Video-laryngoscopes in the adult airway management: a topical review of the literature

Comparison of AirAngel® vs. Storz® videolaryngoscope and Macintosh® laryngoscope for endotracheal intubation training: prospective randomized crossover study

BACKGROUND

For both normal and difficult airway management, VL is thought to be more effective. However, VL seems far from being offered as a standard option in both healthcare delivery and educational activities in low-income countries, considering its high costs. Therefore, three-dimensional(3D)printed VLs may be considered an alternative to conventional VLs in low-income countries and other places with limited resources. Our objective was to compare the efficacy of AirAngel 3D-printed VL (3D-PVL) with those of commercially available Storz® VL (SVL) and conventional Macintosh® laryngoscope (MCL) in normal and difficult airway scenarios in the hands of inexperienced users.

METHODS

This is a prospective randomized crossover manikin study that included 126 senior medical students with no experience in intubation. The effectiveness of all three laryngoscopy devices in the hands of inexperienced users was evaluated in terms of intubation time, glottic visualization, ease of use, endotracheal tube placement, and intubation success rate. Between 2020 and 2022, 126 last year medical students participated in the study.

RESULTS

MCL resulted in significantly longer intubation times than 3D-PVL and SVL in the difficult airway scenario, with no significant difference between 3DPVL and SVL (Wilcoxon test, p < 0.016; Bonferroni correction MCL: 28.54 s; SVL: 26.68 s; 3DPVL: 26.64 s). Both SVL and 3D-PVL resulted in significantly better Cormack - Lehane grades in both normal and difficult airway scenarios, and thus provided better glottic viewing than MCL, with no significant difference between 3D-PVL and SVL (Wilcoxon test, p < 0.016; Bonferroni correction, MCL: 1.73; SVL: 1.29; 3DPVL: 1.25). The SVL was the easiest device to use for normal airway scenarios (1: very easy, 5: very difficult), while the MCL was the most difficult (MCL: 2.64; 3DPVL: 1.98; SVL: 1.49). Conversely, no significant difference was found between 3DPVL and other devices in terms of ease of use in difficult airway scenarios and in terms of accurate placement of the endotracheal tube and successful intubation attempts.

CONCLUSION

3D-PVL is a good educational and possible clinical alternative to conventional VL, particularly in places with limited resources, due to its low cost.

A robot-assisted tracheal intubation system based on a soft actuator?

PURPOSE

Tracheal intubation is the gold standard of airway protection and constitutes a pivotal life-saving technique frequently employed in emergency medical interventions. Hence, in this paper, a system is designed to execute tracheal intubation tasks automatically, offering a safer and more efficient solution, thereby alleviating the burden on physicians.

METHODS

The system comprises a tracheal tube with a bendable front end, a drive system, and a tip endoscope. The soft actuator provides two degrees of freedom for precise orientation. It is fabricated with varying-hardness silicone and reinforced with fibers and spiral steel wire for flexibility and safety. The hydraulic actuation system and tube feeding mechanism enable controlled bending and delivery. Object detection of key anatomical features guides the robotic arm and soft actuator. The control strategy involves visual servo control for coordinated robotic arm and soft actuator movements, ensuring accurate and safe tracheal intubation.

RESULTS

The kinematics of the soft actuator were established using a constant curvature model, allowing simulation of its workspace. Through experiments, the actuator is capable of 90° bending as well as 20° deflection on the left and right sides. The maximum insertion force of the tube is 2 N. Autonomous tracheal intubation experiments on a training manikin were successful in all 10 trials, with an average insertion time of 45.6 s.

CONCLUSION

Experimental validation on the manikin demonstrated that the robot tracheal intubation system based on a soft actuator was able to perform safe, stable, and automated tracheal intubation. In summary, this paper proposed a safe and automated robot-assisted tracheal intubation system based on a soft actuator, showing considerable potential for clinical applications.

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

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

Dynamic versus standard bougies for tracheal intubation with direct or indirect laryngoscopy in simulated or real scenarios: a systematic review and meta-analysis

INTRODUCTION

This systematic review and meta-analysis aimed to compare the efficacy of dynamic versus standard bougies to achieve tracheal intubation.

METHODS

We searched MEDLINE, Embase, CENTRAL, Web of Science, Scopus and Google Scholar on 10 October 2023. We included clinical trials comparing both devices. The primary outcome was the first-attempt intubation success rate. The secondary outcome was the time required for tracheal intubation.

RESULTS

Eighteen studies were included. Dynamic bougies do not increase first-attempt success rate (RR 1.11; p = 0.06) or shorten tracheal intubation time (MD -0.30 sec; p = 0.84) in clinical trials in humans. In difficult airways, first-attempt success intubation rate was greater for dynamic bougies (RR 1.17; p = 0.002); Additionally, they reduced the time required for intubation (MD -4.80 sec; p = 0.001). First-attempt intubation success rate was higher (RR 1.15; p = 0.01) and time to achieve intubation was shorter when using Macintosh blades combined with dynamic bougies (MD -5.38 sec; p < 0.00001). Heterogeneity was high.

CONCLUSION

Dynamic bougies do not increase the overall first-pass success rate or shorten tracheal intubation time. However, dynamic bougies seem to improve first-attempt tracheal intubation rate in patients with difficult airways and in those intubated with a Macintosh blade. Further research is needed for definitive conclusions.

REGISTRATION OF PROSPERO

CRD42023472122.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

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

Spanish Society of Anesthesiology, Reanimation and Pain Therapy (SEDAR), Spanish Society of Emergency and Emergency Medicine (SEMES) and Spanish Society of Otolaryngology, Head and Neck Surgery (SEORL-CCC) Guideline for difficult airway management. Part II

The Airway Management section of the Spanish Society of Anesthesiology, Resuscitation, and Pain Therapy (SEDAR), the Spanish Society of Emergency Medicine (SEMES), and the Spanish Society of Otorhinolaryngology and Head and Neck Surgery (SEORL-CCC) present the Guide for the comprehensive management of difficult airway in adult patients. Its principles are focused on the human factors, cognitive processes for decision-making in critical situations, and optimization in the progression of strategies application to preserve adequate alveolar oxygenation in order to enhance safety and the quality of care. The document provides evidence-based recommendations, theoretical-educational tools, and implementation tools, mainly cognitive aids, applicable to airway management in the fields of anesthesiology, critical care, emergencies, and prehospital medicine. For this purpose, an extensive literature search was conducted following PRISMA-R guidelines and was analyzed using the GRADE methodology. Recommendations were formulated according to the GRADE methodology. Recommendations for sections with low-quality evidence were based on expert opinion through consensus reached via a Delphi questionnaire.

Laryngopharyngeal Mucosal Injury Due to Nasogastric Tube Insertion during Cardiopulmonary Resuscitation: A Retrospective Cohort Study

BACKGROUND

Patients under cardiopulmonary resuscitation (CPR) are at high risk of aspirating gastric contents. Nasogastric tube insertion (NGTI) after tracheal intubation is usually performed blindly. This sometimes causes laryngopharyngeal mucosal injury (LPMI), leading to severe bleeding. This study clarified the incidence of LPMI due to blind NGTI during CPR.

METHODS

We retrospectively analyzed 84 patients presenting with cardiopulmonary arrest on arrival, categorized them into a Smooth group (Smooth; blind NGTI was possible within 2 min), and Difficult group (blind NGTI was not possible), and consequently performed video laryngoscope-assisted NGTI. The laryngopharyngeal mucosal condition was recorded using video laryngoscope. Success rates and insertion time for the Smooth group were calculated. Insertion number and LPMI scores were compared between the groups. Each regression line of outcome measurements was obtained using simple regression analysis. We also analyzed the causes of the Difficult group, using recorded video laryngoscope-assisted videos.

