To date, considerable controversy exists regarding the ability of prehospital providers—typically paramedics in the U.S.—to safely, effectively and consistently perform endotracheal intubation (ETI). This controversy is supported by substantial differences in published reports of ETI success across EMS systems. In some systems, successful placement of the endotracheal tube (ETT) during prehospital airway management may be greater than 75% on the first attempt and upwards of 99% overall.1-6 In other reports, successful placement may attain 75% overall, even after multiple attempts.7-10
Moreover, the process of “successful” ETT placement also differs substantially between these systems. Paramedics in high-performing systems likely intubate relatively quickly, while the procedure may be more protracted in other systems. Finally, correct tube placement of ETI is only the initial step of optimal care. Subsequent oxygenation and ventilation must also be appropriately managed.
In studies demonstrating poor outcomes related to prehospital-attempted ETI, a common topic is the training and expertise of the clinical practitioner. Indeed, researchers demonstrated a direct relationship between a greater number of patient intubation contacts and intubation success.11 Many paramedics, however, receive modest training in and field experience with ETI. National standards require five ETI attempts for paramedic certification. By contrast, consider that the experience requirement of an anesthesia training program typically consists of nearly 1,000 or more intubations.
In this context, the ETI training and certification requirement for paramedics in Seattle and King County, Wash., is substantially more rigorous than the national standard, and successful ETI approaches 99% overall. Although we can’t directly attribute the high rate of successful intubations in this system to greater opportunity for proficiency, we believe the more rigorous programmatic approach to ETI is instrumental in achieving success, and in turn, improving the likelihood of favorable clinical outcomes in these critical conditions.
EMS has increasingly recognized the challenge of successful ETI placement and has offered a variety of alternative approaches designed to improve airway management. These approaches include replacement of ETI with alternate airway techniques as well as enhanced ETI training and experience. The optimal choice for airway management for a given EMS program depends on multiple considerations, such as provider experience and training, equipment and medical oversight. However, for EMS systems that wish to establish and/or maintain a high standard of ETI, we provide any detailed description of the education and clinical efforts designed to support ETI proficiency. We recognize the model from Seattle and King County may not be well-suited to each EMS system, but we believe it provides the core tenets of a comprehensive program designed to achieve a high level of ETI performance.
King County has 1.8 million residents and covers a geographic area of 2,134 square miles of urban, suburban, rural and wilderness areas. The EMS system for Seattle and King County is a two-tier system, with the first tier providing BLS. This tier is composed of approximately 3,500 EMTs from 30 fire departments and arrives on scene approximately five minutes following dispatch. The second tier has about 250 paramedics who work in pairs to provide ALS care, including ETI. These paramedic pairs are stationed across King County at 23 locations and arrive, on average, eight minutes after dispatch. In 2009, the Seattle EMS system responded to a total of 63,239 emergencies, 18,866 of which were ALS dispatches. Greater King County responded to 168,658 BLS and 50,249 ALS dispatches.
Potential paramedic trainees undergo a selection process before being accepted into the training program. Eligible applicants must have current certification as an EMT or paramedic and have at least three years of field experience. Selected candidates enroll into a nine month, full-time paramedic training program through the University of Washington School of Medicine in association with the Seattle Fire Department and Harborview Medical Center, which serves as the state’s only Level 1 trauma center. Approximately 20 students enter Harborview paramedic training each year, with a 90% graduation rate.
The program, which emphasizes the clinical aspect over didactic and simulation experiences, consists of 2,150 hours of training divided into about 350 hours of lectures and 1,800 hours of hospital rotations and field time.
In the first month, students receive six hours of classroom instruction in airway management and 12 hours of intubation practice time on airway manikins from senior paramedics, emergency physicians and anesthesiologists. The training includes education on techniques and clinical indications for ETI, as well as management of the patient once they’re successfully intubated. Competency at this phase is evaluated by a practical intubation examination, and students receive a pass or fail grade. For example, paramedic students are expected to successfully intubate a manikin and verify tube placement in 15 seconds or less in order to pass.
