Prehospital Care

Emerging Prehospital Protocols

Evolving EMS protocols impact the care patients receive before they present to the ED, so emergency physicians should stay up-to-date on these changes in order to offer high-quality integrated care.

Over the course of the past 5 decades, EMS has undergone drastic changes. The use of pneumatic, military anti-shock trousers (MAST Pants) has all but disappeared, and gone are the days of atropine in asystole and “bite block” insertion in seizing patients. The field has expanded to include multiple levels of training, ranging from medical first responders with 80 hours of training to paramedics who often hold associates or even bachelor’s degrees in prehospital care. Evolving EMS protocols impact the care that patients receive before they present to the ED. Therefore, it is crucial for emergency physicians to understand these changes to continue to provide a higher level of integrated care. This article will dive into several of these evolving protocols, including cervical collar and backboard utilization, airway management, ketamine, and the expanding role of EMS.

Cervical Collars/Backboards
The utilization of the rigid cervical collar and backboard date back to the EMT-Ambulance national standard curriculum developed in 1984. Providers were trained to immobilize the spine if there was even the slightest possibility of spinal cord injury. This training became the standard of care, and was further reinforced by courses such as Advanced Trauma Life Support and Prehospital Trauma Life Support.1

It is now widely accepted that rigid backboards still allow for significant movement of the spine and that ambulance gurneys provide a similar level of motion restriction without the risks of respiratory compromise, skin breakdown, and pain caused by backboards. In addition, the use of cervical collars is now being questioned.

Many EMS agencies are implementing “selective spinal motion restriction” using evidence-based guidelines based on NEXUS and Canadian C-Spine rules to determine which patients need spinal precautions based on mechanism of injury, age, and exam findings. Updated clinical decision pathways and protocols allow for more individualized implementation of spinal motion restriction in the prehospital environment and are better patient outcomes.

Non-Invasive Positive Pressure Ventilation (NIPPV) in EMS
Several studies have shown that early institution of CPAP in the prehospital environment has decreased the need for intubation by up to 60%, thereby reducing associated complications.2 CPAP and BiPAP have been available on Advanced Life Support units for some time, but CPAP is now being included on Basic Life Support and First Responder units.3

Early use of CPAP has been  shown to significantly reduce mortality rates not only in rural areas with longer transport times, but also in urban systems with shorter transport times. In a retrospective study of Kansas City Fire Department patients, early use of NIPPV showed a more than 50% decrease in mortality rate with no increase in scene or transport times.4

With a simpler and more cost-effective product design, prehospital NIPPV is becoming nearly universal and is changing the way that care is delivered in the prehospital setting.5

Prehospital Airways
The gold standard for definitive airway management remains endotracheal intubation. However, with effective alternatives and higher prehospital intubation failure rates,6 many systems have moved away from endotracheal intubation.

While there is little debate regarding the importance of airway management, continued debate exists over prehospital endotracheal intubation. Many publications support the notion that prehospital intubation correlates with higher incidence of mortality. One prospective study by Cobas et al. showed a 31% incidence of failed prehospital intubation, but found no difference in mortality between patients who were properly intubated and those who were not.7

Still other studies would suggest that intubation in the field is a vital component to patient survival. Miraflor et al. demonstrated early intubation of initially stable, moderately injured trauma patients reduces mortality by up to 85%.8

Intubation is a highly perishable skill, and with the advent of prehospital CPAP/BiPAP, fewer patients are being intubated and providers have less opportunity to maintain their skills. Additionally, intubation in the prehospital setting is usually performed in non-ideal conditions (low light, poor ergonomics) and without the use of paralytic agents.

Alternatives to endotracheal intubation originated in anesthesia, with the Laryngeal Mask Airway (LMA) developed in 1981. The dual-lumen Combitube was the first to have wide adoption into EMS beginning in 1986. While these were often viewed by many providers as “back-up” devices, studies performed over several decades have shown that successful placement rates are significantly higher for these devices than for endotracheal intubation.9 With improvements in both device design and technology, there is strong literature support for supraglottic devices10 including the King Tube and iGel, with studies demonstrating equal ventilation to that provided via ET tube.

