One theme that continues to re-emerge in the prehospital arena is the practice of airway management. Throughout the U.S., endotracheal intubation (ETI) has been universally accepted as the “gold standard” for definitive airway management.1 It has also been characterized as having as much influence on patient outcomes as defibrillation.2 However, various authors have suggested that the practice of out-of-hospital ETI is too risky considering the lack of evidence suggesting improved outcomes. There’s no doubt that problems exist and solutions must be found, but eliminating the practice might be hailed as a knee-jerk reaction throughout the EMS community.
The paramedic curriculum currently in use was developed by the National Highway Traffic Safety Administration in 1998. The curriculum is divided into eight modules that encompass the fundamental knowledge base of the entry-level paramedic, and the recommended time to achieve competence is 1,000–1,200 hours of instruction. Instructional time during paramedic school is distributed among classroom instruction, psychomotor skill instruction and practice, as well as hospital rotations under the supervision of a nurse or physician. The entire course of study culminates with a field internship on an ambulance under the guidance of a paramedic preceptor.
One of the modules within the paramedic curriculum is Airway Management and Ventilation. The recommendations contained within the curriculum comprise classroom instruction on various technical aspects of airway management in adult and pediatric patients, skills instruction and practice on adult and pediatric manikins and skills performance on “live” humans in the operating room (OR) under the direct supervision of an anesthetist or anesthesiologist with a minimum of five live intubations. Under these ideal conditions, paramedic students require 15–25 patient encounters in order to achieve success rates above 90%.3
One study comparing the effectiveness of training with human patient simulators (HPS) versus training in the OR found both methods to be equally sufficient in the acquisition of intubation skills.4 Unfortunately, although ideal and recommended, HPS are the exception and not the rule when it comes to intubation training. These simulators can be cost prohibitive for many paramedic training centers. And when it comes to OR experience, paramedic students must often compete with medical students, medical residents and nurse anesthesia trainees for skill time. Paramedic students are last in the pecking order and are also frequently hampered by malpractice liability concerns on the part of hospitals and anesthesiologists/anesthetists—even though the American Society of Anesthesiology has passed a resolution encouraging involvement in training paramedics.
Additionally, paramedic students have seen a decrease in the number of ETIs with the advent of such supraglottic airways as the Laryngeal Mask Airway, the Combitube and the King Airway because these airways are easier to insert while performing the same basic function as an ET tube (ETT).
Paramedics are expected to perform independently under sub-optimal conditions with minimal assistance and little supervision. So paramedics should receive as many patient encounters under ideal conditions to master the procedure.
Instead, they’re denied OR time. Or when permitted to enter this clinical area, they obtain minimal contacts and often only on adult patients who are deemed to be ordinary, uncomplicated cases. Often, paramedics aren’t allowed to attempt ETI on patients assessed to be “difficult” airways and rarely on children. This is the area in which the most significant changes must occur to have the greatest impact on all the ETI issues.
Another consideration beyond initial ETI training is the maintenance of proficiency. Many providers don’t frequently intubate. Additionally, because paramedics typically work a rotating shift, there could be extended time periods between opportunities to perform the skill, especially in systems with smaller call volumes. As a result, skill decay can occur without regular exposure.
When an EMS agency has too many paramedics, a dilution of airway management skill capabilities will occur throughout the paramedic ranks. This then becomes a significant quality-of-care issue for the entire system. Under those circumstances, it’s nearly impossible to maintain paramedic-skills proficiency without access to an OR.
Another challenge is the patient population we serve. No two patients are alike, and this old adage is never truer than in the ETI performance. Patients who require ETI don’t fall into a single category, and various reasons exist why a provider may perform the procedure. Generally, these patients represent the highest acuity encounters in the prehospital or in-hospital setting (i.e., the sickest of the sick). Each group presents a unique set of difficulties and impediments to successful performance.
ETI is most commonly initiated on cardiopulmonary arrest patients. This can be further defined as originating from medical or traumatic causes because each group poses different obstacles to success. A cardiopulmonary arrest resulting from medical causes (i.e., the classic heart attack) generally poses minimal complications leading to a successful outcome. Repeated studies have shown that paramedics have a high success rate in managing these patients.
