Constructing clinical questions (or: how to do evidence-based

medicine, part I)

Dr Sean Monaghanseanus.monaghan@gmail.com

Things you are about to learn

• A recipe for a delicious condiment• A recipe for delicious clinical questions• How to use the latter

Pico de Gallo

• Pico de Gallo is a delicious Mexican condiment, made from tomatoes, chillies and onion

• It’s basically chunkier, drier salsa, and is extremely tasty

• Try it with your fajitas

PICO

• PICO is a technique which allows you to build logical clinical questions, which can direct your literature searches to produce meaningful and valid results

www.tripdatabase.com is a wonderful evidence database – go and visit it. Now.

PICO

• There are 4 elements to a PICO question– Population– Intervention– Comparison– Outcome

• I remain unsure how the title ‘PICO’ was arrived at

PICO

• P stands for POPULATION– Who are we interested in?– This could be too broad (“mammals”, “humans”)

or too narrow (“bespectacled 34 year old males”, “females weighing 56kg”)

– Find a happy medium – trial and error may be required for this

PICO

• I stands for INTERVENTION– What are we doing to our population?– The evidence we aim to uncover using this

technique will hopefully tell us whether or not this action is worthwhile

– Remember: the population may be a group of people who have all had the same intervention, e.g. post-operative patients – don’t get confused!

PICO

• C stands for COMPARISON– This may be a null comparison, i.e. you may be

comparing your intervention to no intervention at all, or may be an alternative treatment

– Don’t worry too hard about finding something to compare to if you’re not comparing it to anything; if comparing an intervention to no intervention, you can basically ignore this field

– However, PIO isn’t as catchy

PICO

• O stands for OUTCOME– What effect do you want your intervention to

have on your population?– Could be positive (keep them alive, make them

better, make them feel better) or negative (kill them, make them deteriorate, make them hate their miserable lives)

– Again, could be overly broad or overly narrow – trial and error never fails

Nightmare scenarioConsider the following horrifying scenario:

You’re on a ward round with Dr Consultant, and foolishly ask her why she just crossed off the nebulisers for the three month old with bronchiolitis.She tells you to look up the reason, and tells you she wants you to present the answer in two days’ time.

What most of us would do

What most of us would do

• Give presentation in two days’ time• Explain where to buy discount nebulisers

online, and mention that an NHS website said something about nebulised hypertonic saline

• Look like an idiot.

Constructing PICO questions

• Of course, what you COULD do is work out your Population, Intervention, Comparison and Outcome, and then use this organised, structured question to perform a literature review...

Constructing PICO questions

• Population– Adults don’t get bronchiolitis– Big kids don’t get bronchiolitis– Therefore, let’s look for babies, but let’s write

‘infants’, because it sounds more technically correct• Intervention– Nebulisers– We could search for ‘bronchodilators’ as well, or even

‘nebulised bronchodilators’ to show off

Constructing PICO questions

• Comparison– Given that Dr Consultant didn’t replace the

nebulisers with anything, we could search for ‘no treatment’, or just not bother searching at all

– We could also show off and search for ‘placebo’• Outcome– Let’s look for a couple of outcomes – ‘length of

stay’ and ‘chance of PICU admission’, as they will probably cover both ends of the spectrum

Constructing PICO questions

• In infants with bronchiolitis, do nebulised bronchodilators, compared with placebo, lead to shorter length of stay?

• In infants with bronchiolitis, do bronchodilators (no comparison) lead to lower chance of PICU admission?

And that’s literally it.

• Easy, isn’t it?• In my next slideshow, I’ll show you what to do

with your shiny new PICO question, but for the moment, try creating your own

• In married male doctors, will writing educational presentations compared to eating your wife-prepared dinner lead to shorter life expectancy?

• In other words, I’m off for now!

Credits

• I took screenshots from www.google.co.uk and www.tripdatabase.com and recommend them both

• The Pico de Gallo image is from http://www.thecampuscompanion.com/kitchen/2011/10/05/pico-de-gallo/ - their recipe is equally highly recommended

• Questions/comments/lawsuits – write below or send me a message