Heart rate variability in response to pain stimulus in VLBW infants followed longitudinally during NICU stay.
The objective of this longitudinal study, conducted in a neonatal intensive care unit, was to characterize the response to pain of high-risk very low birth weight infants (<1,500 g) from 23 to 38 weeks post-menstrual age (PMA) by measuring heart rate variability (HRV). Heart period data were recorded before, during, and after a heel lanced or wrist venipunctured blood draw for routine clinical evaluation. Pain response to the blood draw procedure and age-related changes of HRV in low-frequency and high-frequency bands were modeled with linear mixed-effects models. HRV in both bands decreased during pain, followed by a recovery to near-baseline levels. Venipuncture and mechanical ventilation were factors that attenuated the HRV response to pain. HRV at the baseline increased with post-menstrual age but the growth rate of high-frequency power was reduced in mechanically ventilated infants. There was some evidence that low-frequency HRV response to pain improved with advancing PMA.
Age Factors, Arrhythmia, Sinus, Cohort Studies, Electrocardiography, Female, Gestational Age, Heart Rate, Heel, Humans, Infant Behavior, Infant, Newborn, Infant, Very Low Birth Weight, Intensive Care Units, Neonatal, Intensive Care, Neonatal, Longitudinal Studies, Male, Models, Cardiovascular, Pain, Pain Measurement, Respiration, Signal Processing, Computer-Assisted, Video Recording