Alternate airways in the prehospital setting (resource document to NAEMSP position statement)

Airway Management of the Cardiac Arrest Victim

Appropriate airway management is critical to successful cardiac arrest resuscitation. However, the timing and method of airway management during cardiac arrest have traditionally been guided by expert and consensus opinion informed by observational data. In the last 5 years, recent studies, including several randomized controlled trials (RCTs), have provided additional clarity to help guide airway management. This article will review both current data and guidelines for airway management in cardiac arrest, a stepwise approach to airway management, the utility of various airway adjuncts, and best practices for oxygenation and ventilation in the peri-arrest period.

Prehospital Surgical Airway Management Skills in a Rural Emergency Medical Service System

BACKGROUND

The objective of this study is to describe the education, training, and use of prehospital surgical airways in a rural Emergency Medical Service (EMS) system.

MATERIALS AND METHODS

We conducted an internet-based survey instrument of all advanced life support (ALS) EMS agencies in a seven-county rural EMS system in Pennsylvania. ALS agencies were queried regarding basic demographic information as well as the number of surgical airways performed in the previous 10 years as well as the education and training of EMS providers in surgical airways.

RESULTS

The survey was completed by 11 of 20 ALS EMS agencies in our region (55% rate of return). The content and frequency of training varied considerably among EMS agencies. Only four prehospital surgical airways were performed during the study period. One patient survived to hospital discharge to home.

CONCLUSION

Surgical airways are an infrequently performed procedure in the rural prehospital setting. There is no universally accepted standard for teaching or evaluating the competency of this potentially life-saving procedure. Further efforts to establish a core educational curriculum appear warranted.

Optimal Airway Management in Cardiac Arrest

Airway management during cardiac arrest has undergone several advancements. Endotracheal intubation (ETI) often is considered the gold standard for airway management in cardiac arrest; however, other options exist. Recent prospective randomized trials have compared outcomes in bag-valve mask ventilation and supraglottic airways to ETI in out-of-hospital cardiac arrest. ETI, if performed early in resuscitation, is associated with worse patient outcomes and has been de-emphasized so as not to interfere with other aspects of the resuscitation. Hyperventilation has multiple theoretic harms during cardiac arrest, and methods, such as compression-adjusted ventilation, may be utilized to help reduce the incidence of hyperventilation.

A review of ventilation in adult out-of-hospital cardiac arrest

Out-of-hospital cardiac arrest continues to be a devastating condition despite advances in resuscitation care. Ensuring effective gas exchange must be weighed against the negative impact hyperventilation can have on cardiac physiology and survival. The goals of this narrative review are to evaluate the available evidence regarding the role of ventilation in out-of-hospital cardiac arrest resuscitation and to provide recommendations for future directions. Ensuring successful airway patency is fundamental for effective ventilation. The airway management approach should be based on professional skill level and the situation faced by rescuers. Evidence has explored the influence of different ventilation rates, tidal volumes, and strategies during out-of-hospital cardiac arrest; however, other modifiable factors affecting out-of-hospital cardiac arrest ventilation have limited supporting data. Researchers have begun to explore the impact of ventilation in adult out-of-hospital cardiac arrest outcomes, further stressing its importance in cardiac arrest resuscitation management. Capnography and thoracic impedance signals are used to measure ventilation rate, although these strategies have limitations. Existing technology fails to reliably measure real-time clinical ventilation data, thereby limiting the ability to investigate optimal ventilation management. An essential step in advancing cardiac arrest care will be to develop techniques to accurately and reliably measure ventilation parameters. These devices should allow for immediate feedback for out-of-hospital practitioners, in a similar way to chest compression feedback. Once developed, new strategies can be established to guide out-of-hospital personnel on optimal ventilation practices.

Troubleshooting Hypoxemia After Placement of an Extraglottic Airway

The case presented here highlights the feasibility of using an extraglottic airway device as a conduit for delivering high levels of lifesaving positive end expiratory pressure (PEEP), as well as other means of combating recalcitrant hypoxia. The case also highlights the merit of an approach to the hypoxic patient with an in-situ extraglottic airway device based not only on deciding if the device is functioning to maintain a patent airway, but also, simultaneously considering the patient's physiology. A 71 year old male suffered an out-of-hospital cardiac arrest. Part of his resuscitation included placement of a dual-balloon extraglottic airway device by EMS. He was hypoxic, but the device seemed to be providing for a patent airway without an air leak. There was also a favorable end-tidal carbon dioxide waveform. The flight team chose to the leave the device in place. PEEP was up-titrated to 17 cmH20 without issue. Sigh breaths, as well as breath holds, were also able to be delivered. The patient's hypoxia improved over the course of the patient's transport, and he ultimately did well.

