Videolaryngoscopy versus direct laryngoscopy for adult patients requiring tracheal intubation

Macintosh-style videolaryngoscope use for tracheal intubation in elective surgical patients revisited: a sub-analysis of the 2022 Cochrane review data

The Cochrane systematic review and meta-analysis published in 2022 that compared videolaryngoscopy (VL) with direct laryngoscopy (DL) for facilitating tracheal intubation in adults found that all three types of VL device (Macintosh-style, hyper-angulated and channeled) reduced the risk of failed intubation and increased the likelihood of first-pass success. We report the findings of a subgroup re-analysis of the 2022 Cochrane meta-analysis data focusing on the Macintosh-style VL group. This was undertaken to establish whether sufficient evidence exists to guide airway managers in making purchasing decisions for their local institutions based upon individual device-specific performance. This re-analysis confirmed the superiority of Macintosh-style VL over Macintosh DL in elective surgical patients, with similar efficacy demonstrated between the Macintosh-style VL devices examined. Thus, when selecting which VL device(s) to purchase for their hospital, airway managers decisions are likely to remain focused upon issues such as financial costs, portability, cleaning schedules and previous device experience.

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

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

Is older still good, or even better? Evaluation of possibility of using Miller laryngoscope for intubation in adults and comparison with the most widely used Macintosh laryngoscope. Protocol of a crossover randomized control trial

Background

Macintosh laryngoscope is the most widely used laryngoscope for intubation. In some patients, e.g. with flaccid, drooping, aplastic epiglottis, usage of this laryngoscope, or even videolaryngoscopes, may not provide visualization of a glottis. Elevation of the laryngopharynx, like in intubation with Miller laryngoscope, may significantly improve intubating conditions.

Methods

An anaesthesiologist with over 20 years of experience will perform direct laryngoscopy with randomly chosen Miller or Macintosh blade, evaluating the visibility of rima glottidis with Cormack-Lehane classification and POGO score with and without external laryngeal pressure. Then the second evaluation of glottis with other blade type will be obtained and the patient will be intubated. Comparison of the rima glottidis visibility when using both blades will be the primary endpoint of the study. The secondary endpoints consist of: demonstrating whether there is a group of adult patients in whom the use of the Miller blade associated with better vocal cord visibility may be predicted based on an anesthesiological examination, and whether external laryngeal pressure improves vocal cord visualization more when using the Miller blade compared with the Macintosh blade.

Sample size

We performed minimal sample size calculations based on the data derived from the first 60 patients. We assessed the minimal sample size to obtain the alpha of 5 % and power of 90 %. We decide to enroll at least 286 patients.

Discussion

this will be the first trial assessing Miller and Macintosh blades in the same population of adult patients. It will determine group of patients in whom Miller laryngoscope will provide better visualization of rima glottidis than Macintosh blade and associated technique, diminishing rate of prolonging intubations and reducing possible aftermaths of hypoxia.

Evaluating the Usability of a 3D-Printed Video Laryngoscope for Tracheal Intubation of a Manikin

Background

Compared to direct laryngoscopy, videolaryngoscopy (VL) can provide improved laryngeal and glottic view, higher intubation success rates in patients with a known or predicted difficult airway and reduced incidence of laryngeal/airway trauma. However, the cost and availability of these devices handicap its use in resource-restricted facilities. The objective was to design and manufacture a novel VL using additive manufacturing (AM) and evaluate its usability on an intubation manikin by comparing it to one of the most common video laryngoscopes used in clinical practice, the CMAC^®, by measuring the time to first pass of the endotracheal tube as the main outcome.

Methods

A randomised cross-over study was performed with 36 anaesthetists attempting tracheal intubation of a manikin. The novel 3D-printed hyperangulated VL blade was compared to a CMAC^® VL (D-blade). Participants had no prior experience or training with the novel device. The participants included consultants, registrars/trainees and medical officers in the Department of Anaesthesiology at the University of the Free State (UFS) in South Africa.

Results

The CMAC^® had a statistically shorter time to first pass (median 13.8 seconds) compared to the 3D-printed model (median 19.0 seconds) (95% confidence interval [CI] 1.0-6.2; P=0.0013). No failed attempts occurred with either device.

Conclusion

Intubation times were faster with the CMAC^® than with the novel device. However, with a comparable intubation success rate, 3D printing technology potentially can improve access to video laryngoscopy. Further design improvements, validation of materials and manufacturing processes are required before 3D-printed laryngoscope blades can be used in human subjects.

Airway ultrasound for patients anticipated to have a difficult airway: Perspective for personalized medicine

Airway ultrasound allows for precise airway evaluation, particularly for assessing the difficult airway and the potential for front of neck access. Many studies have shown that identification of the cricothyroid membrane by airway ultrasound is more accurate than digital palpation. However, no reports to date have provided clinical evidence that ultrasound identification of the cricothyroid membrane increases the success rate of cricothyroidotomy. This is a narrative review which describes patients with difficult airways for whom airway ultrasound may have been useful for clinical decision making. The role of airway ultrasound for the evaluation of difficult airways is summarized and an approach to the use of ultrasound for airway management is proposed. The goal of this review is to present practical applications of airway ultrasound for patients predicted to have a difficult airway and who undergo cricothyroidotomy.

A Prospective Observational Study of Endotracheal Intubation Practices in an Academic Emergency Department of a Tertiary Care Hospital in South India

INTRODUCTION

Airway management is the first critical step to be addressed in the airway, breathing, and circulation algorithm for stabilizing critically ill patients. Since the emergency department (ED) is the primary contact of these patients in health care, doctors in the ED should be trained to perform advanced airway management. In India, emergency medicine has been recognized as a new specialty by the Medical Council of India (now the National Medical Commission) since 2009. Data related to airway management in the ED in India is sparse.

METHODS

We conducted a one-year prospective observational study to establish descriptive data regarding endotracheal intubations performed in our ED. Descriptive data related to intubation was collected using a standardized proforma that was filled by the physician performing intubation.

RESULTS

A total of 780 patients were included, of which 58.8% were intubated in the first attempt. The majority (60.4%) of the intubations were performed in non-trauma patients and the remaining 39.6% in trauma patients. Oxygenation failure was the most common indication (40%) for intubation followed by a low Glasgow coma scale (GCS) score (35%). Rapid sequence intubation (RSI) was performed in 36.9% of patients, and intubation was done with sedation only in 36.9% of patients. Midazolam was the most commonly used drug - either alone or in combination with other drugs. We found a strong association of first-pass success (FPS) with the method of intubation, Cormack-Lehane grading, predicted difficulty in intubation, and experience of the physician performing the first attempt of intubation (P<0.05). Hypoxemia (34.6%) and airway trauma (15.6%) were the most commonly encountered complications.

CONCLUSION

Our study showed an FPS of 58.8%. Complications were seen in 49% of intubations. Our study highlights the areas for quality improvement in intubation practices in our ED, like the use of videolaryngoscopy, RSI, airway adjuncts like stylet and bougie, and intubation by more experienced physicians in patients with anticipated difficult intubation.

Endotracheal Intubation with King Vision Video Laryngoscope vs Macintosh Direct Laryngoscope in ICU: A Comparative Evaluation of Performance and Outcomes

Background

Endotracheal intubation to protect airway patency in critically ill patients with the use of videolaryngoscopes has been emerging and their expertise to handle is crucial. Our study focuses on the performance and outcomes of King Vision video laryngoscope (KVVL) in intensive care unit (ICU) compared to Macintosh direct laryngoscope (DL).

Materials and methods

This comparative study was conducted by randomizing 143 critically ill patients in ICU into two groups: KVVL and Macintosh DL (n = 73; n = 70). The intubation difficulty was assessed by Mallampati score III or IV, apnea syndrome (obstructive), cervical spine limitation, opening mouth <3 cm, coma, hypoxia, anesthesiologist nontrained (MACOCHA) score. The primary endpoint was the glottic view measured by Cormack-Lehane (CL) grading. The secondary endpoints were a first-pass success, the time required for intubation, airway morbidities, and manipulations required.

Results

The KVVL group showed the primary endpoint of significantly improved glottic visualization measured in terms of CL grading compared with the Macintosh DL group (p < 0.001). In the KVVL group, the first pass success rate was higher (95.7%) compared to the Macintosh DL group (81.4%) (p < 0.05). The time required for intubation in the KVVL group (28.77 ± 2.63 seconds) was significantly less compared with Macintosh DL (38.84 ± 2.72 seconds) group (p < 0.001). The airway morbidities observed were similar in both groups (p = 0.5) and the manipulation required for endotracheal intubation was significantly less (p < 0.05) in our KVVL group (16 cases; 23%) compared to the Macintosh DL group (8 cases; 10%).

