Years of R&D and millions of dollars have gone into advancing today’s prehospital care system, from potent medications to laryngoscopes and intraosseous drills to complicated cardiac arrest algorithms. But studies continue to surface bringing our supposed advances into question.
The most recent study, published by Sanghavi et al in JAMA Internal Medicine last November, has upset the prehospital community by claiming basic life support may lead to better outcomes than advanced life support for out-of-hospital cardiac arrest. The article has drawn criticism from JAMA , The New York Times , community forums and the Journal of EMS . The community has been reluctant to accept the study’s conclusions, asking how advanced cardiac life support could lead to worse outcomes than basic life support.
As with other studies, the key outcome measures were ROSC and survival to discharge at different time points. Many papers, including Sanghavi’s, revealed higher rates of ROSC with treatment by ALS crews, but lower rates of survival to discharge compared to those treated with BLS crews. How much weight should we give this article, though?
While it is tempting to dismiss Sanghavi et al’s findings, they are in line with past research. The New York Times article says “the evidence is compelling. Advanced life support does not seem to provide any benefits…. and it’s often associated with worse outcomes .” They conclude their January article with “Sometimes, more is even harmful. When our policies and care ignore these facts, we all suffer.” Numerous studies have even corroborated Sanghavi’s findings, showing the lack of efficacy of out-of-hospital advanced airway use [6,7], vasopressin , IV drugs  and even ALS care as a whole . The study gained national scale using ICD-9 codes from Medicare data, giving them a sample size almost six times that of the Canadian OPALS study in 2004 , often regarded as the principal study concerning ALS versus BLS for out-of-hospital cardiac arrest.
Soon after Sanghavi’s article came out, Callaham provided JAMA Internal Medicine with an invited commentary, calling the data “provocative” and admitted the study’s strength was the sample size and its generalizability . Sanghavi’s article is a large, robust study, corroborated by others, and whose authors worked hard to control for every variable they could.
So what’s in question?
The main shortcomings of Sanghavi’s, and others’ studies cited by critics include the authors’ reliance on complex assumptions, its method of data selection, and the fact that they use data comparing EMS systems, as opposed to specific treatments . In fact, most major studies with similar conclusions — like the Taiwan study in 2007 and 2004 OPALS study — also compare provider groups, instead of specific treatments. Treatment guidelines and scope of practice are not synonymous with actual care provided, and therefore making conclusions about the treatments themselves when they are not directly observed is subject to many complex variables and bias. Properly studying specific treatments and compliance requires direct supervision and randomized control trials, both of which are difficult in EMS. Since treatment occurs outside the hospital in a small, moving vehicle, researchers, physicians, and EMS leaders rarely have the opportunity to oversee the actual clinical practice of EMS providers. This leaves only ICD-9 codes, billing forms and documentation for quality improvement and assessment, which is subject to bias and confounding variables, a shortcoming to the methodology of these studies.
Since the majority of articles denouncing ACLS’s efficacy are retrospective and not randomized, their results are only generalizable to providers, not treatments and causative relationships are hard to establish. So it’s unclear if the treatments are the problem, or the way providers apply them. If the treatments themselves are worthwhile and boost survival, we need to focus on getting providers to properly apply them through education, training and compliance.
A 2006 study from Scliopou et al. in Prehospital Emergency Care managed to monitor compliance with epinephrine use in ACLS and found a compliance rate of 14% , associated with a decrease in ROSC. This study demonstrates both the potential lack of compliance by EMS crews, and illustrates that studies marking care as “ALS” as Sanghavi did might have significant limitations, as 86% of the ALS crews did not perform ACLS according to guidelines.
The Bottom Line
In addition to compliance and efficacy of ALS interventions, adding intubations, rhythm interpretation, drugs, etc. likely worsen the quality of the foundation of resuscitation – quality, uninterrupted chest compressions. Rittenberger et al. found the quality and quantity of BLS decreases with increased resuscitation complexity. Individually studied ALS interventions have rarely shown to be detrimental per se. Rather, they just do not affect outcomes at all. ALS care is only likely bad if it takes away from BLS care, which has been shown to be helpful when its quality and quantity are maximized 
The New York Times article mentions what ALS treatment “may be doing is slowing things down in the field, distracting people from the useful basic life support measures, and delaying the time until a patient can get to the hospital. It’s hard to not do more if we can, though.”
The authors of “BLS vs. ALS Patient Outcomes After Out-of-Hospital Cardiac Arrest” in the Journal of EMS corroborated the point from the New York Times, saying “evidence repeatedly points to survival being tied to coordination of care, such as ‘pit-crew CPR’… requiring advanced training and repeated practice, regardless of the bundle of care being used.”
The final links of American Heart Association’s chain of survival – early advanced care and definitive care – should add to the previous links, without detracting from their quality or quantity. “Without a system approach to care, without the infrastructure ensuring aspects of care are done in synchrony in EMS, even a physician on an ambulance will fail the patient,” Mark Cichon, DO explained, EMS Medical Director at Loyola University and Regional Physician Advisor for Air Methods.
“If any single point in the process is functioning to the best of its ability, but in a ‘process vacuum’ in relation to the rest, then the system is going to fail the patient,” he said. If each link in the chain of survival is done carefully, each coming after the other, ALS care is likely to be beneficial. Proper ALS care is an expansion of BLS care, not a replacement.
Joe Beirne, DO, EMS Medical Director at Missouri Baptist Medical Center reiterates ALS is unlikely to be successful without a solid BLS foundation. “Our BLS skills will always be the building blocks on which our ALS skills are built and expanded,” he said.
“We went from bicarbonate, calcium chloride, high dose epinephrine, stacked shocks, to amiodarone and vasopressin…..and what did we learn? High quality, uninterrupted CPR, without advanced airway techniques or medications, was more effective at restoring circulation with survival to discharge and good neurologic outcome, than all of the other techniques we had used for years.”
Sanghavi’s study, or any other, is certainly not the nail in the coffin on ALS vs BLS care. Because it is impossible to have a perfect study, and near impossible to have a powerful randomized controlled trial in emergency cardiac care, we may never have a solid answer. But like other abandoned, attempted improvements in prehospital cardiac care (bicarbonate, the precordial thump, pacing asystolic patients, vasopressin, and so on) the efficacy of our prehospital interventions should constantly be questioned and improved, even if it means moving away from advanced techniques once thought to be effective.
Photo by DavidD (Flickr)
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