Stats >> WebLog >> A third search for the evidence (August 2, 2005). Category: Information searching

Our evidence-based Medicine working group was asked to find evidence to answer the following question:

In an otherwise healthy pediatric patient (> 1 month of age and < 5 years of age) which site (rectal, axillary, temporal) is most accurate in obtaining a core body temperature measurement?

Here's the search strategy I used in PubMed:

1. pediatric* or paediatric* or child* (1,478,959 hits)
2. rectal or axillary or temporal (188,073 hits)
3. temperature or thermometer (18,313 hits)
4. #1 AND #2 AND #3 (842 hits)
5. #1 AND #2 AND thermometer (151 hits)
6. Add Publication Types limited to Meta-Analysis (0 hits)
7. Search on the Find Systematic Reviews portion of the PubMed Clinical Queries page (4 hits) This added the condition "AND systematic[sb]" to my list of search parameters.

Here are the four articles:

• Infrared ear thermometry compared with rectal thermometry in children: a systematic review. Craig JV, Lancaster GA, Taylor S, Williamson PR, Smyth RL. Lancet 2002: 360(9333); 603-9. [Medline]
• Meta-analysis of method comparison studies. Williamson PR, Lancaster GA, Craig JV, Smyth RL. Stat Med 2002: 21(14); 2013-25. [Medline]
• The accuracy and reliability of tympanic thermometry compared to rectal and axillary sites in young children. Houlder LC. Pediatr Nurs 2000: 26(3); 311-4. [Medline]
• Temperature measured at the axilla compared with rectum in children and young people: systematic review. Craig JV, Lancaster GA, Williamson PR, Smyth RL. Bmj 2000: 320(7243); 1174-8. [Medline]

The second article in the list is a methodology article that just happens to use thermometry as its prime example. Looking at the Craig 2002 reference, I found their search strategy to be very interesting.

1. PAEDIATRIC in TI,AB,MESH
2. PEDIATRIC in TI,AB,MESH
3. explode 'Pediatrics'/ all subheadings
4. p*ediatric*
5. child*
6. infant*
7. baby or babies
8. neonat*
9. newborn*
10. toddler*
11. 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10
12. THERMOMETER in TI,AB,MESH
13. explode 'Thermometers'/ all subheadings
14. thermometer*
15. TEMPERATURE in TI,AB,MESH
16. temperature
17. 12 or 13 or 14 or 15 or 16
18. ear*
19. aural
20. EAR in TI,AB,MESH
21. explode 'Ear-External'/ all subheadings
22. explode 'Tympanic-Membrane'/ all subheadings
23. tympanic
24. auditory
25. 18 or 19 or 20 or 21 or 22 or 23 or 24
26. RECTUM in TI,AB,MESH
27. explode 'Rectum'/ all subheadings
28. rectum
29. rectal
30. 26 or 27 or 28 or 29
31. 11 and 17 and 25 and 30

 Format shown is for Silver Platter version 3.10. Upper case denotes medical subject (MeSH) terms and lower case denotes free text.

Notice how much more thoroughly these authors looked for articles about children (searches 1-10). Notice also the use of "explode." I'm unfamiliar with this term, but apparently it includes in the search not just the major MeSH heading but the MeSH subheadings as well.

I didn't use CINAHL, which might have been a better choice. CINAHL includes some nursing resources that might not be found in PubMed. I also didn't start with the higher level sources like the Cochrane Review, BestBets.org, or www.guidelines.gov.

Others in this group used (pediatric* or child*) AND (temperature) under guidelines.gov and found "Fever of uncertain origin" created by Cincinnati Children's Hospital. Another participant noticed, as I did, that "temperature" yielded too many hits, so he used thermometer instead. A third person found two good research syntheses at bestbets.org.

The leader of the group emphasized again the hierarchy of sources of evidence. At the top are systems (www.guidelines.gov). Search here first. Synopses (Clinical Evidence, Archimedes, and BestBets.org) represent the next highest level. If searches at this level fail, look for research syntheses (Cochrane). Only if those searches fail should you rely on single studies from PubMed or CINAHL. 

07/08/2008.