Visiting bags: a labile thermal environment.

OBJECTIVE

To define usual colour and site of storage of visiting bags in general practitioners' cars and to investigate effect of these variables on temperature inside bag.

DESIGN

Questionnaire to general practitioners; serial temperature measurements from paired black visiting bags at different storage sites and from bags of different colour.

SETTING

South Devon coastal town during May and June.

SUBJECTS

200 general practitioners, of whom 145 returned legible questionnaires.

MAIN OUTCOME MEASURES

Bag colour, duration and site of storage, temperature inside black bags at defined storage sites, and effects of bag colour on internal temperature.

RESULTS

111 (77%) of the general practitioners carried a black visiting bag, and 76 kept their bag in their car all day. The bag was coolest in the car boot, but irrespective of storage site, maximum internal temperature of the bag was always over 25 degrees C and reached up to 80 degrees C. Spraying a black bag silver significantly reduced the bag's internal temperature (mean difference 8.37 degrees C (95% confidence interval 6.68 to 9.86 degrees C) df = 59, t = 10.29, P < 0.001).

CONCLUSIONS

General practitioners should use a silver coloured visiting bag; when visiting, they should store it in their car boot; at other times they should remove it to a cooler site.