Abstract
Purpose
Shock index (SI), the ratio of heart rate to systolic blood pressure, has found to
outperform conventional vital signs as a predictor of shock. Although age-specific
vital sign norms are recommended in screening for shock, there are no reported age-
or sex-specific norms for SI. Our primary goal was to report age- and sex-specific
SI normal values for a nationally representative population 10 years and older by
5-year age groups. A secondary goal was to report SI normal values for children ages
8 to 19 years by 1-year age groups.
Basic procedures
Weighted data from the National Health and Nutrition Examination Survey 1999-2008
data sets were used to generate age- and sex-specific percentile curves of SI for
subjects 8 years and older.
Main findings
The primary analysis included 33906 subjects (101837 weighted) 10 years and older. The secondary analysis included 13393 subjects (37983 weighted) 8 to 19 years old. Normalized SI values for each percentile decreased
with increasing age and were higher for females across all ages. The most commonly
cited SI threshold of 0.9 exceeded the 97th percentile for males younger than 25 years
and for females younger than 40 years.
Conclusions
This first report of age- and sex-specific normal values for SI indicates that SI
norms vary by age and sex. Just as age-specific vital sign norms are recommended in
screening for shock, our findings suggest that age- and sex-specific SI norms may
be more effective in screening for shock than a single-value threshold.
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Article Info
Publication History
Published online: March 13, 2013
Accepted:
January 15,
2013
Received in revised form:
January 7,
2013
Received:
September 19,
2012
Footnotes
☆Prior presentation: Pediatric Academic Societies, May 2010.
☆☆Sources of support: Supported by NIH/NCRR Colorado CTSI Grant Number UL1 RR025780. Contents are the authors' sole responsibility and do not necessarily represent official NIH views.
Identification
Copyright
© 2013 Elsevier Inc. Published by Elsevier Inc. All rights reserved.
