learning model based on the EfficientNet-B5 architecture, incorporating picture view information through multitask learning. We collected 18,163 pictures from 3053 patients. After under-sampling to achieve a 1:1 image ratio of DDL to non-DDL, the model was trained and validated with a dataset of 6616 pictures from 1283 patients. The deep learning model achieved a receiver operating characteristic area under the curve of 0.81-0.88 and an F1-score of 0.72-0.81 for DDL prediction. Including picture view information improved the model's performance. Gradient-weighted class activation mapping revealed that neck and chin characteristics in frontal and lateral views are important factors in DDL prediction. The deep learning model we developed effectively predicts DDL and requires only a small set of patient pictures taken with a smartphone. The method is practical and easy to implement.

Airway Considerations in Vascular Lesions

Vascular anomalies of the head and neck frequently involve the upper aerodigestive tract and can cause some level of airway obstruction. It is important to fully evaluate the extent of a lesion and resultant functional impairment with a flexible fiberoptic laryngoscopy. Treating these lesions is difficult and considering how to manage the airway during a procedure is critical. A multidisciplinary approach should be used for airway management with alternative intubation plans established prior to induction of anesthesia. Edema and hemorrhage are expected complications from the treatment of vascular anomalies and should be considered when planning for extubation at the end of a procedure.

A Predictor of Difficult Airway: The Tasli Classification in Transnasal Flexible Laryngoscopy

INTRODUCTION

Difficult airway is defined as difficulty or failure in one or more steps in upper airway management. Evaluation of the upper airway with physical examination methods and endoscopic devices is crucial in predicting difficult airway. The aim of this study was to evaluate bedside tests, Cormack Lehane (CL) and Tasli Classification (TC) scores of the patients and it was aimed to reveal the role of TC which will be performed preoperatively as a predictor of difficult tracheal intubation (DTI).

METHODS

The study included a total of 98 patients who underwent surgical treatment under general anesthesia. Demographic data, including age, gender, and body mass index (BMI), and bedside tests consisting Modified Mallampati Classification (MMC), thyromental (TD) and sternomental (SD) distances, neck circumference (NC), interincisor distance (IID), CL and TC were recorded.

RESULTS

Evaluation was made of 64 (65.3%) male and 34 (34.7%) female patients ranging in age from 18 to 84 years (mean age: 50.35 ± 0.47 years). The successfully intubated patients (SIP)  group comprised 68 (69.4%) patients, and the difficult intubation patients (DIP) group, 30 (30.6%). According to CL, the numbers of SIP and DIP constituting grade 1 was 29 (42.6%) and one (3.3%); grade 2a was 29 (42.6%) and one (3.3%); grade 2b was eight (11.8%) and three (10%); grade 3a was one (1.5%) and six (20%); grade 3b was one (1.5%) and 14 (46.7%) respectively. Grade 4 was only detected in the DIP group in 5 (16.7%) patients. According to TC, the numbers of SIP and DIP constituting grade 1 was 20 (29.4%) and 1 (3.3%); grade 2a was 37 (54.4%) and seven (23.3%); grade 2b was 10 (14.7%) and 18 (60%); grade 3 was one (1.5%) and two (6.7%) respectively. Grade 4 was only detected in the DIP group in two (6.7%) patients.

CONCLUSION

The TC, CL, NC and BMI scores were higher in the DIP group and higher TC scores (grade 2b, 3, and 4) can be a predictor of difficult airway. However, it may be more beneficial to use TC as a complementary diagnostic tool with bedside tests such as NC, SM, TM and MMC, rather than used alone.

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

BACKGROUND

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

OBJECTIVES

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

DESIGN

A systematic review of randomised controlled trials and observational studies.

DATA SOURCES

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

ELIGIBILITY CRITERIA

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

RESULTS

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

CONCLUSIONS

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

CLINICAL TRIAL REGISTRATION

CRD42021250574.

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.

Sex Disparities in Prehospital Advanced Cardiac Life Support in Out-of-Hospital Cardiac Arrest in South Korea

OBJECTIVE

Sex disparities have been reported in the prehospital and in-hospital care among patients with out-of-hospital cardiac arrest (OHCA). The aim of this study was to investigate the association between sex and prehospital advanced cardiac life support (ACLS) interventions provided by emergency medical services (EMS).

METHODS

This was a cross-sectional observational study using a nationwide OHCA registry in South Korea. The study included adult OHCAs with presumed cardiac etiology from January 2016 to December 2019. The main exposure was the sex of the victim, and the primary outcomes were prehospital ACLS interventions, including advanced airway management (AAM), intravenous access (IV), and epinephrine (EPI) administration. Multivariable logistic regression analysis accounted for age group, health insurance, comorbidities, place of arrest, urbanization level, witness status, bystander CPR and initial rhythm was performed to calculate adjusted odds ratios (AORs) with 95% confidence intervals (95% CIs).

RESULTS

Among 71,154 eligible patients, females with OHCA received less prehospital ACLS interventions than males: risk difference, (95% CIs) -2.76 (-3.41;-2.11) for AAM, -6.03 (-6.79;-5.27) for IV, and -3.81 (-4.37;-3.25) for EPI. In multivariable logistic regression analysis, female sex was significantly associated with a lower probability of prehospital ACLS provision: AOR, (95% CIs) 0.87 (0.84-0.91) for AAM, 0.85 (0.82-0.88) for IV, and 0.81 (0.77-0.84) for EPI.

