Michael Gerber is a featured speaker at EMS World Expo, Sept. 15–19 in Las Vegas. Visit EMSWorldExpo.com.
Nine years ago, in its comprehensive report on EMS in the United States, the Institute of Medicine (IOM) said, “The prehospital emergency care system provides a stark example of how standards of care and clinical protocols can take root despite an almost total lack of evidence to support their use.”1
The report found that half of EMS interventions lacked an adequate evidence base (or had no evidentiary support at all), compared to only 5% that were supported by high-quality evidence. The IOM concluded that as a result, EMS systems in this country often operate “blindly” when addressing issues such as system design, resource deployment and clinical interventions.
Since then, many EMS leaders have been advocating for evidence-based clinical interventions in the prehospital setting.
In 2008, the National Highway Transportation Safety Administration convened a meeting of EMS stakeholders to discuss the development of national evidence-based guidelines (EBGs) for EMS. Six years later, the first national evidence-based guidelines were released, including guidelines for prehospital pain management,2 pediatric seizures3 and external hemorrhage control.4
The overarching goal of the national EBG development process has been to transition to the use of high-quality evidence—rather than consensus or expert opinion—as the basis for clinical guidelines in EMS.5 Ongoing EMS research is critical to developing the evidence base necessary to support the use of both new and existing clinical interventions in the prehospital setting.
First Do No Harm
One of the guiding maxims for all healthcare providers is to “first do no harm.” The sad truth, however, is that several clinical interventions employed as standard practice in EMS have been found harmful to patients. Military anti-shock trousers (MAST) are a prime example. Adopted by EMS in the 1970s under the premise that they temporarily reversed hypotension in trauma patients, they were removed from most ambulances after research in the late 1990s showed they did not improve patient outcomes and may even have increased mortality.6
More recently, research on endotracheal intubation in the prehospital setting has generated intense debate in EMS regarding the potential harm from performing advanced airway management in the field.7,8 Even oxygen administration—long the mainstay of prehospital care for a variety of medical conditions—has fallen under suspicion due to the potential harm from free radicals and hyperoxia.9 A recent study found high-dose oxygen may harm some patients presenting with ST-elevation MI.10 This study echoes previous research that questioned the benefit of oxygen administration for patients suffering from myocardial infarction.11
Even if not harmful themselves, clinical interventions that lack proven efficacy in EMS may still lead to suboptimal care for patients by distracting from or delaying the application of other therapies that actually confer benefit. The evolution of prehospital CHF treatment over the past decade provides a good example of how evidence-based interventions have come to supplant traditional, but unproven, therapies. Lasix, which has never been proven effective in the prehospital setting, has gradually fallen out of favor.12 In its place, the prehospital application of continuous positive airway pressure (CPAP) and aggressive nitroglycerin administration have been proven to reduce mortality and intubation rates.13,14 EMS research has thus already played an important role in ensuring better outcomes for patients suffering from acute CHF exacerbation.
Prehospital Research Challenges
Research in the prehospital setting faces several challenges. Researchers have relatively little control over patient recruitment, as EMS patients call 9-1-1 at a time and place of their choosing. As a result it is more difficult, if not impossible, for EMS researchers to craft an ideal study sample. Frequent EMS users in particular tend to overrepresent certain segments of the population.16
EMS research also presents ethical barriers not always present in other contexts. For example, obtaining informed consent from patients in the prehospital setting may not be possible. Consequently—and despite the lack of evidence for much of the EMS “standard of care”—deviating from accepted interventions under an exception from informed consent can present a difficult ethical quandary.17 In the past year, media attention surrounding a clinical trial to examine the efficacy of epinephrine in cardiac arrest has questioned whether withholding the medication (obviously without a patient’s permission) would cause harm.18 A recent study, however, found that patients themselves may be highly accepting of exceptions from informed consent.19 The same cannot be said for prehospital providers, as only 30% in one survey agreed with enrolling patients in a study without their informed consent.20
These ethical issues make it more difficult for EMS researchers to perform well-constructed clinical studies in the field. They also often add to the expense and length of research trials. As an example, agencies in Denver, Pittsburgh and Richmond (VA) are currently participating in a study funded by the Department of Defense to examine the prehospital use of blood plasma in trauma patients. To conduct the study under an exception from informed consent, it was necessary for the researchers and EMS agencies to spend several months reaching out to community members through the media and conducting public information sessions. These outreach efforts were required in order to give members of the community an opportunity to opt out of the study.
