Macintosh Videolaryngoscope for Intubation in the Operating Room: A Comparative Quality Improvement Project

Universal paediatric videolaryngoscopy and glottic view grading: a prospective observational study

BACKGROUND

Although videolaryngoscopy has been proposed as a default technique for tracheal intubation in children, published evidence on universal videolaryngoscopy implementation programmes is scarce. We aimed to determine if universal, first-choice videolaryngoscopy reduces the incidence of restricted glottic views and to determine the diagnostic performance of the Cormack and Lehane classification to discriminate between easy and difficult videolaryngoscopic tracheal intubations in children.

METHODS

We conducted a prospective observational study within a structured universal videolaryngoscopy implementation programme. We used C-MAC™ (Karl Storz, Tuttlingen, Germany) videolaryngoscopes in all anaesthetised children undergoing elective tracheal intubation for surgical procedures. The direct and videolaryngoscopic glottic views were classified using a six-stage grading system.

RESULTS

There were 904 tracheal intubations in 809 children over a 16-month period. First attempt and overall success occurred in 607 (67%) and 903 (> 99%) tracheal intubations, respectively. Difficult videolaryngoscopic tracheal intubation occurred in 47 (5%) and airway-related adverse events in 42 (5%) tracheal intubations. Direct glottic view during laryngoscopy was restricted in 117 (13%) and the videolaryngoscopic view in 32 (4%) tracheal intubations (p < 0.001). Videolaryngoscopy improved the glottic view in 57/69 (83%) tracheal intubations where the vocal cords were only just visible, and in 44/48 (92%) where the vocal cords were not visible by direct view. The Cormack and Lehane classification discriminated poorly between easy and difficult videolaryngoscopic tracheal intubations with a mean area under the receiver operating characteristic curve of 0.68 (95%CI 0.59-0.78) for the videolaryngoscopic view compared with 0.80 (95%CI 0.73-0.87) for the direct glottic view during laryngoscopy (p = 0.005).

CONCLUSIONS

Universal, first-choice videolaryngoscopy reduced substantially the incidence of restricted glottic views. The Cormack and Lehane classification was not a useful tool for grading videolaryngoscopic tracheal intubation in children.

Videolaryngoscopy use before and after the initial phases of the COVID-19 pandemic: The report of the VL-iCUE survey with responses from 96 countries

BACKGROUND

The potential benefit of videolaryngoscopy use in facilitating tracheal intubation has already been established, however its use was actively encouraged during the COVID-19 pandemic as it was likely to improve intubation success and increase the patient-operator distance.

OBJECTIVES

We sought to establish videolaryngoscopy use before and after the early phases of the pandemic, whether institutions had acquired new devices during the COVID-19 pandemic, and whether there had been teaching on the devices acquired.

DESIGN

We designed a survey with 27 questions made available via the Joint Information Scientific Committee JISC online survey platform in English, French, Spanish, Chinese, Japanese and Portuguese. This was distributed through 18 anaesthetic and airway management societies.

SETTING

The survey was open for 54 to 90 days in various countries. The first responses were logged on the databases on 28 October 2021, with all databases closed on 26 January 2022. Reminders to participate were sent at the discretion of the administering organisations.

PARTICIPANTS

All anaesthetists and airway managers who received the study were eligible to participate.

MAIN OUTCOME MEASURES

Videolaryngoscopy use before the COVID-19 pandemic and at the time of the survey.

RESULTS

We received 4392 responses from 96 countries: 944/4336 (21.7%) were from trainees. Of the 3394 consultants, 70.8% (2402/3394) indicated no change in videolaryngoscopy use, 19.9% (675/3394) increased use and 9.3% (315/3393) reduced use. Among trainees 65.5% (618/943) reported no change in videolaryngoscopy use, 27.7% (261/943) increased use and 6.8% (64/943) reduced use. Overall, videolaryngoscope use increased by 10 absolute percentage points following the pandemic.

CONCLUSIONS

Videolaryngoscopy use increased following the early phase of the COVID-19 pandemic but this was less than might have been expected.

Videolaryngoscopy in critical care and emergency locations: moving from debating benefit to implementation

The recently published INTUBE study subanalysis and DEVICE trial findings both demonstrate a clear benefit of videolaryngoscopy over direct laryngoscopy in facilitating tracheal intubation of patients in the emergency department and ICU. We consider the increasing evidence supporting the use of videolaryngoscopy, the possible reasons behind its relatively slow adoption into clinical practice, and the potential role of the hyperangulated videolaryngoscope blade. We discuss the significance of improved first-pass tracheal intubation success in reducing the overall risk of complications in critically ill patients. Additionally, we address the need for specific training in videolaryngoscopy in order to maximise patient benefit, and propose that adequate training and rehearsal opportunities in videolaryngoscopy can only be realised by widespread and regular use wherever the clinical setting.

