Prehospital Evidence-Based Guidelines

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Prehospital Evidence-Based Guidelines

• Daniel Spaite, MD
• Professor of Emergency Medicine
• The University of Arizona

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History and Development of EBM

• Historical assumption
• Medical education, CME, experience, and
  interaction with colleagues are adequate to lead
  to good clinical decisions

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Early 1970s Three findings destroyed the
assumption

• 1. Documentation of wide variation in practice
  patterns (Wennberg, 1973)
• Dramatic procedural variation (RAND)
• 2. Most medical practice was founded on
  tradition/experience rather than evidence.
• Cochrane-1972 Many standards of care were found
  to be ineffective, or even dangerous.
• IOM Report-1985 Estimate Only 15 of medical
  practices based upon solid evidence.

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Early 1970s Three findings destroyed the
assumption

• 3. Enormous lag-time from new research findings
  to practice.
• Dutton-1988 Worse than the Disease Pitfalls
  of Medical Progress.

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The ever widening gap

• gt 100 new articles related to EM/day (Medline)

Scientific knowledge (bench)
2008
Practice of Medicine (bedside)
1925
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TERMINOLOGY A decade into the movement

• Evidence-Based Guidelines
• 1990 (Eddy JAMA263 1265)
• Evidence-Based Medicine
• 1991 (Guyatt ACP Journal Club, No. 2 A-16).

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Translating New Knowledge to Patient Care

• Eddys categorization for EBM
• Evidence-Based Individual Decision-making (EBID)
• Brings current knowledge to the bedside in
  real-time.
• DIRECT use of evidence to impact the care of an
  INDIVIDUAL patient.
• Evidence-Based Guidelines (EBG)
• Policies and standards that help guide clinical
  decision-making based upon bring state-of-the-art
  knowledge.
• INDIRECT use of evidence to change policy,
  practice patterns, regulations, insurance
  coverage, etc.

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EBID and EBG

• BOTH are conceptually based upon a hierarchy of
  evidence quality
• University of Arizona EM EBID ?

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General Grades of Evidence

• A
• B
• C
• D

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EBID

• Will this EVER be used in prehospital care???
• Currently not feasible Technical/time
  constraints
• Physician surrogates Medical decision-making???
  

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EBG Around a Long Time

• Traditional methods
• Global subjective judgment
• Preference-based
• Consensus-based
• Opinion-based
• Traditional methods often wrong
• 1916 Once a C-sectionalways a C-section

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EBG The Age of Evidence-Based Methods

• During the 80s, huge advances
• By the late 90s
• it is widely accepted that guidelines should be
  based on evidence and the only acceptable use of
  consensus-based methods is when there is
  insufficient evidence to support an
  evidence-based approach. (Eddy)
• Whats it gonna take in EMS???

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THE MAGNITUDE OF THE CHALLENGE

• An overview of the road thats ahead of us

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Necessary Steps for TRULY Evidence-Based
Guidelines

• STEP 1 Critical evaluation of the literature
• EVERY potential clinical condition
• Comprehensive, systematic literature review.
• UNC Evidence-based Practice Center (EPC) (Lohr
  Intl J Qual Health Care 2004169-18)
• 121 different approaches for rating individual
  study quality.
• Only 19 met standards for proper assessments

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Necessary Steps

• STEP 2 Critical evaluation of the CUMMULATIVE
  evidence
• Must evaluate the quality of the BODY of evidence
• This is more difficult than rating a single
  investigation.
• Assess the consistency and heterogeneity of study
  designs
• Assess the comparability of the Risk Adjustment
  among the studies
• Weight each study
• Study size, methodology, quality
• UNC-EPC (Lohr 2004)
• 40 methods for rating the strength of a body of
  evidence.
• 8 met standards for proper assessments

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Necessary Steps

• STEP 3 Critical evaluation of the CHAINS of
  evidence
• RARE to find a body of knowledge that writes the
  guideline for you.
• Requires explicit cognitive steps that translates
  DIRECT evidence into guideline through
  INFERENCES.
• Example Animal studies ? Human studies ?
  Guideline applied across a broad population in
  potentially dramatically different settings.
• Inevitably requires judgment, inference, and
  opinion

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Necessary Steps

• STEP 4 Critical evaluation of the PREHOSPITAL
  implications of the body of evidence
• Strong evidence for EFFICACY of an intervention
  does not mean that it will be EFFECTIVE in the
  field.
• Lack of prehospital studies must be taken into
  account even with strong positive evidence in
  other settings.
• Medicine-Based Evidence A Prerequisite for
  Evidence-based Medicine. (Knottnerus
  BMJ3151997)
• The Real World ? EFFICACY vs. EFFECTIVENESS

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Necessary Steps

• STEP 5 Critical evaluation of other pertinent
  issues
• Systems-related factors. Effectiveness may vary
  with
• Rural vs. urban settings
• Demography
• e.g. Is a separate pediatric guideline needed?
• Operations (e.g. response/transport intervals)
• Patient populations
• e.g. Cost-effectiveness varies with prevalence
• Socioeconomics At-risk populations
• Impact of delaying an intervention Does it have
  to be done?
• Extremes are easy Cardiac arrest Tinea pedis
• Urgentbut not emergent interventions

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Necessary Steps

• STEP 5 (Continued) Critical evaluation of
  other pertinent issues
• Risk for harm
• Cost
• Feasibility and practicality
• Value-judgments Individual, religious, cultural
  variation
• Example Life vs. profound morbidity
• Confidence of benefit vs. magnitude of benefit
• Confidence of benefit vs. significance of benefit
• Related specialty-based guidelines if they exist
  (AHA CPR/ACLS)
• Evaluation of current guidelines/protocols
• This alone is an enormous undertaking

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Necessary Steps

• STEP 6 Evaluation of whether a guideline is
  appropriate at all
• What if all evidence is WEAK?
• When should a stand be taken that clearly states
  that insufficient evidence existsand that a
  guideline is inappropriate?
• What if there are already LOTS of guidelines out
  there?
• Are there commonly used interventions that should
  be trashed and NOT recommended for use in EMS?
• If CONSENSUS is the basis for a guideline, how is
  this distinguishable from EVIDENCE-based
  guidelines?
• What are the implications of having these
  guidelines LOOK equally authoritative when they
  make it to the street?

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Necessary Steps

• STEP 7 Plan for recurrent, future evaluations
  of evidence and revisions of the guidelines
• If theres a lack of commitment to future changes
  based upon new evidenceis it best not to start
  in the first place?
• Guidelines are NOT harmless!!!
• Guidelines hang around a LONG time!!!
• Example
• Diethylstilbestrol (DES)
• 1938 1971 Recommended by expert consensus
  guideline to prevent miscarriage
• 4.8 million pregnant women received it
• 1971 FDA halted its use No statistical benefit
  but significant harm (vaginal cancer, breast
  cancer, etc.)

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HUGE QUESTIONS

• Are we SURE we mean EVIDENCE-based
  guidelinesORdo we REALLY mean CONSENSUS-based
  guidelines???
• Will protocols be developed and supported where
  the only evidence is opinion and theory?

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Steering Committees Consensus

• A high threshold for requiring solid evidence
  for a guideline to be recommended.
• When in doubt, err on the side of requiring
  strong evidence before propagating guidelines.
• The HOT topic