Predictive monitoring for sepsis and necrotizing enterocolitis to prevent shock

Abstract

Despite vigilant clinical assessment of infants in the neonatal intensive care unit (NICU), diagnosis of sepsis and necrotizing enterocolitis often does not occur until an infant has significant hemodynamic compromise. Predictive monitoring involves analysis of vital signs and other clinical data to identify infants at highest risk and to detect early-stage illness, leading to timelier treatment and improved outcomes. The first vital-sign predictive monitoring device developed for sepsis detection in babies in the NICU is the heart rate characteristics index (HeRO) monitor, which continuously analyzes the electrocardiogram signal for low heart rate variability and transient decelerations. Use of this monitor in very low birth weight infants (<1500 g) was shown in a large multicenter randomized clinical trial to significantly reduce mortality. The purpose of this review is (1) to summarize the physiologic changes in neonatal sepsis and progression to shock, (2) to review efforts toward risk stratification for sepsis shortly after birth based on demographic and physiologic scoring systems, (3) to describe development and implementation of heart rate characteristics monitoring and other important aspects of sepsis early warning systems, and (4) to provide an overview of current research analyzing multiple vital signs and other clinical variables in an attempt to develop even more effective predictive monitoring devices and systems.

Keywords: Heart rate characteristic monitoring; Heart rate characteristics index; Necrotizing enterocolitis; Predictive monitoring; Sepsis; Shock; Systemic inflammatory response syndrome.

Fig. 1.

Preventing shock through predictive monitoring for sepsis and necrotizing enterocolitis (NEC). With conventional neonatal intensive care unit bedside monitors, changes in vital signs in the early stages of illness may go unrecognized. Risk assessment and early detection through analysis of heart rate characteristics or other physiologic changes can lead to earlier treatment with antibiotics. Hemodynamic monitoring early in the course of illness could guide fluid and vasopressor therapy, preventing further compromise. SIRS, systemic inflammatory response syndrome; HRC, heart rate characteristics.

Fig. 2.

Four screen shots from the heart rate characteristics (HRC) index (HeRO) monitor. See text for clinical scenarios. (A) Normal heart rate characteristics and a low HRC index. The individual patient view on the monitor shows the five-day trend in the HRC index (orange, top), the last 30 min of heart rate (green, bottom), and the current HRC index (right, 0.25). (B) At the yellow vertical line, there was a small increase in the HRC index to 1.4. The 30 min HR tracing at that time shows decreased beat-to-beat variability (green). (C) At the yellow line, the HRC index had increased from a baseline of 1–2 to 3.5 and continued to increase for about 12 h before declining. The corresponding HR tracing shows multiple small decelerations and relatively few accelerations. (D) The five-day trend shows the HRC index ranging from 2 to 5 in an infant with severe chronic lung disease.