Emergency Department Management of Out-of-Hospital Laryngeal Tubes

STUDY OBJECTIVE

Laryngeal tubes are commonly used by emergency medical services (EMS) personnel for out-of-hospital advanced airway management. The emergency department (ED) management of EMS-placed laryngeal tubes is unknown. We seek to describe ED airway management techniques, success, and complications of patients receiving EMS laryngeal tubes.

METHODS

Using a keyword text search of ED notes, we identified patients who arrived at our ED with a laryngeal tube from 2010 through 2017. We performed structured chart and video reviews for all eligible patients. In our ED, emergency physicians perform all airway management, and there is no protocol dictating airway management for patients arriving with a laryngeal tube. Using descriptive methods, we report the techniques, success, and complications of ED airway management.

RESULTS

We analyzed data on 647 patients receiving out-of-hospital laryngeal tubes, including 472 (73%) with cardiac arrest from medical causes, 75 (21%) with cardiac arrest from trauma, and 100 (15%) with other conditions. For 580 patients (89%), emergency physicians exchanged the laryngeal tube for a definitive airway in the ED. Of the 67 patients not intubated in the ED, 66 died in the ED without further airway management. Of the 580 patients intubated in the ED, orotracheal intubation was the first method attempted for 578 (>99%) and was successful on the first attempt for 515 of 578 (89%). Macintosh video laryngoscopy (88% of initial attempts) and a bougie (68% of initial attempts) were commonly used adjuncts. For 345 of 578 patients (60%), the laryngeal tube was removed before intubation attempts. For 112 of 578 patients (19%), the first intubation attempt occurred with the deflated laryngeal tube left in place. Three patients (<1%) required a surgical airway.

CONCLUSION

In this cohort, emergency physicians successfully exchanged an out-of-hospital laryngeal tube for an endotracheal tube, using commonly available airway management techniques. ED clinicians should be familiar with techniques for exchanging out-of-hospital extraglottic airways for an endotracheal tube.

Updates in emergency airway management

PURPOSE OF REVIEW

Historically, most evidence supporting emergency airway management strategies have been limited to small series, retrospective analyses and extrapolation from other settings (i.e. the operating room). Over the past year, several large, randomized clinical trials have offered new findings to inform emergency airway management techniques.

RECENT FINDINGS

One large, randomized clinical trial, found improved first attempt success rates with bougie facilitated intubation compared with traditional intubation. Two randomized clinical trials suggested better outcomes in adult out-of-hospital cardiac arrest (OHCA) with supraglottic airways (SGA) than intubation. A randomized clinical trial in OHCA patients could not identify outcome differences between endotracheal intubation (ETI) and bag-valve mask (BVM) ventilation but suggested higher rates of aspiration with BVM.

SUMMARY

These studies offer new findings to inform the practice of emergency airway management. Bougie use should be considered as a first-line approach in emergency intubation. SGA-based strategies should be considered as a first-line approach in the management of OHCA.

Preliminary Report: Comparing Aspiration Rates between Prehospital Patients Managed with Extraglottic Airway Devices and Endotracheal Intubation

INTRODUCTION

There has been a shift from endotracheal intubation (ETI) toward extraglottic devices (EGDs) for prehospital airway management. A concern exists that this may lead to more frequent cases of aspiration.

METHODS

This was a retrospective study using a prehospital quality assurance database. Patients were assigned to groups based on the method that ultimately managed their airways (EGD or ETI). Cases with documented blood/emesis obscuring the airway were considered inevitable aspiration cases and excluded. Aspiration was defined by the radiology report within 48 hours.

RESULTS

A total of 104 EGD and 152 ETI patients were identified. Aspiration data were available for 67 EGD and 94 ETI cases. Of those, 8 EGD and 3 ETI cases had blood/emesis obscuring the airway and were excluded as planned. After exclusions, there were 5 EGD and 11 ETI cases in which aspiration was later diagnosed (EGD aspiration rate = 8%, ETI aspiration rate = 12%; χ²: P = .359; relative risk = .841; 95% confidence interval, .329-2.152).