CONCLUSION

Compared to male patients, female patients were less likely to receive prehospital ACLS. This offers opportunities for EMS systems to reduce disparities and to improve compliance with OHCA resuscitation guidelines and outcomes through quality improvement and educational interventions.

Blunt and Penetrating Airway Trauma

Airway injury, be that penetrating or blunt, is a high-stakes high-stress management challenge for any airway manager and their team. Penetrating and blunt airway injury vary in injury patterns requiring prepracticed skills and protocols coordinating care between specialties. Variables including patient cooperation, coexisting injuries, cardiorespiratory stability, care location (remote vs tertiary care center), and anticipated course of airway injury (eg, oxygenating well and comfortable vs increasing subcutaneous emphysema) all play a role in determining airway if and when airway management is required. Direct airway trauma is relatively infrequent, but its presence should be accompanied by in-person or virtual otolaryngology support.

Airway Ultrasound for Anesthesia and in Intensive Care Patients-A Narrative Review of the Literature

Ultrasound is an everyday diagnostic tool. In anesthesia and intensive care, it has a role as an adjuvant for many procedures, including the evaluation of the airway. Ultrasound airway evaluation can help predict a difficult airway, visualize the proper positioning of an intubation cannula, or evaluate the airway post-intubation. Protocols need to be established for the better integration of ultrasound in the airway evaluation, however until a consensus is reached in this respect, the ultrasound is a reliable aid in anesthesia and intensive care.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Assessment of pre-anesthesia machine check and airway equipment preparedness: A cross-sectional study

Background

Anesthesia Equipment malfunction is one of the most common factors contributing to intraoperative surgical patient morbidity and mortality. It is impossible to give anesthesia without proper anesthesia machine checks and airway equipment preparation. Therefore, all anesthesia professionals should make sure that the anesthetic machine and equipment are working correctly.

Method

An institutional-based prospective observational study was conducted at the University Comprehensive Specialized Hospital, Operation rooms, from April 10, 2020 to May 10, 2020. About 90 anesthetists were working regularly in the operation theater both emergency and elective patients. Those include; 26 Msc holders, 17 MSc students, 7 BSc anesthetists, and 40 graduating BSc students. These descriptive data were presented with frequency, percentage, and table.

Result

The overall compliance rate was 87%. Whereas; 12.46% of clinicians have not met the standard. Out of standards that were not performed, 25.81% were not available from the setup.

Conclusion

The result shows that there was poor compliance with anesthesia machine check and equipment preparation before anesthesia in the operation theater according.

•

It is impossible to give anesthesia without proper anesthesia machine checks and airway equipment preparation.

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Anesthesia Equipment malfunction is one of the most common factors contributing to intraoperative complications.

•

The overall compliance rate was (87%).

•

There was poor compliance of anesthesia machine check and airway equipment preparation.

Head & Neck Hemorrhage: Technical tools and tricks

Background

The purpose of the present work is to provide a fresh, simple, and accessible document for all surgeons who treat traumatic hemorrhage from the head and neck.

Methods

This article arose from the work of a consortium of experienced trauma surgeons who collaborated to produce a first-of-its-kind surgical course for multifocal hemorrhage control. The "Bloody Simple Hemorrhage control masterclass course" has been offered at national and international venues since 2019 and has been both well received by participants and well regarded in academic trauma surgical circles. This paper—and the series of articles which accompany it—was meant to be a literature companion to or extension of the Bloody Simple course, a way to distill and digest the hemorrhage control strategies espoused therein but in the form of a journal article.

Results

The result of this work is a succinct and experience-based set of principles for conquering life-threatening, traumatic bleeding from a variety of sources in the head and neck.

Conclusion

This article translates experience and evidence into a simple and digestible format that will provide a sound approach for any surgeon facing traumatic hemorrhage from the head and neck.

Pre- and apnoeic high-flow oxygenation for rapid sequence intubation in the emergency department (the Pre-AeRATE trial): A multicentre randomised controlled trial

INTRODUCTION

Evidence regarding the efficacy of high-flow nasal cannula (HFNC) oxygenation for preoxygenation and apnoeic oxygenation is conflicting. Our objective is to evaluate whether HFNC oxygenation for preoxygenation and apnoeic oxygenation maintains higher oxygen saturation (SpO₂) during rapid sequence intubation (RSI) in ED patients compared to usual care.

METHODS

This was a multicentre, open-label, randomised controlled trial in adult ED patients requiring RSI. Patients were randomly assigned 1:1 to either intervention (HFNC oxygenation at 60L/min) group or control (non-rebreather mask for preoxygenation and nasal prongs of at least 15L/min oxygen flow for apnoeic oxygenation) group. Primary outcome was lowest SpO₂ during the first intubation attempt. Secondary outcomes included incidence of SpO₂ falling below 90% and safe apnoea time.

