At the Bedside Evidence Based Medicine Stephen R. Hayden, MD Department of Emergency Medicine UCSD Medical Center, San Diego Teaching

The best teaching is taught by patients themselves Sir William Osler

EBM at the Bedside At the bedside, use history and physical exam elements for teaching EBM Take an item of history or physical exam and think of it as a “diagnostic test” Presence or absence of a clinical finding changes the probability of disease

EBM at the Bedside Opportunity to discuss many EBM concepts Test properties of clinical exam parameters Precision (kappa) of clinical examination Accuracy (likelihood ratios, PPV, NPV) Moving from pretest to post test probability Quantifies the utility of diagnostic tests

Example How often do you see a case of chest pain in the emergency department?

How precise are clinical findings in chest pain patients? Interrater reliability (Kappa)

Precision of Clinical Features Clinical FeatureKappa Chest pain radiates to L arm0.89 Pain in substernal location0.74 Pain described as pressure0.57 Pain described as sharp0.30 Pain with movement0.27 Hickan DH, et al. J Chronic Dis. 1985;38:91-100

Precision of Physical Findings Physical signs of heart failure in MI Gadsboll N. European Heart J. 1989;10: Clinical FeatureKappa Dyspnea Neck vein distension0.31 – 0.51 Dependent edema0.27 – 0.64 Third heart sound0.14 – 0.37 Rales0.12 – 0.31

How accurate are clinical findings in chest pain patients?

Accuracy of Clinical Features Clinical FeaturePositive LR (CI) Radiation to left arm Radiation to right shoulder Radiation to both L and R arm 2.3 ( ) 2.9 ( ) 7.1 ( ) Third heart sound3.2 ( ) Hypotension3.1( ) Diaphoresis2.0 ( ) Nausea or vomiting1.9 ( ) Past history of MI Panju AA, et al. JAMA. 1998;280:

Accuracy of Clinical Features Clinical FeatureNegative LR (CI) Pleuritic chest pain0.2 ( ) Chest pain sharp or stabbing0.3 ( ) Positional chest pain0.3 ( ) Chest pain reproduced by palpation Panju AA, et al. JAMA. 1998;280:

Can this really be done in a busy ED?

EBM at the Bedside Don’t attempt to answer all possible questions for every patient Pick one clinical finding relevant to a individual patient Choose cases you see frequently in ED

EBM at the Bedside Requires advance preparation Have Kappa’s, likelihood ratios with you on index cards, palm pilot, workstation Need rapid access to high quality evidence

Medcalc3000.com

(Freeware)

BestBets.org Analgesia and Abdominal Pain

ACP Journal Club

How do you find articles relating to the precision and accuracy of the H&P?

Search Tips Add specific terms to search strategy “Physical examination” “Medical history taking” “Sensitivity” or “specificity” “Clinical assessment” “Observer variation” “Interrater reliability”

MI Reference Panju AA, et al. Is this patient having a myocardial infarction? JAMA. 1998;280:

Summary Reviewed how to take EBM to the bedside Identifying elements of the H&P as “tests” Describing precision and accuracy of H&P Preparing in advance / bedside tools Rapid access to pre-appraised resources

“I desire no other epitaph than the statement that I taught medical students in the wards, as I regard this by far the most useful and important work I have been called upon to do.” Sir William Osler Farewell Address, 1905