Ketamine
Ketamine is being implemented in the prehospital setting for multiple indications intubation, behavioral emergencies, pain management, and procedural sedation.11 Ketamine provides both dissociative anesthesia and analgesic effects and has a long history of use, established safety record, and low cost.

Ketamine is being used in low doses as an alternative to opioid pain medications. Moderate doses are used for intubation or supraglottic airway induction with or without paralytic agents. High dose intramuscular ketamine is being used for excited delirium and violent patients.

Ketamine has a positive side effect of increasing bronchodilation and MAP and is also being used for patients with severe asthma. Recent studies suggest it may also be helpful in septic shock.12,13

Expanding Role of EMS
In many EMS systems,  new and specialized roles of prehospital providers are being  explored.  There has been an effort to increase the education of paramedics beyond the NREMT standard to include specialty certification in air and ground critical care transport and community paramedicine. Many states have critical care paramedic certification with further education on ventilator management, IABPs, sedation medications, and vasopressors. Community paramedics focus on public health and proactively visit patients to manage chronic medical conditions and prevent future 911 calls. The changes currently underway in prehospital medicine mirror the growth and development of emergency medicine itself.


References

1. Sundstrøm T, Asbjørnsen H, Habiba S, et al. Prehospital use of cervical collars in trauma patients: A critical review. J Neurotrauma. 2014;31(6):531–540.
2. Mal S, McLeod S, Iansavichene A, Dukelow A, Lewell M. Effect of Out-of-Hospital Noninvasive Positive-Pressure Support Ventilation in Adult Patients With Severe Respiratory Distress: A Systematic Review and Meta-analysis. Ann Emerg Med. 2014;63(5):600-607.
3. Thompson J, Petrie DA, Ackroyd-Stolarz S, Bardua DJ. Out-of-Hospital Continuous Positive Airway Pressure Ventilation Versus Usual Care in Acute Respiratory Failure: A Randomized Controlled Trial. Ann Emerg Med. 2008;52(2):232-241.
4. Cooper T, Munford C, Schuessler B, Witherspoon K, Allin DM, Murphy SO. 143 Emergency Medical Services Initiation of Non-Invasive Positive Pressure Ventilation in Urban Acute Congestive Heart Failure Patients. Ann Emerg Med. 2014;64(4):S51-S52.
5. Wayne M. Many Benefits of CPAP. JEMS. 2011;S1.
6. Garza AG, Gratton MC, Coontz D, Noble E, Ma OJ. Effect of paramedic experience on orotracheal intubation success rates. J Emerg Med. 2003;25(3):251–256.
7. Cobas MA, De la Peña MA, Manning R, Candiotti K, Varon AJ. Prehospital intubations and mortality: A level 1 trauma center perspective. Anesth Analg. 2009;109(2):489–493.
8. Miraflor E, Chuang K, Miranda MA, et al. Timing is everything: Delayed intubation is associated with increased mortality in initially stable trauma patients. J Surg Res. 2011;170(2):286–290.
9. Pennant JH, Walker MB. Comparison of the endotracheal tube and laryngeal mask in airway management by paramedical personnel. Anesth Analg. 1992;74(4):531–534.
10. Dörges V, Wenzel V, Knacke P, Gerlach K. Comparison of different airway management strategies to ventilate apneic, nonpreoxygenated patients. Crit Care Med. 2003;31(3):800–804.
11. Upchurch CP, Grijalva CG, Russ S, et al. Comparison of Etomidate and Ketamine for Induction During Rapid Sequence Intubation of Adult Trauma Patients. Ann Emerg Med. 2017;69(1):24-33.
12. De Kock M, Loix S, Lavand’homme P. Ketamine and Peripheral Inflammation. CNS Neurol Ther. 2013;19(6):403-410.
13. Pai A, Heining M. Ketamine. BJA Educ. 2007;7(2):59-63.

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