Conclusion

We found that the performance and outcomes of KVVL in intubating critically ill ICU patients were promising when handled by experienced operators who are experts in anesthesiology and airway management.

How to cite this article

Dharanindra M, Jedge PP, Patil VC, Kulkarni SS, Shah J, Iyer S, et al. Endotracheal Intubation with King Vision Video Laryngoscope vs Macintosh Direct Laryngoscope in ICU: A Comparative Evaluation of Performance and Outcomes. Indian J Crit Care Med 2023;27(2):101-106.

Effects of positive end-expiratory pressure and oxygen concentration on non-hypoxemic apnea time during face mask ventilation of anesthesia induction: A randomized controlled trial

Background: The optimal ventilatory strategy for the face mask ventilation during anesthesia induction is still unknow. Methods: We evaluated the effect of two positive end-expiratory pressure (PEEP) levels (0 cmH₂O and 6 cmH₂O) and two oxygen concentration levels (1.0 and .6) on non-hypoxemic apnea time during face mask ventilation of anesthesia induction. Sixty adult patients scheduled for elective surgery were enrolled in this study. The patients were randomized to receive anesthesia induction with four different ventilation strategy under volume-controlled ventilation. Patients assigned to the LOZP group received low fraction of inspiration O₂ (FiO₂ = .6) and 0 PEEP. Patients assigned to the LOHP group received low fraction of inspiration O₂ (FiO₂ = .6) and 6 cmH₂O PEEP. Patients assigned to the HOZP group received high fraction of inspiration O₂ (FiO₂ = 1.0) and 0 PEEP. Patients assigned to the HOHP group received high fraction of inspiration O₂ (FiO₂ = 1.0) and 6cmH₂O PEEP. After 3 min of ventilation, the patient was intubated but disconnected from the breathing circuit. Ventilation was not initiated until the pulse oximetry dropped to 90%. The primary outcome was non-hypoxemic apnea time defined as the time from cessation of ventilation to a pulse oximeter reading of 90%. The secondary outcome was the PaO₂/FiO₂ ratio immediately after ventilation. Results: The non-hypoxemic apnea time was significantly longer in the group of HOHP when compared to the other three groups (192 s ± 70 s, 221 s ± 74 s, 284 s ± 101 s, and 353 s ± 85 s in the LOZP, LOHP, HOZP, and HOHP group, respectively). The PaO₂/FiO₂ ratio immediately after ventilation was significantly higher in the group of LOHP when compared to the other three groups (LOZP 393 ± 130, LOHP 496 ± 97, HOZP 335 ± 58, HOHP 391 ± 50). When compared the PaO₂/FiO₂ ratio immediately after ventilation to its value before administration of anesthesia, the PaO₂/FiO₂ ratio in the group of LOHP was improved, the group LOZP and HOHP remained the same, while the group HOZP significantly decreased. Conclusion: Application of PEEP and 100% of oxygen during face mask ventilation of induction could maximize the non-hypoxemic apnea time. However, the use of PEEP and 60% of oxygen during preoxygenation resulted in improved PaO₂/FiO₂ ratio.

The influence of the COVID-19 pandemic on videolaryngoscopy: a cross-sectional before-and-after survey

BACKGROUND

Guidelines and consensus statements recommend the use of videola-ryngoscopes (VLs) in airway management of patients with COVID-19. However, there is a lack of knowledge about which types of videolaryngoscopes are used, differences of use between countries, and how the COVID-19 pandemic influenced their use. The primary aim of this before-and-after cross-sectional survey study was to assess the frequency of the use of videolaryngoscopy in the operation theatres in different countries. Also, the preferred characteristics of videolaryngoscopes were assessed.

METHODS

With Ethics Committee approval, a questionnaire was distributed among anaes-thesiologists through the European Airway Management Society's network in 2019 before and in 2021 during the COVID-19 pandemic. Responses to the questions were analysed and presented as descriptive statistics.

RESULTS

We reached out to 791 anaesthesiologists; 155 (19.5%) returned the first questionnaire, and 91 (11.5%) returned the second survey. Videolaryngoscopes were used in 24.1% of cases before COVID-19 and in 43.1% after the pandemic ( P < 0.001). We revealed that the availability of videolaryngoscopes increased to 100% in all centres during the pandemic. Routine use of videolaryngoscopes in all cases increased from 12.5% to 38.9%. The type of videolaryngoscope and the blade preference did not change during this period ( P = 1.000).

CONCLUSIONS

This survey reflects that the COVID-19 pandemic significantly increased the availability and use of videolaryngoscopes in operating theatres, and that more anaesthesiologists now use them routinely in all cases. The preferred type of VL or blade did not change during the pandemic.

Comparing laryngeal view in neutral and sniff position during video laryngoscopy-guided intubation

Appropriate positioning of the head is a crucial step for a successful intubation. Laryngoscopy is a commonly used method to facilitate the intubation process. This study evaluated the quality of intubation and its difficulty in sniff and neutral position. This was a clinical randomized trial, conducted in 2021 in Aja university of medical sciences. 40 patients, meeting the inclusion criteria were randomly assigned to sniff and neutral group and were intubated with standard procedure. The required time, number of attempts, laryngeal view, cord status, and the need for maneuver were evaluated between the two positions. Overall, 60 patients were intubated in sniff and 60 in neutral position. 51 of them were male and 69 were female. The mean intubation time was (17/15 ± 8/00) and (16/65 ± 8/66) seconds in neutral and sniff position, respectively (p-value = 0.181). There was no statistically significant difference in the required time. Additionally, 45 patients were intubated in first attempt and 15 were intubated after the second attempt in each group. There was no difference in any difficulty-related parameter of the two groups. No significant difference between the required time, attempt, or any other parameter was detected between the sniff and neutral groups. Evidence suggests that there is no superiority regarding these two positions and the decision should be made by the physician on a case-by-case basis.

Direct vs Video Laryngoscopy for Difficult Airway Patients in the Emergency Department: A National Emergency Airway Registry Study

Introduction: Previous studies suggest improved intubation success using video laryngoscopy (VL) vs direct laryngoscopy (DL), yet recent randomized trials have not shown clear benefit of one method over the other. These studies, however, have generally excluded difficult airways and rapid sequence intubation. In this study we looked to compare first-pass success (FPS) rates between VL and DL in adult emergency department (ED) patients with difficult airways. Methods: We conducted a secondary analysis of prospectively collected observational data in the National Emergency Airway Registry (NEAR) (January 2016–December 2018). Variables included demographics, indications, methods, medications, devices, difficult airway characteristics, success, and adverse events. We included adult ED patients intubated with VL or DL who had difficult airways identified by gestalt or anatomic predictors. We stratified VL by hyperangulated (HAVL) vs standard geometry VL (SGVL). The primary outcome was FPS, and the secondary outcome was comparison of adverse event rates between groups. Data analyses included descriptive statistics with cluster-adjusted 95% confidence intervals (CI). Results: Of 18,123 total intubations, 12,853 had a predicted or identified anatomically difficult airway. The FPS for difficult airways was 89.1% (95% CI 85.9-92.3) with VL and 77.7% (95% CI 75.7-79.7) with DL (P <0.00001). The FPS rates were similar between VL subtypes for all difficult airway characteristics except airways with blood or vomit, where SGVL FPS (87.3%; 95% CI 85.8-88.8) was slightly better than HAVL FPS (82.4%; 95% CI, 80.3-84.4). Adverse event rates were similar except for esophageal intubations and vomiting, which were both less common in VL than DL. Esophageal intubations occurred in 0.4% (95% CI 0.1-0.7) of VL attempts and 1.5% (95% CI 1.1-1.9) of DL attempts. Vomiting occurred in 0.6% (95% CI 0.5-0.7) of VL attempts and 1.4% (95% CI 0.9-1.9) of DL attempts. Conclusion: Analysis of the NEAR database demonstrates higher first-pass success with VL compared to DL in patients with predicted or anatomically difficult airways, and reduced rate of esophageal intubations and vomiting.

