Difficult Airway Characteristics Associated with First-Attempt Failure at Intubation Using Video Laryngoscopy in the Intensive Care Unit

Airway management of adult epiglottitis: a systematic review and meta-analysis

Background

Adult epiglottitis is a life-threatening airway emergency where airway protection is the immediate priority. Despite its importance, the optimal approach to airway management remains unclear. We performed a systematic review of the airway management for adult epiglottitis, including meta-analysis of trends over time.

Methods

We systematically searched PubMed, Ovid MEDLINE®, and Embase® for adult epiglottitis studies that described the airway management between 1980 and 2020. The primary outcome was the prevalence of airway intervention. Secondary outcomes were prevalence of tracheal intubation, tracheostomy, and failed intubation. A random-effects model meta-analysis was performed with subgroups defined by decade of study publication. Cases that described the specific method of airway intervention and severity of epiglottitis were included in a separate technique summary.

Results

Fifty-six studies with 10 630 patients were included in the meta-analysis. The overall rate of airway intervention was 15.6% (95% confidence interval [CI] 12.9-18.8%) but the rate decreased from 20% to 10% between 1980 and 2020. The overall rate of tracheal intubation was 10.2% (95% CI 7.1-13.6%) and that of failed intubation was 4.2% (95% CI 1.4-8.0%). The airway technique summary included 128 cases, of which 75 (58.6%) were performed awake and 53 (41.4%) involved general anaesthesia. We identified 32 cases of primary technique failure.

Conclusion

The rate of airway intervention for adult epiglottitis has decreased over four decades to a current level of 10%. Tracheal intubation is a high-risk scenario with a 1 in 25 failure rate. Specific technique selection is most likely influenced by contextual factors including the severity of epiglottitis.

Modified cadaver technique to simulate contaminated airway scenarios to train medical providers in suction-assisted laryngoscopy and airway decontamination

Simulation training plays a vital role in modern medical education, fostering safe skill development. Task-trainer manikin and cadaveric airway management training (CAMT) offer realistic airway management practice. Simulation allows learners the opportunity to manage high-risk, low-frequency scenarios, including difficult airways and massive airway contamination, common in emergent airway management. The suction-assisted laryngoscopy and airway decontamination (SALAD) technique was developed to address massive airway contamination. This paper describes two methods to simulate massive airway contamination utilizing cadavers. We detail our techniques for both esophageal and nasopharyngeal delivery of simulated airway contaminant. Nasopharyngeal delivery was less invasive and required less time to set up. Utilizing cadavers to simulate massive airway contamination in CAMT provides learners with tools to manage airway complications effectively, enhancing readiness for complex airway challenges while promoting patient safety in clinical practice.

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.

Endotracheal Intubation of Difficult Airways in Emergency Settings: A Guide for Innovators

Over 400,000 Americans are intubated in emergency settings annually, with indications ranging from respiratory failure to airway obstructions to anaphylaxis. About 12.7% of emergency intubations are unsuccessful on the first attempt. Failure to intubate on the first attempt is associated with a higher likelihood of adverse events, including oxygen desaturation, aspiration, trauma to soft tissue, dysrhythmia, hypotension, and cardiac arrest. Difficult airways, as classified on an established clinical scale, are found in up to 30% of emergency department (ED) patients and are a significant contributor to failure to intubate. Difficult intubations have been associated with longer lengths of stay and significantly greater costs than standard intubations. There exists a wide range of airway management devices, both invasive and noninvasive, which are available in the emergency setting to accommodate difficult airways. Yet, first-pass success rates remain variable and leave room for improvement. In this article, we review the disease states most correlated with intubation, the current landscape of emergency airway management technologies, and the market potential for innovation. The aim of this review is to inspire new technologies to assist difficult airway management, given the substantial opportunity for translation due to two key-value signposts of medical innovation: the potential to decrease cost and the potential to improve clinical outcomes.

The use of video laryngoscopy outside the operating room: A systematic review

This study aimed to describe how video laryngoscopy is used outside the operating room within the hospital setting. Specifically, we aimed to summarise the evidence for the use of video laryngoscopy outside the operating room, and detail how it appears in current clinical practice guidelines. A literature search was conducted across two databases (MEDLINE and Embase), and all articles underwent screening for relevance to our aims and pre-determined exclusion criteria. Our results include 14 clinical practice guidelines, 12 interventional studies, 38 observational studies. Our results show that video laryngoscopy is likely to improve glottic view and decrease the incidence of oesophageal intubations; however, it remains unclear as to how this contributes to first-pass success, overall intubation success and clinical outcomes such as mortality outside the operating room. Furthermore, our results indicate that the appearance of video laryngoscopy in clinical practice guidelines has increased in recent years, and particularly through the COVID-19 pandemic. Current COVID-19 airway management guidelines unanimously introduce video laryngoscopy as a first-line (rather than rescue) device.

