1. Noninvasive Positive-Pressure Ventilation In COPD

2. Which car do you want?

3. Which car do you want?

4. Which study do you choose?
And Why?

5. Therapy(single trial)
Is this evidence valid?
Is this valid evidence important?
Can we apply this valid, important evidence in caring for our patient?

6. Validity Randomization Randomization concealment
Similarity at the start
Long and complete follow up
Intention to treat analysis
Blindness-patient, clinician, study personnel
Equal treatment except experimental Tx.

7. Importance Relative risk reduction(RRR) Absolute risk reduction(ARR)
(CER-EER)/CER
Absolute risk reduction(ARR)
CER-EER
Number needed to treat(NNT)
100/ARR
Magnitude and precision of Tx. effect

8. Applicability Patient’s difference Feasibility of Tx.
Potential Benefit and Harm from Tx.
Our patient’s value and expectation