Saturday, February 10, 2018

What Does the Evidence Say?

In yesterday’s “physical exam rounds” morning report, we learned about the JAMA rational clinical examination for ascites.  Our preceptor reviewed the definitions for positive and negative likelihood ratios as well as sensitivity and specificity to create a framework for the discussion.

In 1998, JAMA began creating their “The Rational Clinical Examination” series to evaluate how certain physical examination techniques can aid in our diagnoses.  The series focuses on high-yield topics that come up in common diagnostic dilemmas.  The chapters include an evidence-based approach to a particular examination based on meta-analyses of the literature.  (Garner, 2010). 

The concept of evidence-based medicine (EBM) is defined as the “integration of clinical expertise, patient’s values and best available evidence in [the] process of decision making related to patients’ health care.” (Masic et al., 2008) External clinical evidence does not replace your clinical expertise however, it informs and guides your decision-making.  In fact, you use your clinical expertise to decide if the external evidence applies to the patient in front of you. (Sackett et al., 1996)

These evidence-based rational clinical examinations provide a structure for a focused examination especially when you are in a busy setting such as the emergency department and triaging patients.  From yesterday’s lecture, I learned that one should start with the most sensitive tests when performing your physical exam and then move to more specific tests because the sensitive tests help you to rule out the diagnosis if negative.  For example, in the examination for ascites, the most sensitive findings to rule out the diagnosis are no history of ankle swelling or increased abdominal girth and the inability to demonstrate bulging flanks, flank dullness, or shifting dullness.  The most powerful findings for making the diagnosis of ascites are a positive fluid wave result, shifting dullness, or peripheral edema.  (Simel & Rennie, 2009)

It was brought up in rounds that in theory our pre-test probabilities would be based on epidemiological data and the likelihood of a disease occurring in a particular patient population.  However, in practice we base our pre-test probabilities on history-taking and physical examination.  This is why learning the questions on history or physical examination maneuvers that help you confidently rule in or rule out diagnoses will aid you the most in medical decision-making.  As the Garner article mentions, these physical examinations force us to become resource stewards as well.  Not only does certainty in our examination increase confidence in medical decisions, it also decreases the number of unnecessary tests that are ordered.

In the world of medical education, evidence-based medicine is weaved in throughout.  More than “physical exam rounds,” there are also “EBM rounds” each week where we learn to interpret and critically appraise primary research articles.   I am looking forward to next week’s sessions!

SH

Resources:

Garner, J. (2010). The Rational Clinical Examination: Evidence-Based Clinical Diagnosis. Proc (Baylor University Medical Center Proceedings), 23(1): 87.

Sackett, D. L. et al. (1996). Evidence based medicine: what it is and what it isn’t. BMJ, 312: 71. doi: https://doi.org/10.1136/bmj.312.7023.71

Masic, I. et al. (2008) Evidence Based Medicine – New Approaches and Challenges. Acta Inform Med, 16(4): 219 – 225.

Simel, D. L. & D. Rennie.  (2009).  The Rational Clinical Examination: Evidence-Based Clinical Diagnosis.  JAMAevidence.  Retrieved from https://medicinainternaucv.files.wordpress.com/2013/02/jama-the-rational-clinical-examination.pdf  Accessed on February 10, 2018

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