Use of HEAVEN criteria for predicting difficult intubation in the emergency department

Objective

Most airway prediction tools only consider anatomical factors. The HEAVEN criteria incorporate both anatomical and physiological elements, but have never been studied in the emergency department. This study aimed to evaluate the association between HEAVEN criteria and intubation difficulty.

Methods

We conducted a prospective cross-sectional study from April 1, 2020 to January 31, 2021 in the emergency department of a tertiary public hospital. All patients requiring rapid-sequence or delayed-sequence intubation were included. Patients intubated during cardiopulmonary resuscitation were excluded. We enrolled 174 patients. Study endpoints were first pass success and intubation complications.

Results

The presence of any HEAVEN criteria was associated with a decrease in the first pass success rate (odds ratio [OR], 0.10; 95% confidence interval [CI], 0.02–0.43; P < 0.01). The anatomical challenge was the only criterion associated with first pass sucess (OR, 0.13; 95% CI, 0.05– 0.29; P < 0.01), whilst other criteria (hypoxemia, extremes of size, vomit/blood/fluid, exsanguination, and neck mobility) were not (P > 0.05). All anatomical factor criteria were associated with difficult airway view (P < 0.05). Intubation complications occurred more in the presence of hypoxemia (OR, 7.44; 95% CI, 2.82–19.63; P < 0.01) and vomit/blood/fluid (OR, 5.55; 95% CI, 2.39–12.92; P < 0.01).

Conclusion

Anatomical challenge in HEAVEN criteria can predict first pass success. All anatomical factors in HEAVEN criteria could predict difficult airway view and peri-intubation hypoxemia could be used to anticipate intubation complications. More validation studies are still needed to evaluate the use of HEAVEN criteria as a predictor tool for difficult airway.

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.

Novel Technologies and Techniques for Prehospital Airway Management: An NAEMSP Position Statement and Resource Document

Novel technologies and techniques can influence airway management execution as well as procedural and clinical outcomes. While conventional wisdom underscores the need for rigorous scientific data as a foundation before implementation, high-quality supporting evidence is frequently not available for the prehospital setting. Therefore, implementation decisions are often based upon preliminary or evolving data, or pragmatic information from clinical use. When considering novel technologies and techniques. NAEMSP recommends:Prior to implementing a novel technology or technique, a thorough assessment using the best available scientific data should be conducted on the technical details of the novel approach, as well as the potential effects on operations and outcomes.The decision and degree of effort to adopt, implement, and monitor a novel technology or technique in the prehospital setting will vary by the quality of the best available scientific and clinical information:• Routine use - Technologies and techniques with ample observational but limited or no interventional clinical trial data, or with strong supporting in-hospital data. These techniques may be reasonably adopted in the prehospital setting. This includes video laryngoscopy and bougie-assisted intubation. • Limited use - Technologies and techniques with ample pragmatic clinical use information but limited supporting scientific data. These techniques may be considered in the prehospital setting. This includes suction-assisted laryngoscopy and airway decontamination and cognitive aids. • Rare use - Technologies and techniques with minimal clinical use information. Use of these techniques should be limited in the prehospital setting until evidence exists from more stable clinical environments. This includes intubation boxes.The use of novel technologies and techniques must be accompanied by systematic collection and assessment of data for the purposes of quality improvement, including linkages to patient clinical outcomes.EMS leaders should clearly identify the pathways needed to generate high-quality supporting scientific evidence for novel technologies and techniques.

Reasons behind failed prehospital intubation attempts while combining C-MAC videolaryngoscope and Frova introducer

BACKGROUND

High first-pass success rate is achieved with the routine use of C-MAC videolaryngoscope and Frova introducer. We aim to identify potential reasons and subgroups associated with failed intubation attempts, analyse actions taken after them and study possible complications.

METHODS

We conducted a retrospective observational study of adult intubated patients at a single helicopter emergency medical service unit in southern Finland between 2016 and 2018. We collected data on patient characteristics, reasons for failed attempts, complications and follow-up measures from a national helicopter emergency medical service database and from prehospital patient records.