RESULTS

The success rate was 78.6% (66/84). NGTI time was 48.8 ± 4.0 s in the Smooth group. Insertion number and injury scores in the Smooth group were significantly lower than those in the Difficult group. The severity of LPMI increased with NGT insertion time and insertion number.

CONCLUSIONS

Whenever blind NGTI is difficult, switching to other methods is essential to prevent unnecessary persistence.

Development and validation of an artificial intelligence algorithm for detecting vocal cords in video laryngoscopy

Airway procedures in life-threatening situations are vital for saving lives. Video laryngoscopy (VL) is commonly performed during endotracheal intubation (ETI) in the emergency department. Artificial intelligence (AI) is widely used in the medical field, particularly to detect anatomical structures. This study aimed to develop an AI algorithm that detects vocal cords from VL images acquired during emergent situations. This retrospective study used VL images acquired in the emergency department to facilitate the ETI. The vocal cord image was labeled with a ground-truth bounding box. The dataset was divided into training and validation datasets. The algorithm was developed from a training dataset using the YOLOv4 model. The performance of the algorithm was evaluated using a test set. The test set was further divided into specific environments during the ETI for clinical subgroup analysis. In total, 20,161 images from 84 patients were used in this study. A total of 10,287, 5766, and 4108 images were used for the model training, validation, and test sets, respectively. The developed algorithm achieved F1 score 0.906, sensitivity 0.963, and specificity 0.842 in the validation set. The performance in the test set was F1 score 0.808, sensitivity 0.823, and specificity 0.804. We developed and validated an AI algorithm to detect vocal cords in VL. This algorithm demonstrated a high performance. The algorithm can be used to determine the vocal cord to ensure safe ETI.

New Devices, Innovative Technologies, and Non-Standard Techniques for Airway Management: A Narrative Review

A wide range of airway devices and techniques have been created to enhance the safety of airway management. However, airway management remains a challenge. All techniques are susceptible to failure. Therefore, it is necessary to have and know the greatest number of alternatives to treat even the most challenging airway successfully. The aim of this narrative review is to describe some new devices, such as video laryngeal masks, articulated stylets, and non-standard techniques, for laryngeal mask insertion and endotracheal intubation that are not applied in daily practice, but that could be highly effective in overcoming a difficulty related to airway management. Artificial intelligence and 3D technology for airway management are also discussed.

Comparison of haemodynamic response to tracheal intubation with two different videolaryngoscopes: A randomized clinical trial

BACKGROUND

Endotracheal intubation (ETI), which is the gold standard in coronary artery bypass grafting (CABG), may cause myocardial ischaemia by disturbing the balance between haemodynamic changes and oxygen supply and consumption of the myocardium as a result of sympathetic stimulation. In this study, we aimed to compare two different videolaryngoscopes (C-MAC and Airtraq) in the hemodynamic response to ETI.

METHODS

Fifty ASA II...III CABG surgery patients were randomly assigned to C-MAC or Airtraq. The hemodynamic data included arterial blood pressure [systolic (SAP), diastolic (DAP) and mean (MAP)] and heart rate (HR) and were recorded at six different points in time: before laryngoscopy-T1, during laryngoscopy-T2, immediately after intubation-T3, and 3 (T4), 5 (T5) and 10 (T6) minutes after intubation. Intraoperative complications were recorded. Patients were questioned about postoperative complications 2 and 24...hours following extubation.

RESULTS

The hemodynamic response to ETI was significantly greater with C-MAC. The increase in HR started with the laryngoscopy procedure, whereas increases in SAP, DAP, and MAP started immediately after ETI (p...=...0.024; p...=...0.012; p...=...0.030; p...=...0.009, respectively). In group analyses, T1...T2, T2...T3 and T1...T3 comparisons did not show any significant differences in HR with Airtraq. However, with C-MAC, HR after intubation increased significantly compared to the pre-laryngoscopy values (T1...T3) (p...=...0.004). The duration of laryngoscopy was significantly reduced with C-MAC (p...<...0.001), but the duration of intubation and total intubation were similar (p...=...0.36; p...=...0.79).

CONCLUSIONS

Compared to C-MAC, the hemodynamic response to ETI was less with Airtraq. Thus, Airtraq may be preferred in CABG patients for ETI.

Ease of Intubation with McGrath Videolaryngoscope and Incidence of Adverse Events During Tracheal Intubation in COVID-19 Patients: A Prospective Observational Study

Background

Tracheal intubation in critically ill patients remains high-risk despite advances in equipment, technique, and clinical guidelines. Many patients with COVID-19 were in respiratory distress and required intubation that is considered an aerosol-generating procedure (AGP). The transition to videolaryngoscopy as a routine first line option throughout anesthetic and ICU practice has been reported. We evaluated the ease of intubation, success rate, use of accessory maneuvers and adverse outcomes during and 24 hours after intubation with the McGrath videolaryngoscope.

Methods

This was a prospective, observational single center study conducted at non-operating room locations that included all adults (>18 years old) with suspected or confirmed COVID-19 infection and were intubated by McGrath videolaryngoscope. The anesthesiologist performed tracheal intubation were requested to fill online data collection form. A co-investigator was responsible to coordinate daily with assigned consultants for COVID intubation and follow up of patients at 24 hours after intubation.

Results

A total of 105 patients were included in our study. Patients were predominantly male (n=78; 74.3%), their COVID status was either confirmed (n=97, 92.4%) or suspected (n=8, 7.6%). Most were intubated in the COVID ward (n=59, 56.2%) or COVID ICU (n=23, 21.9%). The overall success rate of intubation with McGrath in the first attempt was 82.9%. The glottic view was either full (n=85, 80.95%), partial (n=16, 15.24%) or none (n=4, 3.81%). During intubation, hypoxemia occurred in 18.1% and hypotension in 16.2% patients. Within 24 hours of intubation, pneumothorax occurred in 1.9%, cardiac arrest and return of spontaneous circulation in 6.7% and mortality in 13.3% of patients.

Conclusion

These results illustrate the ease and utility of the McGrath videolaryngoscope for tracheal intubation in COVID-19 patients. Its disposable blade is of significant value in protectin during tracheal intubation.

Usefulness of preoperative computed tomography findings for airway management in patients with acute odontogenic infection: a retrospective study

Odontogenic infection is more likely to affect the airway and interfere with intubation than non-odontogenic causes. Although anesthesiologists predict the difficulty of intubation and determine the method, they may encounter unexpected cases of difficult intubation. An inappropriate intubation can cause airway obstruction due to bleeding and edema by damaging the pharynx and larynx. This study was performed to determine the most important imaging findings indicating preoperative selection of an appropriate intubation method. This retrospective study included 113 patients who underwent anti-inflammatory treatment for odontogenic infection. The patients were divided into two groups according to the intubation method: a Macintosh laryngoscope (45 patients) and others (video laryngoscope and fiberscope) (68 patients). The extent of inflammation in each causative tooth, the severity of inflammation (S1-4), and their influence on the airway were evaluated by computed tomography. The causative teeth were mandibular molars in more than 90%. As the severity of inflammation increased, anesthesiologists tended to choose intubation methods other than Macintosh laryngoscopy. In the most severe cases (S4), anesthesiologists significantly preferred other intubation methods (33 cases) over Macintosh laryngoscopy (9 cases). All patients with S4 showed inflammation in the parapharyngeal space, and the airway was affected in 41 patients. The mandibular molars were the causative teeth most likely to affect the airway and surrounding region. In addition to clinical findings, the presence or absence of inflammation that has spread to the parapharyngeal space on preoperative computed tomography was considered an important indicator of the difficulty of intubation.