CONCLUSION

In this small quality assurance database, aspiration rates were not significantly different for prehospital patients managed with an EGD versus ETI.

Chest compressions do not disrupt the seal created by the laryngeal mask airway during positive pressure ventilation: a preliminary porcine study

OBJECTIVE

Pulmonary aspiration of gastric contents occurs 20 to 30% of the time during cardiopulmonary resuscitation (CPR) of cardiac arrest due to loss of protective airway reflexes, pressure changes generated during CPR, and positive pressure ventilation (PPV). Although the American Heart Association has recommended the laryngeal mask airway (LMA) as an acceptable alternative airway for use by emergency medical service personnel, concerns over the capacity of the device to protect from pulmonary aspiration remain. We sought to determine the occurrence of aspiration after LMA placement, CPR, and PPV.

METHODS

We inserted a size 4 LMA, modified so that a vacuum catheter could be advanced past the LMA diaphragm, into the hypopharynx of 16 consecutive postexperimental mixed-breed domestic swine. Fifteen millilitres of heparinized blood was instilled into the oropharynx. Chest compressions were performed for 60 seconds with asynchronous ventilation via a mechanical ventilator. We then suctioned through the LMA for 1 minute. The catheter was removed and inspected for signs of blood. The LMA cuff was deflated, removed, and inspected for signs of blood.

RESULTS

None of 16 animals (95% CI 0-17%) had a positive test for the presence of blood in both the vacuum catheter and the intima of the LMA diaphragm.

CONCLUSIONS

In this swine model of regurgitation after LMA placement, there were no cases with evidence of blood beyond the seal created by the LMA cuff. Future studies are needed to determine the frequency of pulmonary aspiration after LMA placement during CPR and PPV in the clinical setting.

Oxygenation, ventilation, and airway management in out-of-hospital cardiac arrest: a review

Recently published evidence has challenged some protocols related to oxygenation, ventilation, and airway management for out-of-hospital cardiac arrest. Interrupting chest compressions to attempt airway intervention in the early stages of OHCA in adults may worsen patient outcomes. The change of BLS algorithms from ABC to CAB was recommended by the AHA in 2010. Passive insufflation of oxygen into a patent airway may provide oxygenation in the early stages of cardiac arrest. Various alternatives to tracheal intubation or bag-mask ventilation have been trialled for prehospital airway management. Simple methods of airway management are associated with similar outcomes as tracheal intubation in patients with OHCA. The insertion of a laryngeal mask airway is probably associated with worse neurologically intact survival rates in comparison with other methods of airway management. Hyperoxemia following OHCA may have a deleterious effect on the neurological recovery of patients. Extracorporeal oxygenation techniques have been utilized by specialized centers, though their use in OHCA remains controversial. Chest hyperinflation and positive airway pressure may have a negative impact on hemodynamics during resuscitation and should be avoided. Dyscarbia in the postresuscitation period is relatively common, mainly in association with therapeutic hypothermia, and may worsen neurological outcome.

Evaluation of the Storz CMAC®, Glidescope® GVL, AirTraq®, King LTS-D™, and direct laryngoscopy in a simulated difficult airway

OBJECTIVE

The aim of this study was to compare first-attempt and overall success rates and success rates in relation to placement time among 5 different airway management devices: Storz CMAC, Glidescope GVL, AirTraq, King LTS-D, and direct laryngoscopy (DL).

METHODS

Emergency medical technician basic (EMT-B), EMT-paramedics (EMT-P), and emergency medicine residents and staff physicians placed each of the 5 devices in a random order into an AirSim (TruCorp, Belfast, UK) part-task training manikin. The difficult airway scenario was created by fixing the manikin head to a stationary object and introducing simulated emesis into the hypopharynx. First-attempt and overall success and success in relation to placement time were compared. Provider feedback about device performance was also evaluated.

RESULTS

Ninety-four providers (16 EMT-basics, 54 EMT-paramedics, and 24 emergency department doctors of medicine) consented to participation. First-attempt and overall success rates for DL, King LTS-D, GVL, and CMAC were not statistically different. Compared with DL, the AirTraq was 96% less likely to be placed successfully (odds ratio, 0.04; 95% confidence interval [CI], 0.01-0.14). When time was factored into the model, the odds of successful placement of the King LTS-D were higher compared with DL (hazard ratio [HR], 1.80; 95% CI, 1.34-2.42) and lower for GVL (HR, 0.59; 95% CI, 0.44-0.80) and AirTraq (HR, 0.228; 95% CI, 0.16-0.325). Providers ranked the CMAC first in terms of performance and preference for use in their practice setting.

