Research ArticleSepsis

A targeted real-time early warning score (TREWScore) for septic shock

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Science Translational Medicine  05 Aug 2015:
Vol. 7, Issue 299, pp. 299ra122
DOI: 10.1126/scitranslmed.aab3719
  • Fig. 1. Example patient features and risk trajectory.

    (A) Example features over time are shown for a patient developing septic shock (time of shock onset indicated by the red line). Point in time data used to calculate TREWScore are displayed in the black box, along with the associated time to onset and the onset of sepsis-related organ dysfunction (indicated by the blue line). Feature measurements are indicated by circles that are filled for new observations or hollow otherwise. Features displayed are Glasgow Coma Scale (GCS), platelets, ratio of blood urea nitrogen to creatinine (BUN/creatinine), arterial pH, temperature, bicarbonate, respiratory rate (RR), white blood cell count (WBC), heart rate/systolic blood pressure (SBP) (shock index), SBP, and heart rate. (B) The TREWScore over time for the patient in (A) is shown in blue. Risk predictions are made as new measurements are added to the EHR, as if in real time. The horizontal dashed gray line indicates the detection threshold corresponding to a sensitivity of 0.85. The figure portrays two sets of potential detection criteria: (i) Identify the patient as at high risk of septic shock the first time the risk score crosses the detection threshold. (ii) Identify the patient only after the risk score remains above the detection threshold for at least 8 hours or some other desired length of time.

  • Fig. 2. ROC for detection of septic shock before onset in the validation set.

    The ROC curve for TREWScore is shown in blue, with the ROC curve for MEWS in red. The sensitivity and specificity performance of the routine screening criteria is indicated by the purple dot. Normal 95% CIs are shown for TREWScore and MEWS. TPR, true-positive rate.

  • Fig. 3. Comparison of prediction performance.

    (A) Each row represents a septic shock patient in the validation set from the time of ICU admission to the onset of septic shock. The graph was truncated to only show time points within 120 hours of septic shock onset. Individuals were aligned on the basis of time to septic shock after ICU admission. For visual clarity, we further subsorted individuals with similar time-to-shock by time of TREWScore identification. (B) Identification times for patients are shown from up to 48 hours before organ dysfunction until the onset of sepsis-related organ dysfunction (blue line). Patients were sorted by time to organ dysfunction and then for visual clarity, patients with similar times until the onset of organ dysfunction were subsorted by the time of identification by TREWScore. (C) Each row depicts a patient from the time of ICU admission (left edge) until the time of septic shock (red line). The individual’s data are shown in gray from the time of admission until first identification by either system. The bar then becomes orange if the patient was first identified by TREWScore or green if the patient was first identified by the routine screening protocol. This color continues unless the patient is later identified by the second system, at which point the bar becomes purple. If a patient is simultaneously identified by both systems, then the bar transitions directly from gray to purple.

Supplementary Materials

  • Supplementary Material for:

    A targeted real-time early warning score (TREWScore) for septic shock

    Katharine E. Henry, David N. Hager, Peter J. Pronovost, Suchi Saria*

    *Corresponding author. E-mail: ssaria{at}cs.jhu.edu

    Published 5 August 2015, Sci. Transl. Med. 7, 299ra122 (2015)
    DOI: 10.1126/scitranslmed.aab3719

    This PDF file includes:

    • Materials and Methods
    • Table S1. Sample feature coefficients learned by TREWScore for a single imputation of the development data set.
    • Table S2. Patient characteristics.

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