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

Abstract

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.

Key words:

• airway
• prehospital
• technology

Introduction

Over the last four decades, novel technologies and techniques have influenced prehospital airway management practices. Examples of new airway management devices or adjuncts that have been widely implemented in clinical practice include video laryngoscopy, bougie, and supraglottic airways, among others. While many new techniques appear to improve airway management performance and success, rigorous studies often cast doubt on their efficacy. When novel technologies, tested in a controlled environment, are deployed across a range of EMS services, they may result in unintended harm to patients. When considering the implementation of a new prehospital airway management technology or technique, EMS agencies and their medical directors should apply a comprehensive assessment that considers effectiveness, ease of use, operational integration, educational burden, cost, and effects on patient outcomes. Changes in practice should demonstrate value by improving patient-centered outcomes. For example, a device that improves a process variable such as increased first-pass success (FPS) at endotracheal intubation (ETI) without an improvement in a patient-centered outcome such as neurologically intact survival is inherently less valuable. Clinician utility may be measured objectively, such as the amount of time it takes to place a supraglottic airway (SGA), or subjectively as a qualitative determination of ease of use. The cost of implementation should consider the full financial effect of the new technology or technique, including the price of purchase, training, skills maintenance, and effect on operations.

Assessing Novel Technology

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 evaluation of a novel technology or technique is service-specific. While all services should prioritize patient-centered outcomes, the need for such technologies are predicated by the patient population, environment, and available resources. A tactical EMS service may choose an SGA over a video laryngoscopy system based on environmental considerations including size, weight, power requirements, and the need for light discipline in the tactical environment. Similarly, a video laryngoscopy system that provides the best image quality and greatest ease of use but costs three times as much as a device that is nearly as good may not be a responsible choice for a service struggling with budgetary constraints. Interactions between these evaluation domains must also be considered. A complicated new technology that improves first pass success without decreasing exposure to hypotension or hypoxia may not add value to the service.

The evidence around most technologies and techniques builds as each is further integrated into the operational and research fabric of the prehospital industry. Consequently, as progress is made through the adoption pipeline, the costs tend to decrease. Additionally, evidence for generalizable patient benefit is created, techniques for training are improved, and the efficiency of operations improves with experience. When evaluating the evidence surrounding a technology or technique, its categorization of adoption with the prehospital industry must be considered.

Evaluation of new technologies or techniques by EMS agencies should be done with active involvement of the medical director, who is responsible for ensuring that there is patient benefit. The medical director should also assist the EMS agency in interpreting the relevant medical literature, outcomes, quality improvement data, safety, and operational burden. The medical director should complement a team of evaluators including administrators and front-line personnel ultimately charged with making the decision to adopt a novel technology or technique.

Few technologies or techniques are rigorously tested in the prehospital environment. As such, EMS agencies and medical directors deciding whether to adopt, implement, and monitor a novel technology or technique will rely on wide range of available scientific, as well as quality improvement and operational data. We describe a series of technologies and techniques that are in various phases of the adoption schema to illustrate some of the challenges and controversies that contribute to their use in the prehospital setting (Figure 1).

Figure 1. Technology’s categorization of adoption: Movement from left to right along the X axis is accompanied by greater availability to evidence for adoption and generally a decrease in cost as more efficient training regimens improve skill acquisition and maintenance as well as economies of scale decrease material cost.

Technologies Routinely Used in Prehospital Airway Management

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.

Video laryngoscopy

In the early 2000s, indirect or video laryngoscopes (VL) were introduced, and the subsequent evaluation of video laryngoscopy in the prehospital environment has been extensive. Comparisons have been made to traditional direct laryngoscopy (DL) in a wide range of prehospital services, including systems with both physician and paramedic operators, air and ground EMS, and services representing disparate geographic and population density characteristics. The results of these studies vary widely depending on the population and environment.

