title: Neurologic Injury Associated with Rewarming from Hypothermia: Is Mild Hypothermia on Bypass Better than Deep Hypothermic Circulatory Arrest?
abstract: Many known risk factors for adverse cardiovascular and neurological outcomes in children with congenital heart defects (CHD) are not modifiable; however, the temperature and blood flow during cardiopulmonary bypass (CPB), are two risk factors, which may be altered in an attempt to improve long-term neurological outcomes. Deep hypothermic circulatory arrest, traditionally used for aortic arch repair, has been associated with short-term and long-term neurologic sequelae. Therefore, there is a rising interest in using moderate hypothermia with selective antegrade cerebral blood flow on CPB during aortic arch repair. Rewarming from moderate-to-deep hypothermia has been shown to be associated with neuronal injury, neuroinflammation, and loss of cerebrovascular autoregulation. A significantly lesser degree of rewarming is required following mild (33-35°C) hypothermia as compared with moderate (28-32°C), deep (21-27°C), and profound (less than 20°C) hypothermia. Therefore, we believe that mild hypothermia is associated with a lower risk of rewarming-induced neurologic injury. We hypothesize that mild hypothermia with selective antegrade cerebral perfusion during CPB for neonatal aortic arch repair would be associated with improved neurologic outcome.
authors.affiliation: Children's Hospital of San Antonio, Baylor College of Medicine , San Antonio, TX , USA.
authors.forename: Utpal S
authors.initials: US
authors.lastname: Bhalala
authors.affiliation: Children's Hospital of San Antonio, Baylor College of Medicine , San Antonio, TX , USA.
authors.forename: Elumalai
authors.initials: E
authors.lastname: Appachi
authors.affiliation: Children's Hospital of San Antonio, Baylor College of Medicine , San Antonio, TX , USA.
authors.forename: Muhammad Ali
authors.initials: MA
authors.lastname: Mumtaz
keywords: cardiopulmonary bypass; children; congenital heart defects; hypothermia; neuroinjury