Prolonged Central Line in Preemies Tied to Fewer Needle Sticks, Better Thalamus Growth

By Lisa Rapaport

October 29, 2020

(Reuters Health) - Premature infants who have central lines maintained for more than 14 days have fewer needle pokes that break the skin and more thalamus growth than infants with lines in place for shorter periods of time, a new study suggests.

Researchers studied two groups of extremely preterm neonates born at less than 28 weeks' gestation with arterial line and central venous line (AC/CVL) used for a prolonged period of at least 14 days (n=86) or for a restricted period of less than 14 days (n=57). The median number of skin breaks from needle pokes was 34 with prolonged AC/CVL use, compared with a median of 91 skin breaks with restricted AC/CVL use.

The neonates who had prolonged AC/CVL also had larger thalamic volume on MRI scans within a few weeks after birth than those with restricted AC/CVL. After adjusting for sex, age at birth, and age at MRI scan, the neonates who had prolonged AC/CVL use had a mean thalamic size of 1,233 cubic millimeters (mm3), compared to 1,110 mm3 in neonates who had restricted AC/CVL use.

While the study didn't examine the reason for the association, it's possible more pain impacts the development of neuronal morphology or synaptic connectivity in the thalamus, leading to slower growth, said senior study author Dr. Steven Miller, a professor of pediatrics at the University of Toronto and a senior scientist at the SickKids Research Institute.

"We recognize from this study, and others, that the thalamus is an important brain structure for motor skills and cognitive function," Dr. Miller said by email. "In these babies born extremely preterm, increased growth of the thalamus in the first weeks of life predicted better developmental function at school age."

Neuropsychological exams done for a total of 118 children (83%) at a median age of 4.9 years found that children with a larger thalamus size as infants achieved higher scores on cognitive and motor assessments than their counterparts with a smaller thalamus size in infancy.

On the Movement Assessment Battery for Children, second edition (MABC-2), scores ranged from the 1st to the 90th percentiles. The median score for the kids who had received prolonged AC/CVL as neonates was 31st percentile, compared with 25th percentile for those who had restricted AC/CVL as neonates.

On the Wechsler Preschool and Primary Scale of Intelligence, third edition (WPPSI), the median score was 104 for those who had prolonged AC/CVL compared with 96 with restricted AC/CVL.

It's not clear from the study results whether reducing needle pokes or invasive procedures during infancy might promote more brain growth or lead to improved outcomes on motor or cognitive assessments later in childhood, the study team notes in Neurology.

"The finding that thalamic health is negatively impacted by pain in the first weeks of life suggests that activation of pain pathways in some manner leads to a disruption of thalamic maturation," said Dr. Brenda Banwell, chief of child neurology at the Children's Hospital of Philadelphia and a professor of neurology and pediatrics at the University of Pennsylvania.

"The authors do not have data to indicate why this occurs at the pathological level," Dr. Banwell, who wasn't involved in the study, said by email.

Even so, the paper has important implications for clinical care, Dr. Banwell said.

"The authors show that reduction of painful procedures - heel sticks in particular - can be achieved by use of a central line, and that infections were not significantly increased in neonates with lines," Dr. Banwell said.

SOURCE: Neurology, online October 21, 2020.