Critical Thinking and Evidence
Based Medicine
for Adult Health Nursing Msc
Students
Dr.Beka A.(GP)

Critical Thinking
Critical thinking is the intellectually disciplined process of actively and
skillfully conceptualizing, applying, analyzing, synthesizing, and/or
evaluating information gathered from, or generated by, observation,
experience, reflection, reasoning, or communication, as a guide to
belief and action.

What is Evidence-based medicine
• Evidence-based medicine(EBM) requires the integration of the best
research evidence with our clinical expertise and our patient's unique
values and circumstances.

What is Evidence-based medicine
• By best research evidence, we mean clinically relevant
research, sometimes from the basic sciences of
medicine,
By clinical expertise, we mean the ability to use our
clinical skills and past experience to rapidly identify
each patient's unique health state and diagnosis
By patient values, we mean the unique preferences,
concerns, and expectations that each patient brings to a
clinical encounter

History of Evidence Based Medicine
• In 1972, Professor Archie Cochrane, a medical doctor and researcher
in the UK, highlighted the fact that most treatment related decisions
were not based on a systematic review of clinical evidence. He
proposed that researchers should collaborate internationally to
systematically review all the best clinical trials specialty by
specialty. This highlighted gaps that existed between research and
clinical practice and started to convince practitioners of the benefits
of an evidence-based approach.

History of Evidence Based Medicine
• The term ‘evidence-based medicine’ was introduced by Gordon
Guyatt and his team in 1991 to shift the emphasis in clinical decision-
making from ‘intuition, unsystematic clinical experience, and
pathophysiologic rationale’ to scientific, clinically relevant research.

History of Evidence Based Medicine
• In 1996, D. L. Sackett, a Canadian-American doctor and founder of the
first department of clinical epidemiology at McMaster University in
Ontario, explained that evidence-based clinical decision-making is a
combination of not only research evidence but also clinical expertise,
as well as the unique values and circumstances of individual patients.

How to Practice EBM

How to Practice EBM
• Step 1—converting the need for information (about
prevention, diagnosis, prognosis, therapy, causation,
etc.) into an answerable question by asking two types of question
Background questions
Ask for general knowledge about a condition, test, or treatment
Foreground questions
Ask for specific knowledge to inform clinical decisions or actions

How to Practice EBM
Step 2—tracking down the best evidence with which
to answer that question
• Always look for the best evidence

How to Practice EBM
Step 3—critically appraising that evidence for its
validity, impact and applicability
• Validity: Internal and external validity ; Construct validity, criteria
validity and Content validity
• Impact: size of the effect
• Applicability: Usefulness in our clinical practice

How to Practice EBM
• Step 4—integrating the critical appraisal(the process of carefully and
systematically examining research to judge its trustworthiness, and its
value and relevance in a particular context) with our
clinical expertise and with our patient's unique biology,
values, and circumstances

How to Practice EBM
•Step 5—evaluating our effectiveness and efficiency in
executing steps 1 to 4 and seeking ways to improve
them both for next time

What are the limitations of EBM?
Discussion about the practice of EBM naturally engenders negative and
positive reactions from clinicians. Some of the criticisms focus on
misunderstandings and misperceptions of EBM, such as the concerns
that it ignores patient values and preferences and promotes a
“cookbook” approach
Relegation of clinical judgment and mechanistic reasoning, and over-
reliance on the reliability of clinical trials and systematic reviews

Thank you