Adequately controlling for extraneous variables is also problematic in EMS research. EMS patients often present with a variety of concomitant health issues, each of which may contribute differently to, or even supersede in terms of clinical importance, the patient’s primary complaint. Even if a patient’s underlying health problem can be isolated, the severity of each patient’s condition may also vary greatly. This is particularly problematic when studying the relative efficacy of interventions that are generally reserved for more critical patients, e.g., endotracheal intubation.
Similarly, the diversity of EMS systems is also an issue for EMS research. To obtain a representative sample, it may be necessary to employ multiple study sites in different jurisdictions, each of which is likely to be served by different EMS systems, each with its own particular system design and deployment model. Even within the same EMS system, patients may receive different levels of first response and transport care (first responder, BLS or ALS). Response times are also likely to vary, especially between urban and rural communities.
Finally, the prehospital setting is anything but a controlled environment. On-scene interventions can take place anywhere from a tiny hall bathroom to the middle of a busy highway. Several factors, including patient presentation and scene safety issues, can influence whether patient care is provided on the scene or for how long. Interventions in the back of a moving ambulance are necessarily constrained in terms of both space and available resources, especially compared to the hospital setting.
Conducting a retrospective trial—using existing data collected from previous incidents—can sidestep some of these research challenges while still providing a wealth of useful information. Similarly, sophisticated statistical analyses can be used to minimize extraneous influences and compensate for imperfect study samples. That said, prospective clinical trials and proper controls are still considered the “gold standard” in medical research. For this reason, retrospective trials are often an initial step prior to undertaking a randomized, prospective clinical trial.
These challenges have two important implications for research in EMS. First, because the prehospital setting differs in many important respects from other research settings, researchers must account for multiple different and possibly confounding variables. Second, research conducted outside the prehospital setting (e.g., in the hospital) may not be easily generalizable to EMS due to the presence of these confounding factors. For these reasons, it is important that EMS researchers make an effort to adapt clinical research methods to the prehospital setting, even if it proves more costly than simply conducting hospital-based research.21
Many EMS systems already collect a large volume of information during their daily operations. These data include information regarding incidents (type of call and location), patients (identifying information and medical history), clinical presentations (symptoms and vital signs) and interventions provided by EMS. In most jurisdictions these data are reported to national and state databases such as the National EMS Information System (NEMSIS).
For the most part, however, EMS systems have not yet been able to translate this wealth of information into actionable clinical research.26 Part of the reason is that the data they collect is often unreliable or incomplete. EMS providers are inconsistent when it comes to information-gathering. Even when relevant information is obtained, it may be incorrectly entered into a patient care report. In any case, not all jurisdictions collect or report the same data elements. Consequently, data collection by itself is not enough to support EMS research; EMS systems must also strive to ensure good data quality.27
The biggest problem with the data currently collected by EMS systems is that it frequently lacks information regarding patient outcomes.28 As a result, data analysis in EMS is often focused on prehospital endpoints (such as return of spontaneous circulation following cardiac arrest) rather than clinical outcomes (such as survival to discharge and neurologic outcome). In order to support quality EMS research, EMS systems must work with hospitals to implement data-sharing that links EMS interventions to relevant patient outcomes. For example, electronic health information exchanges that link EMS and hospital records may allow EMS researchers to more easily obtain and analyze outcomes data.
How EMS Providers Can Contribute to Research
Conducting a research project in EMS can seem intimidating, but it doesn’t have to be. Many published studies first start as small, internal quality improvement efforts, often to help internally validate the results of outside research.38 While these internal efforts may not yield publishable results, they can still promote improvements within a system. Additionally, they can be shared locally with other agencies or at regional and national conferences. Finally, they can serve as the first step toward a more robust research project that can be published in a peer-reviewed journal.
The elimination of Lasix from the medical protocols of our own EMS agency is one example of how a small-scale study can inform EMS practice. In 2013 many EMS systems across the country were already in the process of eliminating Lasix from their medication formularies. In addition to its questionable efficacy in the prehospital setting, there was also concern regarding the ability of EMS providers to accurately discern the underlying cause of a patient’s pulmonary edema, or even distinguish between CHF and other respiratory presentations (such as asthma, COPD or pneumonia).39
Instead of immediately changing our protocols or ignoring the outside research, we decided to conduct an internal study to see if the results of the published studies held true in our agency. This would not only help us to determine how to interpret the research, but also allow us to translate the research in a way that EMS practitioners in our agency could relate to and accept—overcoming the inertia that often compels EMS providers to continue past practices despite mounting evidence against them.
