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Evidence-Based Medicine

Updated: Sep 4, 2021

Currently I teach students at two different universities, The University of Maryland and Indiana Wesleyan University, but have taught at two additional universities previously - all graduate level. One of the most common critiques I offer students is the direction not to use resources written for consumers, but rather, to get into the graduate #library and utilize scholarly literature. Rarely are students doing this; most of them sharing that they find the research library difficult to navigate. I could not appreciate my own alma mater anymore, Frontier Nursing University, as they are dedicated teaching their students how to navigate the research library at the onset of each program.


If anything, students seem to heavily utilize UpToDate. While not a horrible resource and certainly convenient for clinicians who often struggle to keep up to date with new research and advances in care, UpToDate is in fact, expert opinion or a synthesis of the evidence via an editorial staff. This largely eliminates critical thinking by the clinician and an interpretation from their own expertise and experience. It means they are performing based on a script written by someone else with potentially a very different mindset towards care. The university in which I teach doesn't allow faculty access either so students can essential offer whatever they want within their papers and I have no way of evaluating their data.



It frustrates me to hear students and especially clinicians say, "science proves," because this statement is a complete oxymoron. Science is about inquiry; it's about discovery, it asks questions, and stretches one's current understanding. There is no end point that would amount to proof. What I find disheartening is the amount of practitioners - in all disciplines of healthcare - who really haven't the understanding of how to break down a research article and critically evaluate its merit and methodology, identify weaknesses and strengths, and appreciate that this one publication is a mere drop in the bucket within any particular area of science. The more you learn, the more you recognize you don't know. A literature review on any particular area of healthcare takes years to accomplish so feeling or claiming expertise after having completed a six week course or after having written a single paper for a course is profoundly naive, yet students routinely claim superior knowledge to their clients in essentially all facets of care.


Take for example the student who works through the third module of my Advanced Pathophysiology course on #immunology, specifically #immunizations, and shares freely how intimidating this area of science is but then can argue that parents who question the current vaccine schedule are negligent and ignorant. Graduate students aren't asked to read scholarly papers on the utilization, implementation, or effectiveness of vaccines, nor are they reading about their consequences, side effects, public health implications, cost analysis, bias, or questioning theories. Largely, university programs demand students think critically in every aspect of study except with regards to vaccines. Here, we don't ask questions, we don't even dig into the literature; rather, we proceed with blind faith. This is contrary to scholarly work. Admittedly, asking questions here may raise suspicion, can get faculty removed from their position, and even cause practitioners to lose their license.


The Principles


The principles of evidence-based medicine were developed to redress problems with the traditional foundation of medical practice, which was an "understanding of the basic mechanisms of disease coupled with clinical experience. The latter is epitomized by the individual authority ('expert'), or, better still, collective medical authority, such as a panel of experts" (Goer & Romano, 2012, p 11). The difficulty with this model is that conventional wisdom of medical practice tends to be more conventional than wise.


Clinical experience...has been defined as making the same mistakes with increasing confidence over an impressive number of years. The practice of evidence-based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research. Practitioners simply don't have the time to research out the best available evidence to every clinical scenario they may encounter in practice. What often happens, similar to UpToDate, is that experts sift through the research synthesizing it into predigested summaries to guide practice, the oldest and best known of these being the Cochrane Database of Systematic Reviews. Of course, basing medical practice on scientific evidence is clearly a superior strategy to basing it on individual or even collective opinion or experience, but we've created our own set of problems. The issues here are also many.


Take time to really dig into understanding and evaluating research if you are a clinician and admittedly, our recent pandemic grossly demonstrated our country's need to implement some of this teaching at the grammarly level as so few are capable of critical thinking. Trisha Greenhalgh has offered us a worthy book, How to Read a Paper: The Basics of Evidence-Based Medicine. This is not the end of the story however. Maternity care invites problems which are largely outside of the scope of this book.


Understanding "Best Evidence"


A study design hierarchy was devised early into the creation of the "Evidence-based Medicine" era. Nowadays, experts largely reject this hierarchy, particularly the position of the random control trial at the top of this pyramid. There is no 'best evidence,' except in reference to particular types of problems and in particular contexts. Case reports for example, can serve as a warning sign of serious problems that are too rare or too infrequently examined to be detected by random control trials (RCTs). Some things can't even be randomized. RCTs eliminate the reality that some women have strong preferences in their care and won't agree to RCTs so we have effectively eliminated those with preferences from those with indifference to care. Although a RCT on homebirth has been attempted, it failed miserably because women would not agree to randomization on their place of birth. Maybe most importantly is that RCTs make the assumption that the context can be eliminated, as if factors such as environment or care provider philosophy and judgement aren't huge factors in outcomes.


Systematic reviews are also less than perfect. While many do hold these with very high regard, admittedly, we have to assume that biases of the reviewers will not impact the selection of studies, their interpretation, and reporting in the review. Just as important in my mind, and I think a significant issue in clinical practice is that systematic reviews often create a false impression of definite scientific authority. We can disagree or critically analyze these results and have differing opinions as the authors. They are not the ultimate authority, yet I have heard this exact testimony by expert witnesses in #depositions. Evidence-based medicine demands that we trust the experts who are custodians of the evidence to provide accurate, objective information on which to base care, but who is guarding the guards?