RESULTS

1011 tracheal intubations were attempted. First attempt was successful in 994 cases (FPS 994/1011, 98.3%), 15 needed a second or third attempt and two a surgical airway (non-FPS 17/1011, 1.7%, 95% CI 1.0-2.7). The failed first attempt group had heterogenous characteristics. The most common cause for a failed first attempt was obstruction of the airway by vomit, food, mucus or blood (10/13, 76%). After the failed first attempt, there were six cases (6/14, 43%) of deviation from the protocol and the most frequent complications were five cases (5/17, 29%) of hypoxia and four cases (4/17, 24%) of hypotension.

CONCLUSIONS

When a protocol combining the C-MAC videolaryngoscope and Frova introducer is used, the most common reason for a failed first attempt is an airway blocked by gastric content, blood or mucus. These findings highlight the importance of effective airway decontamination methods and questions the appropriateness of anatomically focused pre-intubation assessment tools when such protocol is used.

The impact of a barrier enclosure on time to tracheal intubation: a randomized controlled trial

Purpose

Novel devices such as the barrier enclosure were developed in hopes of improving provider safety by limiting SARS-CoV-2 transmission during tracheal intubation. Nevertheless, concerns arose regarding a lack of rigorous efficacy and safety data for these devices. We conducted a randomized controlled trial to evaluate the impact of the barrier enclosure on time to tracheal intubation.

Method

After Research Ethics Board approval, elective surgical patients with normal airway predictors were randomly allocated 1:1 to tracheal intubation with or without a barrier enclosure. The primary outcome was time to tracheal intubation. Secondary outcomes included first-pass success rate, total time of airway manipulation, anesthesiologists’ perception of intubation difficulty, likelihood of use in SARS-CoV-2-positive patients, and patients’ perception of comfort and acceptability.

Results

There were 48 participants in the barrier enclosure group and 46 participants in the control group. The mean (standard deviation [SD]) time to tracheal intubation was 62 (29) sec with barrier closure and 53 (27) sec without barrier enclosure (mean difference, 9 sec; 95% confidence interval, − 3 to 20; P = 0.14). Anesthesiologists rated the difficulty of intubation higher with barrier enclosure (mean [SD] visual analogue scale score, 27 [26] mm vs 9 [17] mm; P < 0.001). There were no significant differences in other secondary outcomes.

Conclusion

In healthy surgical patients with normal airway predictors, the use of a barrier enclosure during tracheal intubation did not significantly prolong time to intubation or decrease first-pass intubation success. Nevertheless, there was an increase in difficulty of intubation perceived by the anesthesiologists with use of a barrier enclosure.

Trial registration

www.clinicaltrials.gov (NCT04366141); registered 28 April 2020.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12630-021-02024-z.

Effectiveness of Surgical Airway Training Laboratory and Assessment of Skill and Knowledge Fade in Surgical Airway Establishment Among Prehospital Providers

OBJECTIVE

This study aimed to evaluate the effectiveness of surgical airway education composed of training using cadavers. The secondary aim was to evaluate the presence and degree of knowledge and skill fade 3 months after training.

METHODS

Thirteen participants were recruited from a helicopter emergency medical services program. Participants were assessed at multiple points during training using a multiple-choice examination and a timed evaluation of the ability to establish a surgical airway.

RESULTS

Training was effective at increasing knowledge and skill, with a mean increase in multiple-choice examination scores of 14.6 percentage points after training (P < .01) and a mean decrease in time to airway establishment of 26 seconds (P < .01). The training was not associated with the ability to establish a surgical airway in less than 40 seconds, with only 46% of participants able to do so. There was no evidence of knowledge or skill fade at 3 months after training.

CONCLUSION

Surgical airway training that includes both didactic and clinical learning using human cadavers is effective at increasing both knowledge and skill. Additional training is needed to establish competency in consistently performing surgical airways in less than 40 seconds. No knowledge or skill fade was present at 3 months after training.

Suction Assisted Laryngoscopy and Airway Decontamination (SALAD): A technique for improved emergency airway management

Emergency airway management is often complicated by the presence of blood, emesis or other contaminants in the airway. Traditional airway management education has lacked task-specific training focused on mitigating massive airway contamination. The Suction Assisted Laryngoscopy and Airway Decontamination (SALAD) technique was developed in order to address the problem of massive airway contamination both in simulation training and in vivo. We review the evidence describing the dangers associated with airway contamination, and describe the SALAD technique in detail.