First we reviewed every patient care report from the previous year that documented the administration of Lasix. Next we tasked our medical director (who works in the emergency department of our primary receiving hospital) to match each of those PCRs with a hospital patient record for the same episode of care. Finally we looked at whether each patient’s hospital record included a diagnosis of CHF. What we found was that about half the patients to whom our providers administered Lasix over the year were not ultimately diagnosed with CHF. On the basis of that finding, and the potential harm from administering Lasix to patients not in fluid overload, we decided to remove Lasix from our ambulances.
For this small study, we did not perform any formal statistical analysis or submit to an institutional review board process. Moreover, our results were neither publishable nor generalizable to other EMS systems. Nevertheless, the results allowed our agency to make an informed decision regarding a change to our treatment protocol for CHF patients. In addition, the ability to present concrete data to our providers helped convince many who had initially resisted the proposed change.
Conducting a research study for the purpose of publishing results can be a bit more challenging, but there are plenty of opportunities. One barrier is often financial: Most EMS agencies do not prioritize (or even contemplate) research when setting budgets or hiring staff. While large research grants are often limited to major research institutions and universities, funding opportunities for smaller studies exist. In 2013, for example, the Alliance for Emergency Medical Education and Research (AEMER) in Virginia awarded approximately $20,000 in research grants to fund two different EMS-related research projects in the state.
One of the projects funded by AEMER is a study by our agency on the feasibility and safety of a protocol that would permit EMS to transport patients who do not require emergency care to alternative destinations such as medical clinics and urgent care centers. The AEMER grant has allowed our agency to defray the costs of developing an alternative destination protocol, training our providers and analyzing the results. The results of our study are forthcoming, and we plan to present our findings at this year’s Virginia EMS Symposium.
Taking on a true research project was a novel endeavor for our EMS agency, but we made it more feasible by turning to local partners for assistance. The CEO of our local receiving hospital wrote a letter of support during the grant application phase. We also enlisted the help of local emergency and primary care physicians to evaluate the results. In addition, part of our grant funding consists of a small stipend for a graduate student to assist with statistical analysis, often the most intimidating and challenging part of a research study.
There are plenty of resources for EMS researchers who require assistance with statistical analysis. Local health departments often employ epidemiologists or other public health workers who have experience with statistics. Colleges and universities, especially those with medical schools and public health programs, usually also have students looking for research projects to work on.
More generally, healthcare researchers are often willing to help less experienced colleagues at each stage of the research process. Even if a major research institution is not accessible, doctors in the local emergency department often have research experience, or at least an interest in pursuing research. Partnering with other EMS agencies on research projects is also an option.
Areas for Research Airway management—The safety and efficacy of advanced airway management by EMS remains under question, while the administration of high-flow oxygen is becoming increasingly suspect for certain conditions. Additional research in the prehospital setting will be necessary to inform any changes to existing indications for these interventions.
Cardiac arrest—In the context of out-of-hospital cardiac arrest, important EMS research questions abound. Recently the effectiveness of mechanical CPR devices has been the subject of much debate. Several research studies have found the devices improve end-organ perfusion and increase return of spontaneous circulation.29 Large clinical trials, however, have concluded the devices do not provide a benefit in terms of survival to discharge and neurologic outcome.30–32 Similarly, researchers are still searching for evidence of increased survival from the administration of cardiac medications during cardiac arrest.33,34 The same is true for the use of impedance threshold devices, though researchers have recently presented evidence that ITDs may improve survival to discharge if high-quality CPR is performed.35,36 More study will likely be required to confirm their findings.
TXA—Research in the prehospital setting is also needed to support the newest clinical interventions in EMS, such as the administration of tranexamic acid (TXA) to control major traumatic hemorrhage. While TXA has been demonstrated to improve survival in the military setting, the evidence for its use in civilian trauma is very limited.37 No published research has examined the use of TXA in a civilian EMS system.