An Evaluation of the Intubrite Laryngoscope in Simulated In-Hospital and Out-of-Hospital Settings by Individuals with No Clinical Experience: A Randomized, Cross-Over, Manikin Study

Introduction: The aim of the study was to compare the Intubrite laryngoscope and the standard Macintosh blade laryngoscope (MCL) used by persons with no clinical experience in simulated hospital and non-hospital conditions on a manikin model. Materials and methods: The study involved 50 students of Medical Rescue. The hospital conditions (intubation height 110 cm—high position) and those occurring at the scene (intubation of a manikin located at floor level-low position) were simulated. The analysis included: duration of intubation, visibility of the laryngeal opening by the Cormack−Lehane scale, the bioelectrical activity of the intubating muscles, comfort and subjective assessment of physical effort by the Borg scale (Borg’s scale of subjective feeling of effort). The statistical analysis was performed with Microsoft Excel and T-student tests for pairs with unequal variables. The statistical importance was set at p < 0.05. Results: The use of an Intubrite laryngoscope significantly reduces the mean endotracheal intubation time compared to the Macintosh laryngoscope in a low position (17.34 s versus 19.04 s, p < 0.05). A higher rate of repeat intubations was observed in a low position for MCL (from 10% to 14%, p < 0.05). The reverse is true for Intubrite laryngoscope intubation (from 8% to 4%, p < 0.05 Please explain what is compared). The Intubrite laryngoscope improved visualization of glottis in the high and the low positions compared to the Macintosh laryngoscope (54% and 50% to 52% and 38%, respectively, p < 0.05). The risk of tooth damage was the same for the Intubrite and the MCL laryngoscopes in a high position (16% and 14%, respectively, p > 0.05), while in the simulated out-of-hospital setting, it was significantly higher for the MCL (22% versus 8%, p < 0.05). The subjective comfort of intubation in both simulated situations was similar according to the Borg scale (p-value, values). The use of the Intubrite laryngoscope was associated with less effort than the MCL in high versus low positions. For MCL, intubation in a high position was associated with lower mean muscle activity than in a low position (+48.24 µV versus +58.25 µV, p-value). For the Intubrite laryngoscope, these values were at similar levels (+52.03 µV and +52.65 µV, p-value). Conclusions: The use of the Intubrite laryngoscope by people with no clinical experience shortens the time of intubation and improves the laryngeal view compared to the standard Macintosh laryngoscope, but it requires similar muscle work in simulated conditions.

Development of endotracheal intubation devices for patients with tumors

The incidence and mortality of malignant tumors are rapidly increasing in the world. Patients with malignant tumors often need surgery for treatment. Endotracheal intubation is a necessary technique for surgical patients undergoing general anesthesia. It is also an important procedure for critically ill patients in the emergency room or ICU. Most patients with head and neck tumors and some specific patients have difficult airways, so the operator may need to use a variety of intubation devices. The commonly used devices for endotracheal intubation include endotracheal tube, direct laryngoscope, video laryngoscope, introducer, optical stylet, fiberoptic bronchoscope. With the advancement in science and technology, the endotracheal intubation devices have been improved, and new devices have been developed. These devices are safer and more feasible in clinical practice. In this review, we summarized the features and applications of some of the currently used devices. Each device has its own uniqueness and meets different needs. The devices and their respective properties are strongly suggested to be mastered by the anesthesiologists as well as related staffs, so as to select the appropriate device for intubation.

Airway management procedures in Swedish emergency department patients - a national retrospective study

Background

With the on-going debate about which specialty should be responsible for intubations in the emergency department in mind, the aim of this study was to describe the prevalence of endotracheal intubation and other airway management procedures in emergency department patients in Sweden.

Methods

All patients registered in the Swedish Intensive Care Registry with admission date from January 1 2013 until June 7 2018 and reported admission type “from the emergency department” or “emergency department” reported in the SAPS3 scoring were included. All patients missing codes for procedures were excluded.

Results

A total of 110,072 admissions from an emergency department to an ICU were registered during the study period. Of these, 41,619 admissions (37.8%) were excluded due to lack of codes for medical procedures. The remaining 68,453 admissions (62.2%) were included, and 31,888 emergency airway procedures (within 3 h from admission time to the intensive care unit) were registered. Invasive emergency airway procedures were the most common type of airway procedure (n = 23,446), followed by non-invasive airway procedures (n = 8377) and high-flow nasal cannula (n = 880). In 2017 a total of 4720 invasive emergency airway management procedures were registered.

Conclusions

The frequency of invasive airway management procedures in Swedish EDs is low. With approximately 1.9 million adult ED visits per year, this gives an estimated incidence of 2.4 invasive airway management procedures per thousand ED visits in 2017.

Trial registration

Not applicable.

Elective Tracheal Intubation With the VieScope-A Prospective Randomized Non-inferiority Pilot Study (VieScOP-Trial)

Background

Tracheal intubation is commonly performed after direct laryngoscopy using Macintosh laryngoscopes (MacL), but visualization of the larynx may be inadequate. The VieScope (VSC) as a new type of laryngoscope consisting of a straight, shielded, illuminated tube used to perform intubation via a bougie was investigated in this prospective randomized trial in patients without expected difficult airways.

Methods

With ethics approval, 2 × 29 patients for elective surgery were randomized 1:1 to intubation with VSC or MacL. Endpoints were first attempt success rates (FAS), Percentage of Glottis Opening Scale (POGO), time to intubation (TTI), and difficulty ratings on visual analog scales (0–100, lower values better). Data are given as mean ± standard deviation.

Results

The FAS was 83 ± 38% for VSC and 86 ± 34% for MacL (P = 0.723). For VSC, POGO was 86 ± 17% and for MacL 68 ± 30% (P = 0.007). TTI for VSC was 93 ± 67s vs. 38 ± 17 for MacL (P < 0.001). Difficulty of intubation was rated 23 ± 22 for VSC vs. 18 ± 22 for MacL (P = 0.422), viewing conditions 12 ± 15 vs. 24 ± 25 (P = 0.031), and difficulty of tube placement was rated 27 ± 30 vs. 7 ± 8 (P = 0.001).

Conclusion

No difference in FAS was detected between VSC and MacL. Visualization of the larynx was superior using the VSC, while TTI was prolonged and tube placement via bougie was more challenging. The VSC could be an alternative to MacL in patients with difficult laryngoscopy, but this should be investigated further in patients with expected difficult airways.

Videolaryngoscopy versus direct laryngoscopy for adults undergoing tracheal intubation

BACKGROUND

Tracheal intubation is a common procedure performed to secure the airway in adults undergoing surgery or those who are critically ill. Intubation is sometimes associated with difficulties and complications that may result in patient harm. While it is traditionally achieved by performing direct laryngoscopy, the past three decades have seen the advent of rigid indirect videolaryngoscopes (VLs). A mounting body of evidence comparing the two approaches to tracheal intubation has been acquired over this period of time. This is an update of a Cochrane Review first published in 2016.

OBJECTIVES

To assess whether use of different designs of VLs in adults requiring tracheal intubation reduces the failure rate compared with direct laryngoscopy, and assess the benefits and risks of these devices in selected population groups, users and settings.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL and Web of Science on 27 February 2021. We also searched clinical trials databases, conference proceedings and conducted forward and backward citation searches.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and quasi-RCTs with adults undergoing laryngoscopy performed with either a VL or a Macintosh direct laryngoscope (DL) in any clinical setting. We included parallel and cross-over study designs.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We collected data for the following outcomes: failed intubation, hypoxaemia, successful first attempt at tracheal intubation, oesophageal intubation, dental trauma, Cormack-Lehane grade, and time for tracheal intubation.