CONCLUSION

Overall success rates for DL, King-LTS-D, and both video laryngoscope systems were not different. When time was factored into the model, the King LTS-D was more likely to be placed successfully.

Endotracheal intubation versus supraglottic airway insertion in out-of-hospital cardiac arrest

OBJECTIVE

To simplify airway management and minimize cardiopulmonary resuscitation (CPR) chest compression interruptions, some emergency medical services (EMS) practitioners utilize supraglottic airway (SGA) devices instead of endotracheal intubation (ETI) as the primary airway adjunct in out-of-hospital cardiac arrest (OHCA). We compared the outcomes of patients receiving ETI with those receiving SGA following OHCA.

METHODS

We performed a secondary analysis of data from the multicenter Resuscitation Outcomes Consortium (ROC) PRIMED trial. We studied adult non-traumatic OHCA receiving successful SGA insertion (King Laryngeal Tube, Combitube, and Laryngeal Mask Airway) or successful ETI. The primary outcome was survival to hospital discharge with satisfactory functional status (Modified Rankin Scale ≤3). Secondary outcomes included return of spontaneous circulation (ROSC), 24-h survival, major airway or pulmonary complications (pulmonary edema, internal thoracic or abdominal injuries, acute lung injury, sepsis, and pneumonia). Using multivariable logistic regression, we studied the association between out-of-hospital airway management method (ETI vs. SGA) and OHCA outcomes, adjusting for confounders.

RESULTS

Of 10,455 adult OHCA, 8487 (81.2%) received ETI and 1968 (18.8%) received SGA. Survival to hospital discharge with satisfactory functional status was: ETI 4.7%, SGA 3.9%. Compared with successful SGA, successful ETI was associated with increased survival to hospital discharge (adjusted OR 1.40; 95% CI: 1.04, 1.89), ROSC (adjusted OR 1.78; 95% CI: 1.54, 2.04) and 24-h survival (adjusted OR 1.74; 95% CI: 1.49, 2.04). ETI was not associated with secondary airway or pulmonary complications (adjusted OR 0.84; 95% CI: 0.61, 1.16).

CONCLUSIONS

In this secondary analysis of data from the multicenter ROC PRIMED trial, ETI was associated with improved outcomes over SGA insertion after OHCA.

Can emergency medical services personnel effectively place and use the Supraglottic Airway Laryngopharyngeal Tube (SALT) airway?

BACKGROUND

Various alternative airway devices have been developed in the last several years. Among these is the Supraglottic Airway Laryngopharyngeal Tube (SALT), which was designed to function as a basic mechanical airway and as an endotracheal tube (ET) introducer for blind endotracheal intubation (ETI).

OBJECTIVE

To determine the rate of successful placement of the SALT and the success rate of subsequent blind ET insertion by a cohort of emergency medical services (EMS) providers of varying levels of EMS certification.

METHODS

This study was a two-phase, two-group nonblinded, prospective time trial using a convenience cohort of prehospital providers to determine the success rate for SALT placement (i.e., the basic life support [BLS] phase) and ET placement using the SALT (i.e., the advanced life support [ALS] phase) in an unembalmed human cadaver model. The part 1 cohort (group 1) comprised predominantly basic and intermediate emergency medical technician (EMT)-level providers, whereas the part 2 cohort (group 2) comprised exclusively paramedic-level providers.

RESULTS

In group 1, 51 (98%) of the subjects were able to successfully place the SALT and ventilate the cadaver (BLS phase), with 48 (92.3%) subjects successfully placing it on the first attempt. In group 2, 21 (96%) of the subjects were able to successfully place the SALT, with 19 (86%) placing the SALT on the first attempt. Successful blind placement of an ET through the SALT (ALS phase) by group 1 was 48.1% (95% confidence interval [CI]: 34-62), with 37% (95% CI: 24-51) placing the ET on the first attempt. In group 2, 20 subjects (91% [95% CI: 71-99]) were able to successfully place an ET through the SALT, with 13 (59% [95% CI: 36-79]) doing so on the first attempt.

CONCLUSIONS

Emergency medical services providers of varying levels can successfully and rapidly place the SALT and ventilate a cadaver specimen. The success rate for blind placement of an ET through the SALT was suboptimal.