Repeated vital sign measurements in the emergency department predict patient deterioration within 72 hours: a prospective observational study

Abstract

Background: More than one in five patients presenting to the emergency department (ED) with (suspected) infection or sepsis deteriorate within 72 h from admission. Surprisingly little is known about vital signs in relation to deterioration, especially in the ED. The aim of our study was to determine whether repeated vital sign measurements in the ED can differentiate between patients who will deteriorate within 72 h and patients who will not deteriorate.

Methods: We performed a prospective observational study in patients presenting with (suspected) infection or sepsis to the ED of our tertiary care teaching hospital. Vital signs (heart rate, mean arterial pressure (MAP), respiratory rate and body temperature) were measured in 30-min intervals during the first 3 h in the ED. Primary outcome was patient deterioration within 72 h from admission, defined as the development of acute kidney injury, liver failure, respiratory failure, intensive care unit admission or in-hospital mortality. We performed a logistic regression analysis using a base model including age, gender and comorbidities. Thereafter, we performed separate logistic regression analyses for each vital sign using the value at admission, the change over time and its variability. For each analysis, the odds ratios (OR) and area under the receiver operator curve (AUC) were calculated.

Results: In total 106 (29.5%) of the 359 patients deteriorated within 72 h from admission. Within this timeframe, 18.3% of the patients with infection and 32.9% of the patients with sepsis at ED presentation deteriorated. Associated with deterioration were: age (OR: 1.02), history of diabetes (OR: 1.90), heart rate (OR: 1.01), MAP (OR: 0.96) and respiratory rate (OR: 1.05) at admission, changes over time of MAP (OR: 1.04) and respiratory rate (OR: 1.44) as well as the variability of the MAP (OR: 1.06). Repeated measurements of heart rate and body temperature were not associated with deterioration.

Conclusions: Repeated vital sign measurements in the ED are better at identifying patients at risk for deterioration within 72 h from admission than single vital sign measurements at ED admission.

Keywords: Accident & emergency medicine; Patient deterioration; Sepsis; Vital signs.

Fig. 1

Flow chart of patient recruitment. Consecutive adult medical patients visiting the emergency department of the University Medical Center Groningen between March 2016 and February 2017 were screened for eligibility

Fig. 2

Receiver operating curves of the logistic regression models for patient deterioration using various repeated vital sign measurements in 30-min intervals during the first three hours of the patient’s stay in the emergency department. The base model includes age, gender and comorbidities. Model M1 contains the base model combined with the value of the vital sign at admission, model M2 contains model M1 combined with the change of the vital sign over time, model M3 contains model M1 combined with the variability of the vital. A) the ROC curve for the base model combined with heart rate (HR). B) the ROC curve for the base model combined with mean arterial pressure (MAP). C) the ROC curve for the base model combined with respiratory rate (RR). ^* Base model only including patients with respiratory rate at admission (AUC .638). D) the ROC curve for the base model combined with body temperature (BT)