MAIN RESULTS

We included 222 studies (219 RCTs, three quasi-RCTs) with 26,149 participants undergoing tracheal intubation. Most studies recruited adults undergoing elective surgery requiring tracheal intubation. Twenty-one studies recruited participants with a known or predicted difficult airway, and an additional 25 studies simulated a difficult airway. Twenty-one studies were conducted outside the operating theatre environment; of these, six were in the prehospital setting, seven in the emergency department and eight in the intensive care unit.  We report here the findings of the three main comparisons according to videolaryngoscopy device type. We downgraded the certainty of the outcomes for imprecision, study limitations (e.g. high or unclear risks of bias), inconsistency when we noted substantial levels of statistical heterogeneity and publication bias. Macintosh-style videolaryngoscopy versus direct laryngoscopy (61 studies, 9883 participants) We found moderate-certainty evidence that a Macintosh-style VL probably reduces rates of failed intubation (risk ratio (RR) 0.41, 95% confidence interval (CI) 0.26 to 0.65; 41 studies, 4615 participants) and hypoxaemia (RR 0.72, 95% CI 0.52 to 0.99; 16 studies, 2127 participants). These devices may also increase rates of success on the first intubation attempt (RR 1.05, 95% CI 1.02 to 1.09; 42 studies, 7311 participants; low-certainty evidence) and probably improve glottic view when assessed as Cormack-Lehane grade 3 and 4 (RR 0.38, 95% CI 0.29 to 0.48; 38 studies, 4368 participants; moderate-certainty evidence). We found little or no clear difference in rates of oesophageal intubation (RR 0.51, 95% CI 0.22 to 1.21; 14 studies, 2404 participants) but this finding was supported by low-certainty evidence. We were unsure of the findings for dental trauma because the certainty of this evidence was very low (RR 0.68, 95% CI 0.16 to 2.89; 18 studies, 2297 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 96%). Hyperangulated videolaryngoscopy versus direct laryngoscopy (96 studies, 11,438 participants) We found moderate-certainty evidence that hyperangulated VLs probably reduce rates of failed intubation (RR 0.51, 95% CI 0.34 to 0.76; 63 studies, 7146 participants) and oesophageal intubation (RR 0.39, 95% CI 0.18 to 0.81; 14 studies, 1968 participants). In subgroup analysis, we noted that hyperangulated VLs were more likely to reduce failed intubation when used on known or predicted difficult airways (RR 0.29, 95% CI 0.17 to 0.48; P = 0.03 for subgroup differences; 15 studies, 1520 participants). We also found that these devices may increase rates of success on the first intubation attempt (RR 1.03, 95% CI 1.00 to 1.05; 66 studies, 8086 participants; low-certainty evidence) and the glottic view is probably also improved (RR 0.15, 95% CI 0.10 to 0.24; 54 studies, 6058 participants; data for Cormack-Lehane grade 3/4 views; moderate-certainty evidence). However, we found low-certainty evidence of little or no clear difference in rates of hypoxaemia (RR 0.49, 95% CI 0.22 to 1.11; 15 studies, 1691 participants), and the findings for dental trauma were unclear because the certainty of this evidence was very low (RR 0.51, 95% CI 0.16 to 1.59; 30 studies, 3497 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 99%). Channelled videolaryngoscopy versus direct laryngoscopy (73 studies, 7165 participants) We found moderate-certainty evidence that channelled VLs probably reduce rates of failed intubation (RR 0.43, 95% CI 0.30 to 0.61; 53 studies, 5367 participants) and hypoxaemia (RR 0.25, 95% CI 0.12 to 0.50; 15 studies, 1966 participants). They may also increase rates of success on the first intubation attempt (RR 1.10, 95% CI 1.05 to 1.15; 47 studies, 5210 participants; very low-certainty evidence) and probably improve glottic view (RR 0.14, 95% CI 0.09 to 0.21; 40 studies, 3955 participants; data for Cormack-Lehane grade 3/4 views; moderate-certainty evidence). We found little or no clear difference in rates of oesophageal intubation (RR 0.54, 95% CI 0.17 to 1.75; 16 studies, 1756 participants) but this was supported by low-certainty evidence. We were unsure of the findings for dental trauma because the certainty of the evidence was very low (RR 0.52, 95% CI 0.13 to 2.12; 29 studies, 2375 participants). We were not able to pool data for time required for tracheal intubation owing to considerable heterogeneity (I2 = 98%).

AUTHORS' CONCLUSIONS

VLs of all designs likely reduce rates of failed intubation and result in higher rates of successful intubation on the first attempt with improved glottic views. Macintosh-style and channelled VLs likely reduce rates of hypoxaemic events, while hyperangulated VLs probably reduce rates of oesophageal intubation. We conclude that videolaryngoscopy likely provides a safer risk profile compared to direct laryngoscopy for all adults undergoing tracheal intubation.

Case Report: Double Visualization Intubation Strategy for Patients With Ankylosing Spondylitis

Background

Ankylosing spondylitis is an autoimmune disease involving the axial bone. Because it leads to rigidity of the spine and joints, especially when involving the cervical spine, it will cause a difficult airway, creating a major challenge for airway management. Herein, we report presents a double visual intubation strategy for severe ankylosing spondylitis patients who are difficult to intubate with a video laryngoscope.

Case Presentation

A 31-year-old patient with severe ankylosing spondylitis has a seriously restricted neck movement that makes it hard to insert a tracheal tube using only a video laryngoscope. With the aid of video laryngoscope, we then guided the endotracheal intubation using a lighted stylet. Eventually, the oropharynx was opened sufficiently so that the tracheal tube could be rapidly introduced below the epiglottis and entered the glottis.

Conclusion

In conclusion, the video laryngoscope is a viable operation to assist lighted stylet guided endotracheal intubation in severe ankylosing spondylitis patients after video laryngoscope intubation failure.

Comparisons of Videolaryngoscopes for Intubation Undergoing General Anesthesia: Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Background: The efficacy and safety of videolaryngoscopes (VLs) for tracheal intubation is still conflicting and changeable according to airway circumstances. This study aimed to compare the efficacy and safety of several VLs in patients undergoing general anesthesia. Methods: Medline, EMBASE, and the Cochrane Library were searched until 13 January 2020. The following VLs were evaluated compared to the Macintosh laryngoscope (MCL) by network meta-analysis for randomized controlled trials (RCTs): Airtraq, Airwayscope, C-MAC, C-MAC D-blade (CMD), GlideScope, King Vision, and McGrath. Outcome measures were the success and time (speed) of intubation, glottic view, and sore throat (safety). Results: A total of 9315 patients in 96 RCTs were included. The highest-ranked VLs for first-pass intubation success were CMD (90.6 % in all airway; 92.7% in difficult airway) and King Vision (92% in normal airway). In the rank analysis for secondary outcomes, the following VLs showed the highest efficacy or safety: Airtraq (safety), Airwayscope (speed and view), C-MAC (speed), CMD (safety), and McGrath (view). These VLs, except McGrath, were more effective or safer than MCL in moderate evidence level, whereas there was low certainty of evidence in the intercomparisons of VLs. Conclusions: CMD and King Vision could be relatively successful than MCL and other VLs for tracheal intubation under general anesthesia. The comparisons of intubation success between VLs and MCL showed moderate certainty of evidence level, whereas the intercomparisons of VLs showed low certainty evidence.

Video screen visualization patterns when using a video laryngoscope for tracheal intubation: A systematic review

OBJECTIVE

Published studies of video laryngoscopes are often limited by the lack of a clear definition of video laryngoscopy (VL). We performed a systematic review to determine how often published studies of VL report on video screen visualization.

METHODS

We searched PubMed, EMBASE and Scopus for interventional and observational studies in which a video laryngoscope equipped with a standard geometry blade was used for tracheal intubation. We excluded simulation based studies. Our primary outcome was data on video laryngoscope screen visualization. Secondary outcomes were explicit methodology for screen visualization.

RESULTS

We screened 4838 unique studies and included 207 (120 interventional and 87 observational). Only 21 studies (10% of 207) included any data on video screen visualization by the proceduralist, 19 in a yes/no fashion only (ie, screened viewed or not) and 2 with detail beyond whether the screen was viewed or not. In 11 more studies, visualization patterns could be inferred based on screen availability and in 16 more studies, the methods section stated how screen visualization was expected to be performed without reporting data collection on how the proceduralist interacted with the video screen. Risk of bias was high in the majority of included studies.

CONCLUSIONS

Published studies of VL, including many clinical trials, rarely include data on video screen visualization. Given the nuances of using a video laryngoscope, this is a critical deficiency, which largely prevents us from knowing the treatment effect of using a video laryngoscope in clinical practice. Future studies of VL must address this deficiency.

Guidelines for Perioperative Care in Bariatric Surgery: Enhanced Recovery After Surgery (ERAS) Society Recommendations: A 2021 Update

Background

This is the second updated Enhanced Recovery After Surgery (ERAS®) Society guideline, presenting a consensus for optimal perioperative care in bariatric surgery and providing recommendations for each ERAS item within the ERAS® protocol.

Methods

A principal literature search was performed utilizing the Pubmed, EMBASE, Cochrane databases and ClinicalTrials.gov through December 2020, with particular attention paid to meta-analyses, randomized controlled trials and large prospective cohort studies. Selected studies were examined, reviewed and graded according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. After critical appraisal of these studies, the group of authors reached consensus regarding recommendations.

Results

The quality of evidence for many ERAS interventions remains relatively low in a bariatric setting and evidence-based practices may need to be extrapolated from other surgeries.

Conclusion

A comprehensive, updated evidence-based consensus was reached and is presented in this review by the ERAS® Society.

How to Maintain Safety and Maximize the Efficacy of Cardiopulmonary Resuscitation in COVID-19 Patients: Insights from the Recent Guidelines

Since December 2019, the novel coronavirus disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has remained a challenge for governments and healthcare systems all around the globe. SARS-CoV-2 infection is associated with increased rates of hospital admissions and significant mortality. The pandemic increased the rate of cardiac arrest and the need for cardiopulmonary resuscitation (CPR). COVID-19, with its pathophysiology and detrimental effects on healthcare, influenced the profile of patients suffering from cardiac arrest, as well as the conditions of performing CPR. To ensure both the safety of medical personnel and the CPR efficacy for patients, resuscitation societies have published modified guidelines addressing the specific reality of the COVID-19 pandemic. In this review, we briefly describe the transmission and pathophysiology of COVID-19, present the challenges of CPR in SARS-CoV-2-infected patients, summarize the current recommendations regarding the algorithms of basic life support (BLS), advanced life support (ALS) and pediatric life support, and discuss other aspects of CPR in COVID-19 patients, which potentially affect the risk-to-benefit ratio of medical procedures and therefore should be considered while formulating further recommendations.

