ALS and BLS, an Historical Perspective: Time for a New Paradigm!

In this issue of the journal, Stiell et al. publish an important paper about the efficacy of out-of-hospital advanced life support (ALS) interventions as contrasted with basic life support (BLS) interventions on patient outcomes, in this case specifically for patients with chest pain (1). This work must be interpreted very carefully as it was performed over 20 years ago, with different definitions of basic and advanced life support.

Indeed, to this day there are no standardized definitions of what is considered ALS as compared to BLS. Despite the presence of a standardized National EMS Scope of Practice Model in the US, the scopes of practice of the different “levels” of EMS clinicians educated and authorized to perform basic and advanced life support interventions are constantly evolving and often differ from one state to another, and sometimes even among counties within a single state. In other nations, including Canada where the study by Stiell et al. was performed, different definitions and scopes of practice apply.

The lines between ALS and BLS became blurred very early in the history of EMS with the introduction of automated external defibrillators (AEDs) into out-of-hospital systems (2,3). Prior to this time, defibrillation, a life-saving skill, could only be performed by advanced practitioners. By 1994, defibrillation by frontline EMTs was permitted in 36 US states, and, by 1997, in nearly all states (4).

In May 1992, 11 years before the results of the current OPALS study were presented at the Society for Academic Emergency Medicine annual meeting, Dr. Marion Lyver (co-author on the paper) invited several of us who were attending another SAEM meeting in Ontario to a consultation meeting on the future strategy for the Ontario EMS system. The consensus opinion was that the evidence base at the time supported only two out-of-hospital interventions as portending a survival benefit: early defibrillation and advanced airway management. The group’s recommendation was to build a system that included only AEDs and the Combitube as initial out-of-hospital professional skills. Any additional interventions would be studied to prove their benefit prior to implementation as “advanced” skills.

While “advanced” life support generally denotes the performance of more “invasive” procedures, such as the establishment of advanced airways or intravenous lines, from a patient-centered, outcomes-based viewpoint, there are relatively few out-of-hospital interventions that are critical and time-sensitive. Treatments that can be immediately life, limb, or brain saving include:

• Defibrillation

• Epinephrine for anaphylaxis

• Naloxone for reversal of opioid overdose

• Direct pressure/tourniquet for external hemorrhage control

• Airway obstruction reversal

• Glucose for hypoglycemia

• Oxygen for hypoxemia

After the introduction of the AED, several other “advanced” skills moved to the realm of the “basic” EMS clinician. In some cases these transitions were due to advances in technology (as was the case with the AED, and later with various supraglottic airways (5)), and in others due to the recognition that tasks such as using a glucometer, administering nitroglycerin and aspirin for chest pain, and treating anaphylaxis with epinephrine auto-injectors were being performed routinely by laypersons with no medical training whatsoever. Medical directors noted it made little sense to prohibit EMTs from using the very same glucometers or epinephrine auto-injectors that patients without certification in professional competencies commonly use on themselves.

From the Canadian perspective, the national scope of practice permits BLS clinicians to deliver “symptom-relief” medications including aspirin and sublingual nitroglycerin for chest pain, oral dextrose and intramuscular glucagon for hypoglycemia (with glucometry in the BLS scope of practice), intramuscular or intranasal naloxone for suspected opioid overdose, inhaled salbutamol for bronchospasm, intramuscular ketorolac for pain, oral acetaminophen and ibuprofen for pain or fever, and intramuscular epinephrine for anaphylaxis.

This “symptom relief” program, which was initiated at the same time as OPALS and continues to this day, complicates the findings of Stiell’s study in that 12% of patients being managed in the BLS arm of the study received sublingual nitroglycerin, and 12.5% received oral aspirin – medications that were considered “ALS” for study purposes. Very few patients in the ALS arm received interventions that we still consider ALS today, such as intubation (12 patients total, or 0.12%), IV fluid boluses (3.5%), or IV medications of any kind (7.4%). Conversely, almost exactly half of the patients in the ALS arm received oral aspirin, and over half received sublingual nitroglycerin from ALS personnel. Additionally, roughly half of the patients in both arms received nitroglycerin prior to EMS arrival. Thus, while the conclusion of benefit in the ALS arm held at the time of study, by today’s admittedly still blurry ALS/BLS distinctions, it appears that most of the survival benefit came from interventions that are presently considered BLS. One might argue that the study conclusions, while valid in the early 2000s, no longer hold inasmuch as the interventions that appear to have provided the majority of the survival benefit are now permitted in most BLS systems, and are no longer considered ALS.