Airway Management: The Current Role of Videolaryngoscopy

Airway management is usually an uncomplicated and safe intervention; however, when problems arise with the primary airway technique, the clinical situation can rapidly deteriorate, resulting in significant patient harm. Videolaryngoscopy has been shown to improve patient outcomes when compared with direct laryngoscopy, including improved first-pass success at tracheal intubation, reduced difficult laryngeal views, reduced oxygen desaturation, reduced airway trauma, and improved recognition of oesophageal intubation. The shared view that videolaryngoscopy affords may also facilitate superior teaching, training, and multidisciplinary team performance. As such, its recommended role in airway management has evolved from occasional use as a rescue device (when direct laryngoscopy fails) to a first-intention technique that should be incorporated into routine clinical practice, and this is reflected in recently updated guidelines from a number of international airway societies. However, currently, overall videolaryngoscopy usage is not commensurate with its now widespread availability. A number of factors exist that may be preventing its full adoption, including perceived financial costs, inadequacy of education and training, challenges in achieving deliverable decontamination processes, concerns over sustainability, fears over "de-skilling" at direct laryngoscopy, and perceived limitations of videolaryngoscopes. This article reviews the most up-to-date evidence supporting videolaryngoscopy, explores its current scope of utilisation (including specialist techniques), the potential barriers preventing its full adoption, and areas for future advancement and research.

Glidescope Video Laryngoscopy in Patients with Severely Restricted Mouth Opening-A Pilot Study

BACKGROUND

An inter-incisor gap <3 cm is considered critical for videolaryngoscopy. It is unknown if new generation GlideScope Spectrum™ videolaryngoscopes with low-profile hyperangulated blades might facilitate safe tracheal intubation in these patients. This prospective pilot study aims to evaluate feasibility and safety of GlideScopeTM videolaryngoscopes in severely restricted mouth opening.

METHODS

Feasibility study in 30 adults with inter-incisor gaps between 1.0 and 3.0 cm scheduled for ENT or maxillofacial surgery. Individuals at risk for aspiration or rapid desaturation were excluded.

RESULTS

The mean mouth opening was 2.2 ± 0.5 cm (range 1.1-3.0 cm). First attempt success rate was 90% and overall success was 100%. A glottis view grade 1 or 2a was achieved in all patients. Nasotracheal intubation was particularly difficult if Magill forceps were required (n = 4). Intubation time differed between orotracheal (n = 9; 33 (25; 39) s) and nasotracheal (n = 21; 55 (38; 94) s); p = 0.049 intubations. The airway operator's subjective ratings on visual analogue scales (0-100) revealed that tube placement was more difficult in individuals with an inter-incisor gap <2.0 cm (n = 10; 35 (29; 54)) versus ≥2.0 cm (n = 20; 20 (10; 30)), p = 0.007, while quality of glottis exposure did not differ.

CONCLUSIONS

GlidescopeTM videolaryngoscopy is feasible and safe in patients with severely restricted mouth opening if given limitations are respected.

Videolaryngoscopy as a first-intention technique for tracheal intubation in unselected surgical patients: a before and after observational study

BACKGROUND

Using a Macintosh-style videolaryngoscope as a first-intention device for tracheal intubation of unselected patients in the operating room has not often been studied. We hypothesised that using a Macintosh-style videolaryngoscope as a first-intention device is associated with an increased proportion of easy tracheal intubation.

METHODS

In a quality improvement project for airway management aimed at implementing a Macintosh-style videolaryngoscope as a first-intention device, we included all consecutive tracheal intubations in adults from March, 2017 to September, 2020 in two French teaching hospitals. We divided the cohort into three temporal cohorts: the pre-intervention, implementation, and post-intervention periods. The primary outcome was the proportion of easy airway management. The secondary outcomes were the rescue technique, Cormack-Lehane III or IV view, and operator-reported difficulty of intubation. Data from one hospital compliant with the quality improvement project were compared with data from a non-compliant hospital.

RESULTS

A total of 26 692 tracheal intubations were performed. Among 11 938 intubations included in the compliant hospital, 5487 were included in the pre-intervention, 1845 in the implementation, and 4606 in the post-intervention periods. In comparison to the pre-intervention period, the proportions of easy tracheal intubation increased from 94.3% (5177 of 5487) to 98.7% (4547 of 4606)) in the post-intervention period (+4.4% [95% confidence interval 3.7-5.1%], P<0.001). In comparison to the pre-intervention period, all secondary outcome proportions were significantly lower in the post-intervention period. No significant changes were noted in the non-compliant hospital between the pre- and post-intervention periods.

