Utility of specific laboratory biomarkers to predict severe sepsis in pediatric patients with SIRS

Abstract

Objective: To identify the association between readily available laboratory biomarkers and the development of severe sepsis in children presenting to the emergency department (ED) with systemic inflammatory response syndrome (SIRS).

Methods: In this retrospective cohort study, ED patient encounters from June 2018 to June 2019 that triggered an automated sepsis alert based on SIRS criteria were analyzed. Encounters were included if the patient had any of the following laboratory tests sent within 6 h of ED arrival: C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), lactic acid, and procalcitonin. For each of the biomarkers, a receiver operating characteristic (ROC) curve was created for our primary outcome, severe sepsis within 24 h of ED disposition, and our secondary outcome, severe sepsis with a positive bacterial culture. For each ROC curve, we calculated the area under the curve (AUC) with 95% confidence intervals (95% CI) and created cutoff points to achieve 90% sensitivity and 90% sensitivity for the primary and secondary outcomes.

Results: During the study period, 4349/61,195 (7.1%) encounters triggered an automated sepsis alert. Of those, 1207/4349 (27.8%) had one of the candidate biomarkers sent within 6 h of ED arrival and were included in the study. A total of 100/1207 (8.3%) met criteria for severe sepsis within 24 h of arrival, and 41/100 severe sepsis cases (41%) were deemed culture-positive. Procalcitonin had the highest AUC for identifying severe sepsis [0.62 (95% CI 0.52-0.73)] while ESR and CRP had the highest AUC for culture-positive sepsis [0.68 (95% CI 0.47-0.89) and 0.67 (95% CI 0.53-0.81), respectively]. At 90% sensitivity for detecting severe sepsis, all of the biomarker threshold values fell within that laboratory test's normal range. At 90% specificity for severe sepsis, threshold values were as follows: procalcitonin 2.72 ng/mL, CRP 16.79 mg/dL, ESR 79.5 mm/h and lactic acid 3.6 mmol/L.

Conclusion: Our data indicate that CRP, ESR, lactic acid, and procalcitonin elevations were all specific, but not sensitive, in identifying children in the ED with SIRS who go on to develop severe sepsis.

Keywords: Biomarkers; Pediatric; Systemic inflammatory response syndrome; sepsis.