Therapeutic Hypothermia and the Limits of Hospital Research
The implementation of therapeutic hypothermia for patients who have suffered cardiac arrest provides a recent and potentially cautionary example of the limitations of using hospital-based research as the basis for EMS interventions. Studies conducted in the hospital setting have shown that post-resuscitation therapeutic hypothermia is associated with improved survival and neurologic outcome.22,23 Studies conducted in the prehospital setting, however, have failed to demonstrate any added benefit from commencing patient cooling prior to arrival at the hospital. In other words, delaying the initiation of hypothermia until a patient arrives at the hospital may not have an impact on clinical outcome.24 More worrisome is the potential for harm from prehospital cooling (often achieved through rapid administration of chilled IV fluids), which has been associated with an increased incidence of pulmonary edema and greater administration of diuretics during the first 12 hours of hospitalization.25
The Reimbursement Link
The proven efficacy, or lack thereof, of clinical interventions in EMS may ultimately have profound implications for EMS reimbursement. Since 2012 Medicare, the largest payer for EMS services, has adjusted reimbursements to hospitals on the basis of a value-based purchasing (VBP) program that takes into account factors such as patient experience, outcomes and efficiency. A similar program will be applied to physician reimbursement starting in 2015. It is probably only a matter of time until value-based purchasing is extended to EMS.15 Research will ultimately prove crucial to demonstrating the value EMS provides to both patients and the healthcare system.
If EMS is to continue its professional evolution and become a respected member of the healthcare community, it is critical that prehospital clinical decisions be made on the basis of good research. The next step will require that more EMS providers become actively engaged in conducting EMS research—in order to supplement the small cadre of academic EMS researchers and also bolster the credibility of EMS as a stand-alone profession that can contribute to its own clinical development.
References 1. Institute of Medicine. Committee on the Future of Emergency Care in the United States Health System. Emergency Medical Services: At the Crossroads. Washington, DC: National Academies Press, 2006. 2. Gausche-Hill M, et al. An evidence-based guideline for prehospital analgesia in trauma. Preh Emerg Care, 2014; 18(s1): 25–34. 3. Shah MI, et al. An evidence-based guideline for pediatric prehospital seizure management using GRADE methodology. Preh Emerg Care, 2014; 18(s1): 15–24. 4. Bulger EM, et al. An evidence-based prehospital guideline for external hemorrhage control: American College of Surgeons Committee on Trauma. Preh Emerg Care, 2014; 18(2): 163–73. 5. Lang ES, et al. A national model for developing, implementing, and evaluating evidence-based guidelines for prehospital care. Acad Emerg Med, 2012; 19(2): 201–9. 6. Bledsoe BE. EMS Myth #1: Medical Anti-Shock Trousers (MAST) autotransfuse a significant amount of blood and save lives. EMS World, www.emsworld.com/10325078. 7. Wang HE, Yealy DM. Out-of-hospital endotracheal intubation—it’s time to stop pretending that problems don’t exist. Acad Emerg Med, 2005; 12(12): 1,245. 8. Fouche PF, et al. Airways in out-of-hospital cardiac arrest: Systematic review and meta-analysis. Preh Emerg Care, 2014; 18(2): 244–56. 9. Gandy WE, Grayson S. More Oxygen Can’t Hurt…Can It? EMS World, www.emsworld.com/10915304. 10. Stub D. AVOID Study: Air Versus Oxygen in ST-Elevation MyocarDial Infarction. Paper presented at AHA Scientific Sessions, www.cardiosource.org/Science-And-Quality/Clinical-Trials/A/AVOID.aspx. 11. Wijesinghe M, et al. Routine use of oxygen in the treatment of myocardial infarction: systematic review. Heart, 2009; 95(3): 198–202. 12. Grayson S, Gandy WE. CHF Treatment: Is Furosemide on the Way Out? EMS World, www.emsworld.com/10712890. 13. Williams TA, et al. Prehospital continuous positive airway pressure for acute respiratory failure: a systematic review and meta-analysis. Preh Emerg Care, 2013; 17(2): 261–73. 14. Mattu A, Lawner B. Prehospital management of congestive heart failure. Heart Fail Clin, 2009; 5(1): 19–24. 15. Zavadsky M. Get Ready for Value-Based Purchasing. EMS World, www.emsworld.com/11446135. 16. Knowlton A, et al. Patient demographic and health factors associated with frequent use of emergency medical services in a midsized city. Acad Emerg Med, 2013; 20(11): 1,101–11. 