Table 3. Studies evaluating the use of HRC index in neonatal sepsis.

Author of study	Year of study	Study population	Aims of study	Results	Comments (if any)
Moorman et al. (62)	2011	3,003 VLBW neonates in 9 NICUs	Comparing number of days alive and ventilator-free for 120 days post-randomisation between neonates with and without HRC monitoring	2% mortality reduction rate in infants with HRC monitoring displayed (10.2% to 8.1%, P=0.04), with increased days alive and ventilator-free (95.9 days compared to 93.6 days in control subjects, P=0.08)
Griffin et al. (63)	2003	633 infants in 2 NICUs, of which 270 were VLBW infants	To derive and validate multivariable statistical models involving HRC to predict for sepsis and sepsis-like illness in newborn infants	Regression models involving the use of HRC index is highly predictive for sepsis and sepsis-like illness in both NICUs (P<0.001), and added significantly to demographic information of birth weight, gestational age, and days of post-natal age (P<0.001). Regression models including HRC index performed better with a ROC curve of 0.77, as compared to 0.72 without HRC index	Reduced variability and transient decelerations precede clinical signs and symptoms of sepsis and sepsis-like illness in newborn infants
Griffin et al. (64)	2005	1,022 infants in 2 NICUs, of which 458 were VLBW infants	To evaluate the use of continuous HRC index monitoring as a risk index to identify infants who are at increased risk of sepsis, urinary tract infections or death in the NICU	Neonates with high-risk HRC index and abnormal laboratory test results had an 11% incidence of adverse outcomes compared with 2% in neonates with normal HRC and normal laboratory test results (P<0.001). High HRC with an abnormal laboratory test result have a 6- to 7-fold increase in relative risk compared to High HRC without abnormal laboratory test results (P<0.001)	HRC monitoring adds information to abnormal laboratory results in predicting neonatal outcomes

HRC, heart rate characteristics; NICUs, neonatal intensive care units; VLBW, very-low-birth-weight; ROC, receiver operating characteristics.