Tuesday, May 29, 2012

Clinical Training Wheels

The Gist:  Emergency Medicine (EM) physicians must read patients and situations quickly and accurately.  Clinical gestalt and decision rules variably aid EM physicians in making vital decisions.  As students, the opportunity exists to build this mysterious, elusive "gestalt" during clinical exposure and to cultivate this as we grow into physician learners.  Clinical decision rules probably serve as an important stepping stone towards the boulder of clinical gestalt, but are accompanied by the potential to serve as a crutch.

As a medical student, I always seem to finagle a decision aid like Wells', PERC, NEXUS, OTTAWA, or TIMI score into my ED patient presentation. This is my way of overcompensating for my relative clinical naivety - my lack of gestalt.  When the weight of someone's life lies in your judgement, do you trust that over an expert's calculated risk?  Sometimes, however, it seems as though this places me between a figurative rock and a hard place.  The rock symbolizing my fund of clinical knowledge and patient evaluation, whereas the hard place symbolizes the decision of utilizing a clinical decision rule, even if I know it's not that great or I know I'm solely employing the decision aid as a security blanket.  

What is "clinical gestalt?"
  • A gut instinct, or overall analysis, cultivated by personal experience and established through history and physical.  
  • Evidence suggests that additional years of clinical experience improves ones overall clinical assessment of a patient.  A 2005 study in Chest demonstrated a trend towards increased accuracy in diagnosis of PE in more experienced clinicians, although this did not reach statistical significance.   Strange how that works, eh?  We get better with practice, maybe.  
What about clinical decision rules?
  • As a student, I innately love these although I know they're fraught with problems and validity issues.  They build a framework and a guideline to substitute for the judgment and gestalt I have not yet cultivated.  The rules seem to back up and quantify the components that might comprise an experienced clinician's gestalt - and it seems there's a rule for nearly everything.
  • Decision rules allow one to assess various aspects of a patient, add up a few numbers (typically countable on two hands), and provide us with a clean, black and white statistic, such as pre-test probability.  Here are calculators for popular PE rules:  the Wells' Criteria and, for low risk patients, the Pulmonary Embolism Rule Out Criteria (PERC).  
  • Offsets risk.  These rules may give a physician a safety net of scientific evidence what they've already surmised with their gestalt.  For example, the Canadian Head CT rule could have a promising impact on reducing the number of CT scans in minor head injury.
  • Clinical decision rules represent a wide variety of levels of evidence, depending partially on the validation of the rule, internally or externally.  Perhaps the numbers aren't as clean as they seem.  
Clinical decision rules seem easy, shouldn't we just use those?
  • As algorithms, there's the possibility that clinicians may become too dependent on decision rules as opposed to continuing to develop and utilize clinical reasoning and thought.
  • The rules turn out to be nowhere near perfect and the external validation studies rarely seem to concur with the original derivations.  The San Francisco Syncope Rule serves an excellent example of a failure of a decision rule.  The validation studies for this rule, hoping to identify all serious outcomes within 7 days of the presenting syncopal episode, had sensitivities in the 79-80% range, far below an acceptable percentage for ED purposes and well below the touted 96% sensitivity in the original study (1,2).  Of note, clinicians were 100% sensitive in meeting the primary endpoint the rule was designed to detect (3).  
    • Affected by variations in disease prevalence, variable application of the rules by clinicians, and instability of the model from which the rule was derived.
  • Clinical decision rules are not uniformly agreed upon because they exist as a tool, rather than a rule (despite the nomenclature).  
    • This debate between Dr. David Newman and Dr. Scott Weingart is exemplary in demonstrating disagreement between excellent physicians over decision rules in PE.
    • Utilization of these rules could be problematic when it conflicts with a less measurable and quantifiable measure such as clinical gestalt, particularly in the setting of a highly litigious health care climate.
  • Wide variation in use and familiarity of rules exists between academic and community medicine practices.  
So what do we do?
  • Use a mixture and encourage this practice.   This 2003 analysis in JAMA demonstrated "similar" outcomes in clinicians who used gestalt versus those who used clinical decision rules.
    • This algorithm for PE from EMCrit demonstrates an integration of gestalt with clinical decision rules (where clinical gestalt trumps everything).
  • Historically, EM physicians (lumped together as a group), have pretty good clinical gestalt so use clinical encounters to cultivate away!  
  • As a student, my inclination is that decision rules serve as the building blocks for gestalt, a way of beginning to form those pattern recognition skills.  Additionally, they may prevent us from harming patients (or planning to, before an attending kindly guides us in a more appropriate direction).  Yet, we must cast off our training wheels at some point.
  • Continue the dialogue regarding gestalt and decision rules so that both become better.  See Twitter for banter from the Annual Scientific Meeting of the College of Intensive Care medicine (#CICMASM) where one tweeter stated, "NICE guidelines favor esophageal Doppler, grey haired intensivists favor bedside thought + clinical exam." 
1.  Sun  BC, Mangione  CM, Merchant  G, et al.  External validation of the San Francisco Syncope Rule.  Ann Emerg Med. 2007;49(4):420–427. 
2.  Cosgriff  TM, Kelly  AM, Kerr  D.  External validation of the San Francisco Syncope Rule in the Australian context. CJEM.  2007;9(3):157–161.
3.  Birnbaum A, Esses D, Bijur P, Wollowitz A, Gallagher EJ. Failure to validate the San Francisco Syncope Rule in an independent emergency department population. Ann Emerg Med. 2008;52(2):151–159.

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