One must consider if evidence-based medicine, that is well conducted, permits the attainment of scientifically objective truth? Holmes and colleagues (2006) writes, rather brilliantly, "Those who are wedded to the idea of 'evidence' in the health sciences maintain... a Newtonian, mechanistic world view [that] reality is objective, which is to say that it exists, 'out there,' absolutely independent of the human observer, and of the observer's intentions and observations" (p. 182), but, the authors fully acknowledge this is a false premise. "Rarely does objective truth in medical research exist independently of the observer or the system within which the observer works," (Goer & Romano, 2012, p 15). "Nonetheless," authors Goer and Romano continue, "the powerful claim that it replaces subjective opinion with objective fact has enabled evidence-based medicine to become the 'organizing structure for knowledge and a mechanism of ideological reinforcement for the dominant scientific paradigm."


There is a profound sense of entitlement in those conducting the research and essentially controlling the evidence. Worse yet, this ideology of evidence-based medicine or this regime of truth ostracises those with deviant forms of knowledge, rejecting their work as scientifically unsound. Immunizations are a perfect example here. No matter one's position or conclusion after evaluating the literature, it is contrary to scientific inquiry to demand conclusively that vaccines are safe and should no longer be tested and evaluated for safety and efficacy. Acceptance of each and every one, or even the schedule on blind-faith is an absolute contraindication to scholarly thinking.


I've sat at the table where professional guidelines are written and will attest to the lack of adherence to the evidence by members of the writing team. There is absolutely, without hesitation, a desire to please adversaries, a need to protect the profession, the desire to expand our scope and business successes that can and does contradict the evidence. The great advantage to this era of evidence-based medicine however, is the ability to self-correct. Even if the vast majority of studies are flawed, they can offer valuable information if read with a critical eye. Our task is to reject the dogmatic approach and maintain a healthy skepticism. Not every practice or policy that claims to be evidence-based actually is and as a practicing clinician and expert in our speciality field, we should be able to argue these points not just to protect ourselves, but to also advance the profession and offer true informed consent to our clients.


Ubiquity of the Medical Model based on Iatrogenic Norms


There are a few examples here, but consider that cutting the umbilical cord immediately after birth is well known to deprive the child of a significant amount of their own blood volume. They are essentially hemorrhaged at birth. As a result their bilirubin distribution curve for the next few days of life is determined or established based on infants who have been deprived of the normal physiologic amount of blood volume; the babies setting the norm values have fewer red blood cells in their earlier days than they should. As a consequence, when we delay cord cutting and allow the child to receive the vast majority of their entire blood volume, they will have a higher number of red blood cells and ultimately, a higher red blood cell volume which causes clinicians to assume they are polycythemic. This is a deviation from the norm and assumed then to be an anomaly or pathologic, when in fact, this is the biologic norm.


Iatrogenic norms affect everything from the duration of pregnancy to the length of labor to blood loss after birth. Another example is the finding that routine ultrasounds in pregnancy do not offer additional benefit or that continuous fetal monitoring in labor for low risk women is advantageous. The problem comes in having already set a societal norm. Clients expect it and practitioners are unwilling to deviate their practice. We prescribe antibiotics everyday for symptoms that do not necessitate treatment, but do so because the healthcare consumer demands it. By definition, these deviations in our research results are abnormal and therefore, care that produces abnormal results, by definition, equates to substandard care. The midwifery model of care therefore, is a salmon swimming upstream.


Another important point is that because obstetrics is long accustomed to introducing interventions without first evaluating their effectiveness or safety, we have imposed narrow definitions of normal on the physiology of pregnancy and labor. Once we began evaluating these interventions, simply for purposes of creating the study, even more strict definitions are introduced that further restrict our practice. We are classifying deviations as abnormal, similar to iatrogenic norms, further reinforcing this model. For example, the average pregnancy endures 41 weeks, yet study definitions have created this as the abnormal and therefore, a new standard is adopted. The same is true of the Friedman curve. This wasn't the finding of a study as a best outcome, but essentially the parameter created by the researchers for that specific study which was then adopted as the standard post-publication for all women! Subsequent research has demonstrated the Friedman curve as outside the physiologic norm, yet women are cut open daily for falling off this arbitrary curve.


None of this even appreciates that rigid boundaries, limited variables, precise measurements, and objectivity as the exclusive perspective conflicts with the complex and variable nature of childbirth. Safety, empowerment, comfort, freedoms are vital components of this experience for women, babies, and their support team. Rigidity, control, limitations, and precision are the antithesis of normal in this maternal and child health, yet our "best evidence" is consumed by this approach.


Writing and research is vital in our profession, but it doesn't eliminate the necessity to critically think. Clinicians must also be excellent scientists and be able to critically evaluate the literature. It concerns me that so many aren't capable of even navigating the research library and if they do, few read beyond the abstract. This impacts our ability as clinicians to have authentic discussions about informed consent with our clients. It also limits our ability to engage in mutual decision-making and causes us to demand specific behaviors based on our prescribed recommendations - complete compliance. The consequence will ultimately be the loss of human rights in steps such as mandatory vaccines and loss of birth rights. We have a duty to do better as clinicians. It is our responsibility to not just get into the graduate library but become high skilled at navigating among research articles and critically evaluating their contribution to the body of science of our profession. We, the practicing clinicians, are the experts making these decisions.

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