Emergency Pediatric Intubations in an Urban Children’s Hospital Before and After Just-in-Time Training for Video Laryngoscopy

Objectives: The use of video laryngoscopy (VL) may augment emergency pediatric intubations outside the operating room (OR). Our objective was to describe the proportion of use and complications with VL before and after implementation of a VL just-in-time training (JITT).

Study design: This study was a retrospective chart review of pediatric intubations performed outside the OR at a single women and children’s hospital from January 2015 to March 2020. Data were collected on patient age, intubation method, operator characteristics, adverse events, number of attempts, condition leading to intubation, and hospital location. Data were separated into pre-JITT (January 1, 2015 to April 31, 2018) and post-JITT (May 1, 2018 to March 1, 2020) periods. Descriptive statistics were used comparing pre- and post-JITT periods for VL use, and the complications of intubations with multiple attempts (IMAs) and intubations with one or more adverse events (AEs).

Results: A total of 231 pediatric patients were intubated during the study period; 154 intubations in the pre-JITT and 77 intubations in the post-JITT periods. Pre- and post-JITT VL use was 17 (11%) and 17 (22%), respectively. With pre-JITT VL, there were four (23%) IMAs and zero (0%) intubation with one or more AE. With post-JITT VL, there were eight (47%) IMAs and one (6%) intubation with one or more AE.

Conclusion: The proportion of emergency pediatric intubations using VL increased after the institution of a JITT. There was no significant change in IMAs and AEs. The infrequency of pediatric intubations makes drawing conclusions regarding the impact on IMAs and AEs challenging. JITT may increase VL use for emergency pediatric intubations outside the OR and may be considered for refresher training, especially during the coronavirus disease 2019 (COVID-19) pandemic.

Intubation using VieScope vs. Video laryngoscopy in full personal protective equipment - a randomized, controlled simulation trial

BACKGROUND

VieScope is a new type of laryngoscope, with a straight, transparent and illuminated blade, allowing for direct line of sight towards the larynx. In addition, VieScope is disposed of after single patient use, which can avoid cross-contaminations of contagious material. This has gained importance especially when treating patients with highly contagious infectious diseases, such as during the SARS-CoV2 pandemic. In this context, VieScope has not been evaluated yet in a clinical study.

MATERIAL AND METHODS

This study compared intubation with VieScope to video-laryngoscopy (GlideScope) in normal and difficult airway in a standardized airway manikin in a randomized controlled simulation trial. Thirty-five medical specialists were asked to perform endotracheal intubation in full personal protective equipment (PPE). Primary endpoint was correct tube position. First-pass rate (i.e., success rate at the first attempt), time until intubation and time until first correct ventilation were registered as secondary endpoints.

RESULTS

For correct tracheal tube placement, there was no significant difference between VieScope and GlideScope in normal and difficult airway conditions. VieScope had over 91% fist-pass success rate in normal airway setting. VieScope had a comparable success rate to GlideScope in difficult airway, but had a significantly longer time until intubation and time until ventilation.

CONCLUSION

VieScope and GlideScope had high success rates in normal as well as in difficult airway. There was no unrecognized esophageal intubation in either group. Overall time for intubation was longer in the VieScope group, though in an acceptable range given in literature. Results from this simulation study suggest that VieScope may be an acceptable alternative for tracheal intubation in full PPE.

TRIAL REGISTRATION

The study was registered at the German Clinical Trials Register www.drks.de (Registration date: 09/11/2020; TrialID: DRKS00023406 ).

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

TRIAL REGISTRATION

NCT04794764.

Does seniority always correlate with simulated intubation performance? Comparing endotracheal intubation performance across medical students, residents, and physicians using a high-fidelity simulator

Background

Endotracheal intubation is crucial in emergency medical care and anaesthesia. Our study employed a high-fidelity simulator to explore differences in intubation success rate and other skills between junior and senior physicians.

Methods

We examined the performance of 50 subjects, including undergraduate students (UGY), postgraduate trainees (PGY), residents (R), and attending physicians (VS). Each participant performed 12 intubations (i.e. 3 devices x 4 scenarios) on a high-fidelity simulator. Main outcome measures included success rate, time for intubation, force applied on incisor and tongue, and Cormack Lehane grades.

Results

There was no primary effect of seniority on any outcome measure except success rate and Cormack Lehane grades. However, VS demonstrated shorter duration than medical students using Glidescope and direct laryngoscopy, whereas VS and R applied significantly more force on the incisor in the normal airway and rigid neck scenario respectively.

Discussion

Seniority does not always correlate with skill perfection in detailed processes. Our study suggests that the use of video laryngoscopy enhances the intubation success rate and speed, but the benefit only accrues to senior learners, whereby they applied more force on the incisor at a single peak under difficult scenarios. These findings are discussed in terms of psychological and cognitive perspectives.

Conclusion

Speed and safety are essential for high quality critical medical procedures. A tool should be designed and implemented to educate junior physicians with an emphasis on practice and efficiency, which should also contribute to updating senior physicians’ knowledge and competence by providing instant feedback on their performance. This type of fine-grained feedback could serve as a complement to traditional training and provide a sustainable learning model for medical education.

Improving first-pass success rates during emergency intubation at an academic emergency department: a quality improvement initiative

BACKGROUND

Airway management is a high-stakes procedure in emergency medicine. Continuously monitoring this procedure allows performance improvement while revealing safety issues. We instituted a quality improvement initiative in the emergency department to improve first-pass success rates in the emergency department.

METHODS

This was a quality improvement initiative at an academic emergency department from 2018 to 2020. We developed a rapid sequence intubation guideline for procedure standardization and introduced an intubation procedure note for performance monitoring. Data were entered directly by the primary physician and nurse during intubation. The quality improvement team thereafter collected the data retrospectively and entered into a local airway database. More importantly, we introduced a culture of quality improvement and safety in airway management via regular education and feedback.

RESULTS

We included a total of 146 intubations. The first-pass success rate started at 57.1% and increased to 80.0% during the study period (P < 0.01). Fifty-six percent were male, and the mean age (±SD) was 55.56 (±17.64). Video laryngoscopy was used in 101 (69.2%) patients, while direct laryngoscopy was used in only 44 (30.8%) patients. A logistic regression analysis was conducted to determine the independent factors associated with first-pass success. These factors included the use of video laryngoscopy (odds ratio (OR) 2.47 95% confidence interval (95% CI) [1.62-3.76]) (adjusted OR 3.87 [1.13-13.23]) and good Cormack-Lehane views (grades 1-2) (OR 2.71 95% CI [1.74-4.20]) (adjusted OR 7.88 [2.43-25.53]).

CONCLUSION

Our study shows that implementing and maintaining an airway quality improvement program improves first-pass intubation success. Moreover, the use of video laryngoscopy and obtaining good Cormack-Lehane views (grades 1-2) are independently associated with improved first-pass success.

Pre-hospital management of penetrating neck injuries: a scoping review of current evidence and guidance

Penetrating injuries to the neck pose a unique challenge to clinicians due to the proximity of multiple significant anatomical structures with little protective soft tissue coverage. Injuries to this area, whilst low in incidence, are potentially devastating. Respiratory, vascular, gastro-oesophageal and neurological structures may all be involved, either in isolation or combination. These injuries are particularly difficult to manage in the resource poor, often austere and/or remote, pre-hospital environment. A systematic scoping review of the literature was conducted to evaluate the current available research pertaining to managing this injury profile, prior to the patient arriving in the emergency department. The available research is discussed in sections based on the commonly used trauma management acronym ‘cABCD’ (catastrophic haemorrhage, Airway, Breathing, Circulation, Disability) to facilitate a systematic approach and clinical evaluation familiar to clinicians. Based on the available reviewed evidence, we have proposed a management algorithm for this cohort of patients. From this we plan to instigate a Delphi process to develop a consensus statement on the pre-hospital management of this challenging presentation.

Maintenance of basic endotracheal intubation skills with direct or video-assisted laryngoscopy: A randomized crossover follow-up study in inexperienced operators

BACKGROUND

Laryngoscopy is a difficult skill to acquire and maintain and even more so by less frequent users. Numerous studies have compared limitations of direct laryngoscopic (DL) and video-assisted laryngoscopic (VL) techniques for endotracheal intubation in different scenarios, but individual retention over time of intubation skills with either technique has, to our knowledge, never been reported. The primary aim of this study was to evaluate to what extent recently acquired basic skills of endotracheal intubation, based on DL or VL, are being maintained over time by inexperienced operators.