RESULTS

One hundred and ninety patients were included, with 97 in the intervention and 93 in the control group. Median lowest SpO₂ during the first intubation attempt was 100% in both groups. Incidence of SpO₂ falling below 90% was lower in the intervention group (15.5%) compared to the control group (22.6%) (adjusted relative risk=0.68, 95% confidence interval [CI] 0.37-1.25). Post hoc quantile regression analysis showed that the first quartile of lowest SpO₂ during the first intubation attempt was greater by 5.46% (95% CI 1.48-9.45%, P=0.007) in the intervention group.

CONCLUSION

Use of HFNC for preoxygenation and apnoeic oxygenation, when compared to usual care, did not improve lowest SpO₂ during the first intubation attempt but may prolong safe apnoea time.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictive performance of thyromental height for difficult laryngoscopies in adults: a systematic review and meta-analysis

BACKGROUND

Thyromental height (TMH) was first reported as a great single test for prediction of difficult laryngoscopies, although further studies have shown variable estimates of its accuracy. We thus performed this meta-analysis to summarize the predictive values of TMH mainly for prediction of difficult laryngoscopies.

METHODS

A search in PubMed, EMBASE, LILACS, and Scielo was conducted in June 2020. We included prospective cohorts fully reported with patients ≥ 16 years old, providing data on predictive values of TMH for prediction of either difficult laryngoscopies or difficult intubations. Diagnostic properties and association between TMH and Cormack and Lehanes's classification by direct laryngoscopy were evaluated. A random-effects meta-analysis using hierarchical models was performed.

RESULTS

Eight studies evaluating 2844 patients were included. All included studies had high risk of bias and low concern regarding applicability. There was significant heterogeneity among the studies. The pooled diagnostic odds ratio (DOR) and positive (LR+) and negative (LR-) likelihood ratios were as follows: DOR, 57.94 (95% CI: 18.19-184.55); LR+, 11.32 (95% CI: 4.28-29.92); and LR-, 0.23 (95% CI: 0.15-0.35). Summary sensitivity and specificity for studies with common threshold were 82.6 (95% CI: 74-88.8%) and 93.5 (95% CI: 79-98.2%), respectively. The estimated AUC was 81.1%.

CONCLUSION

TMH arises as a good predictor of difficult laryngoscopies in adult patients from diverse populations presenting better predictive values than most previously reported bedside tests. However, the high risk of bias throughout the studies may have skewed the results of the individual research as well as the summary points of the present meta-analysis.

Effects of head positions on awake fiberoptic bronchoscope oral intubation: a randomized controlled trial

Background

There are many factors affecting the success rate of awake orotracheal intubation via fiberoptic bronchoscope. We performed this study was to investigate the effects of head positions on awake Fiberoptic bronchoscope oral intubation.

Methods

Seventy-five adult patients, received general anaesthesia were included in this study. After written informed consent, these patients were undergoing awake orotracheal intubation via fiberoptic-bronchoscope and according to the head position, the patients were randomized allocated to neutral position group (NP group), sniffing position group (SP group) or extension position group (EP group). After sedation the patients were intubated by an experienced anesthesiologist. The time to view the vocal cords, the percentage of glottic opening scores (POGO), the time to insert the tracheal tube into trachea and the visual analog scale (VAS) scores for ease experienced of passing the tracheal tube through glottis, the hemodynamic changes and the adverse events after surgery were recorded.

Results

The time to view the vocal cords was significantly shorter and the POGO scores was significantly higher in the EP group compared with the other two groups (P < 0.05); The SpO₂ in the EP group was higher than NP group at before intubation and higher than SP group and NP group at immediate after intubation (P < 0.05); The time to insert the tracheal tube into trachea, the VAS scores for passing the tracheal tube through glottis, the coughing scores had no significant differences among groups (P > 0.05). There were also no significant differences regard to the incidence of postoperative complications, mean arterial pressure and heart rate among the groups (P > 0.05).

Conclusions

The head at extension position had a best view of glottic opening than neutral position or sniffing position during awake Fiberoptic bronchoscope oral intubation, so extension position was recommended as the starting head position for awake Fiberoptic bronchoscope oral intubation.

Trial registration

Clinical Trials.gov. no. NCT02792855. Registered at https://register.clinicaltrials.gov on 23 september 2017.

Infrared flashing light through the cricothyroid membrane to guide flexible bronchoscopic tracheal intubation

Flexible bronchoscopic tracheal intubation is a fundamental technique in the management of the difficult airway but requires specific skills which may be both difficult to achieve and maintain. Therefore, techniques to improve its success should be developed. We present two cases, one where the ear, nose and throat surgeon could not view the glottis due to laryngeal pathology, and one where pathology in the oropharynx obscured access to the trachea during attempts at flexible bronchoscopic and videolaryngoscopic tracheal intubation. In both cases, tracheal intubation was subsequently successful due to the use of the Infrared Red Intubation System. This is an infrared light source that is secured to the anterior neck. It emits a flashing infrared light that is captured by the flexible bronchoscope, thus guiding the way to the trachea. These are the first reports of this technology being used for flexible bronchoscopic tracheal intubation in patients with severe airway pathology where conventional approaches had failed. Both cases emphasise that this technique can be of benefit in avoiding a surgical airway.