Although numerous studies comparing DL to VL have been published in the peer-reviewed literature, there has been considerable heterogeneity in results and scientific debate regarding whether VL is better or worse than traditional DL. Although the literature base is large, these studies suffer from variability in the clinical scenarios necessitating airway management. These variables include patient factors (e.g. mouth opening, neck mobility, age, obesity, airway anatomy), clinician factors (e.g. type of medical training, number of prior intubations, experience with the specific device), environmental factors (e.g. prehospital, emergency department, intensive care unit), the indication for intubation (e.g. cardiac arrest, hypoxia, hypercarbia, airway protection), and what additional devices or airway techniques are used (e.g. laryngeal manipulation, ramped position, bougie), all of which may or may not be fully reported in each publication. In addition, publication bias may be present if EMS agencies only share their experience when large differences in outcomes are observed.

EMS agencies considering the implementation of VL should evaluate the studies that are most applicable to their specific clinical needs and environment, and it is reasonable to give more weight to these studies. Ideally, these studies will not only show a benefit to process outcomes (e.g. time to intubation, number of attempts) but also patient-centered outcomes (e.g. intubation without hypoxia or hypotension, survival to hospital discharge). In a plurality of studies, VL is associated with improved process outcomes including FPS, laryngoscopic grade, and number of attempts (1–6); however, few studies to date report patient-centered outcomes. Following a decade of experience, the risk of harm associated with VL is low and concerns can be mitigated through training (7). VL can be considered in place of DL when implemented as part of a systematic and comprehensive approach to advanced airway management. Initial and ongoing training and quality improvement activities are critically important.

Bougie/tracheal tube introducer

Bougies, or tracheal tube introducers, have been in use as a difficult airway adjunct device for over 65 years. They were introduced into North American practice more recently than in Europe and Australia, gaining in popularity since the early 2000s (8). Compared to the hospital setting, prehospital advanced airway management is known to have more complications due to factors such as airway anatomy and altered physiology, environmental issues, and training/experience of the operator. Therefore, it is reasonable to believe that a bougie may offer additional benefits in the prehospital setting to mitigate the risks of repeated attempts at intubation (9,10).

Bougies may confer the most significant advantage in patients with higher Cormack-Lehane grades, as they facilitate ETI when an incomplete glottic view is obtained (11). However, the bougie has been documented to be most effective in facilitating ETI with Cormack-Lehane grades 2 and 3, with limited data to support its use with Cormack-Lehane grade 4 view (4).

Operationally, the cost to implement bougies into prehospital practice is relatively small. The devices are inexpensive, easy to train, and if used on all airways, device-specific skills are easy to maintain (12).

In a prospective, observational, pre-post study that compared FPS rate using the bougie with direct laryngoscopy in a large prehospital system during out-of-hospital cardiac arrest, the FPS rate increased from 70% to 77% (12). A higher success rate was observed when the bougie was used across Cormack-Lehane grades, with rates of 91%, 60%, 27%, and 6% for grades 1, 2, 3, and 4 respectively during the control period (i.e. no bougie), and 96%, 85%, 50%, and 14% respectively during the bougie period. The odds ratio for FPS rate using a bougie with direct laryngoscopy was 2.85 (CI 1.96-4.01) in this study.

EMS agencies may consider use of a bougie to improve FPS when undertaking emergent intubation (11–13). Its use is recommended as part of a standardized bundle for prehospital ETI rather than as a rescue device (14,15). Agencies must weigh the existing evidence that supports the use of bougies across a range of patient characteristics, environments, and individual clinician skill levels, but lacks data demonstrating reduced morbidity or mortality. Strategies that integrate training and skill maintenance into a comprehensive airway management program are essential. Agencies must include a robust quality management program to ensure that the devices improve measurable process outcomes without causing harm. Quality management for new device evaluation should include retrospective chart reviews, provider evaluation and receiving facility outcomes. Further research is necessary to determine if the bougie affects patient-centered outcomes.

Technologies & Techniques with Limited Use in Prehospital Airway Management

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 laryngoscopic airway decontamination and cognitive aids.

Suction assisted laryngoscopy and airway decontamination (SALAD technique)

The incidence of regurgitation and aspiration is 25-30% during out-of-hospital cardiac arrest (16). Airway contamination has also been recognized as a significant cause of failure in FPS in the intensive care unit setting (17), potentially increasing the occurrence of adverse events during airway management such as severe hypoxemia, hypotension, and cardiac arrest (9). A novel airway management strategy that addresses the problem of massive airway contamination involves the proactive use of suction during airway management in the form of the SALAD technique (18). This technique advocates for the use of the rigid suction catheter to assist in the insertion of oral airways, SGA, and laryngoscopes via mechanical distraction of the tongue into the floor of the mouth and elevation of its base from the posterior pharyngeal wall.