Comparison of the McGRATHTM Video Laryngoscope and Macintosh Laryngoscope for Orotracheal Intubation in a Simulated Difficult Airway Scenario: An Open-Label, Randomized Clinical Trial

Background and Objectives: Difficult intubation, which may be encountered unexpectedly during anesthesia, can increase patients' morbidity and mortality. The McGRATH video laryngoscope is known to provide improved laryngeal visibility in patients with difficult or normal airways. The purpose of this study was to evaluate the efficacy of the McGRATH video laryngoscope for orotracheal intubation compared with that of conventional Macintosh laryngoscopes in simulated difficult airway scenarios. Materials and Methods: In this randomized controlled trial, patients who were scheduled for surgery under general anesthesia requiring orotracheal intubation were assigned to the Macintosh laryngoscope (n = 50) or McGRATH video laryngoscope (n = 45) groups. In this study, to create a simulated difficult airway condition, the subjects performed manual in-line stabilization and applied a soft cervical collar. The primary outcome was the rate of successful intubation within 30 s. The time required for an intubation, glottis grade, intubation difficulty scale (IDS score), the subjective ease of intubation, and optimal external laryngeal manipulation (OLEM) were evaluated. In addition, complications caused by each blade were investigated. Results: The intubation success rate within 30 s was not significantly different between the two groups (44 (88.0%) vs. 36 (80.0%), p = 0.286). The glottic grade was better in the McGRATH group than in the Macintosh group (p = 0.029), but neither the intubation time (26.3 ± 8.2 s vs. 24.2 ± 5.0 s, p = 0.134) nor the rates of oral bleeding (2 (4.0%) vs. 0 (0.0%)) and tooth injury (0 (0.0%) vs. 1 (2.2%)) were significantly different between the two groups. Conclusions: The use of the McGRATH video laryngoscope did not improve the intubation success rate or shorten the intubation time. However, the McGRATH video laryngoscope provided a better glottis view than the conventional Macintosh laryngoscope in patients with a simulated difficult airway.

The Evolution of Equipment and Technology for Visualising the Larynx and Airway

Laryngoscopy and endotracheal intubation are the core skills of an anaesthetist. The tools and equipment used today are unrecognisable from the methods used in the first recorded attempts at laryngoscopy over 200 years ago. The evolution of the modern-day laryngoscopes has mirrored advancements in technology within general society, and particularly with regard to computer and fibreoptic technology over the last 30 years. The development of these modern visualisation devices would not have been possible without those that went before it, as each new device has been influenced by the previous. Video laryngoscopes have quickly gained popularity as the primary intubating device in many scenarios, driven by ease of use as well as positive patient outcomes. While it is still debated whether videolaryngoscopes can replace direct laryngoscopy for routine intubations, their effectiveness in difficult airways is unquestioned. This chapter will cover the anatomy of the airway and the development of technology from the rudimentary creations in the early 1700s to the modern larynsgocopes created in the twenty-second century which allow the user to view the airway in more detail in order to secure endotracheal intubation even in an airway where intubation would be difficult.

A comparison of endotracheal intubation characteristics between Macintosh, CMAC and Smart Trach laryngoscopes; A randomized prospective clinical trial

BACKGROUND

In this study, we compared the performance characteristics of Macintosh laryngoscope, CMAC videolaryngoscope with a recently developed videolaryngoscope called Smart Trach.

RESEARCH DESIGN AND METHODS

: Three hundred seventy-five patients belonging to mixed population without having anticipated difficult airways undergoing elective surgeries were randomly allocated to be intubated using either of the three laryngoscopes (Macintosh, CMAC or Smart Trach). Time needed for successful intubation, number of attempts, Cormack Lehane's (CL) grading, optimisation maneuverers, intubation difficulty score (IDS), subjective ease of intubation (VAS), subjective lifting force and complications were recorded.

RESULTS

: Demographic and anthropometric measurements (sex, height, weight and body mass index) among the groups were comparable. CL grades, lifting force, IDS, VAS and intubation times (seconds) were significantly different whereas need for maneuver, attempts and complications were similar. (p>0.05 each). Intubation times (seconds) were significantly different between Macintosh [36(29-43) seconds] CMAC [30(24-37)] and Smart Trach [35(30-42] groups. (p<0.001). Subjective ease of intubation based on VAS score was lowest in Smart trach group [1(1-2)] (p<0.001).

CONCLUSION

Shortest intubation times were achieved with CMAC with least use of lifting force. First attempt success rates of were similar. Intubation was easiest subjectively using Smart Trach as manifested by lowest VAS and IDS.

TRIAL REGISTRATION

Clinical Trial registry of India (CTRI/2019/09/021279 dated 17/09/2019).

Effect of table inclination angle on videolaryngoscopy and direct laryngoscopy: Operator's muscle activation and laryngeal exposure analysis

BACKGROUND

Optimal vocal cord visualization depends on the patient's anatomical factors, characteristics of the laryngoscope, and the operator's muscle action. This study evaluated the effect of table inclination and three different laryngoscopic methods on procedural variables. The primary aim of this study is to compare differences in laryngoscopic view among clinicians based on the instrument used and table orientation. The secondary aim is to determine differences in upper extremity muscle activity based on laryngoscope use and table inclination.

METHODS

Fifty-five anesthesia providers with different experience levels performed intubations on a manikin using three angles of table inclination and three laryngoscopy methods. Time to intubation, use of optimization maneuvers, glottic view, operator's comfort level, and upper extremity muscle activation measured by surface electromyography were evaluated.

RESULTS

Table inclination of 15° and 30° significantly reduced intubation time and the need for optimization maneuvers. Fifteen degrees inclination gave the highest comfort level. Anterior deltoid muscle intensity was decreased when table inclination at 15° and 30° was compared to a flat position.

CONCLUSION

Table inclination of 15° reduces intubation time and the need to use optimization maneuvers and is associated with higher operator's comfort levels than 0° and 30° inclination in a simulated scenario using a manikin. Different upper extremity muscle groups are activated during laryngoscopy, with the anterior deltoid muscle exhibiting significantly higher activation levels with direct laryngoscopy at zero-degree table inclination.

Successful laryngoscope view using oversized C-Mac® D-blade in children presenting with difficult airway

Management of the difficult paediatric airway is challenging due to anatomical differences, congenital anomalies, paucity of paediatric airway management algorithms, and the limited availability of paediatric-sized airway devices. In this case report, we describe two cases highlighting the potential use of seemingly oversized videolaryngoscopes in the management of the difficult paediatric airway. Recognising the cause of difficult airway in the paediatric population is potentially useful in the selection of a larger videolaryngoscope blade to aid laryngoscopy and intubation.

A review on the anesthetic management of obese patients undergoing surgery

There has been an observed increase in theprevalence of obesity over the past few decades. The prevalence of anesthesiology related complications is also observed more frequently in obese patients as compared to patients that are not obese. Due to the increased complications that accompany obesity, obese patients are now more often requiring surgical interventions. Therefore, it is important that anesthesiologists be aware of this development and is equipped to manage these patients effectively and appropriately. As a result, this review highlights the effective management of obese patients undergoing surgery focusing on the preoperative, perioperative and postoperative care of these patients.

Pre-formed endotracheal tube and stepwise insertion for more successful intubation with video laryngoscopy

BACKGROUND

In anesthesia practice, orotracheal intubation remains the primary concern of the anesthesiologist. The introduction of video laryngoscopy (VL) has increased the success rate of orotracheal intubation; however, conflicting results have been reported regarding the usefulness of the current technique with VL in clinical practice.

AIM

To describe a modification to improve intubation with VL, followed by evaluation of the practice in vivo.