Trauma patients, conversely, pose considerable obstacles to a successful intubation. For these patients, paramedics encounter such barriers as optimal positioning due to spinal injury precautions; injury to the face, head or neck that create potential obstructions from excessive bleeding; or trismus from a closed-head injury. Managing the airway of a trauma patient is technically more difficult, which means these patients are more likely to have a misplaced ETT than medical patients.5
Managing the airway of a pediatric patient poses a unique challenge. The frequency of encounters with pediatric patients is far less than that of adult patients; the frequency of situations requiring ETI is extremely small.
Therefore, the level of experience a paramedic has in performing this skill on pediatric patients is minute. Smaller anatomy, smaller equipment and the stress of performing while surrounded by agitated parents make pediatric patients the ultimate difficult airway management situation.
Paramedics rarely obtain the opportunity to perform airway management on pediatric patients during OR rotations. So there’s a significant risk of intubation non-attempt or intubation failure in the pediatric cardiac arrest patient.6
Paramedics also encounter “awake” patients (adult or pediatric) who require airway management as a result of the worsening of a pre-existing condition (e.g., asthma) or severe emergent condition (e.g., acute allergic reaction). Due to the severity of the immediate condition, these patients will “fight” to breathe and survive. They’ll likely be uncooperative and possibly combative as a survival mechanism. Under these conditions, training and experience will mean the difference in patient outcome.
One difficulty providers often encounter in the field is that the patient is found in a position that’s least likely to provide the person performing ETI with the correct angle and view to accomplish the skill. Patients might be trapped in an automobile after a collision or wedged between the toilet and the bathtub after having the “big one” on the toilet. These scenarios all decrease the odds of success.
Many of these pitfalls and difficulties could be anticipated with the correct training and education. What the novice paramedic lacks in knowledge, or often fails to recognize due to lack of experience, is that certain patient characteristics will affect the degree of difficulty with ETI, such as obesity, jaw/neck length, mouth aperture, tongue size or a combination of these factors.
These characteristics that define a “difficult airway” will increase the probability of ETI failure when coupled with a complex patient or scenario. Many initial or refresher training programs fail to properly educate paramedics on these finer points. As a result, paramedics rate poorly in accurately grading and assessing different airways.7
Management, Not Intubation
“Get the tube” has been the marching order I’ve heard for more than 20 years during refresher training and specialized courses. Instructors tell their paramedic students that intubation is the “gold standard,” and without it, the patient won’t survive. Unfortunately, it has been over-emphasized at an unknown cost to the patient. Recent studies now suggest that early ETI is actually detrimental to the patient when it causes an interruption in CPR.8 Additional studies with trauma patients have also demonstrated increased mortality when intubation delays transport to the hospital.9–12
The current recommendations are for instructors to emphasize improving deficiencies with oxygenation and ventilation while maintaining consistent chest compression without interruption. Many patients can be adequately managed with techniques that are less invasive than ETI—a fact often overlooked.
Application of oxygen or manual assistance with breathing can dramatically improve a patient’s condition. In some situations, there’s a concurrent failure to identify the underlying cause of a patient’s problem, such as hypoglycemia, when ETI was misapplied. This demonstrates a pervasive need to identify opportunities to increase awareness and improve paramedic training and education.
Most, if not all, medical procedures have some degree of risk. The overall practice of airway management is one of the highest liability procedures in medicine. This is the reason why anesthesiologists pay some of the highest premiums in medical malpractice insurance.
In fact, the Closed-Claims Project of the American Society of Anesthesiologists has examined the results of closed malpractice claims and maintained a database since 1985 in an effort improve quality and reduce errors in anesthesiology. In some of the initial studies, the organization evaluated adverse respiratory events that led to malpractice claims without regard to outcome (see Figure 1). As Figure 1 identifies, diverse issues can create an adverse respiratory event, but inadequate ventilation is the most prevalent situation.
Those early studies were extended in an attempt to identify outcomes that increase morbidity and mortality (see Figure 2). Again, we see similar results with respect to inadequate ventilation and its profound effect on death or permanent brain damage.
These results are significant when considering that this data originates from physicians whose sole practice is airway management. The level of concern that exists within the medical community, with respect to paramedic intubation, is understood when evaluated in this light. Multiple studies have attempted to quantify adverse events in prehospital ETI.
Because the most serious and potentially devastating iatrogenic event is an unrecognized esophageal intubation, several prospective and retrospective studies have been conducted to determine if this is a significant problem in the prehospital setting. Surprisingly, multiple authors identified the rate of unrecognized esophageal intubation from an almost non-existent (0.1%) to a shocking and unacceptable 25%. Additional studies are needed because the results are so mixed.
