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 70’s – principles delivery health care • Promote RCT’s 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 > 2 groups, with and without characteristic, in terms of outcome 6. Clinical trial: Comparison > 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 < 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)