Peripheral Perfusion Index as a Marker of Sepsis in Preterm Neonates

Abstract

Background: Neonatal sepsis is a major contributor to neonatal mortality in India. Blood culture, the gold standard for the diagnosis of sepsis takes 48-72 h while the serological markers have suboptimal diagnostic test characteristics. Perfusion index (PI) is a real time, non-invasive marker that can detect microcirculatory changes before other clinical manifestation of sepsis.

Objective: To determine the diagnostic accuracy of PI in detecting hospital-acquired sepsis before overt clinical manifestations.

Study design: A prospective observational study conducted in the Neonatal Intensive Care Unit (NICU) of a tertiary care hospital.

Participants: Preterm neonates admitted to NICU.

Methods: PI was continuously monitored in all enrolled neonates. Clinical sepsis was defined using the NeonatalKrankenhaus-Infektions-Surveillance-System (NeoKISS). The time of fall of PI below 0.88 and time of clinical sepsis as per NeoKISS were noted and the difference was calculated.

Results: Among 65 preterm neonates (gestational age: 31.5 ± 2.6 weeks, birth weight: 1350, IQR 1100-1700 g), a total of 86 events of suspected sepsis were noted, of which 69 were sepsis screen positive. Fifteen events were associated with culture positive sepsis. PI yielded a sensitivity of 89.47% (95% CI 78.48-96.04%), specificity of 56% (95% CI 34.93-75.60%), positive predictive value of 82.26% (95% CI 74.70-87.92%) and negative predictive value of 70% (95% CI 50.36-84.29%) in detection of hospital-acquired sepsis.

Conclusion: PI might serve as an early, non-invasive marker of hospital-acquired sepsis in preterm neonates.

Keywords: diagnostic accuracy study; neonatal sepsis; non-invasive marker; perfusion index.