METHODS

This randomized crossover follow-up study was designed to compare endotracheal intubation with direct (McIntosh blade) versus video-assisted (hyperangulated blade) laryngoscopy by 20 undergraduate medical students in identical manikins three months after brief basic intubation training with no further intubation practice.

RESULTS

No significant differences in skills retention were found between DL and VL regarding the time for successful intubation or number of adverse events. However, the first intubation was significantly slower regardless of the technique compared with the last one three months earlier. Furthermore, DL was slower and associated with more incidents of esophageal intubation and dental manipulation than was VL.

CONCLUSIONS

Although basic intubation skills seem to be similarly well maintained over time regardless of the laryngoscopic technique, endotracheal intubation with VL by inexperienced operators is faster and associated with fewer adverse events than is DL after a three-month period with no further intubation training.

Comparison of the novel VieScope with conventional and video laryngoscope in a difficult airway scenario - a randomized, controlled simulation trial

Background

Endotracheal intubation continues to be the gold standard for securing the airway in emergency situations. Difficult intubation is still a dreadful situation when securing the airway.

Objective

To compare VieScope with Glidescope and conventional Macintosh laryngoscopy (MAC) in a simulated difficult airway situation.

Methods

In this randomized controlled simulation trial, 35 anesthesiologists performed endotracheal intubation using VieScope, GlideScope and MAC in a randomized order on a certified airway manikin with difficult airway.

Results

For the primary endpoint of correct tube position, no statistical difference was found (p = 0.137). Time until intubation for GlideScope (27.5 ± 20.3 s) and MAC (20.8 ± 8.1 s) were shorter compared to the VieScope (36.3 ± 10.1 s). Time to first ventilation, GlideScope (39.3 ± 21.6 s) and MAC (31.9 ± 9.5 s) were also shorter compared to the VieScope (46.5 ± 12.4 s). There was no difference shown between handling time for VieScope (20.7 ± 7.0 s) and time until intubation with GlideScope or MAC. Participants stated a better Cormack & Lehane Score with VieScope, compared to direct laryngoscopy.

Conclusion

Rate of correct tracheal tube position was comparable between the three devices. Time to intubation and ventilation were shorter with MAC and Glidescope compared to VieScope. It did however show a comparable handling time to video laryngoscopy and MAC. It also did show a better visualization of the airway in the Cormack & Lehane Score compared to MAC.

Trial registration

The study was registered at the German Clinical Trials Register www.drks.de (Identifier: DRKS00024968) on March 31st 2021.

Multivariate Analysis of the Failure Risk of First Tracheal Intubation Attempt in a Population of Patients Scheduled for Bariatric Surgery

BACKGROUND

Airway management during the administration of anesthesia to patients undergoing bariatric surgery is challenging. The goal is to avoid multiple intubation attempts because the risk of complications increases with the number of attempts. The objective of this study was to determine the failed first intubation attempt rate, as well as variables associated with this failure, in patients undergoing bariatric surgery.

METHODS

We enrolled patients scheduled for bariatric surgery in this prospective, observational, single-center study. We determined predictive criteria for difficult intubation at the preoperative anesthesia consultation. All patients were evaluated for obstructive sleep apnea by polygraphy. The primary study endpoint was a failed first intubation attempt.

RESULTS

We enrolled 519 patients between December 2012 and January 2015. The cohort consisted of 425 women (82%), with a median (interquartile range [IQR]) age of 39 (30-50) years and a body mass index of 42 (39-46) kg/m². The first intubation attempt failed in 60 patients, with an incidence rate of 11.5% (95% confidence interval [CI], 8.8-14.2%). We included nine variables in the final multivariate model. Two variables were associated with failed first intubation attempt: male sex (odds ratio [OR] [95% CI], 6.9% [2.5-18.7%]) and Mallampati score 3-4 (OR [95% CI], 2.2% [1.0-4.7%]).

CONCLUSIONS

In this morbidly obese population, the first intubation attempt failed in 11.5% of patients, and the risk factors for failure were male sex and a high Mallampati score.

Emergency Tracheal Intubation in Patients with COVID-19: A Single-center, Retrospective Cohort Study

INTRODUCTION

The objective of this study was to compare airway management technique, performance, and peri-intubation complications during the novel coronavirus pandemic (COVID-19) using a single-center cohort of patients requiring emergent intubation.

METHODS

We retrospectively collected data on non-operating room (OR) intubations from February 1-April 23, 2020. All patients undergoing emergency intubation outside the OR were eligible for inclusion. Data were entered using an airway procedure note integrated within the electronic health record. Variables included level of training and specialty of the laryngoscopist, the patient's indication for intubation, methods of intubation, induction and paralytic agents, grade of view, use of video laryngoscopy, number of attempts, and adverse events. We performed a descriptive analysis comparing intubations with an available positive COVID-19 test result with cases that had either a negative or unavailable test result.

RESULTS

We obtained 406 independent procedure notes filed between February 1-April 23, 2020, and of these, 123 cases had a positive COVID-19 test result. Residents performed fewer tracheal intubations in COVID-19 cases when compared to nurse anesthetists (26.0% vs 37.4%). Video laryngoscopy was used significantly more in COVID-19 cases (91.1% vs 56.8%). No difference in first-pass success was observed between COVID-19 positive cases and controls (89.4% vs. 89.0%, p = 1.0). An increased rate of oxygen desaturation was observed in COVID-19 cases (20.3% vs. 9.9%) while there was no difference in the rate of other recorded complications and first-pass success.

DISCUSSION

An average twofold increase in the rate of tracheal intubation was observed after March 24, 2020, corresponding with an influx of COVID-19 positive cases. We observed adherence to society guidelines regarding performance of tracheal intubation by an expert laryngoscopist and the use of video laryngoscopy.

Rapid sequence induction: where did the consensus go?

Background

Rapid Sequence Induction (RSI) was introduced to minimise the risk of aspiration of gastric contents during emergency tracheal intubation. It consisted of induction with the use of thiopentone and suxamethonium with the application of cricoid pressure.

This narrative review describes how traditional RSI has been modified in the UK and elsewhere, aiming to deliver safe and effective emergency anaesthesia outside the operating room environment. Most of the key aspects of traditional RSI – training, technique, drugs and equipment have been challenged and often significantly changed since the procedure was first described. Alterations have been made to improve the safety and quality of the intervention while retaining the principles of rapidly securing a definitive airway and avoiding gastric aspiration. RSI is no longer achieved by an anaesthetist alone and can be delivered safely in a variety of settings, including in the pre-hospital environment.

Conclusion

The conduct of RSI in current emergency practice is far removed from the original descriptions of the procedure. Despite this, the principles – rapid delivery of a definitive airway and avoiding aspiration, are still highly relevant and the indications for RSI remain relatively unchanged.

A systematic review of meta-analyses comparing direct laryngoscopy with videolaryngoscopy

PURPOSE

In the preceding 20 years, many randomized-controlled trials and meta-analyses have compared direct Macintosh laryngoscopy with videolaryngoscopy. The videolaryngoscope blades have included both traditional Macintosh blades and hyperangulated blades. Macintosh and hyperangulated blades differ in their geometry and technique for tracheal intubation; certain patient populations may benefit from one blade type over another. The primary objective of this systematic review was to assess whether published meta-analyses comparing direct Macintosh laryngoscopy to videolaryngoscopy have accounted for the videolaryngoscope blade type. Secondary objectives evaluated heterogeneity among practitioner experience and specialty, clinical context, patient population, and original primary study outcomes.

SOURCE

A search was performed across Ovid Medline, Ovid Embase, ClinicalKey, PubMed, TRIP, AccessAnesthesiology, Google Scholar, and ANZCA discovery. A systematic review identified meta-analyses which compared direct Macintosh laryngoscopy to videolaryngoscopy. There were no patient age or clinical specialty restrictions. Exclusion criteria included non-English language, studies comparing non-Macintosh blade to videolaryngoscopy, and studies in awake patients.

PRINCIPAL FINDINGS

Twenty-one meta-analyses were identified that were published between 1 January 2000 and 7 May 2020. Macintosh and hyperangulated videolaryngoscope blades were combined in most studies (16/21; 76%). Heterogeneity was also present among practitioner experience (20/21; 95%), clinician specialty (15/21; 71%), and clinical locations (10/21; 48%). Adult and pediatric patients were combined or not defined in 5/21 studies (24%). The primary outcomes of the meta-analyses varied, with the most common (7/21; 33%) being first-pass tracheal intubation success.