METHODS

First, a mannequin trial was conducted with operators having different experience and background. Then, a retrospective analysis was performed for an > 1-year period with patients who underwent general anesthesia with orotracheal intubation. The endotracheal tube used had been pre-formed with two curves. Stepwise intubation had been performed with direct eye vision, followed by screen assistance and rotation of the tube as needed to direct it toward the glottis. In the mannequin trial, the outcome measures were quantification of torque (force with angular acceleration during levering), need for external maneuvers, and time to intubate. In the clinical experience, orotracheal intubation used VL (pre-formed tube) or direct laryngoscopy (DL) at the anesthetist’s discretion and throat discomfort was reported by the patient.

RESULTS

In the mannequin trials using VL, there was less torque with the pre-formed tube than with a regular tube (8% and 65%, respectively). The first-pass rate was higher with the pre-formed tube (95%) than with a regular tube (81%). However, the time to intubate was longer with the pre-formed tube than with a regular tube (22 s and 12 s, respectively). In clinical practice, 562 patients underwent surgery under general anesthesia with orotracheal intubation using either VL (n = 244) or DL (n = 318) at the discretion of the attending anesthetist. VL was specifically planned in 62 of the patients, due to anticipated difficulty. Second attempts by readjustment of the curve of the tube were significantly fewer with VL than with DL (10% vs 18%). Throat discomfort was reported by fewer patients who underwent VL than those who underwent DL (6% vs 24%).

CONCLUSION

Pre-formed endotracheal tube with stepwise insertion produces less torque, fewer external maneuvers and higher first-pass success rate during VL intubation. Further, prospective studies are warranted.

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 ).

Comparison of the effects of the McGRATH MAC, C-MAC, and Macintosh laryngoscopes on the intraocular pressures of non-ophthalmic patients: A prospective, randomised, clinical trial

INTRODUCTION

In this prospective, randomised study, we compared the effects of the Macintosh, McGRATH MAC, and C-MAC laryngoscopes on intraocular pressure (IOP) and haemodynamics of non-ophthalmic patients during endotracheal intubation.

METHODS

One hundred and twenty adult patients undergoing non-ophthalmic surgeries performed in the supine position under general anaesthesia requiring orotracheal intubation were included in this study. The patients were separated randomly and prospectively into 3 groups: Macintosh group (n = 40), McGRATH MAC group (n = 40), and C-MAC group (n = 40). Mean arterial pressure (MAP), heart rate (HR) and IOP of left and right eye were measured at specified times.

RESULTS

There were no significant differences with regard to patients characteristics. After intubation, the HR increased significantly in the Macintosh group when compared to the other groups (p = 0.001) and the MAP increased significantly in the Macintosh group when compared to the McGRATH MAC group (p = 0.001) and the C-MAC group (p < 0.001). The IOP values increased in the Macintosh group when compared to the McGRATH MAC group (p < 0.001) and the C-MAC group (p < 0.001) after intubation. Additionally, there was a significant difference between the McGRATH MAC group and C-MAC group in the IOP values of the eyes after intubation (p < 0.001). According to the evaluation within the groups, there were significant differences in all of the groups at all times when compared with the baseline values (p < 0.001).

CONCLUSIONS

In this study, we concluded that the C-MAC VL may be preferable when compared to the Macintosh and McGRATH MAC laryngoscopes for use in ophthalmic patients in whom a rise in the IOP is undesirable.

Videolaryngoscopy vs. Direct Laryngoscopy for Elective Airway Management in Paediatric Anaesthesia: A prospective randomised controlled trial

BACKGROUND

The indirect visualisation of the glottic area with a videolaryngoscope could improve intubation conditions which may possibly lead to a higher success rate of the first intubation attempt.

OBJECTIVE

Comparison of videolaryngoscopy and direct laryngoscopy for elective airway management in paediatric patients.

DESIGN

Prospective randomised controlled trial.

SETTINGS

Operating room.

PARTICIPANTS

535 paediatric patients undergoing elective anaesthesia with tracheal intubation. 501 patients were included in the final analysis.

INTERVENTIONS

Patients were randomly allocated to the videolaryngoscopy group (n  = 265) and to the direct laryngoscopy group (n  = 269) for the primary airway management.

MAIN OUTCOME MEASURES

The first attempt intubation success rate was assessed as the primary outcome. The secondary outcomes were defined as: the time to successful intubation (time to the first EtCO2 wave), the overall intubation success rate, the number of intubation attempts, the incidence of complications, and the impact of the length of the operator's clinical practice.

RESULTS

The study was terminated after the planned interim analysis for futility. There were no significant demographic differences between the two groups. The first attempt intubation success rate was lower in the videolaryngoscopy group; 86.8% (n  = 211) vs. 92.6% (n  = 239), P = 0.046. The mean time to the first EtCO2 wave was longer in the videolaryngoscopy group at 39.0 s ± 36.7 compared to the direct laryngoscopy group, 23.6 s ± 24.7 (P < 0.001). There was no difference in the overall intubation success rate, in the incidence of complications nor significant difference based on the length of the clinical practice of the operator.

CONCLUSIONS

The first attempt intubation success rate was lower in the videolaryngoscopy group in comparison to the direct laryngoscopy group. The time needed for successful intubation with videolaryngoscopy was longer compared with direct laryngoscopy.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT03747250.

A Comparative Study in Airway Novices Using King Vision Videolaryngoscope and Conventional Macintosh Direct Laryngoscope for Endotracheal Intubation

Background and Objectives

Tracheal intubation using laryngoscopy is a fundamental skill, for an anesthesiologist. However, teaching this skill is difficult since Macintosh direct laryngoscope (DL) allows only one individual to view the larynx during the procedure. Hence, this study aimed to determine whether King Vision® videolaryngoscope (KVL) provides any advantage over direct laryngoscopy in teaching this skill to airway novices.

Materials and Methods

In this prospective randomized crossover study, Ethical Committee clearance was obtained from the institutional review board (MSRMC/EC/2017) and the study was registered with Clinical Trial Registry. After informed consent, 53 medical students were allotted to perform laryngoscopy and endotracheal intubation on a manikin by using either KVL or Macintosh DL. The participants first performed laryngoscopy with either KVL or Macintosh DL following a brief instruction and then crossed over to the second arm of the study to perform laryngoscopy using the other scope. The primary outcome measure was the time for successful endotracheal intubation. The secondary outcome measures were incidence of esophageal intubation (EI), excess application of pressure on maxillary teeth excess maxillary pressure, and success rate.

Results

Mean time for endotracheal intubation was significantly faster using KVL than in DL (44.64 vs. 87.72 s; P < 0.001). No significant difference was found in the incidence of esophageal intubation 15.1% in KVL group versus 24.5% in DL group (P = 0.223). In the KVL group, 81.1% did not apply pressure on maxillary teeth versus 26.4% in the DL group (P < 0.001). The success rate of intubation was 100% in the KVL group versus 86.8% in the DL group (P = 0.006).

Conclusion

The KVL is a more effective tool to teach endotracheal intubation in comparison to Macintosh laryngoscope in airway novice medical students. Clinical trial registry India registration number: CTRI/2017/11/010491.

Comparison of video-stylet and video-laryngoscope for endotracheal intubation in adults with cervical neck immobilisation: A meta-analysis of randomised controlled trials

BACKGROUND

The efficacy of video-stylet versus video-laryngoscope for tracheal intubation in patients with cervical spine immobilisation, which is known to impede the intubation process, remains unclear.

METHODS

We searched electronic databases including EMBASE, MEDLINE, Google Scholar, and Cochrane Library for randomised controlled trials comparing video-stylets with video-laryngoscopes in human subjects with cervical spine immobilisation from inception to the 25^th of January 2021. The primary outcome was the rate of successful first-attempt intubation, while secondary outcomes included overall intubation success rate, time for successful intubation, and risk of tissue damage.

