Effects of ambient temperature on volume, specialty composition and triage levels of emergency department visits.
OBJECTIVE
To evaluate the effects of change of ambient temperature on emergency department (ED) patient visits.


METHODS
This prospective observational study was conducted in the ED of National Taiwan University Hospital from January 2002 to January 2007. The daily ED patient numbers of different triage levels in different service specialties were collected and correlated with the daily average temperature (T) and change in temperature (deltaT) compared with the previous day. A univariate analysis was performed with the Pearson correlation and a multivariate analysis with multiple linear regression analysis.


RESULTS
A total of 505,224 patient visits were included in this study. On univariate analysis, there was no significant correlation between T and the ED volume (r = 0.012, p = 0.608), but there was a significant correlation between deltaT and ED volume (r = 0.109, p<0.001). On multivariate analysis, deltaT and holidays were identified as independent predictors of ED volume. We established the following formula in predicting the ED patient number: y = 265.42 + (0.06 x T) + (2.57 x deltaT) + (59.77 x holiday). There was a positive association between T and the trauma patient number, while there was a negative association between T and medical and paediatric patient numbers. On the triage level, a low T was associated with increased patient triage level, while no significant association was noted between deltaT and the proportion in any triage level.


CONCLUSIONS
Our study demonstrated that ambient temperature had differential effects on ED patient visits of different specialties and severities.
Tai
Chia-Chun
CC
Department of Emergency Medicine, National Taiwan University Hospital, No. 7, Chung-Shan South Road, Taipei 100, Taiwan.
Lee
Chien-Chang
CC
Shih
Chung-Liang
CL
Chen
Shyr-Chyr
SC
D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013624:Taiwan; D013696:Temperature; D014218:Triage
J Trauma. 2001 Jul;51(1):118-22
11468478
Pediatr Emerg Care. 2006 Feb;22(2):104-6
16481926
Sports Med. 2002;32(3):143-68
11839079
Ann Emerg Med. 2002 Apr;39(4):430-2
11919530
Eur J Clin Nutr. 2002 Apr;56(4):288-96
11965504
Women Health. 2002;36(2):75-90
12487142
Emerg Med J. 2003 Sep;20(5):402-5
12954674
Med Care. 1971 Sep-Oct;9(5):415-27
5123759
South Med J. 1981 Jun;74(6):709-12
7244751
Am J Emerg Med. 1985 Jul;3(4):327-30
4005005
J Emerg Med. 1987;5(1):49-52
3584916
J Gen Intern Med. 1996 Apr;11(4):237-9
8744882
Am J Emerg Med. 1998 Jul;16(4):374-5
9672454
Injury. 2005 Jan;36(1):40-6
15589911
J Community Health. 2001 Dec;26(6):423-45
11759094