Developmental features and predicting airway failure risk in critically ill children with mandibular hypoplasia using 3D computational tomographic analysis

In children with mandibular hypoplasia, airway management is challenging. However, detailed cephalometric assessment data for this population are sparse. The aim of this study was to find risk factors for predicting difficult airways in children with mandibular hypoplasia, and compare upper airway anatomical differences using three-dimensional computed tomography (3D CT) between children with mandibular hypoplasia and demographically matched healthy controls. There were significant discrepancies in relative tongue position (P < 0.01) and anterior distance of the hyoid bone (P < 0.01) between patients with mandibular hypoplasia and healthy controls. All mandibular measures were significantly different between the two groups, except for the height of the ramus of the mandible. After adjusting for age and sex, the anterior distance of hyoid bone and inferior pogonial angle were significantly associated with a difficult airway (P = 0.01 and P = 0.02). Quantitative analysis of upper airway structures revealed significant discrepancies, including relative tongue position, hyoid distance, and mandible measures between patients with mandibular hypoplasia and healthy controls. The anterior distance of the hyoid bone and inferior pogonial angle may be risk factors for a difficult airway in patients with mandibular hypoplasia.

Difficult airway predictors were associated with decreased use of neuromuscular blocking agents in emergency airway management: a retrospective cohort study in Thailand

Background

It is recommended that difficult airway predictors be evaluated before emergency airway management. However, little is known about how patients with difficult airway predictors are managed in emergency departments. We aimed to explore the incidence, management and outcomes of patients with difficult airway predictors in an emergency department.

Methods

We conducted a retrospective study using intubation data collected by a prospective registry in an academic emergency department from November 2017 to October 2018. Records with complete assessment of difficult airway predictors were included. Two categories of predictors were analyzed: predicted difficult intubation by direct laryngoscopy and predicted difficult bag-mask ventilation. The former was evaluated based on difficult external appearance, mouth opening and thyromental distance, Mallampati score, obstruction, and limited neck mobility as in the mnemonic “LEMON”. The latter was evaluated based on difficult mask sealing, obstruction or obesity, absence of teeth, advanced age and reduced pulmonary compliance as in the mnemonic “MOANS”. The incidence, management and outcomes of patients with these difficult airway predictors were explored.

Results

During the study period, 220 records met the inclusion criteria. At least 1 difficult airway predictor was present in 183 (83.2%) patients; 57 (25.9%) patients had at least one LEMON feature, and 178 (80.9%) had at least one MOANS feature. Among patients with at least one difficult airway predictor, both sedation and neuromuscular blocking agents were used in 105 (57.4%) encounters, only sedation was used in 65 (35.5%) encounters, and no medication was administered in 13 (7.1%) encounters. First-pass success was accomplished in 136 (74.3%) of the patients. Compared with patients without predictors, patients with positive LEMON criteria were less likely to receive neuromuscular blocking agents (OR 0.46 (95% CI 0.24–0.87), p = 0.02) after adjusting for operator experience and device used. There were no significant differences between the two groups regarding glottic view, first-pass success, or complications. The LEMON criteria poorly predicted unsuccessful first pass and glottic view.

Conclusions

In emergency airway management, difficult airway predictors were associated with decreased use of neuromuscular blocking agents but were not associated with glottic view, first-pass success, or complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-021-00434-2.

A new approach to airway assessment-"Line of Sight" and more. Recommendations of the Task Force of Airway Management Foundation (AMF)

Assessment of airway is recommended by every airway guideline to ensure safe airway management. Numerous unifactorial and multifactorial tests have been used for airway assessment over the years. However, there is none that can identify all the difficult airways. The reasons for the inadequacy of these methods of airway assessment might be their dependence on difficult to remember and apply mnemonics and scores, inability to identify all the variations from the “normal”, and their lack of stress on evaluating the non-patient factors. Airway Management Foundation (AMF) experts and members have been using a different approach, the AMF Approach, to overcome these problems inherent to most available models of airway assessment. This approach suggests a three-step model of airway assessment. The airway manager first makes the assessment of the patient through focused history, focused general examination, and focused airway assessment using the AMF “line of sight” method. The AMF “line of sight” method is a non-mnemonic, non-score-based method of airway assessment wherein the airway manager examines the airway along the line of sight as it moves over the airway and notes down all the variations from the normal. Assessment of non-patient factors follows next and finally there is assimilation of all the information to help identify the available, difficult, and impossible areas of the airway management. The AMF approach is not merely intubation centric but also focuses on all other methods of securing airway and maintaining oxygenation. Airway assessment in the presence of contagion like COVID-19 is also discussed.

Management of the Unexpected Difficult Airway in Neonatal Resuscitation

A "difficult airway situation" arises whenever face mask ventilation, laryngoscopy, endotracheal intubation, or use of supraglottic device fail to secure ventilation. As bradycardia and cardiac arrest in the neonate are usually of respiratory origin, neonatal airway management remains a critical factor. Despite this, a well-defined in-house approach to the neonatal difficult airway is often lacking. While a recent guideline from the British Pediatric Society exists, and the Scottish NHS and Advanced Resuscitation of the Newborn Infant (ARNI) airway management algorithm was recently revised, there is no Norwegian national guideline for managing the unanticipated difficult airway in the delivery room (DR) and neonatal intensive care unit (NICU). Experience from anesthesiology is that a "difficult airway algorithm," advance planning and routine practicing, prepares the resuscitation team to respond adequately to the technical and non-technical stress of a difficult airway situation. We learned from observing current approaches to advanced airway management in DR resuscitations in a university hospital and make recommendations on how the neonatal difficult airway may be managed through technical and non-technical approaches. Our recommendations mainly pertain to DR resuscitations but may be transferred to the NICU environment.

