Electrical grounding improves vagal tone in preterm infants.

Passi et al, 2017 [prospective observational, within-subjects cross-over, n=26, male and female, 26–36 weeks of postmenstrual age and 6–60 days of age hospitalized in the NICU] aimed to measure the electric field strengths in the NICU environment and to determine if connecting an infant to electrical ground would reduce the skin potential and improve Vagal Tone (VT). Also, wished to determine if the skin potential correlated with VT. Environmental magnetic flux density (MFD) was measured in and around incubators. Electrical grounding (EG) was achieved with a patch electrode and wire that extended to a ground outlet. We measured the skin potential and heart rate variability before, during, and after grounding. The background MFD in the NICU was below 0.5 mG, but it ranged between 1.5 and 12.7 mG in the closed incubator. A 60-Hz oscillating potential was recorded on the skin of all infants. With EG, the skin voltage dropped by about 95%. Pre-grounding VT was inversely correlated with the skin potential. VT increased by 67% with EG. After grounding, the VT fell to the pregrounding level. The authors concluded that the electrical environment affects autonomic balance. EG improves VT and may improve resilience to stress and lower the risk of neonatal morbidity in preterm infants.