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Assessing Dehydration Employing End-Tidal Carbon Dioxide in Children With Vomiting and Diarrhea

Freedman, Stephen B. MDCM, MSc*; Johnson, David W. MD; Nettel-Aguirre, Alberto PhD, PStat; Mikrogianakis, Angelo MD*; Williamson-Urquhart, Sarah BScKIN§; Monfries, Nicholas MD§; Cheng, Adam MD*

doi: 10.1097/PEC.0000000000001177
Original Articles

Objective Serum bicarbonate reflects dehydration severity in children with gastroenteritis. Previous work in children receiving intravenous rehydration has correlated end-tidal carbon dioxide (EtCO2) with serum bicarbonate. We evaluated whether EtCO2 predicts weight change in children with vomiting and/or diarrhea.

Methods A prospective cohort study was conducted. Eligible children were 3 months to 10 years old and presented for emergency department (ED) care because of vomiting and/or diarrhea. End-tidal carbon dioxide measurements were performed after triage. The diagnostic standard was weight change determined from serial measurements after symptom resolution. A receiver operating characteristic curve was constructed to identify a cut-point to predict 5% or more dehydration.

Results In total, 195 children were enrolled. Among the 169 (87%) with EtCO2 measurements, the median (interquartile range [IQR]) was 30.4 (27.8 to 33.1). One hundred fifty-eight had repeat weights performed at home; the median (IQR) weight change from ED presentation to well weight was +0.06 (−0.14 to +0.30) or +0.72% (−1.2% to +2.1%). Sixteen percent (25/158) had 3% or more and 4% (6/158) had 5% or more weight gain (ie, percent dehydration). One hundred sixteen (60%) completed home follow-up and had acceptable EtCO2 recordings. Receiver operating curve analysis revealed an area under the curve of 0.34 (95% confidence interval, 0.06 to 0.62) for EtCO2 as a predictor of 5% or more dehydration.

Conclusions The limited accuracy of EtCO2 measurement to predict 5% or more dehydration precludes its use as a tool to assess dehydration severity in children. End-tidal carbon dioxide monitoring does not have the ability to identify those children with 5% or more dehydration in a cohort of children with vomiting and/or diarrhea presenting for ED care.

From the *Section of Pediatric Emergency Medicine and Gastroenterology, Department of Pediatrics,

Section of Pediatric Emergency Medicine, Departments of Pediatrics and Physiology and Pharmacology,

Department of Pediatrics, Alberta Children's Hospital, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada; and

§Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.

Disclosure: The authors declare no conflict of interest.

Reprints: Stephen B. Freedman, MDCM, MSc, FRCPC, Section of Pediatric Emergency Medicine, Alberta Children's Hospital, 2888 Shaganappi Trail NW, Calgary, AB, Canada, T3B 6A8 (e-mail:

The study was supported by the Department of Pediatrics Innovation Award from the Department of Pediatrics, Alberta Children's Hospital. S.F. is supported by the Alberta Children's Hospital Foundation Professorship in Child Health and Wellness.

Presented at the Pediatric Academic Societies' Annual Meeting, April 27, 2015, San Diego, CA.

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