Videolaryngoscopy in critically ill patients

Intubation is frequently required for patients in the intensive care unit (ICU) but is associated with high morbidity and mortality mainly in emergency procedures and in the presence of severe organ failures. Improving the intubation procedure is a major goal for all ICU physicians worldwide, and videolaryngoscopy may play a relevant role.

Videolaryngoscopes are a heterogeneous entity, including Macintosh blade-shaped optical laryngoscopes, anatomically shaped blade without a tube guide and anatomically shaped blade with a tube guide, which might have theoretical benefits and pitfalls. Videolaryngoscope/videolaryngoscopy improves glottis view and allows supervision by an expert during the intubation process; however, randomized controlled trials in the ICU suggest that the systematic use of videolaryngoscopes for every intubation cannot yet be recommended, especially in non-expert hands. Nevertheless, a videolaryngoscope should be available in all ICUs as a powerful tool to rescue difficult intubation or unsuccessful first-pass laryngoscopy, especially in expert hands.

The use of associated devices such as bougie or stylet, glottis view needed (full vs incomplete) and patient position during intubation (ramped, sniffed position) should be further evaluated. Future trials will better define the role of videolaryngoscopy in ICU.

Recent advances in laryngoscopy in adults

Recent advances in technology have made laryngoscopy less dependent upon a direct line of sight to achieve tracheal intubation. Whether these new devices are useful tools capable of increasing patient safety depends upon when and how they are used. We briefly consider the challenges in reviewing the emerging literature given the variety of devices, "experience" of the care providers, the clinical settings, and the definitions of outcome. We examine some of the limitations of conventional direct laryngoscopy, question the definitions we have used to define success, discuss the benefits of indirect (video) techniques, and review evidence pertaining to their use in the patients in the operating room, emergency department, and intensive care unit.

Necessity to depict difficult neck anatomy for training of cricothyroidotomy: A pilot study evaluating two surgical devices on a new hybrid training model

BACKGROUND

Everyone dealing with airway emergencies must be able to accomplish cricothyroidotomy, which cannot be trained in real patients. Training models are necessary.

OBJECTIVE

To evaluate the suitability of a hybrid training model combining synthetic and porcine parts to depict variable neck anatomy.

DESIGN

Model-based comparative trial.

SETTING

Armed Forces Hospital Ulm, Germany, August 2018.

INTERVENTION

On four anatomical neck variations (long slim/long obese/short slim/short obese) we performed two surgical approaches to cricothyroidotomy (SurgiCric II vs. ControlCric).

PARTICIPANTS

Forty-eight volunteers divided into two groups based on their personal skill level: beginners group and proficient performers group.

MAIN OUTCOME MEASURES

Time to completion was recorded for each procedure. Once the operator had indicated completion, the correct anatomical tube placement was confirmed by dissection and structures were inspected for complications. Primary outcomes were successful tracheal placement of an airway tube and time needed to achieve a patent airway. Secondary outcome was assessment of complications.

RESULTS

Overall, 384 procedures were performed. Median time to completion was 74 s. In total, 284 procedures (74%) resulted in successful ventilation. Time to completion was longer in short obese than in long slim and the risk of unsuccessful procedures was increased in short obese compared with long slim. Even if ControlCric resulted in faster completion of the procedure, its use was less successful and had an increased risk of complications compared with SurgiCric II. Proficient performers group performed faster but had an increased risk of injuring the tracheal wall compared with beginners group.

CONCLUSION

Participants had difficulties in performing cricothyroidotomy in obese models, but various and difficult anatomical situations must be expected in airway management and therefore must be taught. A new hybrid model combining porcine and synthetic materials offers the necessary conditions for the next step in training of surgical airway procedures.

TRIAL REGISTRATION

The study was performed without human tissue or living animals, and was therefore exempted from ethical review by the University of Ulm Ethical Committee, Germany (Chairperson Prof Dr C. Lenk) on 9 August 2018. Hence a protocol number was not attributed.

Effect of Use of a Bougie vs Endotracheal Tube and Stylet on First-Attempt Intubation Success Among Patients With Difficult Airways Undergoing Emergency Intubation: A Randomized Clinical Trial

IMPORTANCE

The tracheal tube introducer, known as the bougie, is typically used to aid tracheal intubation in poor laryngoscopic views or after intubation attempts fail. The effect of routine bougie use on first-attempt intubation success is unclear.

