Optimizing (Longer, Deeper) Cooling for Neonatal Hypoxic-Ischemic Encephalopathy(HIE)

Overview

The Optimizing Cooling trial will compare four whole-body cooling treatments for infants born at 36 weeks gestational age or later with hypoxic-ischemic encephalopathy: (1) cooling for 72 hours to 33.5°C; (2) cooling for 120 hours to 33.5°C; (3) cooling for 72 hours to 32.0°C; and (4) cooling for 120 hours to 32.0°C. The objective of this study is to evaluate whether whole-body cooling initiated at less than 6 hours of age and continued for 120 hours and/or a depth at 32.0°C in will reduce death and disability at 18-22 months corrected age.

Hypoxic-ischemic encephalopathy (HIE) is a rare, but life-threatening condition characterized by brain injury due to asphyxia diagnosed at or shortly after birth. According to the World Health Organization, more than 722,000 children died from birth asphyxia and birth trauma worldwide in 2004. An estimated 50-75 percent of infants with severe (stage 3) HIE will die, with 55 percent of these deaths occurring in the first month. Up to 80 percent of infants who survive stage 3 HIE develop significant long-term disabilities, including intellectual disabilities, epilepsy, and cerebral palsy with hemiplegia, paraplegia, or quadriplegia; 10-20 percent develop moderately serious disabilities; and up to 10 percent are normal. Previous studies have shown treatment with hypothermia to be an effective therapy for HIE. Currently, infants diagnosed with HIE at less than six hours of age are given whole-body cooling, decreasing their core body temperature to 33.5°C (93.2° Fahrenheit) for a period 72 hours using a cooling blanket. This treatment appears to protect the brain, decreasing the rate of death and disability and improving the chances of survival and neurodevelopmental outcomes at 18 months correct age. But additional trials are needed to help define the most effective cooling strategies. The Optimizing Cooling trial will examine whether cooling for a longer time period and/or to a lower temperature will improve the chance of survival and neurodevelopmental outcomes at 18-22 months corrected age. Eligible infants with HIE will be placed in one of four cooling groups: (1) cooling for 72 hours to 33.5°C; (2) cooling for 120 hours to 33.5°C; (3) cooling for 72 hours to 32.0°C; and (4) cooling for 120 hours to 32.0°C. Infants will be monitored closely and receive the care of the Neonatal Intensive Care Unit (NICU). Infants enrolled in the study will be placed on a cooling blanket - the same type of blanket children's hospitals use in the NICU, in operating rooms during surgeries, and to cool children with high fevers. Each infant will be cooled according to the study group he or she is assigned to. During cooling, the infant's temperature will be very closely monitored by continuous esophageal (core)temperature readings. This will be done by placing a soft, narrow, flexible plastic tube into the infant's nose and down to just above the stomach. Skin temperatures will also be monitored closely. At the end of the assigned period of cooling, the infant will be slowly re-warmed until a normal core temperature of 36.5 to 37.0°C (97.7 to 98.6°C) is reached. Infants will be examined at 18-22 months corrected age to assess their neurodevelopmental outcomes. Secondary Studies include: A. Using aEEG to 1)predict mortality or moderate to severe disability at 18-22 months in term infants with HIE treated with systemic hypothermia and 2) to record electrical seizure activity to compare rewarming initiated at 72 hours and later rewarming that is initiated at 120 hours. B. Secondary Study includes determining an association between MRI detectable injury and neurodevelopment at 18-22 months.