17. Burns J. Seeking consent from those who cannot answer: New light on emergency research conducted under the exception from informed consent. Crit Care Med, 2015; 43(3): 710–1. 18. Smith R, Hill G. Heart Patients to Be Given Placebo by Paramedics in Controversial Trial. The Telegraph, Aug. 12, 2014, www.telegraph.co.uk/health/healthnews/11028692/Heart-patients-to-be-given-placebo-by-paramedics-in-controversial-trial.html. 19. Dickert NW, et al. Patients’ perspectives of enrollment in research without consent: The patients’ experiences in emergency research-progesterone for the treatment of traumatic brain injury study. Crit Care Med, 2015; 43(3): 603–12. 20. Jasti J, et al. EMS provider attitudes and perceptions towards prehospital EFIC research. Abstract. Preh Emerg Care, 2015; 19(1): 142–3. 21. Hatez S. The Beneficial Failure of the FAST-MAG Trial. EMS World, www.emsworld.com/11519792. 22. Hypothermia After Cardiac Arrest Study Group. Mild therapeutic hypothermia to improve the neurologic outcome after cardiac arrest. New Eng J Med, 2012; 346(8): 549–56. 23. Bernard SA, et al. Treatment of comatose survivors of out-of-hospital cardiac arrest with induced hypothermia. New Eng J Med, 2002; 346(8): 557–63. 24. Bernard SA, et al. Induction of therapeutic hypothermia by paramedics after resuscitation from out-of-hospital ventricular fibrillation cardiac arrest: A randomized controlled trial. Circ, 2010; 122(7): 737–42. 25. Kim F, et al. Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial. JAMA, 2014; 311(1): 45–52. 26. Goodwin J. Delivering on the Data: More Than 10 Years In, Where Does NEMSIS Stand? Best Practices in Emergency Services, http://info.zolldata.com/Portals/152170/docs/delivering%20on%20the%20data%20%20best%20practices%20in%20emergency%20services.pdf. 27. Garza A. What Is Data Good For? EMS World, www.emsworld.com/10977730. 28. Mears G, Gunderson M. A seamless exchange. J Emerg Med Serv, 2014 Jan; Suppl: 27–31. 29. Westfall M, et al. Mechanical versus manual chest compressions in out-of-hospital cardiac arrest: a meta-analysis. Crit Care Med, 2013, 41(7): 1,782–9. 30. Perkins GD, et al. Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial. Lancet, 2015 Mar 14; 385(9,972): 947–55. 31. Wik L, et al. Manual vs. integrated automatic load-distributing band CPR with equal survival after out of hospital cardiac arrest. The randomized CIRC trial. Resuscitation, 2014; 85(6): 741–8. 32. Rubertsson S, et al. Mechanical chest compressions and simultaneous defibrillation vs conventional cardiopulmonary resuscitation in out-of-hospital cardiac arrest: The LINC randomized trial. JAMA, 2014; 311(1): 53–61. 33. Lin S, et al. Adrenaline for out-of-hospital cardiac arrest resuscitation: A systematic review and meta-analysis of randomized controlled trials. Resuscitation, 2014; 85(6): 732–40. 34. Neumar RW, et al. Part 8: Adult advanced cardiovascular life support: 2010 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation, 2010; 122(18 suppl 3): S729–S767. 35. Aufderheide TP. A trial of an impedance threshold device in out-of-hospital cardiac arrest. New Eng J Med, 2011; 365(9): 798–806. 36. Yannopoulos D, et al. The effect of CPR quality: A potential confounder of CPR clinical trials. Abstract presented at AHA Resuscitation Science Symposium. Resuscitation, 2014; 130(s2): A9. 37. Cole E, et al. Tranexamic acid use in severely injured civilian patients and the effects on outcomes: a prospective cohort study. Ann Surg, 2015 Feb; 261(2): 390–4. 38. Erich J. Conducting Research, Getting Published. EMS World, www.emsworld.com/10364695. 39. Jaronik J, et al. Evaluation of prehospital use of furosemide in patients with respiratory distress. Preh Emerg Care, 2006; 10(2): 194–7.
Mario J. Weber, JD, MPA, NRP, is a paramedic and field training officer at the Alexandria (VA) Fire Department, where he focuses on quality management, advanced training and evidence-based protocol development. He also reviews quality assurance cases and advises on the ALS training program for the Montgomery County (MD) Fire and Rescue Service. Reach him at firstname.lastname@example.org.
Michael Gerber, MPH, NRP, is an instructor, author and consultant in Washington, DC. He is also a paramedic with the Bethesda-Chevy Chase Rescue Squad and previously worked as an EMS supervisor for the Alexandria (VA) Fire Department. Gerber has experience as an EMS educator and quality management coordinator and has presented original research at state and national EMS conferences. Reach him at email@example.com.