Introduction to Evidence Based Medicine and Literature Review

1
Introduction to Evidence Based Medicine and
Literature Review

• Evan Pivalizza, M.D.
• October, 2005

2

• Background
• Cochrane, Sackett
• Origin 70s principles delivery health care
• Promote RCTs most reliable source evidence based
  decisions
• Comprehensive catalog valid trials

3
EBM

• Conscientious, explicit, judicious use best
  evidence make decisions individual patients
• De-emphasizes (not eliminate) intuition,
  unsystematic clinical experience
• Integrate clinical expertise best available
  evidence
• Emphasizes systematic evaluation evidence from
  clinical research
• ACGME core category resident education
• Practice based learning, medical knowledge,
  patient care

4
Principles

• Ask clear, focused question can be answered
• Who is it about?
• Which treatment/maneuver considering?
• What desired outcome?
• Search evidence
• Cochrane library, Medline etc
• Critical appraisal evidence
• Are results important?
• Are results relevant/valid?

5

• 4. Clinical applicability findings (does apply
  this patient)?
• Not in original study (age, morbidity)
• Subgroup analysis (male, female)
• 5. Evaluation process
• Did ask right (any) question?
• Is anything we can do better?

6

• How Critically Appraise evidence
• Study design?
• What is intervention, and compared to what?
• Randomized?
• Blinded? researchers, patients, assessors
• Prospective?
• Were all patients accounted for?
• What outcome?
• Appropriate statistics?
• Is conclusion justified by results?

7
Types publications (? importance)

• Case Report Select patient specific
  condition/outcome
• Case Series Select group patients
• Cross-sectional study Comparison characteristics
  and endpoint of sample patients

8

• 4. Case-control study Comparison group with
  outcome to group without, in terms particular
  characteristics
• 5. Cohort Comparison gt 2 groups, with and
  without characteristic, in terms of outcome
• 6. Clinical trial Comparison gt 2 groups,
  randomized to treatment groups, terms of outcome

9
RCT

• Quantitative, comparative, controlled experiment
• Randomization ? risk imbalance unknown factors
  could influence
• Open to manipulation (bias) up to 30-50 change
• Historical control overestimate 30-40

10

• Execution of trial
• Size Was large enough, sufficient duration?
• Drop-outs ? bias
• Intention to treat all pts included in
  analysis in group assigned, whether completed or
  not
• Methods What were interventions, by whom, how?
• Statistics Another session

11

• RCT ? Systematic review
• Scientific strategies to decrease bias in
• Collection
• Appraisal
• Interpretation
• Statistics
• Collating RCTs

12

• Clear question
• Clear method selection RCTs
• Language
• Inclusion, exclusion criteria
• Statistical method (expert)
• ? power (number) of study

13
1. ASA practice parameters (04)

• Designed provide guidance/direction mx pts
• Anesthesiologists leaders development/adoption
• Standard Rule, minimum requirement, generally
  accepted principles.
• Guideline Systematic recommendations
  management strategy. NOT intended as standards

14

• C. Advisory Systematic reports (expert opinion,
  consensus surveys, open forum commentary,
  clinical feasibility data) assist decision making
  
• Summarize state literature, report opinions task
  force
• NOT supported scientific evidence same extent
  stds/guidelines (insufficient)
• D. Alert Facilitate awareness problem patient
  safety

15

• Perioperative Mx Cardiac Rhythm Device (05)
• Cannot guarantee specific outcome
• Adopted, modified, rejected according clinical
  needs, constraints
• Basic Anesthesia Monitoring (04)
• Apply to all anesthesia care, although in
  emergencies, appropriate life support measures
  precedence
• Delineation clinical privileges (03)
• Assist physicians/organizations develop program

16
2. ACC/AHA guidelines

• 2002 ACC/AHA Guideline Update for Perioperative
  Cardiac Evaluation for Noncardiac Surgery
• Systematic approach, literature based, specific
  recommendations/algorithm
• Already 3 years old

17

• ACC/AHA Classification Recommendations
• Class I Evidence/general agreement procedure
  useful/effective
• Class II Conflicting evidence/divergence opinion
• IIa Weight evidence favor efficacy
• IIb Efficacy lt well established
• Class III Evidence/general agreement
  procedure/treatment not useful/effective,
  possibly harmful

18

• Level of Evidence
• A Multiple RCTs/ meta-analyses
• B Single RCT, or nonrandomized studies
• C Consensus opinion experts, or Case studies, or
  Standard of care

19
3. Cochrane Anesthesia Review Topics

• International organization ? systematic reviews
  multiple topics (Anes Analg)
• 1. Ambulatory Anesthesia
• Anesthesia for ECT
• 2. Anesthesia and Medical Diseases
• Preop evaluation
• 3. Drugs in Anesthesia and intensive care

20

• 4. Perioperative care
• Caudal
• PONV
• 5. Postanesthetic care
• Fluid, hemodynamic, nutrition, infection
• 6. Regional Anesthesia
• Protocols developed
• 7.Technology in Anesthesia
• Pulse oximetry

21
Summary EBM

• Seek best evidence (RCT)
• Unavailable ? observational studies
• Unavailable ? (own) systematic clinical
  observations, pathophysiologic reasoning
• Little evidence (yet) from RCTs that practice
  EBM ? improved patient outcomes
• IS evidence (reliable) knowledge RCTs ?
  evidence-based therapy ? ? outcome

22

• Make clinical decision making
• Explicit
• Conscious
• Science based
• Supplement, not supplant other approaches patient
  care/ teaching

23
References

• Pronovost PJ, Anes Analg 2001 92 787
• Pedersen T, Acta Anaesthesiol Scand 2001 45
  267
• Moller AM, BJA 2000 84 655
• Cochrane review topics (www.cochrane.org/reviews)