Prehospital Evidence-Based Guidelines. Daniel Spaite, MD Professor of Emergency Medicine The University of Arizona. 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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Daniel Spaite, MD
Professor of Emergency Medicine
The University of Arizona
Medical education, CME, experience, and interaction with colleagues are adequate to lead to good clinical decisions
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.
3. Enormous lag-time from new research findings to practice.
Dutton-1988: “Worse than the Disease: Pitfalls of Medical Progress.”
> 100 new articles related to EM/day (Medline)
Practice of Medicine
1990 (Eddy: JAMA:263; 1265)
1991 (Guyatt: ACP Journal Club, No. 2: A-16).
Eddy’s 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.
BOTH are conceptually based upon a hierarchy of evidence quality
University of Arizona EM: EBID
Will this EVER be used in prehospital care???
Currently not feasible: Technical/time constraints
Physician surrogates: Medical decision-making???
“Global subjective judgment”
Traditional methods often wrong:
1916: “Once a C-section…always a C-section”
During the 80’s, huge advances:
By the late 90’s:
“…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)
What’s it gonna take in EMS???
An overview of the road that’s ahead of us
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: 2004;16:9-18)
121 different approaches for rating individual study quality.
Only 19 met standards for proper assessments
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
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
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: BMJ;315:1997)
The “Real World” EFFICACY vs. EFFECTIVENESS
STEP #5: Critical evaluation of other pertinent issues
Systems-related factors. Effectiveness may vary with:
Rural vs. urban settings
e.g. Is a separate pediatric guideline needed?
Operations: (e.g. response/transport intervals)
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
Urgent…but not emergent interventions
STEP #5 (Continued): Critical evaluation of other pertinent issues
Risk for harm
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
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 exists…and 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?
STEP #7: Plan for recurrent, future evaluations of evidence and revisions of the guidelines
If there’s a lack of commitment to future changes based upon new evidence…is it best not to start in the first place?
Guidelines are NOT harmless!!!
Guidelines hang around a LONG time!!!
1938 – 1971: Recommended by expert consensus guideline to prevent miscarriage
4.8 million pregnant women received it
1971 FDA halted it’s use: No statistical benefit but significant harm (vaginal cancer, breast cancer, etc.)
Are we SURE we mean EVIDENCE-based guidelines…OR…do we REALLY mean CONSENSUS-based guidelines???
Will protocols be developed and supported where the only “evidence” is opinion and theory?
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