Dataset Information

Later cooling within 6?h and temperatures outside 33-34?°C are not associated with dysfunctional autoregulation during hypothermia for neonatal encephalopathy.

ABSTRACT:

Background

Cooling delays, temperature outside 33-34?°C, and blood pressure below the mean arterial blood pressure with optimal cerebral autoregulation (MAP_OPT) might diminish neuroprotection from therapeutic hypothermia in neonates with hypoxic-ischemic encephalopathy (HIE). We hypothesized that longer time to reach temperature <34?°C and having temperature outside 33-34?°C would be associated with worse autoregulation and greater brain injury.

Methods

Neonates with HIE had rectal temperature and near-infrared spectroscopy autoregulation monitoring during hypothermia (n?=?63) and rewarming (n?=?58). All underwent brain MRI, and a subset received diffusion tensor imaging MRI before day 10 (n?=?41).

Results

Most neonates reached <34?°C at 3-6?h of life. MAP_OPT was identified in 54/63 (86%) during hypothermia and in 53/58 (91%) during rewarming. Cooling time was not related to blood pressure deviation from MAP_OPT. Later cooling was associated with lower ADC scalar in unilateral posterior centrum semiovale but not in other regions. Temperatures >34?°C were associated with blood pressure above MAP_OPT but not with brain injury.

Conclusions

In neonates who were predominantly cooled after 3?h, cooling time was not associated with autoregulation or overall brain injury. Blood pressure deviation above MAP_OPT was associated with temperature >34?°C. Additional studies are needed in a more heterogeneous population.

Impact

Cooling time to reach target hypothermia temperature within 6?h of birth did not affect cerebral autoregulation measured by NIRS in neonates with hypoxic-ischemic encephalopathy (HIE). Temperature fluctuations >33-34?°C were associated with blood pressures that exceeded the range of optimal autoregulatory vasoreactivity. Cooling time within 6?h of birth and temperatures >33-34?°C were not associated with qualitative brain injury on MRI. Regional apparent diffusion coefficient scalars on diffusion tensor imaging MRI were not appreciably affected by cooling time or temperature >33-34?°C. Additional research in a larger and more heterogeneous population is needed to determine how delayed cooling and temperatures beyond the target hypothermia range affect autoregulation and brain injury.

SUBMITTER: Gilmore MM

PROVIDER: S-EPMC7541414 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Later cooling within 6 h and temperatures outside 33-34 °C are not associated with dysfunctional autoregulation during hypothermia for neonatal encephalopathy.

Gilmore Maureen M MM Tekes Aylin A Perin Jamie J Parkinson Charlamaine C Spahic Harisa H Chavez-Valdez Raul R Northington Frances J FJ Lee Jennifer K JK

Pediatric research 20200408 1

<h4>Background</h4>Cooling delays, temperature outside 33-34 °C, and blood pressure below the mean arterial blood pressure with optimal cerebral autoregulation (MAP<sub>OPT</sub>) might diminish neuroprotection from therapeutic hypothermia in neonates with hypoxic-ischemic encephalopathy (HIE). We hypothesized that longer time to reach temperature <34 °C and having temperature outside 33-34 °C would be associated with worse autoregulation and greater brain injury.<h4>Methods</h4>Neonates with HI ...[more]

PMID: 32268341

Similar Datasets

Project description:We previously reported early results of a randomized trial of whole-body hypothermia for neonatal hypoxic-ischemic encephalopathy showing a significant reduction in the rate of death or moderate or severe disability at 18 to 22 months of age. Long-term outcomes are now available.In the original trial, we assigned infants with moderate or severe encephalopathy to usual care (the control group) or whole-body cooling to an esophageal temperature of 33.5°C for 72 hours, followed by slow rewarming (the hypothermia group). We evaluated cognitive, attention and executive, and visuospatial function; neurologic outcomes; and physical and psychosocial health among participants at 6 to 7 years of age. The primary outcome of the present analyses was death or an IQ score below 70.Of the 208 trial participants, primary outcome data were available for 190. Of the 97 children in the hypothermia group and the 93 children in the control group, death or an IQ score below 70 occurred in 46 (47%) and 58 (62%), respectively (P=0.06); death occurred in 27 (28%) and 41 (44%) (P=0.04); and death or severe disability occurred in 38 (41%) and 53 (60%) (P=0.03). Other outcome data were available for the 122 surviving children, 70 in the hypothermia group and 52 in the control group. Moderate or severe disability occurred in 24 of 69 children (35%) and 19 of 50 children (38%), respectively (P=0.87). Attention-executive dysfunction occurred in 4% and 13%, respectively, of children receiving hypothermia and those receiving usual care (P=0.19), and visuospatial dysfunction occurred in 4% and 3% (P=0.80).The rate of the combined end point of death or an IQ score of less than 70 at 6 to 7 years of age was lower among children undergoing whole-body hypothermia than among those undergoing usual care, but the differences were not significant. However, hypothermia resulted in lower death rates and did not increase rates of severe disability among survivors. (Funded by the National Institutes of Health and the Eunice Kennedy Shriver NICHD Neonatal Research Network; ClinicalTrials.gov number, NCT00005772.).