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

GOOGLE

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]