RESULTS

Five trials (709 patients) published between 2009 and 2020 met the inclusion criteria. There were four types of video-stylets and three types of video-laryngoscopes examined. Hard cervical collar was applied in four studies, while manual inline stabilisation was used in one study for cervical immobilisation. There was no difference in successful first-attempt intubation rate between the video-stylet and the video-laryngoscope groups [risk ratio (RR) = 0.96, 95% CI: 0.90-1.03, p = 0.3; I² = 47%] (5 trials, 709 patients). The overall success rate (RR = 0.98, 95% CI: 0.96-1.0, p = 0.05; I² = 0%), intubation time [mean difference (MD) = 5.24, 95% CI: -8.95 to 19.43, p = 0.47; I² = 92%], and risk of tissue damage (RR = 0.87, 95% CI: 0.26-2.85, p = 0.81; I² = 39%) were also comparable between the two groups.

CONCLUSIONS

This study validates the efficacy of both video-stylets and video-laryngoscopes for tracheal intubation in the situation of cervical spine immobilisation. Further large-scale trials are warranted to support our findings in this clinical setting.

Efficacy of stylet angulation at the holding position during tracheal intubation with a videolaryngoscope: a randomized controlled trial

The aim of this randomized controlled trial was to determine the efficacy of stylet angulation at the holding position during tracheal intubation with a McGRATH MAC videolaryngoscope. Patients were randomized to a group for intubation without stylet angulation at the holding position (non-angulation group) and to a group for intubation with stylet angulation at the holding position (angulation group). The primary outcome was the time for placement of the tracheal tube. Sixty patients were analyzed. The mean (standard deviation) times for tube placement were 21.3 (5.6) s in the non-angulation group and 16.9 (3.8) s in the angulation group (P < 0.001). The scores of operator's perception of difficulty in tube delivery, number of attempts for tube delivery, and degrees of extension, abduction, internal rotation of the right upper arm and extension of the right wrist during tube placement in the angulation group were significantly smaller than those in the non-angulation group (P < 0.001, P = 0.002, P < 0.001, P < 0.001, P < 0.001, P < 0.001, respectively). Our results suggest that stylet angulation at the holding position improves maneuverability of the tracheal tube and enables easy, smooth, and swift tube placement during tracheal intubation with a McGRATH MAC videolaryngoscope.

Comparative evaluation of glidescope videolaryngosocope and conventional macintosh laryngoscope for nasotracheal intubation in patients undergoing oropharyngeal cancer surgeries: A prospective randomized study

BACKGROUND AND AIMS

Nasotracheal intubation in oropharyngeal cancer patients is challenging owing to anatomical alterations. Various videolaryngoscopes have been compared to conventional laryngoscope and also amongst each other in different clinical scenarios; the supremacy of videolaryngoscopes over conventional laryngoscope in oropharyngeal cancer patients is yet to be established. We compared the efficacy of glidescope videolaryngoscopes and Macintosh laryngoscope for nasotracheal intubation in patients posted for routine oropharyngeal cancer.

MATERIAL AND METHODS

120 ASA I and II oropharyngeal cancer patients scheduled for elective surgery were randomized to undergo nasotracheal intubation after induction of general anesthesia with glide scope video laryngoscope (Group GVL, N = 60) or Macintosh laryngoscope (Group L, N = 60) as per group allocation. Time to glottic view, total intubation time (primary objective), hemodynamic fluctuations, and additional manoeuvres to aid intubation were recorded.

RESULTS

Time to visualize the glottic opening (9.20 ± 4.6 sec vs 14.8 ± 6.3 sec) (P = 0.000) and the total intubation time was significantly less in group GVL (35.6 ± 9.57 sec vs 42.2 ± 11 sec) (P = 0.001). Glidescope videolaryngosocpe provided better glottic views and resulted in significantly fewer manoeuvres to facilitate NTI (P = 0.009). The median numeric rating scale (NRS), hemodynamic parameters and complications were similar in both the groups.

CONCLUSION

Glidescope videolaryngosocpe is better than conventional Macintosh laryngoscope for intubation times and need of manoeuvres to facilitate intubation and should be a preferred device for NTI in patients with oropharyngeal cancer.

The Efficacy of O-Mac®, Patent Video Laryngoscope, and Conventional Laryngoscope for Intubation in the Operating Room

BACKGROUND: Management of the airway in patients undergoing surgery is increasingly difficult. The airway management in the operating room in terms of the initial action of anesthesia is very important. Video-laryngoscopy has been shown to provide a better view of the larynx’s structure compared to direct visualization. AIM: We describe our experience using a custom made and inexpensive tool for a video-laryngoscopy. METHODS: This is an experimental research with single randomized clinical trial conducted at the Anesthesiology Department of Sanglah General Hospital Denpasar. There were 270 patients divides into three group with conventional, O-Mac® and Mc-GRATH™ BF laryngoscope, aged 18–65 years old, with Mallampati grade 1–2, randomly selected, and signed informed consent. RESULTS: Intubation time fastest with O-Mac® median 26 (15–36) s, p = 0.000. Laryngoscopy time fastest with O-Mac® median 5.5 (2–13 s), p = 0.000. O-Mac® does not use many tools, p = 0.000. All three did not produce tissue damage with results p = 0.007. Hemodynamic changes p = 0.000. CONCLUSION: The O-Mac® is superior in terms of laryngoscope time and intubation time compared to the Mc-GRATH™ BF blade and has the same level of safety as the patented Mc-GRATH ™ video laryngoscope, and better than conventional laryngoscopes.

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.

Wristbands use to identify adult patients with difficult airway: a scoping review

Background

Difficult airway is a clinical situation in which a trained anesthesiologist experiences trouble with facemask ventilation and/or laryngoscopy and/or intubation. Poor identification of at-risk patients has been identified as one of the causes of difficult airway management.

Objectives

We aimed to review the literature regarding the use of wristbands to identify adult patients with known or predicted difficult airway in hospitals.

Methods

We searched Web of Science (WoS), Scopus, MEDLINE and OVID following the stages described by the PRISMA Extension for Scoping Reviews (PRISMA-ScR). We used a combination of MeSH terms and non-controlled vocabulary regarding the use of difficult airway wristbands in adults. Three researchers independently reviewed the full texts and selected the papers to be included based on the inclusion criteria.

Results

Our search generated 334 articles after removing duplicates. After reviewing full text articles, only seven studies were included. Here we found that most were from the United States, in which the authors report the use of in-patients’ wristbands in adults. According to the authors, the use of wristbands is being implemented as a measure of improved quality and safety of in-patients with difficult airway either known or suspected.

Conclusions

The identification with wristbands of a difficult airway at an appropriate time is an identification strategy can have a low cost but a high impact on morbidity. It is pertinent to develop a methodology such as the use of wristbands, that allows a good classification and identification of patients with difficult airway in hospitals from Latin America.

Video laryngoscopy for out of hospital cardiac arrest

INTRODUCTION

Endotracheal intubation is an import component of out-of-hospital cardiac arrest (OHCA) resuscitation. In this analysis, we evaluate the association of video laryngoscopy (VL) with first pass success and return of spontaneous circulation (ROSC) using a national OHCA cohort.

METHODS

We analyzed 2018 data from ESO Inc. (Austin, TX), a national prehospital electronic health record. We included all adult, non-traumatic cardiac arrests undergoing endotracheal intubation. We defined VL and direct laryngoscopy (DL) based on paramedic recorded intubation device. The primary outcomes were first pass success, ROSC, and sustained ROSC. Using multivariable, mixed models, we determined the association between VL and first pass success rate, ROSC, and sustained ROSC (survival to ED or ROSC in the field for greater than 20 min), fitting agency as a random intercept and adjusting for confounders.

RESULTS

We included 22,132 patients cared for by 914 EMS agencies, including 5702 (25.7%) VL and 16,430 (74.2%) DL. Compared to DL, VL had a lower rate of bystander CPR, but other characteristics were similar between the groups. VL exhibited higher first pass success than DL (75.1% v 69.5%, p < .001). On mixed model analysis, VL was associated with a higher first pass success (OR 1.5, CI 1.3-1.6) but not ROSC (OR 1.1, CI 0.97-1.2) or sustained ROSC (OR 1.1, CI 0.9-1.2).