OBJECTIVE

To compare first attempt intubation success facilitated by the bougie vs the endotracheal tube + stylet.

DESIGN, SETTING, AND PATIENTS

The Bougie Use in Emergency Airway Management (BEAM) trial was a randomized clinical trial conducted from September 2016 through August 2017 in the emergency department at Hennepin County Medical Center, an urban, academic department in Minneapolis, Minnesota, where emergency physicians perform all endotracheal intubations. Included patients were 18 years and older who were consecutively admitted to the emergency department and underwent emergency orotracheal intubation with a Macintosh laryngoscope blade for respiratory arrest, difficulty breathing, or airway protection.

INTERVENTIONS

Patients were randomly assigned to undergo the initial intubation attempt facilitated by bougie (n = 381) or endotracheal tube + stylet (n = 376).

MAIN OUTCOMES AND MEASURES

The primary outcome was first-attempt intubation success in patients with at least 1 difficult airway characteristic (body fluids obscuring the laryngeal view, airway obstruction or edema, obesity, short neck, small mandible, large tongue, facial trauma, or the need for cervical spine immobilization). Secondary outcomes were first-attempt success in all patients, first-attempt intubation success without hypoxemia, first-attempt duration, esophageal intubation, and hypoxemia.

RESULTS

Among 757 patients who were randomized (mean age, 46 years; women, 230 [30%]), 757 patients (100%) completed the trial. Among the 380 patients with at least 1 difficult airway characteristic, first-attempt intubation success was higher in the bougie group (96%) than in the endotracheal tube + stylet group (82%) (absolute between-group difference, 14% [95% CI, 8% to 20%]). Among all patients, first-attempt intubation success in the bougie group (98%) was higher than the endotracheal tube + stylet group (87%) (absolute difference, 11% [95% CI, 7% to 14%]). The median duration of the first intubation attempt (38 seconds vs 36 seconds) and the incidence of hypoxemia (13% vs 14%) did not differ significantly between the bougie and endotracheal tube + stylet groups.

CONCLUSIONS AND RELEVANCE

In this emergency department, use of a bougie compared with an endotracheal tube + stylet resulted in significantly higher first-attempt intubation success among patients undergoing emergency endotracheal intubation. However, these findings should be considered provisional until the generalizability is assessed in other institutions and settings.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02902146.

Management of Patients with Predicted Difficult Airways in an Academic Emergency Department

BACKGROUND

Patients with difficult airways are sometimes encountered in the emergency department (ED), however, there is a little data available regarding their management.

OBJECTIVES

To determine the incidence, management, and outcomes of patients with predicted difficult airways in the ED.

METHODS

Over the 1-year period from July 1, 2015 to June 30, 2016, data were prospectively collected on all patients intubated in an academic ED. After each intubation, the operator completed an airway management data form. Operators performed a pre-intubation difficult airway assessment and classified patients into routine, challenging, or difficult airways. All non-arrest patients were included in the study.

RESULTS

There were 456 patients that met inclusion criteria. Fifty (11%) had predicted difficult airways. In these 50 patients, neuromuscular blocking agents (NMBAs) were used in 40 (80%), an awake intubation technique with light sedation was used in 7 (14%), and no medications were used in 3 (6%). In the 40 difficult airway patients who underwent NMBA facilitated intubation, a video laryngoscope (GlideScope 21, Verathon, Bothell, WA and C-MAC 19, Karl Storz, Tuttlingen, Germany) was used in each of these, with a first-pass success of 90%. In the 7 patients who underwent awake intubation, a video laryngoscope was used in 5, and a flexible fiberoptic scope was used in 2. Ketamine was used in 6 of the awake intubations. None of these difficult airway patients required rescue with a surgical airway.

CONCLUSIONS

Difficult airways were predicted in 11% of non-arrest patients requiring intubation in the ED, the majority of which were managed using an NMBA and a video laryngoscope with a high first-pass success.

Recent trends in airway management

Tracheal intubation remains a life-saving procedure that is typically not difficult for experienced providers in routine conditions. Unfortunately, difficult intubation remains challenging to predict and intubation conditions may make the event life threatening. Recent technological advances aim to further improve the ease, speed, safety, and success of intubation but have not been fully investigated. Video laryngoscopy, though proven effective in the difficult airway, may result in different intubation success rates in various settings and in different providers’ hands. The rescue surgical airway remains a rarely used but critical skill, and research continues to investigate optimal techniques. This review highlights some of the new thoughts and research on these important topics.