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

PURPOSE

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

SOURCE

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

FINDINGS AND KEY RECOMMENDATIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Airway Management with Dexmedetomidine and High-Flow Nasal Cannula in a Patient with Deep Neck Infection

Retropharyngeal deep neck infection sometimes necessitates securing of the airway and surgery for drainage. Airway management in patients with deep neck infection is challenging for anesthesiologists. A 56-year-old woman diagnosed with deep neck infection was admitted for incision and drainage. In the first operation for incision and drainage, indirect videolaryngoscope was utilized to confirm the airway before tracheal intubation, and the patient was intubated successfully. In the second operation for wound closure, dexmedetomidine administration and high-flow nasal cannulation were used during monitored anesthesia care throughout a subsequent procedure. The outcome in the present case suggests that indirect videolaryngoscope, dexmedetomidine, and high-flow nasal cannula can facilitate effective management during surgery in patients with retropharyngeal deep neck space infection.

Project for Universal Management of Airways - part 1: concept and methods

Multiple professional groups and societies worldwide have produced airway management guidelines. These are typically targeted at the process of tracheal intubation by a particular provider group in a restricted category of patients and reflect practice preferences in a particular geographical region. The existence of multiple distinct guidelines for some (but not other) closely related circumstances, increases complexity and may obscure the underlying principles that are common to all of them. This has the potential to increase cognitive load; promote the grouping of ideas in silos; impair teamwork; and ultimately compromise patient care. Development of a single set of airway management guidelines that can be applied across and beyond these domains may improve implementation; promote standardisation; and facilitate collaboration between airway practitioners from diverse backgrounds. A global multidisciplinary group of both airway operators and assistants was assembled. Over a 3-year period, a review of the existing airway guidelines and multiple reviews of the primary literature were combined with a structured process for determining expert consensus. Any discrepancies between these were analysed and reconciled. Where evidence in the literature was lacking, recommendations were made by expert consensus. Using the above process, a set of evidence-based airway management guidelines was developed in consultation with airway practitioners from a broad spectrum of disciplines and geographical locations. While consistent with the recommendations of the existing English language guidelines, these universal guidelines also incorporate the most recent concepts in airway management as well as statements on areas not widely addressed by the existing guidelines. The recommendations will be published in four parts that respectively address: airway evaluation; airway strategy; airway rescue and communication of airway outcomes. Together, these universal guidelines will provide a single, comprehensive approach to airway management that can be consistently applied by airway practitioners globally, independent of their clinical background or the circumstances in which airway management occurs.

Difficult and failed intubation in the first 4000 incidents reported on webAIRS

A review of the first 4000 reports to the webAIRS anaesthesia incident reporting database was performed to analyse cases reported as difficult or failed intubation. Patient, task, caregiver and system factors were evaluated. Among the 4000 reports, there were 170 incidents of difficult or failed intubation. Difficult or failed intubation incidents were most common in the 40-59 years age group. More than half of cases were not predicted. A total of 40% involved patients with a body mass index >30 kg/m² and 41% involved emergency cases. A third of the reports described multiple intubation attempts. Of the reports, 18% mentioned equipment problems including endotracheal tube cuff rupture, laryngoscope light failure, dysfunctional capnography and delays with availability of additional equipment to assist with intubation. Immediate outcomes included 40 cases of oxygen desaturation below 85%; of these cases, four required cardiopulmonary resuscitation. The majority of the incidents resulted in no harm or minor harm (45%). However, 12% suffered moderate harm, 3.5% severe harm and there were three deaths (although only one related to the airway incident). Despite advances and significant developments in airway management strategies, difficult and failed intubation still occurs. Although not all incidents are predictable, nor are all preventable, the information provided by this analysis might assist with future planning, preparation and management of difficult intubation.

Anesthesiology airway-related medicolegal cases from the Canadian Medical Protection Association

Purpose

We analyzed closed civil legal cases in 2007-2016 from the Canadian Medical Protective Association (CMPA) involving specialist anesthesiologists where airway management was the central concern.

Methods

We included all airway-related civil legal cases involving specialist anesthesiologists that closed from 2007 to 2016. The following variables were abstracted by CMPA medical analysts: clinical context, peer expert opinions of contributing factors, and patient and legal outcomes.

Results

We found 46 of the 406 (11%) closed cases involving anesthesiologists to be airway-related. Twenty-six cases (57%) involved elective surgery and 31 patients (67%) were categorized as American Society of Anesthesiologists physical status III. Twenty-five cases (54%) occurred outside the operating room (e.g., postanesthesia care unit, intensive care unit, or other satellite locations). In 19 (42%) cases, there was at least one predictor of a difficult airway. Peer experts identified judgement failures in 30 cases (65%), most commonly inadequate airway evaluation. In 30 cases (65%), the patient died or had a permanent brain injury. The medicolegal outcome favoured the patient in 27 (59%) cases, with a median [interquartile range] payment of 422,845 [257,637-935,673] CAD.