CONCLUSIONS

Using a Macintosh-style videolaryngoscope as a first-intention device for tracheal intubation in the operating room was associated with a significant increase in the proportion of easy tracheal intubation, compared with use of the standard Macintosh laryngoscope.

How to improve intubation in the intensive care unit. Update on knowledge and devices

Tracheal intubation in the critically ill is associated with serious complications, mainly cardiovascular collapse and severe hypoxemia. In this narrative review, we present an update of interventions aiming to decrease these complications. MACOCHA is a simple score that helps to identify patients at risk of difficult intubation in the intensive care unit (ICU). Preoxygenation combining the use of inspiratory support and positive end-expiratory pressure should remain the standard method for preoxygenation of hypoxemic patients. Apneic oxygenation using high-flow nasal oxygen may be supplemented, to prevent further hypoxemia during tracheal intubation. Face mask ventilation after rapid sequence induction may also be used to prevent hypoxemia, in selected patients without high-risk of aspiration. Hemodynamic optimization and management are essential before, during and after the intubation procedure. All these elements can be integrated in a bundle. An airway management algorithm should be adopted in each ICU and adapted to the needs, situation and expertise of each operator. Videolaryngoscopes should be used by experienced operators.

Impact of Macintosh blade size on endotracheal intubation success in intensive care units: a retrospective multicenter observational MacSize-ICU study

Purpose

To investigate the impact of Macintosh blade size used during direct laryngoscopy (DL) on first-attempt intubation success of orotracheal intubation in French intensive care units (ICUs). We hypothesized that success rate would be higher with Macintosh blade size No3 than with No4.

Methods

Multicenter retrospective observational study based on data from prospective trials conducted in 48 French ICUs of university, and general and private hospitals. After each intubation using Macintosh DL, patients’ and operators’ characteristics, Macintosh blade size, results of first DL and alternative techniques used, as well as the need of a second operator were collected. Complications rates associated with intubation were investigated. Primary outcome was success rate of first DL using Macintosh blade.

Results

A total of 2139 intubations were collected, 629 with a Macintosh blade No3 and 1510 with a No4. Incidence of first-pass intubation after first DL was significantly higher with Macintosh blade No3 (79.5 vs 73.3%, p = 0.0025), despite equivalent Cormack–Lehane scores (p = 0.48). Complications rates were equivalent between groups. Multivariate analysis concluded to a significant impact of Macintosh blade size on first DL success in favor of blade No3 (OR 1.44 [95% CI 1.14–1.84]; p = 0.0025) without any significant center effect on the primary outcome (p = 0.18). Propensity scores and adjustment analyses concluded to equivalent results.

Conclusion

In the present study, Macintosh blade No3 was associated with improved first-passed DL in French ICUs. However, study design requires the conduct of a nationwide prospective multicenter randomized trial in different settings to confirm these results.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00134-022-06832-9.

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.

Effect of the use of an endotracheal tube and stylet versus an endotracheal tube alone on first-attempt intubation success: a multicentre, randomised clinical trial in 999 patients

Purpose

The effect of the routine use of a stylet during tracheal intubation on first-attempt intubation success is unclear. We hypothesised that the first-attempt intubation success rate would be higher with tracheal tube + stylet than with tracheal tube alone.

Methods

In this multicentre randomised controlled trial, conducted in 32 intensive care units, we randomly assigned patients to tracheal tube + stylet or tracheal tube alone (i.e. without stylet). The primary outcome was the proportion of patients with first-attempt intubation success. The secondary outcome was the proportion of patients with complications related to tracheal intubation. Serious adverse events, i.e., traumatic injuries related to tracheal intubation, were evaluated.

Results

A total of 999 patients were included in the modified intention-to-treat analysis: 501 (50%) to tracheal tube + stylet and 498 (50%) to tracheal tube alone. First-attempt intubation success occurred in 392 patients (78.2%) in the tracheal tube + stylet group and in 356 (71.5%) in the tracheal tube alone group (absolute risk difference, 6.7; 95%CI 1.4–12.1; relative risk, 1.10; 95%CI 1.02–1.18; P = 0.01). A total of 194 patients (38.7%) in the tracheal tube + stylet group had complications related to tracheal intubation, as compared with 200 patients (40.2%) in the tracheal tube alone group (absolute risk difference, − 1.5; 95%CI − 7.5 to 4.6; relative risk, 0.96; 95%CI 0.83–1.12; P = 0.64). The incidence of serious adverse events was 4.0% and 3.6%, respectively (absolute risk difference, 0.4; 95%CI, − 2.0 to 2.8; relative risk, 1.10; 95%CI 0.59–2.06. P = 0.76).

Conclusions

Among critically ill adults undergoing tracheal intubation, using a stylet improves first-attempt intubation success.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00134-021-06417-y.

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.