Revitalizing a vital sign: improving detection of tachypnea at primary triage.
OBJECTIVE
This study evaluates the accuracy of emergency department (ED) triage respiratory rate measurement using the usual care method and a new electronic respiratory rate sensor (BioHarness, Zephyr Technology Corp.), both compared to a criterion standard measurement.


METHODS
This is a cross-sectional study with convenience sampling conducted in an urban academic adult ED, including 3 separate respiratory rate measurements performed at ED triage: usual care measurement, electronic BioHarness measurement, and criterion standard measurement. The criterion standard measurement used was defined by the World Health Organization as manual observation or auscultation of respirations for 60 seconds. The resultant usual care and BioHarness measurements were compared with the criterion standard, evaluating accuracy (sensitivity and specificity) for detecting tachypnea, as well as potential systematic biases of usual care and BioHarness measurements using a Bland Altman analysis.


RESULTS
Of 191 analyzed patients, 44 presented with tachypnea (>20 breaths/min). Relative to criterion standard measurement, usual care measurement had a sensitivity of 23% (95% confidence interval [CI] 12% to 37%) and specificity of 99% (95% CI 97% to 100%) for tachypnea, whereas BioHarness had a sensitivity of 91% (95% CI 80% to 97%) and specificity of 97% (95% CI 93% to 99%) for tachypnea. Usual care measurements clustered around respiratory rates of 16 and 18 breaths/min (n=144), with poor agreement with criterion standard measurement. Conversely, BioHarness measurement closely tracked criterion standard values over the range of respiratory rates.


CONCLUSIONS
Current methods of respiratory rate measurement at ED triage are inaccurate. A new electronic respiratory rate sensor, BioHarness, has significantly greater sensitivity for detecting tachypnea versus usual care method of measurement.
Johns Hopkins University School of Medicine, Department of Emergency Medicine, Baltimore, MD, USA. William.Bianchi@med.lecom.edu
William
W
Bianchi
Andrea Freyer
AF
Dugas
Yu-Hsiang
YH
Hsieh
Mustapha
M
Saheed
Peter
P
Hill
Cathleen
C
Lindauer
Andreas
A
Terzis
Richard E
RE
Rothman
D000328:Adult; D001314:Auscultation / Q000592:standards; D003430:Cross-Sectional Studies; D004636:Emergency Service, Hospital; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010808:Physical Examination / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D012015:Reference Standards; D015203:Reproducibility of Results; D056152:Respiratory Rate; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D059246:Tachypnea / Q000175:diagnosis*; D014218:Triage