While the current study was quite elegant in design, there are some additional important limitations. The authors note that “Randomization was not possible because paramedics considered it unethical to randomly withhold potentially lifesaving procedures for patients.” This seems to be more of a belief than a reality. Further, the paper discusses patients “not requiring advanced life support interventions,” but we suggest this could be more accurately described as patients not “receiving” ALS interventions, as there is no criterion standard for the requirement. Finally, the investigators conclude that “Results from this study suggest that community emergency medical services have the potential to save a large number of additional lives through the use of ALS programs, particularly for patients diagnosed with myocardial infarction,” and that ALS was “associated with significantly decreased mortality for chest pain patients.” As this was not a randomized controlled trial, the emphasis on association rather than causation is appropriate, and calls into question the conclusion that ALS programs have the potential to save a large number of additional lives.

Although the lack of a mature EMS system (as was the case at the time in Ontario) is challenging in some ways, it is likely much more straightforward to build a science-based infrastructure from the ground up than to inherit the complexities of an existing system and strive to implement changes that improve outcomes. In the US, some scientists suggest it would be unethical to study adult endotracheal intubation in a prospective randomized trial in today’s world, despite no clear evidence that this technique is superior to bag-valve-mask ventilation from a survival perspective. Of note, Gausche et al. demonstrated in a prospective randomized trial published in 2000 that pediatric intubation did not improve survival or neurologic outcomes when compared with effective bag-valve-mask ventilation (6). This in turn led to the removal of this skill in Los Angeles and Orange Counties and later from the entire State of California. While the data were clear, the removal of this “advanced” life support skill proved challenging. Paramedics, who had long performed pediatric intubations and were understandably concerned about losing their ability to initiate this intervention, vigorously challenged EMS medical directors.

Since the time of the OPALS study, ALS and BLS have evolved. There are numerous political and financial influences for deeming and designating agencies, vehicles, personnel, and levels of care to be one or the other. Our true focus should be on patient-centered care and using evidence to inform interventions that lead to improved patient outcomes. Such outcomes extend beyond morbidity and mortality to also include timely relief of suffering from pain and shortness of breath. Another point to consider, again from a patient-centered standpoint, is that disturbing terminology has crept into the out-of-hospital lexicon: after a patient is evaluated on the scene by an ALS practitioner and determined not to need ALS care, we will sometimes hear the phrase “downgrade to BLS.” We wonder how it feels for patients who have perceived acute emergencies to be told they are being “downgraded.” People usually prefer to be upgraded!

As novel integrated systems of care like community paramedicine emerge, we should revisit the traditional ALS versus BLS category divide, which has become increasingly muddled and influenced by political and financial pressures. Our focus should be on patient-centered, outcomes-based EMS professionals who can perform all immediately life and limb saving interventions, with layered access to higher levels of care in the rare cases where such would make a difference, e.g., dispatching an advanced practice paramedic or EMS physician to the scene. Rather than “ALS” or “BLS” to describe a responding EMS vehicle, we can simply say “ambulance,” and call the EMS professional staff “paramedics” and “EMTs” as appropriate.

If we could build an EMS system from the ground up today, we would not label treatment as ALS or BLS, but rather apply a patient-centric focus and the use of interventions with proven safety and efficacy in the out-of-hospital setting. Ambulances are not “ALS” or “BLS”; rather, they are the specialized vehicles used to transport patients. Let’s just call them ambulances. Likewise, BLS and ALS as labels for professional EMS staff can at present have ambiguous meanings, both in the US and elsewhere. A more common and easily understood nomenclature would be to simply say paramedic and EMT. The terms ALS and BLS no longer have helpful precise meaning and are therefore ready to be moved to the category of “historical interest only.” It is time for a new paradigm!

Acknowledgments

The authors thank Dr Russell MacDonald for his assistance regarding current BLS scope in Canada, and Dr Steven J. Davidson for his thoughtful review of this editorial.