CONCLUSION

While associated with higher FPS, VL was not associated with increased rate of ROSC. The role of VL in OHCA remains unclear.

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.

Evolution of videolaryngoscopy in pediatric population

Direct laryngoscopy has remained the sole method for securing airway ever since the inception of endotracheal intubation. The recent introduction of video-laryngoscopes has brought a paradigm shift in the pratice of airway management. It is claimed that they improve the glottic view and first pass success rates in adult population. The airway management in children is more challenging than adults. The role of videolaryngoscopy for routine intubation in children is not clearly proven. This review attempts to discuss various videolaryngosocpes available for use in pediatric patients.

A manikin study comparing the performance of the GlideScope®, the Airtraq® and the C-MAC® in endotracheal intubation using suction-assisted laryngoscopy airway decontamination techniques in a simulated massive haematemesis scenario by emergency doctors

Background:

The suction-assisted laryngoscopy and airway decontamination (SALAD) techniques (level 1, SALAD-1 and level 2, SALAD-2) are newly proposed airway management skills to facilitate endotracheal intubation in patients with massive haematemesis. A pilot study using GlideScope® demonstrated the superior performance of SALAD-1 technique in massive haematemesis simulation.

Objectives:

To compare the performance of three different video laryngoscopes (the GlideScope®, the Airtraq® and the C-MAC®) in endotracheal intubation using SALAD techniques by emergency doctors in a manikin simulating massive haematemesis.

Methods:

Forty-eight emergency doctors were recruited. The participants’ performance of endotracheal intubation using the GlideScope®, the Airtraq® and the C-MAC® with the conventional and the two SALAD techniques in a manikin simulating massive haematemesis was evaluated. The time for intubation, number of attempts, rate of failed intubation, amount of aspirated fluid and the subjective ease of different devices and techniques were compared.

Results:

The C-MAC® had shorter intubation time compared with GlideScope® when using conventional (mean intubation time: 28.48 vs 47.00 s, p = 0.018) and SALAD-1 technique (mean intubation time: 29.35 vs 43.25 s, p < 0.039). The intubation time of all three video laryngoscopes was similar in SALAD-2 technique. There was no significant difference in the number of attempts and failed intubation rate among different video laryngoscopes in using different techniques. Intubation with the C-MAC® resulted in the least mean amount of aspiration in all the conventional (35.63 mL), SALAD-1 (14.06 mL) and SALAD-2 (18.13 mL) techniques. However, the results were not significantly different from the GlideScope® and the Airtraq®. The C-MAC® was rated the most favourable video laryngoscope for the SALAD-1 technique (p < 0.001). There was no significant preference for different video laryngoscopes in using the SALAD-2 technique (p = 0.111).

Conclusion:

All the video laryngoscopes have similar intubation performance with the SALAD-1 and SALAD-2 techniques. The C-MAC® performed better than GlideScope® in terms of intubation time. The C-MAC® was the most favourable video laryngoscope for the SALAD-1 technique.

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.

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.

Technologies to Optimize the Care of Severe COVID-19 Patients for Health Care Providers Challenged by Limited Resources

Health care systems are belligerently responding to the new coronavirus disease 2019 (COVID-19). The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a specific condition, whose distinctive features are severe hypoxemia associated with (>50% of cases) normal respiratory system compliance. When a patient requires intubation and invasive ventilation, the outcome is poor, and the length of stay in the intensive care unit (ICU) is usually 2 or 3 weeks. In this article, the authors review several technological devices, which could support health care providers at the bedside to optimize the care for COVID-19 patients who are sedated, paralyzed, and ventilated. Particular attention is provided to the use of videolaryngoscopes (VL) because these can assist anesthetists to perform a successful intubation outside the ICU while protecting health care providers from this viral infection. Authors will also review processed electroencephalographic (EEG) monitors which are used to better titrate sedation and the train-of-four monitors which are utilized to better administer neuromuscular blocking agents in the view of sparing limited pharmacological resources. COVID-19 can rapidly exhaust human and technological resources too within the ICU. This review features a series of technological advancements that can significantly improve the care of patients requiring isolation. The working conditions in isolation could cause gaps or barriers in communication, fatigue, and poor documentation of provided care. The available technology has several advantages including (a) facilitating appropriate paperless documentation and communication between all health care givers working in isolation rooms or large isolation areas; (b) testing patients and staff at the bedside using smart point-of-care diagnostics (SPOCD) to confirm COVID-19 infection; (c) allowing diagnostics and treatment at the bedside through point-of-care ultrasound (POCUS) and thromboelastography (TEG); (d) adapting the use of anesthetic machines and the use of volatile anesthetics. Implementing technologies for safeguarding health care providers as well as monitoring the limited pharmacological resources are paramount. Only by leveraging new technologies, it will be possible to sustain and support health care systems during the expected long course of this pandemic.

GlideScope® versus C-MAC®(D) videolaryngoscope versus Macintosh laryngoscope for double lumen endotracheal intubation in patients with predicted normal airways: a randomized, controlled, prospective trial

BACKGROUND

The double lumen endotracheal tube (DLT) is the most widely-used device for single lung ventilation in current thoracic anesthesia practice. In recent years, the routine application of the videolaryngoscope for single lumen endotracheal intubation has increased; nevertheless there are few studies of the use of the videolaryngoscope for DLT. We wondered whether there were benefits to using the videolaryngoscope for DLT placement in patients with predicted normal airways. Therefore, this study was designed to compare the performances of the GlideScope®, the C-MAC®(D) videolaryngoscope and the Macintosh laryngoscope in DLT intubation.

METHODS

This was a randomized, controlled, prospective study. We randomly allocated 90 adult patients with predicted normal airways into three groups. All patients underwent routine anesthesia using different laryngoscopes according to group allocation. We compared DLT insertion times, first-pass success rates, numerical rating scales (NRS) of DLT delivery and DLT insertion, Cormack-Lehane degrees (C/L), hemodynamic changes and incidences of intubation complications. All outcomes were analyzed using SPSS13.0.

RESULTS

Compared with the GlideScope, the Macintosh gave shorter times for DLT insertion (median: 96 (IQR: 51 [min-max: 62-376] s vs 73 (26 [48-419] s, p = 0.003); however, there was no difference between the Macintosh and C-MAC(D) (p = 0.610). The Macintosh had a significantly higher successful first attempt rate than did the GlideScope or C-MAC(D) (p = 0.001, p = 0.028, respectively). NRS of DLT delivery and insertion were significantly lower in the Macintosh than in the others (p < 0.001). However, the C/L degree in the Macintosh was significantly higher than in the others (p < 0.001). The incidences of oral bleeding, hoarseness, sore throat and dental trauma were low in all groups (p > 0.05). There were no significant differences in DLT misplacement, fiberoptic time or hemodynamic changes among the groups.

CONCLUSIONS

Compared with the Macintosh laryngoscope, the GlideScope® and C-MAC®(D) videolaryngoscopes may not be recommended as the first choice for routine DLT intubation in patients with predicted normal airways.

TRIAL REGISTRATION

The study was prospectively registered at the Chinese Clinical Trial Registry (no. ChiCTR1900025718); principal investigator: Z.L.H.; date of registration: September 6, 2019.

Comparison of Macintosh Laryngoscope and GlideScope® for Orotracheal Intubation in Children Older Than One Year

Objectives:

We aim to investigate intubation conditions, intubation times, and hemodynamic response with the GlideScope video laryngoscope or the Macintosh direct laryngoscope for orotracheal intubation in children older than one year.

