Evidenced Based Medicine

Guiding tool for Practice

New Order

• I.E. add 40 mg furosemide to HHN Q4h

• Never heard of it? Now what do you do?

1. Call the Doctor?

2. Call your Supervisor?

3. Just do it?

Appraise using JAMA Guide Evidence-Based Medicine Working Group

• Are the results valid?

• What are the results?

• Will the results help me in patient care?

• http://medicine.ucsf.edu/resources/guidelines/users.html

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Types of health care professional

EvidenceFinders

Evidence Users

Evidencegenerator

Evidence Ignorer

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What is the best evidence?• Friend once told me• Group of old

Professors • Case series • Systematic Review• RCT• Case control trial• Case

– http://cebm.jr2.ox.ac.uk/docs/levels.html

Levels of Evidence

• The evidence pyramid is used to illustrate the evolution of the literature.

• As you move up the pyramid the amount of available literature decreases, but …

• increases in its relevance for application in clinical settings.

What’s Best Evidence?

Best:

• Randomized. Prospective, double-blind trials with control and experimental group carefully selected to be equal.

• Sufficient sample size

• Low p score < .005

• Above considered Level or Class I evidence

Evidenced Based MedicineWhat Are the Steps to the EBM

Process?

1. Compose a focused clinical question 2. Conduct a search for evidence 3. Appraise the evidence you find 4. Present and apply your results 5. Evaluate the EBM process and your skill .

Those Which Weaken the Evidence

• Small sample size (low n)

• Retrospective studies weaker than prospective studies

• High p or CI (confidence intervals)

• Physiologic studies weaker than outcome studies

Emergency Medicine• A 36 year old patient well known to the ED with

brittle asthma presents with a severe flare-up of her symptoms that developed over the course of the day. Her asthma has necessitated admission on three occasions over the last year and she suffered a life-threatening attack 3 years ago which necessitated intubation and ICU, and was associated with the development of pneumothoraces. She presents today in marked respiratory distress with significant accessory muscle use and unable to speak. Her oxygen saturation was 82% on presentation but has now improved with supplemental oxygen. She responds only minimally to initial maximum therapy consisting of continuous bronchodilators, high dose corticosteroids and IV magnesium; she appears to be tiring but her pCO2 is 38 mm Hg. The respiratory tech wants to know if she should call down for the Heliox tank from ICU.

Critical Care Medicine

• You admit a 77 year old female with community acquired pneumonia to the ICU. She was admitted from the emergency department with hypoxemia that is refractory to supplemental oxygen. She is intubated but this required fiber optic intubation because she could not be intubated by direct laryngoscopy. She was placed on antibiotics. She does not have other significant past medical history. Two days later, her fraction of inspired oxygen is 40% and she is off positive end expiratory pressure. You decide she is ready to be extubated but the critical care fellow expresses concern that she will fail extubation and will not be able to be reintubated. You state that you would like to use some diagnostic test to help predict if she will be successfully extubated. Your fellow states that the respiratory rate to tidal volume ratio can be used to predict successful extubation and her ratio is 50.

Neonatal Medicine

• Thick meconium is passed during the delivery of a term infant. Immediately after birth, the trachea is intubated and suctioned for copious amounts of meconium. Despite intensive therapy which includes mechanical ventilation with pure oxygen and exogenous surfactant, the infant remains hypoxemic. Echocardiography confirms the presence of an anatomically normal heart and is consistent with the clinical diagnosis of Persistent Pulmonary Hypertension of the Newborn (PPHN). The resident asks whether to refer the patient to the Extracorporeal Membrane Oxygenation (ECMO) team in your tertiary care centre. You recently read about the benefits of inhaled nitric oxide and wonder whether this should be tried first.