CONCLUSIONS

Heterogeneity across important clinical variables is common in meta-analyses comparing direct Macintosh laryngoscopy to videolaryngoscopy. To better inform patient care, future videolaryngoscopy research should differentiate blade type, clinical context, and patient-related primary outcomes.

Haemodynamic responses following orotracheal intubation in patients with hypertension---Macintosh direct laryngoscope versus Glidescope®videolaryngoscope

BACKGROUND AND AIMS

Glidescope®videolaryngoscope (GVL) is a video intubation system with 60° angle blade that provides excellent laryngeal view, does not require alignment of oral, pharyngeal, and laryngeal axes for visualisation of glottis, thus causing less stimulation of orolaryngopharynx. The aim of this study was to compare haemodynamic responses (blood pressure and heart rate) and airway morbidity using the Macintosh direct laryngoscope (MDL) and the Glidescope®videolaryngoscope (GVL) in hypertensive patients.

METHODS

Fifty patients with hypertension controlled on antihypertensive medications scheduled for elective surgery under general anaesthesia were randomly assigned to group GVL (n = 25) or group MDL (n = 25). Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP) were recorded at baseline, after induction, pre-intubation, at intubation, 1, 2, 3, 4, and 5 min after intubation. Time to intubation, number of attempts, complications during intubation, and postoperative airway complications (sore throat, hoarseness, dysphagia, and cough) were also recorded.

RESULTS

There was a statistically significant increase in SBP, DBP, and MBP at intubation [(P = 0.003, 0.013, 0.03), 1 min (P = 0.001, 0.012, 0.02), 2 min (P = 0.04, 0.02, 0.04), and 3 min (P = 0.02, 0.01)] in the MDL group as compared to GVL group. The time to intubate was significantly greater in the GVL group as compared to MDL group (P = 0.0006). There was no significant difference in the incidence of intraoperative and postoperative airway complications.

CONCLUSION

In the hands of an experienced anaesthesiologist, the use of GVL in controlled hypertensive patients is associated with less haemodynamic response as compared to Macintosh Laryngoscope without any increase in airway complications.

Analysis of tracheal intubation in out-of-hospital helicopter emergency medicine recorded by video laryngoscopy

Background

Tracheal intubation remains the gold standard of airway management in emergency medicine and maximizing safety, intubation success, and especially first-pass intubation success (FPS) in these situations is imperative.

Methods

We conducted a prospective observational study on all 12 helicopter emergency medical service (HEMS) bases of the Swiss Air Rescue, between February 15, 2018, and February 14, 2019. All 428 patients on whom out-of-hospital advanced airway management was performed by the HEMS crew were included. The C-MAC video laryngoscope was used as the primary device for tracheal intubation. Intubation procedures were recorded by the video laryngoscope and precise time points were recorded to verify the time necessary for each attempt and the overall procedure time until successful intubation. The videos were further analysed for problems and complications during airway management by an independent reviewer. Additionally, a questionnaire about the intubation procedure, basic characteristics of the patient, circumstances, environmental factors, and the provider’s level of experience in airway management was filled out. Main outcome measures were FPS of tracheal intubation, overall success rate, overall intubation time, problems and complications of video laryngoscopy.

Results

FPS rate was 87.6% and overall success rate 98.6%. Success rates, overall time to intubation, and subjective difficulty were not associated to the providers’ expertise in airway management. In patients undergoing CPR FPS was 84.8%, in trauma patients 86.4% and in non-trauma patients 93.3%. FPS in patients with difficult airway characteristics, facial trauma/burns or obesity ranges between 87 and 89%. Performing airway management indoors or inside an ambulance resulted in a significantly higher FPS of 91.1% compared to outdoor locations (p < 0.001). Direct solar irradiation on the screen, fogging of the lens, and blood on the camera significantly impaired FPS. Several issues for further improvements in the use of video laryngoscopy in the out-of-hospital setting and for quality control in airway management were identified.

Conclusion

Airway management using the C-MAC video laryngoscope with Macintosh blade in a group of operators with mixed experience showed high FPS and overall rates of intubation success. Video recording emergency intubations may improve education and quality control.

Post operative sore throat: Comparison between Macintosh versus Video Laryngoscope in patients intubated by trainee anaesthetists - A Randomised Control Trial

Objectives:

Postoperative sore throat (POST) is a common complication related to endotracheal intubation. The aim of this study was to compare the incidence of POST in patients intubated by trainee anaesthetist using Video Laryngoscope™ (VDL) or Conventional Macintosh Laryngoscope (CL).

Methods:

Total 110 patient scheduled for elective laparoscopic cholecystectomy were included from main operating room of Aga Khan University Hospital between June 2017-2018. The standardized perioperative protocol was used for general anaesthesia. Selected patients were randomly allocated into conventional laryngoscopy (CL) group or video laryngoscopy (VDL) group. The evaluation of sore throat was done at 1st, 12th and 24th hour postoperatively using a ten-point visual analogue scale.

Results:

The demographic characteristics, including intubation time, related complications or any other maneuver required were similar between the groups. The incidence of POST at 1st hour was 47% patients in CL group and 38% in VDL group (p=0.335). At 12th hour, 34.5% patients in CL and 38% in VDL reported POST (p=0.692). Similarly at 24th hour, 25% patients in CL and 16% in VDL group reported POST (p=0.669).

Conclusions:

There was no significant difference in incidence of POST for patients intubated by trainee anaesthetists using either CL or VDL. Objective evidence of training and laryngoscope technique can impact of POST.

A prospective, observational, cohort study of airway management of patients with COVID-19 by specialist tracheal intubation teams

PURPOSE

Because of the anticipated surge in cases requiring intensive care unit admission, the high aerosol-generating risk of tracheal intubation, and the specific requirements in coronavirus disease (COVID-19) patients, a dedicated Mobile Endotracheal Rapid Intubation Team (MERIT) was formed to ensure that a highly skilled team would be deployed to manage the airways of this cohort of patients. Here, we report our intubation team experience and activity as well as patient outcomes during the COVID-19 pandemic.

METHODS

The MERIT members followed a protocolized early tracheal intubation model. Over a seven-week period during the peak of the pandemic, prospective data were collected on MERIT activity, COVID-19 symptoms or diagnosis in the team members, and demographic, procedural, and clinical outcomes of patients.

RESULTS

We analyzed data from 150 primary tracheal intubation episodes, with 101 (67.3%) of those occurring in men, and with a mean (standard deviation) age of 55.7 (13.8) yr. Black, Asian, and minority ethnic groups accounted for 55.7% of patients. 91.3% of tracheal intubations were performed with videolaryngoscopy, and the first pass success rate was 88.0%. The 30-day survival was 69.2%, and the median [interquartile range] length of critical care stay was 11 [6-20] days and of hospital stay was 12 [7-22] days. Seven (11.1%) MERIT healthcare professionals self-isolated because of COVID-19 symptoms, with a total 41 days of clinical work lost. There was one reported incident of a breach of personal protective equipment and multiple anecdotal reports of doffing breaches.

CONCLUSION

We have shown that a highly skilled designated intubation team, following a protocolized, early tracheal intubation model may be beneficial in improving patient and staff safety, and could be considered by other institutions in future pandemic surges.

A randomized controlled trial comparing McGRATH series 5 videolaryngoscope with the Macintosh laryngoscope for nasotracheal intubation

Background and Aims:

The aim of this study was to compare the efficacy of McGRATH series 5 videolaryngoscope (VL) with Macintosh laryngoscope for nasotracheal intubation (NTI) in patients without anticipated difficult airways undergoing head and neck cancer surgeries.

Material and Methods:

We randomized 60 adult patients for NTI by experienced anesthetists with either Macintosh laryngoscope or McGRATH series 5 VL (VL group). The primary objective was to compare time taken for intubation (TTI). The secondary objectives included success rates, number of attempts, need for optimization maneuvers, Cormack and Lehane (CL) grade, and percentage of difficult intubations.

Results:

The mean TTI in the VL group was 43 (±10.6) versus 75 (±38.0) s in the Macintosh group (99% CI: 12.5; –51.6 s; P < 0.001). The overall intubation success rate was 100% in both groups. All 29 (100%) patients in the VL group were intubated in the first attempt versus 26 (86%) patients in the Macintosh group (99% CI –5; 33%; P = 0.11). In the Macintosh group, 20 (66%) patients needed optimization maneuver versus none in the VL group (99% CI 40; 91%; P < 0.001). In the VL group, 28 (96%) patients had a CL grade 1 view versus 9 (31%) in Macintosh group (99% CI 38; 92%; P < 0.001). There were no difficult intubations in the VL group versus 3 (10%) in the Macintosh group (99% CI: 7; 28%; P = 0.237). There was no trauma to oropharyngeal structures in either group.

