EBP Step 2: Rapid Access to the best evidence
Dr Sue Wells
Effective Practice, Informatics & Quality Improvement
Section of Epidemiology and Biostatistics
School of Population Health
Using PubMed to find research evidence in quickest possible time-
future proof your searching!
PubMed 101
Get this lecture ppt from CECIL and on “Normal View” find all the step-by step instructions
Medline widely available on different platforms eg, OVID or PubMed
produced in USA. (National Library of Medicine)
premier electronic source for biomedical literature
contains mostly US/UK journals 4000 / 10,000 published worldwide http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed
Tip Number 1
PUBMED!
PubMed – Free Internet version of Medline
Go straight to the INDEX- MeSH
MeSH 1
Medline Subject Headings (MeSH terms) are assigned to each article.
Provide consistent way to retrieve articles MeSH “a controlled vocabulary organised in a tree structure”
index = like chapter headings in a text book– Major Subject Headings (eg Leg)
• Subject Headings (eg knee)– Subheadings (eg cruciate ligament)
Each new paper is “tagged” by NLM librarians using MeSH terms representing the key things about each study (eg rct ligament surgery)
CLINICAL SCENARIOA 65 yr old woman with stable angina and on HRT for 8 years comes to see you. She has read a magazine article about the possible harms of Hormone Replacement Therapy (HRT) on heart disease. She
Is a non-smoker. Has a BMI of 25 Has no menopausal symptoms
Should her prescription for HRT be stopped?
Reframe into PECOT question
Among postmenopausal women with angina or
other coronary heart disease (P),
Does hormone replacement therapy (HRT) (E),
Compared to no HRT (C) ,
affect the risk of further CHD events (eg
MI, bypass surgery) (O)
over the next 5 years (T) ?
HRT EXAMPLE
Break the question into the following components
Participants
Exposure Comparison
Outcome Time
angina orcoronary heart disease ANDPost-menopausal
Hormone replacement therapyORHRT
No HRT Coronary heart disease events
5 years
AND AND AND
MeSH 2
Explode retrieves all articles with that MeSH term or a term beneath it on the tree
eg explode “leg” retrieves all articles tagged with either leg, hip, thigh, knee, ankle, foot
Restrict (or Focus) restricts search to those articles where the specified MeSH term is the major focus.
Previous indexing -Subject Headings change over time – may need to check “old” headings as well as MeSH term
Introducing PubMed TABS
HISTORY– Gives you a summary of what you have searched, limits or filters used and number of articles retrieved
LIMITS
Limits your search eg; to particular
study types, population groups
studied, or language
Helpful tip- clear limits or every
search from now on will have them!
“Clinical Queries” searches for you by applying a filter for specific
study types
Highlight the search terms, copy (Ctrl-C) and paste (Ctrl-V)
into Clinical Queries dialogue box
SENSITIVITY
Sensitivity is calculated by
Results of a sensitive search
RCT’s required (blue)
Results of a specific search
number studies foundtotal number of relevant
studies
Your Assignment
What if the question is not about an intervention?
Scenario You are a 2nd year house surgeon at Whangarei-its night time.
16yr old brought in by Mum with signs & symptoms of acute appendicitis
Ring surgeon on call, up to theatre and remove a normal appendix
Find patient has PID – gonorrhea Disappointed in your mistake you wonder if a CT scan would be have been useful as a diagnostic test. You decide to search PubMed.
Reframe into PECOT question
Among adolescents and adults who are admitted
acutely with signs and symptoms suggestive of
appendicitis (P),
Will a computerised tomography scan help to
differentiate (O) between those who
have acute appendicitis (E),
Compared to those with other diagnoses (C) ,
At the time of admission (T) ?
Appendicitis Example
Break the question into the following components
Participants
Exposure Comparison
Outcome Time
Adolescents and adults
Acute Appendicitis
Not acute appendicitis
CT Scan One point in time
AND AND
GO TO MeSH
Still too many to scroll through? – what
could I do now??
OK- what if you have a really tricky question and it doesn’t
map to a MeSH term.............????
Should interventional radiologists or general surgeons be using antibiotic or antiseptic-impregnated central venous lines to prevent line-associated sepsis?
Reframe into PECOT question
For patients requiring a CVP line (P),
Does an antibiotic or antiseptic-impregnated
central venous line (E),
compared to a non-drug impregnated one
(C) ,
prevent line-associated sepsis (O)
over the time of use (T) ?
CVP line example
Break the question into the following components
Participants
Exposure Comparison
Outcome Time
Any hospitalised patient
antibiotic or antiseptic-impregnated central venous line
“Plain” CVP line
InfectionSepsisdeath
Over time of use
AND AND
MeSH- type in CVP line
Scroll down to
“Display”
Click on
Click on drop-down menu
Find “Citation”
MeSH terms “tagged” to
this publication
Catheterization, Central Venous
What about the other options?
Send to search box with OR Send to Search box with NOT
Boolean AND
ANDChildren aged 2-15
Asthma
Boolean OR
Asthma Bronchitis
Green area = Asthma or Bronchitis
Boolean NOT
Asthma not drugs
Drug therapy
Yellow circle = AsthmaWhite Circle = Drug therapy
PubMed Single Citation Matcher Quick way to find a
single paperA consultant mentions in passing a randomised trial published in the Lancet in 2001 looking at prevention of deep vein thrombosis on long flights. You want to find a copy of the paper.
Use Single Citation Matcher tool-put in journal name, year and title words
Saving citations / printing off articles
PMID:11377600 OVID platform 11377600.ui
Organisation of Evidence
Adapted from Haynes RB (2001). Evidence-Based Mental Health 4:37-38.
Evidence-based guidelines eg NZGG
Megasearch engines eg TRIP, SumSearch (just google!)
one stop shops for Evidence based information multi-database search includes
– Evidence-based synopses (eg EBM journals), – global guidelines, – E-textbooks, medical images, – Patient Information Leaflets, – Systematic reviews, Health Technology
assessments,– Core general medical journals, specialist
journals ·etc very dependent on spelling, very dependent on
appropriate terms Use MeSH terms!!!! without [MeSH]