Conclusions

Severe patient harm is common when airway management is the focus of a CMPA medicolegal complaint involving anesthesiologists. Patients were otherwise typically low risk cases presenting for elective surgery. Failure to assess or to change management based on the airway exam or encountered difficulty were the most common errors. Our findings support the continued need for adoption, adherence, and practice of guidelines for anticipated and unanticipated difficult airway management for every patient encounter.

Extubation of the Challenging or Difficult Airway

Purpose of Review

This review explores relevant definitions, epidemiology, management, and potential future research directions in the extubation of the challenging/difficult airway. It provides guidance on identifying patients at risk and how to approach these clinical scenarios.

Recent Findings

Based on recent literature, including large-scale audits and closed claims analysis, it is increasingly recognized that extubation of the difficult airway is a situation at risk of severe adverse events. Some strategies to manage the extubation of the challenging/difficult airway have been described.

Summary

Extubating the challenging/difficult airway is a high-risk situation. However, it is fundamental to keep in mind that intended extubation is always an elective procedure. As such, it is imperative to adhere to principles of careful patient and context assessment, planning, and execution only when optimal conditions have been secured.

Ultrasound-guided superior laryngeal nerve block - A description of the technique

Complications in airway management remain a common cause of anesthesia-associated mortality. When a patient is considered with anticipated difficult airway, the management depends on several variables, however, at present, the standard of management continues to be the patient awake approach. In scenarios of acute upper airway obstruction, the only way to guarantee adequate ventilation is to obtain a translaryngeal or transtracheal access, for which, it is necessary to use local anesthesia and grade I / II sedation, avoiding loss of spontaneous ventilation. For this purpose, we propose ultrasound-guided superior laryngeal nerve block, in order to standardize an ultrasound landmark that is reproduceable, with a high success rate, which allows limiting complications related to regional anatomic techniques and thus facilitating the securing of the airway in these patients.

Simultaneous en bloc endotracheal tube insertion with GlideScope® Titanium™ video laryngoscope use: a randomized-controlled trial

PURPOSE

Intubation-associated trauma with the GlideScope is rare, but when it occurs, it is likely due to advancing the endotracheal tube (ETT) blindly between the direct view of the oropharynx and the video view of the glottis. It is also occasionally difficult to advance the ETT to the glottic aperture despite a good view of the glottis on the monitor. One technique to potentially address both issues is to introduce the ETT en bloc with the GlideScope, thus visualizing the ETT tip throughout its entire path. We hypothesized that this en bloc technique could be faster and potentially easier than the standard technique.

METHODS

Fifty patients with normal-appearing airways who required orotracheal intubation for elective surgery were randomly allocated to intubation with either the en bloc or the standard (GlideScope-first-then-ETT) technique. A three-dimensional printed clip was utilized to secure the ETT to the GlideScope during en bloc insertion. The primary outcome was time to intubation, defined from mask removal to first end-tidal carbon dioxide detection, recorded by a blinded observer. Secondary outcomes were subjective ease of intubation (100-mm visual analogue scale [VAS], 0 = easy; 100 = difficult), number of intubation attempts/failures, and incidence of oropharyngeal trauma (bleeding).

RESULTS

The median [interquartile range (IQR)] intubation time was 36 [31-42] sec with the en bloc technique vs 41 [37-50] sec with the standard technique (difference in medians, 5 sec; 95% confidence interval [CI], 2 to 11; P = 0.008). The median [IQR] ease of intubation VAS was 11 [9-21] mm with the en bloc technique, and 15 [11-24] mm with the standard technique (difference in medians, 4 mm; 95% CI, -2 to 8; P = 0.19). Laryngoscopic grade and number of intubation attempts were similar between the groups; there was no oropharyngeal trauma noted.

CONCLUSION

In this study of video laryngoscopy, intubation was slightly faster with the en bloc technique than with the standard GlideScope intubation technique, although the clinical importance of this difference is unknown.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02787629); registered 1 June 2016.

Flexible fibreoptic intubation in swine - improvement for resident training and animal safety alike

Background

Efficient airway management to facilitate tracheal intubation encompasses essential skills in anaesthesiologic and intensive care. The application of flexible fibreoptic intubation in patients with difficult airways has been identified as the recommended method in various international guidelines. However, providing the opportunity to adequately train residents can be challenging. Using large animals for practice during ongoing studies could help to improve this situation, but there is no recent data on fibreoptic intubation in swine available.

Methods

Thirty male German landrace pigs were anesthetized, instrumented and randomized into two groups. The animals were either intubated conventionally using direct laryngoscopy or a single-use flexible video-endoscope. The intervention was carried out by providers with 3 months experience in conventional intubation of pigs and a brief introduction into endoscopy. Intubation attempts were supervised and aborted, when SpO2 dropped below 93%. After three failed attempts, an experienced supervisor intervened and performed the intubation. Intubation times and attempts were recorded and analysed.

Results

Flexible fibreoptic intubation showed a significantly higher success rate in first attempt endotracheal tube placement (75% vs. 47%) with less attempts overall (1.3 ± 0.6 vs. 2.1 ± 1.3, P = 0.043). Conventional intubation was faster (42 s ± 6 s vs. 67 s ± 10s, P < 0.001), but showed a higher complication rate and more desaturation episodes during the trial.