Methods:

Eighty patients aged 1–12 years, scheduled to undergo elective surgery under general anesthesia with endotracheal intubation were included in a prospective, single-blinded, randomized trial. Exclusion criteria were risk of pulmonary aspiration, craniofacial malformation, difficult intubation, emergency surgery, cardiovascular disease, respiratory disease, and hemodynamic instability. After standard anesthesia induction, patients were randomized into two groups. The group G patients (n=40) were intubated with the GlideScope and the group M patients (n=40) were intubated with the Macintosh laryngoscope. Intubation time, number of attempts, Cormack–Lehane score, airway maneuvers, and visual analog score were recorded. Hemodynamic variables were recorded before and after anesthesia induction, at intubation, and 1., 3., and 5. minutes after intubation. Student’s t-test, Mann–Whitney U test, and the χ² test were used for statistical analysis, with p<0.05 considered significant.

Results:

The demographic data, operation time and hemodynamic parameters were similar between the two groups. The intubation time was longer in Group G than Group M. The incidence of Cormack–Lehane score 1 was higher in Group G than Group M while Cormack–Lehane score 2 was higher in Group M.

Conclusion:

We concluded that the GlideScope video laryngoscope provided better glottis visualization, but prolonged intubation time. There was no superiorty on hemodynamic effect with the video laryngoscope.

Cuff Failure of Spiral-Filled Polyvinyl Chloride Endotracheal Tube Immediately after Tracheal Intubation Using a Channeled Videolaryngoscope (Pentax Airway Scope)

We report on a case of mechanical damage to the spiral-filled polyvinyl chloride endotracheal tube that occurred shortly after tracheal intubation using a channeled videolaryngoscope (Pentax airway scope). We also found this problem in two other cases among 350 neurosurgery patients over the past 5 years. Prior to intubation, we did not observe any defect in the cuff. However, the cuff could not be filled with air immediately after the intubation. Anesthesiologists should be aware that, during tracheal intubation using an airway scope, friction between the endotracheal tube and inner surface of the introducer might result in sudden rupture of the cuff.

The usefulness of endotracheal tube twisting in facilitating tube delivery to glottis opening during GlideScope intubation in infants: randomized trial

Despite an excellent view of the glottis, technical difficulties with endotracheal tube delivery remains in GlideScope intubation. We evaluated whether a spiral-shape twisted tube can facilitate placement of the tracheal tube tip at the center of glottis opening compared to conventional tube for GlideScope intubation in infants. Eighty-six infants were randomly placed in either the conventional tube group (group C) or the twist tube group (group T). In group T, the shaft of the tube was manually twisted into a loose spiral shape. The primary outcome was the initial center location of the tube tip at the glottis opening, and the secondary outcome was total tube handling time. The initial center location rate of the tube tip at the glottis opening was significantly higher in group T than in group C (88% [38/43] vs. 47% [20/43], P < 0.001). In addition, total tube handling time (sec) was significantly shorter in group T than in group C (15.4 ± 4.7 vs. 18.2 ± 5.3, P = 0.012). In this study, the spiral shape twist tube successfully improved the rate of initial center location of the tube tip at glottis opening and facilitated tube delivery in GlideScope intubation in infants.

A Convolutional Neural Network for Real Time Classification, Identification, and Labelling of Vocal Cord and Tracheal Using Laryngoscopy and Bronchoscopy Video

BACKGROUND

The use of artificial intelligence, including machine learning, is increasing in medicine. Use of machine learning is rising in the prediction of patient outcomes. Machine learning may also be able to enhance and augment anesthesia clinical procedures such as airway management. In this study, we sought to develop a machine learning algorithm that could classify vocal cords and tracheal airway anatomy real-time during video laryngoscopy or bronchoscopy as well as compare the performance of three novel convolutional networks for detecting vocal cords and tracheal rings.

METHODS

Following institutional approval, a clinical dataset of 775 video laryngoscopy and bronchoscopy videos was used. The dataset was divided into two categories for use for training and testing. We used three convolutional neural networks (CNNs): ResNet, Inception and MobileNet. Backpropagation and a mean squared error loss function were used to assess accuracy as well as minimize bias and variance. Following training, we assessed transferability using the generalization error of the CNN, sensitivity and specificity, average confidence error, outliers, overall confidence percentage, and frames per second for live video feeds. After the training was complete, 22 models using 0 to 25,000 steps were generated and compared.

RESULTS

The overall confidence of classification for the vocal cords and tracheal rings for ResNet, Inception and MobileNet CNNs were as follows: 0.84, 0.78, and 0.64 for vocal cords, respectively, and 0.69, 0.72, 0.54 for tracheal rings, respectively. Transfer learning following additional training resulted in improved accuracy of ResNet and Inception for identifying the vocal cords (with a confidence of 0.96 and 0.93 respectively). The two best performing CNNs, ResNet and Inception, achieved a specificity of 0.985 and 0.971, respectively, and a sensitivity of 0.865 and 0.892, respectively. Inception was able to process the live video feeds at 10 FPS while ResNet processed at 5 FPS. Both were able to pass a feasibility test of identifying vocal cords and tracheal rings in a video feed.

CONCLUSIONS

We report the development and evaluation of a CNN that can identify and classify airway anatomy in real time. This neural network demonstrates high performance. The availability of artificial intelligence may improve airway management and bronchoscopy by helping to identify key anatomy real time. Thus, potentially improving performance and outcomes during these procedures. Further, this technology may theoretically be extended to the settings of airway pathology or airway management in the hands of experienced providers. The researchers in this study are exploring the performance of this neural network in clinical trials.

Impact of retrograde transillumination while securing the airway in obese patients undergoing bariatric surgery

Video laryngoscopy (VL) is a well-established technique used in anaesthetising obese patients who present with higher risks of airway-related difficulties and desaturations due to shorter safe apnoea periods. However, VL has certain limitations and may fail. We present the Infrared Red Intubation System (IRRIS), a new technique facilitating glottis identification in severely obese patients undergoing anaesthesia for bariatric surgery. This single-centre, prospective trial assessed the efficacy of the IRRIS for VL tracheal intubation in 20 severely obese adult patients undergoing elective bariatric surgery under general anaesthesia. We assessed the ability of the IRRIS to differentiate the transilluminated glottis from the oesophagus and laryngeal folds and evaluated the ease of intubation. The average weight in the investigated patient cohort was 145 ± 29 kg, the suprasternal tissue thickness was 12 ± 4 mm. The median IQR [range] larynx recognition time was 10 [2-50] s, which was similar to that of lean patients. The degree of obesity correlated with the duration to achieve optimal laryngoscopic view and complete the intubation procedure. We achieved successful VL insertion on the first attempt in 13 of 20 cases (65%), and on the second attempt in 7 cases (35%), emphasising the increased probability of successful intubation on the first attempt. Tracheal intubation with the IRRIS lasted 50 [IQR 20-100] s. The lowest SpO₂ during intubation was 98 [IQR 83-100] %. Addition of IRRIS to VL insertion facilitated the intubation of difficult airways in severely obese patients. IRRIS improves the visualization of the intubation pathway by selectively highlighting the airway entrance and shortens the time to successfully conclude the intubation procedure.

A comparison of King vision video laryngoscope with CMAC D-blade in obese patients with anticipated difficult airway in tertiary hospital in India - Randomized control study

Background and Aims:

This randomized control trial was conducted to compare two video laryngoscopes in obese patients with anticipated difficult airway. Video laryngoscopes have shown to be beneficial in many difficult airway scenarios including obesity. Many studies have shown that even though the glottic view is better, it takes longer to negotiate the endotracheal tube. We proposed to compare CMAC D-blade with King vision-channeled blade for intubating obese patients with anticipated airway difficulty. We hypothesized that channeled scope may be superior as once visualized, tube could be easily negotiated. This would be reflected by time taken for the glottis visualization, time taken for intubation, incidence of complications, and hemodynamic stability.

