Preterm infant heart rate is lowered after Family Nurture Intervention in the NICU: Evidence in support of autonomic conditioning

Abstract

BackgroundCardiac complications after premature birth are associated with negative long-term consequences to health. The Family Nurture Intervention (FNI) has been designed to support mother-infant parasympathetic calming sessions in the neonatal intensive care unit (NICU). FNI has shown neurodevelopmental and autonomic benefit across infant development. AimsWe tested the hypothesis that heart rate (HR) will decrease after FNI over the course of the NICU stay, compared to matched controls. Study designWe used a case-matched design. The intervention included on average four ~1-hour facilitated mother-infant ‘calming’ sessions per week. We collected 24/7 real time heart rate data from a central monitoring system and analyzed data from two time-periods. SubjectsThe intervention group comprised 37 infants born ~30 weeks gestational age (GA) in a level IV NICU, treated with FNI. From the same NICU and time-period, we created a contemporaneous comparison group of 32 infants who were case-matched to each intervention infant for sex, age-at-birth, singleton or twin status, month of admission and length of stay. Outcome measuresUsing generalized estimating equation (GEE) modeling, we analyzed 24/7 HR data during a 1-hour period between 4:30 and 5:30 am each day in the NICU, when all infants were least disturbed. Using repeated measures ANOVA, we analyzed 24/7 HR data during a 6-week period starting 1 week prior to the start of FNI and ending 5 weeks after start. ResultsGEE modeling of the 1-hour data from all subjects showed significant lower HR in the FNI group, compared with controls. ANOVA modeling on a subset of subjects over the five-week period showed that FNI infant HR decreased in a dose-response manner relative to SC HR. ConclusionThis study suggests FNI may condition lower infant HR in a dose-response manner during the NICU stay.