Abnormal Heart Rate Characteristics Prior to Clinical Diagnosis of Necrotizing Enterocolitis

OBJECTIVE: Earlier diagnosis and treatment of necrotizing enterocolitis (NEC) in preterm infants, prior to clinical deterioration, might improve outcomes. A monitor that measures abnormal heart rate characteristics (HRC) of decreased variability and repetitive decelerations was developed as an early warning system for sepsis. Since NEC shares pathophysiologic features with sepsis, we tested the hypothesis that abnormal HRC occur prior to clinical diagnosis of NEC. STUDY DESIGN: Retrospective review of Bells stage II to III NEC cases among infants <34 weeks gestation enrolled in a prospective randomized clinical trial of HRC monitoring at 3 neonatal intensive care units. RESULTS: Of 97 infants with NEC and HRC data, 33 underwent surgical intervention within one week of diagnosis. The baseline HRC index from 1 to 3 days before diagnosis was higher in patients who developed surgical versus medical NEC (2.06 ± 1.98 vs. 1.22 ± 1.10, p=0.009). The HRC index increased significantly 16 hours prior to the clinical diagnosis of surgical NEC and 6 hours prior to medical NEC. At the time of clinical diagnosis, the HRC index was higher in patients with surgical versus medical NEC (3.3 ± 2.2 vs 1.9 ± 1.7, p<0.001). CONCLUSIONS: Abnormal HRC occur before clinical diagnosis of NEC, suggesting that continuous HRC monitoring may facilitate earlier detection and treatment.