Conclusion:

The McGRATH series 5 VL has faster TTI, better glottic visualization, and less need for optimization maneuvers than the Macintosh laryngoscope for NTI in patients with unanticipated difficult airways, when performed by experienced anesthetists.

Comparison of videolaryngoscopy and direct laryngoscopy for tracheal intubation in obstetrics: a mixed-methods systematic review and meta-analysis

PURPOSE

The incidence of difficult and failed intubation is higher in obstetrical patients than in the general population because of anatomic and physiologic changes in pregnancy. Videolaryngoscopy improves the success rate of intubation and reduces complications when compared with direct laryngoscopy in adults; however, it is not known whether this extends to obstetrical surgery. The aim of this study was to examine the efficacy, efficiency, and safety of videolaryngoscopy compared with direct laryngoscopy in obstetrics.

SOURCE

Central, CINAHL, Embase, MEDLINE and Web of Science databases were searched from inception to 27 May 2020 with no restrictions. Inclusion criteria included randomized-controlled trials (RCTs), observational studies, case series, and case reports that reported the application of videolaryngoscopy to intubate the trachea in pregnant patients having general anesthesia.

PRINCIPAL FINDINGS

Overall, four RCTs with 428 participants, nine observational studies, and 35 case reports/series with 100 participants were included. On meta-analysis of three trials, the co-primary outcomes of first-attempt success rate (risk ratio, 1.02; 95% confidence intervals [CI], 0.98 to 1.06; P = 0.29; I2 = 0%) and time to tracheal intubation (mean difference, 1.20 sec; 95% CI, -6.63 to 9.04; P = 0.76; I² = 95%) demonstrated no difference between videolaryngoscopy and direct laryngoscopy in parturients without difficult airways. Observational studies and case reports underline the role of videolaryngoscopy as a primary choice when difficulty with tracheal intubation is expected or as a rescue modality in difficult or failed intubations.

CONCLUSIONS

Evidence for the utility of videolaryngoscopy continues to evolve but supports its increased adoption in obstetrics where videolaryngoscopes should be immediately available for use as a first-line device.

TRIAL REGISTRATION

PROSPERO (CRD42020189521); registered 6 July 2020.

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.

Canadian Airway Focus Group updated consensus-based recommendations for management of the difficult airway: part 2. Planning and implementing safe management of the patient with an anticipated difficult airway

PURPOSE

Since the last Canadian Airway Focus Group (CAFG) guidelines were published in 2013, the published airway management literature has expanded substantially. The CAFG therefore re-convened to examine this literature and update practice recommendations. This second of two articles addresses airway evaluation, decision-making, and safe implementation of an airway management strategy when difficulty is anticipated.

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 is lacking, statements are based on group consensus.

FINDINGS AND KEY RECOMMENDATIONS

Prior to airway management, a documented strategy should be formulated for every patient, based on airway evaluation. Bedside examination should seek predictors of difficulty with face-mask ventilation (FMV), tracheal intubation using video- or direct laryngoscopy (VL or DL), supraglottic airway use, as well as emergency front of neck airway access. Patient physiology and contextual issues should also be assessed. Predicted difficulty should prompt careful decision-making on how most safely to proceed with airway management. Awake tracheal intubation may provide an extra margin of safety when impossible VL or DL is predicted, when difficulty is predicted with more than one mode of airway management (e.g., tracheal intubation and FMV), or when predicted difficulty coincides with significant physiologic or contextual issues. If managing the patient after the induction of general anesthesia despite predicted difficulty, team briefing should include triggers for moving from one technique to the next, expert assistance should be sourced, and required equipment should be present. Unanticipated difficulty with airway management can always occur, so the airway manager should have a strategy for difficulty occurring in every patient, and the institution must make difficult airway equipment readily available. Tracheal extubation of the at-risk patient must also be carefully planned, including assessment of the patient's tolerance for withdrawal of airway support and whether re-intubation might be difficult.

Learning curve and performance in simulated difficult airway for the novel C-MAC® video-stylet and C-MAC® Macintosh video laryngoscope: A prospective randomized manikin trial

Difficult airways can be managed with a range of devices, with video laryngoscopes (VLs) being the most common. The C-MAC® Video-Stylet (VS; Karl-Storz Germany), a hybrid between a flexible and a rigid intubation endoscope, has been recently introduced. The aim of this study is to investigate the performance of the VS compared to a VL (C-MAC Macintosh blade, Karl-Storz Germany) with regards to the learning curve for each device and its ability to manage a simulated difficult airway manikin. This is a single-center, prospective, randomized, crossover study involving twenty-one anesthesia residents performing intubations on a Bill 1™ (VBM, Germany) airway manikin model. After a standardized introduction, six randomized attempts with VL and VS were performed on the manikin. This was followed by intubation in a simulated difficult airway (cervical collar and inflated tongue) with both devices in a randomized fashion. The primary end-point of this study was the total time to intubation. All continuous variables were expressed as the median [interquartile range] and analyzed using the Mann-Whitney U test. A 2-way ANOVA with Bonferroni's post hoc test was used to compare both devices at each trial. All reported p values are two sided. The median total time to intubation on a simulated difficult airway was faster with the VS compared to VL (17 [13.5-25] sec vs 23 [18.5-26.5] sec, respectively; 95% CI; P = 0.031). Additionally, on a normal airway manikin, the VS has a comparable learning curve to the VL. In this manikin-based study, the novel VS was comparable to the VL in terms of learning curve in a normal airway. In a simulated difficult airway, the total time to intubation, though likely not clinically relevant, was faster with the VS to the VL. However, given the above findings, this study justifies further human clinical trials with the VS to see if similar benefits-faster time to intubation and similar learning curve to VL-are replicated clinically.

COVID-19 respiratory support in the emergency department setting

Introduction

Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19), may result in severe complications, multiorgan dysfunction, acute respiratory failure, and death. SARS-CoV-2 is highly contagious and places healthcare workers at significant risk, especially during aerosol-generating procedures, including airway management.

Objective

This narrative review outlines the underlying respiratory pathophysiology of patients with COVID-19 and discusses approaches to airway management in the emergency department (ED) based on current literature.

Discussion

Patients presenting with SARS-CoV-2 infection are at high risk for acute respiratory failure requiring airway management. Among hospitalized patients, 10–20% require intensive care unit admission, and 3–10% require intubation and mechanical ventilation. While providing respiratory support for these patients, proper infection control measures, including adherence to personal protective equipment policies, are necessary to prevent nosocomial transmission to healthcare workers. A structured approach to respiratory failure in these patients includes the use of exogenous oxygen via nasal cannula or non-rebreather, as well as titrated high-flow nasal cannula and non-invasive ventilation. This review offers several guiding principles and resources designed to be adapted in conjunction with local workplace policies for patients requiring respiratory support.

Conclusions

While the fundamental principles of acute respiratory failure management are similar between COVID-19 and non-COVID-19 patients, there are some notable differences, including a focus on provider safety. This review provides an approach to airway management and respiratory support in the patient with COVID-19.

Suitability and realism of the novel Fix for Life cadaver model for videolaryngoscopy and fibreoptic tracheoscopy in airway management training

Background

Videolaryngoscopy is increasingly advocated as the standard intubation technique, while fibreoptic intubation is broadly regarded as the ‘gold standard’ for difficult airways. Traditionally, the training of these techniques is on patients, though manikins, simulators and cadavers are also used, with their respective limitations. In this study, we investigated whether the novel ‘Fix for Life’ (F4L) cadaver model is a suitable and realistic model for the teaching of these two intubation techniques to novices in airway management.

Methods

Forty consultant anaesthetists and senior trainees were instructed to perform tracheal intubation with videolaryngoscopy and fibreoptic tracheoscopy in four F4L cadaver models. The primary outcome measure was the verbal rating scores (scale 1–10, higher scores indicate a better rating) for suitability and for realism of the F4L cadavers as training model for these techniques. Secondary outcomes included success rates of the procedures and the time to successful completion of the procedures.

Results

The mean verbal rating scores for suitability and realism for videolaryngoscopy was 8.3 (95% CI, 7.9–8.6) and 7.2 (95% CI, 6.7–7.6), respectively. For fibreoptic tracheoscopy, suitability was 8.2 (95% CI, 7.9–8.5) and realism 7.5 (95% CI, 7.1–7.8). In videolaryngoscopy, 100% of the procedures were successful. The mean (SD) time until successful tracheal intubation was 34.8 (30.9) s. For fibreoptic tracheoscopy, the success rate was 96.3%, with a mean time of 89.4 (80.1) s.

Conclusions

We conclude that the F4L cadaver model is a suitable and realistic model to train and teach tracheal intubation with videolaryngoscopy and fibreoptic tracheoscopy to novices in airway management training.