Next, students spend 40 hours in the operating room, where they gain airway management skills, including such techniques as bag-valve-mask (BVM) ventilation, placement of oral and nasal airways, ETI, basic anesthesia induction and use of muscle relaxants and sedatives. They also learn advanced airway rescue techniques under direct supervision of an attending anesthesiologist at Harborview Medical Center.
Additionally, students spend a day in the operating room at Children’s Regional Hospital and Medical Center in Seattle to practice infant and pediatric airway management and intubation. Students are integrated into field care during the first month of training. They work in teams of two, paired with two senior paramedics. The permission for field intubations is granted by the director of paramedic training after students complete a written exam, a timed manikin intubation and at least five successful intubations in the operating room.
The current minimum requirements for graduation are 18 adult and two pediatric tracheal intubations. The paramedic students of the 2008 class successfully performed an average of 25 adult and six pediatric intubations—10 of which occurred in the field setting and 21 in the hospital setting. A review of ETI skill acquisition by paramedic students demonstrated that although paramedic students begin with an average first-pass prehospital ETI success rate of around 60%, by the end of the training, the average student has a first-pass ETI success rate around 80% and an overall success rate (regardless of number of attempts) approaching 95%.12
Ongoing clinical experience: As with paramedic training, graduated field paramedics from Seattle and King County are required to achieve a minimum number of successful intubations a year.
The current requirement is a minimum of 12 annually, a standard in place for the past three decades. The average number of field intubations in 2009 at King County Medic One was 16 per paramedic and an average of 13 field intubations for Seattle paramedics. Paramedics who don’t achieve 12 intubations in a given year return to the Harborview Medical Center operating room, where they must successfully intubate the balance of the requirement under the supervision of an anesthesiologist.
Continuous assessment and education: The core components and structure of the Medic One system in Seattle and King County provide insight into a successful EMS program for airway management (see Figure 1, right). After each attempted ETI, the paramedic is required to complete a confidential quality assurance report, which details the rationale for intubation, the challenges to intubation (including the Cormack-Lehane airway grade, which measures how well vocal cords and surrounding structures can be visualized with laryngoscopy), the actions to address the challenges, medication and equipment used, measures of physiologic status of the patient before and after intubation, methods to verify correct tube placement, the number of attempts required, and the patient’s hospital destination and final status.
The goal of the reporting process is to review each component of ETI, so paramedics recognize what went well and what could be improved. It’s also valuable for medical oversight of
individual cases, and it provides additional evidence of programmatic efforts designed to improve and justify a cornerstone paramedic procedure.
Components of Care
Equipment and medications: The goal is to provide essential and practical tools but not to expand adjuncts and treatments in a manner that de-emphasizes the basic techniques of oral ETI. Paramedics are provided with treatments and equipment necessary to achieve the definitive airway. Field paramedics are provided with standard equipment, including a variety of laryngoscope blades and the gum elastic bougie. They’re trained in and practice rapid sequence intubation (RSI) in a manner similar to hospital-based physicians. Thus, they’re equipped with medications for sedation, induction and short-term paralysis, as well as non-depolarizing skeletal muscle relaxants for circumstances following successful RSI that require ongoing paralysis. Expecting paramedics to achieve comparable rates of successful ETI without RSI techniques isn’t practical because RSI is used in about two-thirds of all intubations. Seattle and King County paramedics have access to a standard—but not expanded—compendium of medication and equipment to achieve ETI.
Paramedics in Seattle and King County operate under a medical control model where they provide care based on contact with a medical control physician. In many cases, they decide if and how to intubate the patient in phone consultation with the emergency physician. Medical consultation prior to intubation isn’t required for patients in cardiac arrest or other critical situations in which a delay is judged to be detrimental for patient outcome.
The success of this system also depends on a core infrastructure of facilities, philosophy and personnel. Specifically, the infrastructure requires a partnership with a hospital-based institution to enable sufficient opportunities to engage in supervised ETI performance. This supervised open-door policy is based on an understanding that such an investment will help provide better airway care for future patients.
