Neonatal Total Body Cooling Device for Treating Hypoxic-Ischemic Encephalopathy
The neonatal cooling device is used to reduce and treat brain injuries and neurological dysfunctions caused by asphyxia in newborns. When encephalopathy in a newborn occurs due to damage from reduced blood oxygenation (hypoxia) and reduced blood flow (ischemia) in the brain, it is referred to as hypoxic-ischemic encephalopathy (HIE) or asphyxia. This condition can have maternal, fetal, or placental origins. Hypoxic-ischemic brain injuries occur in three stages of brain cell damage or death. This condition leads to mortality, epilepsy, and long-term manifestations such as cerebral palsy or developmental delays.
The global incidence of HIE is 15 to 20 newborns per 1,000 full-term births, with a mortality rate of 15 to 20%. Among survivors, 25-30% suffer from neurological developmental defects such as cerebral palsy and mental retardation. According to the Neonatal Health Department’s statistics from 2018 to mid-2021, 7,920 cases of asphyxia were diagnosed in Iran, with 1,582 severe cases and 934 moderate to severe cases, resulting in 82% and 44% mortality rates, respectively. Unfortunately, surviving newborns also suffer severe complications, imposing significant lifelong costs on the healthcare system and their families. Notably, with increasing maternal age, the birth of third and fourth children, and the rise in natural deliveries, the incidence of neonatal asphyxia has
significantly increased, necessitating attention to managing these potential complications.
This condition is typically graded into mild, moderate, and severe levels. The initial phase of injury causes necrotic damage and brain cell death shortly after the onset of asphyxia. The latent phase, occurring 2-8 hours after hypoxic-ischemic injury, provides an opportunity for specific treatments like cooling therapy to prevent further brain damage in subsequent stages. The secondary phase of injury starts 6-24 hours after the injury and can continue for several days, while the tertiary phase can last from weeks to years after the initial injury.
Therefore, the only treatment method that can slightly reduce the severity of moderate or severe encephalopathy is head or whole-body hypothermia therapy, which can be performed as a specific treatment protocol. The standard cooling therapy protocol involves starting treatment within the first 6 hours after birth, cooling the core temperature to around 33.5°C, maintaining this temperature for 72 hours, and then gradually warming the body at a rate of 0.5°C per hour until reaching normal temperature.
There are two general methods for cooling: passive and active. Despite requiring more extensive equipment, the active method is preferred by healthcare centers due to its much more precise temperature control and reduced need for human resources.
In this device, cooling therapy is performed by circulating a coolant through a soft, flexible polyurethane mattress and continuously monitoring the rectal temperature of the newborn as an indicator of core temperature. The coolant is chilled by a cooling system. Cooling continues until the rectal temperature reaches 33.5°C, after which it is maintained at this level for 72 hours based on rectal temperature readings and the performance of temperature controllers. After this period, the heating system activates, gradually raising the newborn’s temperature at a rate of 0.5°C per hour until reaching 37°C.