Material and Methods:

Sixty-three patients who fulfilled inclusion criteria were enrolled after informed consent. Based on the computer-generated randomization, they were assigned to group 1 (King vision laryngoscope – KVL) and group 2 (CMAC D-blade). All anesthetists who intubated, performed 20 intubations with both video laryngoscopes on manikin before performing the study case. The parameters analyzed were time to visualize the glottis, time to successful intubation, and intubation-related hemodynamic variations and complications.

Results:

The mean time taken to visualize the glottis with KVL was 12.93 s compared to 10 s with CMAC D-blade (P value 0.12). Time taken to intubate was 50.04 s with KVL compared to CMAC D-blade which took 46.93 s (P value 0.64). KVL had a complication rate of 20.7% compared to 3.1% with CMAC D-blade (P value 0.04).

Conclusion:

There was no statistically significant difference in time to visualize the glottis and intubation between KVL and CMAC D-blade. But there was a high incidence of complications with KVL.

Frequency distribution of modified Cormack-Lehane views-A retrospective audit of tracheal intubation in children with normal airways

BACKGROUND

Paediatric patients with an unanticipated poor grade of laryngoscopic view during tracheal intubation represent a challenging situation potentially associated with increased morbidity and mortality. The aim of this study was to investigate the frequency of modified Cormack-Lehane (MCL) views and to elucidate variables for poor views in a large collective of children without anticipated airway difficulties.

METHODS

The departmental anaesthesia patient database was searched for patients who had undergone general anaesthesia with tracheal intubation between January 2007 and March 2017. Inclusion criteria were age from birth to 17.99 years, general anaesthesia with tracheal intubation using direct laryngoscopy, no history, symptoms or signs of a difficult airway and the best obtained MCL view documented in the database. Patient- and anaesthesia-related variables associated with a poor view (MCL IIb, III and IV) were elucidated using a logistic regression model.

RESULTS

In all, 22 965 patients were included; of these, 17 593 were observed only once. The prevalence of the first observed MCL views I, IIa, IIb, III and IV was 90.6%, 8.5%, 0.86%, 0.05% and 0%, respectively. The logistic regression model indicates that age and gender are the most important variables associated with MCL views IIb and III in the model. The probability for MCL views IIb/III decreases across the first 5-7 years before increasing again.

CONCLUSIONS

The incidence of a poor grade of laryngoscopic view was found to be very low in children with a normal airway. They mainly occurred in infants and adolescent patients and were more common in male patients.

Postoperative sore throat and subglottic injury after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score: a randomized controlled trial

Background

A tracheal tube stylet can be used to assist successful tracheal intubation, especially during videolaryngoscopic intubation because videolaryngoscopes with a Macintosh-type blade such as McGrath® MAC videolaryngoscope have more acute angle than conventional Macintosh laryngoscope. However, the use of a stylet during tracheal intubation can raise concerns about stylet-induced postoperative airway complications, such as sore throat, subglottic injury, and hoarseness. In this study, we compared the incidence of postoperative airway complications after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score.

Methods

In 104 patients with Mallampati score III or IV and who were scheduled for lumbar or thoracic spine surgery, McGrath® MAC videolaryngoscopic intubation was performed either with a stylet (group S, n = 52) or without a stylet (group N, n = 52). The primary outcome measure was the incidences of sore throat evaluated at 1 and 24 h postoperatively. Secondary outcome measures were the incidences of subglottic injury and postoperative hoarseness.

Results

The incidence of CL grade III in group S and N was 3.8 and 5.8%, respectively. No patient showed CL grade IV. The incidences of sore throat at 1 (26.9 vs 19.2%, P = 0.485) and 24 h (17.3 vs 13.5%, P = 0.786, respectively) postoperatively were not significantly different between the group S and N. However, the incidence of subglottic injury was significantly higher in the group S, compared with the group N (65.4 vs 42.3%, P = 0.030). The incidence of postoperative hoarseness did not differ significantly between the two groups.

Conclusions

The use of a stylet during McGrath® MAC videolaryngoscopic intubation did not have a significant impact on the incidence of postoperative sore throat in patients with a high Mallampati score. Avoiding the use of a stylet during intubation with McGrath® MAC videolaryngoscope may reduce the incidence of subglottic injury in such patients.

Trial registration

Clinical Research Information Service (identifier: KCT0002427, date of registration: June 12, 2017).

Effect of the introduction of C-MAC videolaryngoscopy on first-pass intubation success rates for emergency medicine registrars

OBJECTIVES

The present study investigated the impact of introducing C-MAC videolaryngoscopy as the standard method of visualising glottic structures on first-pass intubation success of emergency medicine (EM) registrars in a large tertiary academic hospital in New Zealand.

METHODS

In this retrospective cohort study, all patients receiving attempted orotracheal intubation in Auckland City Hospital ED 1 year prior to and 1 year after the introduction of C-MAC videolaryngoscopy were compared. The primary outcome was first-pass intubation success rates by EM registrars. Secondary outcomes were first-pass success rates by all intubators, and incidence of any complication of intubation.

RESULTS

There were 163 intubations by EM registrars from June 2015 to August 2017. There was a clinically important and statistically significant improvement in first-pass success from 59.2% (95% confidence interval [CI] 44.1-68.8%) to 85.1% (95% CI 76.0-91.2%, P < 0.001) after the introduction of C-MAC. In multivariate analysis, the independent predictors of success were: Airway Not Predicted Difficult, odds ratio (OR) 2.49 (95% CI 1.06-5.85, P = 0.037); and use of videolaryngoscope, OR 4.49 (95% CI 1.85-10.91, P = 0.001). Overall, complications of intubation improved significantly after introduction of C-MAC (28.9%, 95% CI 19.9-40.0% prior to C-MAC introduction; 16.1%, 95% CI 9.7-25.3% after; P = 0.048).

CONCLUSION

This is the first published study specifically addressing EM registrar intubation success rates in New Zealand, adding to the existing body of data suggesting that videolaryngoscopy may improve success rates for novice intubators.

Endotracheal Intubation Criteria and Stress Response: Airtraq versus Macintosh Laryngoscopes - A Prospective Randomized Controlled Trial

Background:

Airtraq^® is a single-use video laryngoscope used to facilitate tracheal intubation in both expected and unexpected difficult airways.

Aims:

We hypothesized that Airtraq laryngoscope would facilitate better intubation criteria and lower stress response to laryngoscopy in comparison to the Macintosh laryngoscope.

Materials and Methods:

In this randomized, single-blinded, prospective study, 70 adult patients were randomly assigned to be intubated with either Airtraq (Group AT) or Macintosh (Group M) laryngoscope (35 patients in each). The primary outcomes involved intubation time, first-attempt success rate, time to best laryngoscopic view, and percentage of glottic opening (POGO) score. Other recorded parameters involved the hemodynamic and intraocular pressure (IOP) responses to laryngoscopy and intubation and complications during and after laryngoscopy and after extubation. Serum samples were collected before anesthesia induction and 2 min after intubation and analyzed for epinephrine, cortisol, and glucose.

Results:

Group AT had significantly higher POGO score and significantly shorter intubation time and time to best laryngoscopic view than Group M (P < 0.001). The first-attempt success rate was 97.1% in Group AT and 94.3% in Group M (P = 0.55). Postoperatively, laryngospasm and sore throat were encountered in 2.9% of Group M patients compared to 0% in Group AT (P = 1.00). The heart rate, mean arterial pressure, IOP, serum epinephrine, and cortisol were significantly increased in Group M than Group AT.

Conclusion:

In comparison to the Macintosh laryngoscope, Airtraq conferred significantly better intubation criteria and lesser stress response to laryngoscopy and intubation.