Continually suctioning the hypopharynx of blood, emesis, and secretions during laryngoscopy has been found to reduce the chance of failure to intubate in case reports (19,20). The SALAD technique has also been suggested as an option to manage and secure a bleeding upper airway (21), in trauma (22), and for airway management outside the operating room when performed by anesthesiologists (23); however, evidence supporting its use has yet to fully extend beyond simulation-based environments.

EMS agencies may look to the SALAD technique to mitigate the consequences of the contaminated airway, but there are no controlled trials to support its use. The SALAD technique can be considered in specific clinical circumstances relating to copious secretions, blood, or emesis, but the operator must be technically proficient, and the EMS agency must have the appropriate quality improvement practices in place to allow for a review of every case.

Cognitive aids

Cognitive aids are tools to facilitate successful completion of a task and are increasingly used in medicine to support clinicians delivering interventions that may be high-risk, infrequently performed, or time-sensitive. Prehospital airway management can be all the above and has the additional risk that it is often performed in uncontrolled settings by teams who may not regularly train together.

Checklists ensure that standard procedures are followed and that the patient and clinicians are prepared for the task to be undertaken (24). They are one of the most common cognitive aids in medicine and are increasingly used to facilitate airway management procedures, such as rapid sequence intubation, despite a lack of clear evidence of patient benefit (25).

Standardized “kit dumps” are a more novel cognitive aid and involve arranging the equipment necessary for a task, and for predictable contingencies, before starting the task in a predefined manner according to a standard operating procedure. This is done to ensure all necessary equipment is available and easily accessible, and the team can practice scenarios with the appropriate equipment arranged in this fashion. Shadow boards, also known as visual checklists or equipment templates, are materials with visual spaces outlined for all necessary equipment that facilitate setting up a kit dump for a particular task.

Shadow boards have been shown to help standardize layout of equipment when preparing for emergency procedures, reducing the time to prepare the equipment by over half (26), and reducing the omission of necessary equipment by 20% (27). Simple methods of implementing these cognitive aids, such as printing the shadow board on clinical waste bags, have been reported (28), including specifically designed shadow boards to support intubation of critically ill adults (29).

Shadow boards have been integrated into bags specifically designed for prehospital use and trialed in simulation studies of prehospital emergency airway management by air EMS physicians and paramedics. A bag with a shadow board and prepared drugs and equipment was compared against standard practice of a separate airway and drugs bags. Use of the bag with the shadow board significantly reduced the overall time to anesthesia (11:45 vs 20:59, p= <0.001) but did not affect time to intubation (00:37 vs 00:42, p = 0.407). In addition, it reduced the number of reported errors and the cognitive load on the intubation assistant (30). The bag with the shadow board was also compared to a resuscitation cart in a study exploring setting up a kit dump for management of a difficult airway in a remote setting. In a simulation-based randomized controlled trial, use of the bag with the shadow board reduced the time needed to set up the kit dump by 29%, was reported to be easier to use, and reduced omission of necessary equipment (31).

Guidelines on tracheal intubation in critically ill adults from the Difficult Airway Society state that ‘Cognitive aids improve performance in stressful situations and should be prominent wherever airway interventions are performed’ (32). In addition, preparation of a standardized kit dump is recommended in the guidelines for safer prehospital anesthesia produced by the Association of Anesthetists of Great Britain and Ireland (15). Draft 2022 practice guidelines for the management of the difficult airway from the American Society of Anesthesiologists suggest inclusion of a ‘locally accepted difficult airway algorithm/cognitive aid/checklist’ as part of the equipment for difficult airway management (32,33).