Ultimately, the question becomes, what’s an acceptable rate? From the patient’s perspective, it’s zero.
One study identified the most prevalent outcomes associated with prehospital intubation errors and demonstrated a corresponding increase in mortality or severe neurological impairment.8 This is the first study in the prehospital arena to establish causation with adverse events. Another study also demonstrated that as attempts at performing ETI in the same patient increased, there was a resulting decrease in success with each additional attempt.13
However, capnography has had a positive effect in reducing misplacement of the ETT.14 In a study of 284 patients who received ETI in the prehospital setting, there were no unrecognized esophageal intubations in patients for which continuous waveform capnography was used.
These findings, if future studies yield similar results, indicate that continuous waveform capnography, when used appropriately, can eliminate the most disastrous consequence of a failed prehospital ETI. These results are highly promising to maximize ETI success and the overall care paramedics provide.
Where Do We Go from Here?
Finding solutions won’t be easy, but EMS providers can take some steps now to ensure better ETI proficiency.
Paramedics have been taught multiple “low-tech” ways to confirm ETT placement. Most of these methods are unreliable when used individually, and they all only provide a “snapshot” in time. The hustle and bustle of prehospital care doesn’t lend itself well to low-tech methods when a patient’s airway needs to be maintained.
The technology is available to continuously ensure the ETT is correctly placed. Continuous waveform capnography has been considered standard practice by anesthesiologists for quite some time. Although this capability is available for use in the prehospital setting, some EMS agencies continue to try and “get by” using colorimetric carbon-dioxide detectors. Colorimetric detectors can be prone to give “false positives” and don’t provide information about the actual gas exchange that’s occurring within the lungs.
The only way to completely eliminate unrecognized esophageal intubations and ETT displacements is to make continuous waveform capnography mandatory in ETI. Regulatory agencies should limit authorizations or licenses of EMS agencies that choose to ignore this practice. It’s expensive, but it should be the standard.
Greater advocacy should exist within the medical community by EMS medical directors, the National Association of EMS Physicians and the American College of Emergency Physicians. They should seek a dialogue with their colleagues in anesthesiology to increase OR access for paramedics and paramedic students. Enhanced proficiency can only occur through repetition of the skill. Repetition builds “muscle-memory,” leading to mastery of the psychomotor skill. When in place, this will also be an avenue to stop the skill decay that occurs from lack of exposure.
EMS needs to take a play out of the American Society of Anesthesiologists’ playbook and continuously evaluate the performance of airway management. However, EMS also needs to take a proactive approach and collect the data prospectively and not from closed malpractice cases. The creation of a national adverse events registry lends itself to the principles of total quality management. The system should be mandatory but anonymous; there can be no fear of punitive action. It has already been demonstrated in Pennsylvania that an anonymous reporting system encourages reporting.15 Maintaining a registry will allow continuous monitoring of all aspects of prehospital airway management throughout the country.
Paramedics need to go back to the classroom on a regular basis to obtain the most current information relative to airway management. This can’t simply be the same repetitive practice on manikins that has become a rote process. There’s no denying that regular practice of the manipulative skill is important, but it’s only one spoke in the wheel. Instructors should place a greater emphasis on scenario-based training (SBT) to develop the critical-thinking skills that some lack. Through SBT, paramedics are able to obtain valuable experience in a controlled environment.
These recommendations are starting points for a process that will always be “a work in progress” as newer technology becomes available and the data from scientific research causes a course correction. Airway and ETI success will be accomplished through the dedication and sheer tenacity of the individuals who chose EMS as a profession.
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11. Ochs M, Davis D, Hoyt D, et al. Paramedic-performed rapid sequence intubation of patients with severe head injuries. Ann Emerg Med. 2002;40(2):159–167.
12. Stockinger Z, McSwain N. Prehospital endotracheal intubation for trauma does not improve survival over bag-valve-mask ventilation. J Trauma. 2004;56(3):531–536.
13. Wang H, Yealy D. How many attempts are required to accomplish out-of-hospital endotracheal intubation? Acad Emerg Med. 2006;13(4):372–377.
14. Silvestri S, Ralls GA, Krauss B, et al. The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubations within a regional emergency medical services system. Ann Emerg Med. 2005;45(5):497–503.
15. Wang H, Kupas D, Paris P, et al. Preliminary experience with a prospective, multi-centered evaluation of out-of-hospital endotracheal
This article originally appeared in July 2011 JEMS as “Addressing Airway Issues: How to keep ETI a prehospital skill.”