Elsevier

Journal of Critical Care

Volume 38, April 2017, Pages 1-5
Journal of Critical Care

Outcomes/Predictions
Combining quick Sequential Organ Failure Assessment with plasma lactate concentration is comparable to standard Sequential Organ Failure Assessment score in predicting mortality of patients with and without suspected infection

https://doi.org/10.1016/j.jcrc.2016.10.005Get rights and content

Abstract

Purpose

We sought to determine whether quick Sequential Organ Failure Assessment (qSOFA) score can be used to predict mortality of patients without suspected infection.

Materials and methods

Using prospectively collected data within the first hour of intensive care unit admission, the predictive ability of qSOFA was compared with the Simplified Acute Physiology Score III, Admission Mortality Prediction Model III, Acute Physiology and Chronic Health Evaluation II model, and standard (full-version) SOFA score using area under the receiver operating characteristic (AUROC) curve and Brier score.

Results

Of the 2322 patients included, 279 (12.0%) died after intensive care unit admission. The qSOFA score had a modest ability to predict mortality of all critically ill patients (AUROC, 0.672; 95% confidence interval [CI], 0.638-0.707; Brier score 0.099) including the noninfected patients (AUROC, 0.685; 95% CI, 0.637-0.732; Brier score 0.081). The overall predictive ability and calibration of the qSOFA was comparable to other prognostic scores. Combining qSOFA score with lactate concentrations further enhanced its predictive ability (AUROC, 0.730; 95% CI, 0.694-0.765; Brier score 0.097), comparable to the standard SOFA score.

Conclusions

The qSOFA score had a modest ability to predict mortality of both septic and nonseptic patients; combining qSOFA with plasma lactate had a predictive ability comparable to the standard SOFA score.

Introduction

The ability to identify patients who are at risk for subsequent deterioration and mortality, starting from prehospital care, emergency department to acute hospital ward and intensive care unit (ICU), is important [1]. Many prognostic models have been developed in the past 3 decades, and each has its own strengths and weaknesses [2]. Some prognostic models, including the Acute Physiology and Chronic Health Evaluation (APACHE II-IV models), use the worst physiological parameters of the patients within a period to estimate the risk of death [3], whereas others—including the Admission Mortality Prediction Model (MPM0 III), Admission APACHE II, and Simplified Acute Physiology Score (SAPS III) models—rely solely on patient characteristics on admission to the ICU to estimate the patient's risk of death [4], [5], [6]. None of these scores can be considered simple and user-friendly enough to be used in the hospital ward and emergency department settings as an early warning score.

Using a composite score of different physiological parameters, many different medical emergency alert systems have been developed and are in use to identify patients who are at risk for deterioration in many health care institutions [7]. The “quick Sequential Organ Failure Assessment” (qSOFA) score has recently been developed to facilitate early identification of patients who are at risk for mortality from suspected infection [8], [9]. The qSOFA score uses only 3 physiological parameters (respiration rate ≥22 breaths/min, altered mental state [Glasgow Coma Scale [GCS] score <15], and systolic blood pressure ≤100 mm Hg: total score ranges between 0 and 3), and despite its simplicity, it had a reasonable ability to predict mortality for patients with sepsis both in the ICU (area under the receiver operating characteristic [AUROC], 0.66) and hospital ward (AUROC, 0.81) [9].

Although the standard full-version SOFA score has been shown to predict outcomes of both septic and nonseptic critically ill patients [10], [11], [12], it is uncertain whether qSOFA is only useful to predict mortality of patients with suspected infection. In this study, we assessed the ability of ICU admission qSOFA score in predicting mortality in critically ill patients with and without suspected infection, using the physiological and biochemical data of patients obtained within the first hour of ICU admission. Specifically, we also compared the prognostic significance of the qSOFA score, either on its own or in combination with plasma lactate concentration, with 4 well-established ICU admission prognostic scores (including the SAPS III, Admission MPM0 III, Admission APACHE II models, and the standard full-version admission SOFA score) [4], [5], [6], [10].

Section snippets

Materials and methods

This prospective audit study was initiated in 2008 when the study center started to collect physiological and biochemical data obtained within the first hour of ICU admission for all ICU admissions. In this study, we used the data of patients, admitted between January 1, 2008, and December 31 2013, including those who died within 24 hours of ICU admission. The clinical data analyzed were deidentified, and as such, this study was exempt from review by the Royal Perth Hospital Ethics Committee

Characteristics of the patients

Of the 9549 patients admitted to the study center during the study period, 2322 patients (24.3%) were not intubated within the first hour of ICU admission and were eligible for further analysis. Of the 2322 patients included in the study, 163 (7.0%) required noninvasive ventilation at the time of ICU admission, 345 patients (15%) required invasive mechanical ventilation within 24 hours of ICU admission, and 279 patients (12.0%) died during the same hospital stay. Patient admission

Discussion

This study showed that the qSOFA score within the first hour of ICU admission had a modest ability to differentiate between survivors and nonsurvivors for both septic and nonseptic critically ill, nonintubated, patients, comparable to some well-established ICU admission prognostic scores. Combining qSOFA with lactate concentration further enhanced its ability to predict mortality of critically ill patients, comparable to the standard (full-version) admission SOFA score. In addition, the qSOFA

Acknowledgments

This study was solely funded by the Department of Intensive Care Medicine, Royal Perth Hospital. KMH is funded by Raine Clinical Research Fellowship from the Raine Medical Research Foundation and WA Department of Health. No funding was received from the National Institutes of Health, NHMRC, and Wellcome Trust.

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Conflict of interest statements: The authors have no involvement with organization(s) with financial interest in the subject matter of this study.

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