Conclusions

Flexible fibreoptic intubation in swine is feasible and appears to be a safer and more accessible method for inexperienced users to learn. This could not only improve resident training options in hospitals with animal research facilities but might also prevent airway complications and needless animal suffering.

Airway Leads and Airway Response Teams: Improving Delivery of Safer Airway Management?

Purpose of Review

Airway management remains a source of significant morbidity and mortality. This review considers recent summaries of complications and looks toward strategies to improve practice using a coordinated approach.

Recent Findings

A safety gap can exist between national recommendations and local practice. A lack of attention to end tidal carbon dioxide has repeatedly contributed to airway mismanagement. Clinicians must be trained in newer airway devices (videolaryngoscopes or supraglottic airways) to use them effectively. Time must be found to teach rarely performed skills (e.g., front-of-neck access). Both larger and smaller hospitals have benefitted from an airway lead or response team, coordinating education programs, ensuring the adoption of guidelines, standardizing equipment, and recognizing the role of human factors and ergonomics.

Summary

Even in the twenty-first century, the incidence of airway-related morbidity and mortality can be reduced, by an institutionally supported, coordinated approach to the whole process of airway care.

Aligning difficult airway guidelines with the anesthetic COVID-19 guidelines to develop a COVID-19 difficult airway strategy: a narrative review

The coronavirus disease 2019 (COVID-19) pandemic is caused by a coronavirus that is transmitted primarily via aerosol, droplets or direct contact. This may place anesthetists at higher risk of infection due to their frequent involvement in aerosol-generating airway interventions. Many anesthethetic COVID-19 guidelines have emerged, whose underlying management principles include minimizing aerosol contamination and protecting healthcare workers. These guidelines originate from Australia and New Zealand, Canada, China, India, Italy, Korea, Singapore, the United States and the United Kingdom. Hospitalized COVID-19 patients may require airway interventions, and difficult tracheal intubation secondary to laryngeal edema has been reported. Pre-pandemic difficult airway guidelines include those from Canada, France, Germany, India, Japan, Scandinavia, the United States and the United Kingdom. These difficult airway guidelines require modifications in order to align with the principles of the anesthetic COVID-19 guidelines. In turn, most of the anesthetic COVID-19 guidelines do not, or only briefly, discuss an airway strategy after failed tracheal intubation. Our article identifies and compares pre-pandemic difficult airway guidelines with the recent anesthetic COVID-19 guidelines. We combine the principles from both sets of guidelines and explain the necessary modifications to the airway guidelines, to form a failed tracheal intubation airway strategy in the COVID-19 patient. Valuing, and a greater understanding of, these differences and modifications may lead to greater adherence to the new COVID-19 guidelines.

Maintaining competence in airway management

BACKGROUND

Airway management is a defining skill for anaesthesiologists. Anaesthesiologists must maintain and update these crucial skills throughout their career, but how this is best achieved remains unclear. This study aimed to clarify anaesthesiologists' procedural volume, confidence in airway management and their current and preferred future educational strategies.

METHODS

A questionnaire was developed consisting of 28 items exploring essential skills in airway management. All anaesthesiologists in the Capital Region of Denmark were invited to participate.

RESULTS

The response rate was 84% (240/285). Most anaesthesiologists felt competent to a high or very high degree in basic airway management. Anaesthesiologists from anaesthesia felt confident to a significantly higher degree than those working in the intensive care unit (ICU) regarding the practical aspects of airway management in both the anticipated difficult airway (93% vs 73%, P < .001) and the unanticipated difficult airway (81% vs 61%, P = .002). Both groups performed most of the key advanced techniques ≤4 times yearly, whereas anaesthesiologists from the ICU had a lower and less diverse procedural volume than those working in anaesthesia. The anaesthesiologists preferred training through their daily clinical work, hands-on workshops, and scenario-based simulation training. However, a large discrepancy was identified between the current and the desired level of training.

CONCLUSION

The anaesthesiologists felt competent to a high or very high degree in basic airway management but the current procedural volume in advanced airway management causes concern for skill maintenance. Furthermore, we found a gap between the current and the desired level of supplemental training.

Recommendations for the evaluation and management of the anticipated and non-anticipated difficult airway of the Societat Catalana d'Anestesiologia, Reanimació i Terapèutica del Dolor, based on the adaptation of clinical practice guidelines and expert consensus

The Airway Division of the Catalan Society of Anaesthesiology, Intensive Care and Pain Management (SCARTD) presents its latest guidelines for the evaluation and management of the difficult airway. This update includes the technical advances and changes observed in clinical practice since publication of the first edition of the guidelines in 2008. The recommendations were defined by a consensus of experts from the 19 participating hospitals, and were adapted from 5 recently published international guidelines following an in-depth analysis and systematic comparison of their recommendations. The final document was sent to the members of SCARTD for evaluation, and was reviewed by 11 independent experts. The recommendations, therefore, are supported by the latest scientific evidence and endorsed by professionals in the field. This edition develops the definition of the difficult airway, including all airway management techniques, and places emphasis on evaluating and classifying the airway into 3 categories according to the anticipated degree of difficulty and additional safety considerations in order to plan the management strategy. Pre-management planning, in terms of preparing patients and resources and optimising communication and interaction between all professionals involved, plays a pivotal role in all the scenarios addressed. The guidelines reflect the increased presence of video laryngoscopes and second-generation devices in our setting, and promotes their routine use in intubation and their prompt use in cases of unanticipated difficult airway. They also address the increased use of ultrasound imaging as an aid to evaluation and decision-making. New scenarios have also been included, such as the risk of bronchoaspiration and difficult extubation Finally, the document outlines the training and continuing professional development programmes required to guarantee effective and safe implementation of the guidelines.