The second critical piece of infrastructure is the philosophical approach to prehospital emergency care. In some 9-1-1 calls, ALS care and interventions aren’t required. Conversely, critical ALS skills and care can have an important influence on outcomes in a subset of critically ill patients. Dispatch and EMT triage determine paramedic active involvement, which occurs in about a quarter of all dispatches. A relatively modest number of paramedics serve King County compared to most single-tier systems. This typically enables substantially more procedures per paramedic, which is why the current system generally supports the requirement of 12 intubations per year.
The medical model strongly influences personnel involvement and provides an external audit that requires the paramedic to relate constructively with a medical peer group. As such, the paramedic and physician can understand the continuum of care and the complex nature of some illnesses.
The use of advanced techniques, such as prehospital ETI can be mastered by EMS systems and aid in patient care so long as they’re supported by the framework of training, experience and continuous assessment.
We strongly believe the driving determinant of proficient prehospital ETI is the quantity and quality of training and clinical experience with an important emphasis on the volume of ETI experience. This formula would help explain why some systems appear more proficient with ETI, while others are not.
Thomas D. Rea, MD, is the medical director of the Emergency Medical Services Division of Public Health for Seattle and King County, Wash. He can be contacted at email@example.com.
Andreas Grabinsky, MD, is an assistant professor at the department of Anesthesiology at Harborview Medical Center in Seattle, Wash. He can be contacted at firstname.lastname@example.org.
Michael Damm, MICP, is a paramedic with King County Medic One.
Keir J. Warner, BS, is research coordinator at the department of Surgery at the Harborview Medical Center.
Michael K. Copass, MD, is the medical program director of Seattle Medic One.
- Warner KJ, Sharar SR, Copass MK, et al. Prehospital management of the difficult airway: A prospective cohort study. J Emerg Med. 2009;36:257-265.
- Fakhry SM, Scanlon JM, Robinson L, et al. Prehospital rapid sequence intubation for head trauma: Conditions for a successful program. J Trauma. 2006;60:997-1001.
- Bulger EM, Copass MK, Maier RV, et al. An analysis of advanced prehospital airway management. J Emerg Med. 2002;23:183-189.
- Adnet F, Jouriles NJ, Le Toumelin P, et al. Survey of out-of-hospital emergency intubations in the French prehospital medical system: A multicenter study. Ann Emerg Med. 1998;32:454-460.
- Helm M, Hossfeld B, Schafer S, et al. Factors influencing emergency intubation in the prehospital setting: A multicentre study in the German helicopter emergency service. Br J Anaesth. 2006;96:67-71.
- Gunning M, O’Loughlin E, Fletcher M, et al. Emergency intubation: A prospective multicenter descriptive audit in an Australian helicopter emergency medical service. Emerg Med J. 2009;26;65-69.
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- Wang HE, Yealy DM. How many attempts are required to accomplish out-of-hospital endotracheal intubation: Acad Emerg Med. 2006;13:372-377.
- Wang HE, Kupas DF, Paris PM, et al. Multivariate predictors of failed prehospital endotracheal intubation. Acad Emerg Med. 2003;10:717-724.
- Davis DP, Fisher R, Buono C, et al. Predictors of intubation success and therapeutic value of paramedic airway management in a large, urban EMS system. Prehosp Emerg Care. 2006;10:356-362.
- Garza AG, Gratton MC, Coontz D, et al. Effect of paramedic experience on orotracheal intubation success rates. J Emerg Med. 2003;25:251-256.
- Warner KJ, Carlbom D, Cooke CR, et al. Paramedic training for proficient prehospital endotracheal intubation. Prehosp Emerg Care. 2010;14:103-108.
Reprinted from JEMS Vol. 36, Issue 2 with the permission of Elsevier Inc., copyright 2011. For more information or to subscribe, visit www.jems.com.