Despite inclusion in multiple guidelines, the literature on the use of cognitive aids in prehospital advanced airway management is sparse and frequently from hospital settings. Although the literature is generally supportive of cognitive aids based on potential improvements in workflow and low costs, there is limited evidence of their effect on patient outcomes. An EMS agency implementing this technology must do so within a rigorous quality management program, and adverse consequences of implementation, such as delays in definitive airway, must be tracked. Clinicians must be familiar with, and deliberately practice and train with, the cognitive aids used in their system if they are to be successfully implemented into practice and improve patient care.

Technologies with Rare Use in Prehospital Airway Management

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.

Technologies and techniques not supported in the literature should be limited in prehospital settings to clinical trials or pilot projects with robust program evaluation. Although the decision to deploy an untested technology or technique may be appealing from a managerial perspective, changing the status quo invariably comes with an increased risk of patient harm.

Should an EMS agency choose to implement a program using a novel technology or technique with little to no prehospital experience, it should be done under either extreme circumstances when an alternative is not available, or under the guidance of an institutional review board sanctioned research study.

Intubation boxes

During the COVID-19 pandemic, in addition to the deployment of standard personal protective equipment (PPE)—masks, gowns, eye protection, and gloves—several novel mechanisms intended to protect clinicians providing advanced airway management were developed in rapid succession. They came in a variety of formats, but most created a physical barrier between the clinician and the patient with the goal of preventing patient-to-clinician aerosol transmission (34,35).

Given the rapid pace of evaluation, testing, and research happening during this time, it quickly became apparent that these devices had the potential to cause more harm than good (35–37). Although hypotheses vary on how and why that harm occurred, most agree it was some combination of increased variation, non-conducive biomechanics, and the lack of adequate training and familiarity by clinicians. Additionally, it was shown that standard PPE was enough to protect EMS clinicians from infection (38,39).

Standard PPE should be given priority over novel innovations when protecting the EMS clinician against respiratory pathogens and should be donned prior to any prehospital airway management.

Quality Management

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.

Adoption of novel technologies and techniques requires a robust quality management program to ensure that their use both produces the intended outcome and does not have negative unintended consequences. When possible, quality improvement processes should focus on patient-centered outcomes and evaluate the effectiveness of the technology or technique in that agency’s specific work environment. For example, implementing high flow nasal cannula (HFNC) in a rural service with long transport times may not be practical due to logistics, need for heat and humidification, and limits of oxygen stores. Conversely, use of HFNC in an urban system may improve oxygenation in patients with hypoxemic respiratory failure and reduce the need for intubation among some patient types. If the technology does not improve patient outcomes or operational efficiency for an agency’s unique needs, then adoption is ill-advised.

Addressing novel technologies and techniques through a quality management lens, like quality improvement in EMS in general, is inconsistently done (40). In addition to focusing on patient-centered outcomes, quality management programs must also be systematic and continuous, focus on measurable outcomes, and inform decisions regarding the continued deployment of the technology (41). A broader description of the implementation of quality management programs in the context of prehospital airway management is discussed by Vithalani et al. in this compendium (24).

Considerations for Future Research

EMS leaders should clearly identify the pathways needed to generate high-quality supporting scientific evidence for novel technologies and techniques.

Although the initial implementation of most novel technologies and techniques comes before the accumulation of enough evidence to declare their effectiveness, this should not overshadow the continued need for robust, scientific evaluation. While not all individual EMS agencies will have the infrastructure to support such an academic exercise, the industry must prioritize these efforts through funding and publications. Innovators and early adopters in EMS have the responsibility to identify knowledge gaps associated with the implementation of these tools. These gap analyses may identify differences between efficacy in controlled environments versus effectiveness in the field or in a service-specific environment. They may identify educational or operational challenges that must be addressed prior to greater adoption of the technology or technique. EMS agencies that can disseminate their experiences are obligated to do so, not only to inform the larger community of the risks and benefits of adoption, but to provide a body of observations that form the basis of future research. Rigorous research is necessary to understand the relative patient and clinician benefits of novel technologies and techniques while mitigating risk and cost. While unfiltered commentary via social media and other informal channels has its place, parallel efforts to perform rigorous unbiased research are critically important.

Conclusions

The decision to use a novel technology or technique within the prehospital setting is a multifactorial process that should balance clinical effectiveness, feasibility of implementation within a specific agency, economic cost, and ability to rigorously evaluate the post-implementation use.