Heart rate response profiles to tilting in healthy and unhealthy neonates

Clinical observations suggest the immaturity of the neonate's ability to respond appropriately to cardio-respiratory challenges and tilt test could help in detecting autonomic dysfunction in neonates.

Heart rate (HR) responses following a 45 degrees head-up tilt during sleep were measured within the first week of adjusted age in 7 healthy full-term neonates, 7 healthy preterm infants and 5 neonates with abstinence syndrome.

The tilt and the return to the horizontal position generally provoked a sustained or transient tachycardia, or a flat response in healthy full-term neonates and in preterm neonates, but a sustained or transient bradycardia in neonates with abstinence syndrome.

When compared to previous studies in older infants, our data point to the immaturity of the neonate's ability to respond appropriately to cardio-respiratory challenges. No difference is noted between full-term and preterm neonates. The altered HR response in neonates with abstinence syndrome suggests an autonomic dysregulation in this group.