Mathematical Modeling for Prediction of Survival From Resuscitation Based on Computerized Continuous Capnography: Proof of Concept

Authors

  • Sharon Einav MD,

    1. From the Adult (SE) and Neonatal (RB) Critical Care Units, Shaare Zedek Medical Center, and the Department of Anesthesia (CFW), Hadassah-Hebrew University Medical Center, Jerusalem; and the Department of Anesthesia of the Sourasky Medical Center (IM), Tel-Aviv, Israel.
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  • Ruben Bromiker MD,

    1. From the Adult (SE) and Neonatal (RB) Critical Care Units, Shaare Zedek Medical Center, and the Department of Anesthesia (CFW), Hadassah-Hebrew University Medical Center, Jerusalem; and the Department of Anesthesia of the Sourasky Medical Center (IM), Tel-Aviv, Israel.
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  • Carolyn F. Weiniger MB, ChB,

    1. From the Adult (SE) and Neonatal (RB) Critical Care Units, Shaare Zedek Medical Center, and the Department of Anesthesia (CFW), Hadassah-Hebrew University Medical Center, Jerusalem; and the Department of Anesthesia of the Sourasky Medical Center (IM), Tel-Aviv, Israel.
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  • Idit Matot MD

    1. From the Adult (SE) and Neonatal (RB) Critical Care Units, Shaare Zedek Medical Center, and the Department of Anesthesia (CFW), Hadassah-Hebrew University Medical Center, Jerusalem; and the Department of Anesthesia of the Sourasky Medical Center (IM), Tel-Aviv, Israel.
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  • The preliminary results of this study were presented at the 9th Scientific Congress of the European Resuscitation Council, Ghent, Belgium, 2008.

  • This study was supported by a grant from the Chief Scientist of the Ministry of Health, Jerusalem, Israel (Grant 5397). Oridion provided the capnography equipment, developed the dedicated software, and funded the mathematician who performed data extraction. Neither the Ministry of Health or Oridion had a role in study design, data analyses and interpretation, writing of the manuscript or manuscript submission for publication.

  • The authors have no relevant financial information or potential conflicts of interest to disclose.

  • Supervising Editor: James E. Olson, PhD.

Address for correspondence and reprints: Sharon Einav, MD; e-mail: einav_s@szmc.org.il.

Abstract

ACADEMIC EMERGENCY MEDICINE 2011; 18:468–475 © 2011 by the Society for Academic Emergency Medicine

Abstract

Objectives:  The objective was to describe a new method of studying correlations between real-time end tidal carbon dioxide (ETCO2) data and resuscitation outcomes.

Methods:  This was a prospective cohort study of 30 patients who underwent cardiopulmonary resuscitation (CPR) in a university hospital. Sidestream capnograph data were collected during CPR and analyzed by a mathematician blinded to patient outcome. The primary outcome measure was to determine whether a meaningful relationship could be drawn between detailed computerized ETCO2 characteristics and the return of spontaneous circulation (ROSC). Significance testing was performed for proof-of-concept purposes only.

Results:  Median patient age was 74 years (interquartile range [IQR] = 60–80 years; range = 16–92 years). Events were mostly witnessed (63%), with a median call-to-arrival time of 150 seconds (IQR = 105–255 seconds; range = 60–300 seconds). The incidence of ROSC was 57% (17 of 30), and of hospital discharge 20% (six of 30). Ten minutes after intubation, patients with ROSC had higher peak ETCO2 values (p = 0.035), larger areas under the ETCO2 curve (p = 0.016), and rising ETCO2 slopes versus flat or falling slopes (p = 0.016) when compared to patients without ROSC. Cumulative maxETCO2 > 20 mm Hg at all time points measured between 5 and 10 minutes postintubation best predicted ROSC (sensitivity = 0.88; specificity = 0.77; p < 0.001). Mathematical modeling targeted toward avoiding misdiagnosis of patients with recovery potential (fixed condition, false-negative rate = 0) demonstrated that cumulative maxETCO2 (at 5–10 minutes) > 25 mm Hg or a slope greater than 0 measured between 0 and 8 minutes correctly predicted patient outcome in 70% of cases within less than 10 minutes of intubation.

Conclusions:  This preliminary study suggests that computerized ETCO2 carries potential as a tool for early, real-time decision-making during some resuscitations.

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