Controversies in EMS Airway Management

INTRODUCTION

Although airway management has been a fundamental part of emergency medical services (EMS) for many decades, there remain areas of controversy that deserve focused attention. By the very nature of being considered controversial, it is presumed that there is insufficient evidence to make definitive recommendations. In contrast to other chapters where the pertinent evidence is summarized at the end, we will do our best to consider the available evidence and our experiences, as we discuss each topic, to provide balanced guidance.

SKILL TRAINING AND MAINTENANCE

Human factor study has shown that in high-stress, high-risk, low-frequency procedures, we will sink to our level of training rather than rise to the occasion. Confounding this, there is no consistent standard for initial EMS airway training, particularly with regards to how many intubations a paramedic student should complete and whether all need to be live. Research in the operating room demonstrates little improvement in success or decrease in complications during the first 13 intubation attempts by paramedic students with significant improvement between the 14th and 30th intubations, and by the 30th intubation most students were achieving 90% first-pass success in a controlled environment.¹

Turning research into standards, the U.S. Committee on Accreditation of Education Programs for the Emergency Medical Services Professional (CoAEMSP) recommends a combination of a minimum of 50 “airway encounters” across all age ranges, with 100% success in 20 consecutive encounters.² They state that airway management “may be accomplished utilizing any combination of live patients, high-fidelity simulations, low-fidelity simulations, or cadaver labs.” Although discouraged, it is possible for a paramedic student to complete initial training without a single live intubation. On the other hand, the Provence of Alberta, Canada, requires 10 intubations in a simulated setting and 15 on live patients in a clinical practicum.³ Throughout the world, there is variability with regards to initial training requirements that depend on number of learners and availability of operating room time. It is our belief that simulators are excellent for developing muscle memory in optimal technique as well as the sequencing of medication-facilitated airway management (MFAM), but a variety of live or cadaver tissue is necessary to become comfortable with human diversity. It seems reasonable that the more live intubations a student performs the more successful they will become, but there is little research to support this assumption.

There is even less consensus on recommendations for skill maintenance. There are several studies demonstrating that even with targeted training, skills degrade with time.4 Most importantly, there is a study that correlates patient outcome to the number of airway procedures performed by the treating provider in the previous 5 years; as a result, many agencies set minimum numbers of encounters and success requirements, often relying on low-fidelity simulation.⁵ The Commission on Accreditation of Medical Transport Systems (CAMTS) requires three adult, pediatric, and infant intubations per quarter, or a total of 36 intubations per year, all of which may be simulated.⁶ Despite this mandate, a 2014 study of almost 5,000 intubations by air medical crews primarily using rapid sequence intubation (RSI) demonstrated a first-pass success of less than 80% and an overall success of 92%.⁷ This suggests that the standards may be insufficient to maintain competence. It is incumbent on each provider, agency, and system to set their own standard that ensures patient safety and optimizes success.

PEDIATRICS

Prehospital pediatric intubations are exceedingly uncommon, and success rates are less than that for adults. One large air medical study found that only 5% of intubation cases were for patients above or below 14 years of age.⁷ A ground-based study in a large metropolitan area that allows MFAM recently reported only 299 pediatric intubation in 6.3 years, with a first-pass success of 66% overall, 53% for infants, and 56% for children with cardiac arrest.⁸ This system reports that an average paramedic student performs six pediatric intubations during training, which we suspect far exceeds the national average, yet still performs poorly on pediatric intubation. At the same time there is high-quality evidence from a large, randomized, controlled trial that pediatric patients do just as well with simple bag-mask ventilation (BMV) as they do with endotracheal intubation (ETI).⁹ There are now numerous extraglottic devices (EGDs) available for pediatric patients, providing another option to endotracheal intubation. This has led some jurisdictions to remove pediatric intubation from the scope of practice or protocols in favor of BMV or EGDs. Each patient is unique, and firm recommendations cannot be made at this point; however, it seems reasonable for prehospital providers to rely on solid rescue mask ventilation skills or EGD use in lieu of tracheal intubation. EMS systems that continue to perform pediatric intubation, and especially pediatric MFAM, should carefully track their success, complications, and outcomes, and must have processes in place to ensure patient safety.

ATTEMPTS

Many EMS Quality Assurance programs and publications report overall success for prehospital intubation without a breakdown of the number of attempts it required to successfully place an endotracheal tube in the trachea. There is evidence from the hospital setting that complications increase significantly with each successive attempt. For instance, there is a marked increase in complications including cardiac arrest, with three or more attempts at intubation compared with fewer than three attempts.¹⁰ Another group reported that complications increased from 14.2% on the first attempt to 63.6% with more than three attempts.¹¹ Bodily et al.¹² demonstrated an increase in hypoxemia with more than a single intubation attempt. Taken together, it is clear that when intubating critically ill and injured patients in the prehospital setting the focus should be on first-attempt success rather than overall success.

The obvious implication of this mindset is that providers must set themselves, and the patient, up for success on the first attempt using all the techniques discussed in this text. We must simultaneously be ready, both mentally and physically, to move quickly to an alternative technique. There may be patients for whom intubation is clearly preferred to BMV or an EGD, such as those with massive obesity or upper airway pathology. In these cases, providers may consider the relative risks and benefits of a second or third attempt but only if there is something that can be changed to increase the chance of success on the subsequent attempt such as position, device, technique, or intubator.

NIPPV

Although Noninvasive Positive Pressure Ventilation (NIPPV) has become commonplace in most EMS systems, it is often restricted to paramedics. Given that this technology is very simple to employ using disposable devices, and can be used to manage a wide range of hypoxemic conditions, and this device is used routinely by patients at home, we believe this technology should be included in BLS and ILS scopes of practice. However, acquiring new skills and learning new equipment, even one as simple as continuous positive airway pressure (CPAP), requires adding hours to training programs, which can spread resources thin and limit the number of providers being trained, especially in volunteer systems.

Altered mental status (AMS) was traditionally considered an absolute contraindication to NIPPV because the patient may have to remove the mask in the event of vomiting or, at a minimum, alert a provider that he/she is about to vomit. It is our opinion that AMS should be considered a relative contraindication, and the pros and cons should be weighed in each individual case. Clearly, a patient with Glasgow comas scale (GCS) of 3 and poor respiratory effort needs rescue mask ventilation. On the hand, a slightly sleepy or confused patient with hypercarbia or hypoxemia who can remain seated may be a very reasonable CPAP candidate when EMS crews can provide vigilant one-on-one observation at all times during transport. It also makes sense to employ CPAP liberally, despite AMS, for preoxygenation. If, for example, a crew of two or three is trying to quickly set up for MFAM in a spontaneously breathing but unconscious patient, tying up one crew member to assist respirations may not be an optimal use of resources.

Another area of controversy with NIPPV is its use in conditions other than congestive heart failure and asthma/chronic obstructive pulmonary disease, such as pneumonia. Some sources state that pneumonia is a contraindication owing to the potential for increasing the risk of bacteremia from the translocation of bacteria into the bloodstream. Other sources state that NIPPV is a good temporary treatment option for suspected pneumonia with hypoxemia in the prehospital setting.13 Generally, pending further evidence, we believe the risks from both hypoxemia refractory to simple supplemental oxygen as well as the risks of prehospital MFAM outweigh the small potential risk of bacteremia from the short-term use of NIPPV.

SEDATION-FACILITATED INTUBATION

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