An international survey of airway management education in 61 countries†

BACKGROUND

Deficiencies in airway management skills and judgement contribute to poor outcomes. Airway management practice guidelines emphasise the importance of education. Little is known about the global uptake of guidelines, availability of equipment, provision of training, assessment of skills, and confidence with procedures.

METHODS

We devised a survey to examine these issues. Initially, 24 127 anaesthetists were questioned in New Zealand, Canada, South Africa, UK, India, and Germany, representing the home countries of the members of the Worldwide Airway Meeting (2015) Education Group; however, the survey could be forwarded to others. The survey was open for a maximum of 90 days.

RESULTS

We received 4948 fully or partially completed surveys from 61 countries: 33 high-income and 28 middle- or low-income countries. Most respondents were consultants (77.2%, n=4948), and the remainder trainees, with a male/female ratio of 1.8:1 (3105 males, n=4866). Of those responding, 1358 (76.6%, n=1798) were members of an airway interest group. Most respondents (91.3% of 2910) agreed with assessment of airway skills, fewer (2237; 59.7%, n=3750) reported requiring airway training for completion of training, and only 810 (33.6%, n=2408) reported it as a requirement for continuing medical education. Reported confidence was lowest for awake tracheal intubation, front-of-neck access, and retrograde intubation.

CONCLUSIONS

Global training is variable in its delivery and necessity. Confidence is limited in potentially life-saving techniques. The desire for assessment appears universal and may improve standards, but in resource- or time-limited environments this will be challenging.

Tracheal intubation in patients at risk for cervical spinal cord injury: A systematic review

BACKGROUND

Tracheal intubation in patients at risk for secondary spinal cord injury is potentially difficult and risky.

OBJECTIVES

To compare tracheal intubation techniques in adult patients at risk for secondary cervical spinal cord injury undergoing surgery. Primary outcome was first-attempt failure rate. Secondary outcomes were time to successful intubation and procedure complications.

DESIGN

Systematic review and meta-analysis of randomized controlled trials (RCTs) with trial sequential analysis (TSA).

DATA SOURCES

Databases searched up to July 2019.

ELIGIBILITY

Randomized controlled trials comparing different intubation techniques.

RESULTS

We included 18 trials enrolling 1972 patients. Four studies used the "awake" approach, but no study compared awake versus non-awake techniques. In remaining 14 RCTs, intubation was performed under general anesthesia. First-attempt failure rate was similar when comparing direct laryngoscopy or fiberoptic bronchoscopy versus other techniques. A better first-attempt failure rate was found with videolaryngoscopy and when pooling all the fiberoptic techniques together. All these results appeared not significant at TSA, suggesting inconclusive evidence. Intubating lighted stylet allowed faster intubation. Postoperative neurological complications were 0.34% (no significant difference among techniques). No life-threatening adverse event was reported; mild local complications were common (19.5%). The certainty of evidence was low to very low mainly due to high imprecision and indirectness.

CONCLUSIONS

Videolaryngoscopy and fiberoptic-assisted techniques might be associated with higher first-attempt failure rate over controls. However, low to very low certainty of evidence does not allow firm conclusions on the best tracheal intubation in patients at risk for cervical spinal cord injury.

Methodological quality and transparency of clinical practice guidelines for difficult airway management using the appraisal of guidelines research & evaluation II instrument: A systematic review

BACKGROUND

Complications arising from airway management represent an important cause of morbidity and mortality. Clinical practice guidelines (CPGs) are systematically created documents that summarise knowledge and assist the delivery of high-quality medical care by identifying evidence that supports best clinical care.

OBJECTIVE

Using the Appraisal of Guidelines for Research & Evaluation II instrument, we aimed to evaluate the methodological rigour and transparency of unanticipated difficult airway management CPGs in adults.

DESIGN

Using PUBMED without language restrictions, we identified eligible CPGs between 1 January 1996 and 30 June 2019. All versions of a CPG were included as independent guidelines to assess improvements over time or the methodological limitations of each version. CPGs-related obstetrics or paediatrics or the management extubation in cases of difficult airway were excluded.

RESULTS

Fourteen CPGs were included. Of the six domains suggested by the Appraisal of Guidelines for Research & Evaluation II instrument, 'applicability' had the lowest score (23%) and 'scope and objectives' had the highest score (88%). The remaining domains (stakeholder involvement, editorial independence, rigour of development and clarity of presentation) had scores ranging between 56 and 81%. Overall, the highest scored CPG was the Difficult Airway Society 2015.

CONCLUSION

Future updates of CPGs for difficult airway management in adults and severely ill patients should consider more emphasis on the applicability of their recommendations to real clinical practice.