title: Review of current research at Boston Children's Hospital.
abstract: Both clinical and laboratory studies are being undertaken to investigate the deleterious neurologic and developmental effects associated with cardiopulmonary bypass, hypothermia, and circulatory arrest in the neonate and infant. A prospective, randomized clinical study of 171 neonates and young infants compared circulatory arrest with low-flow bypass (50 mL.kg-1.min-1). Circulatory arrest was associated with a higher incidence of early postoperative seizures as well as greater release of creatine kinase-BB. There was a strong correlation between duration of circulatory arrest and seizures (p = 0.004). The late consequences of these findings will be known at the completion of developmental assessment of all patients at 1 and 4 years of age. Laboratory studies have used a miniature piglet model that closely replicates clinical circulatory arrest. High-energy phosphate stores determined by magnetic resonance spectroscopy were maintained in animals undergoing 1 hour of low-flow bypass but became undetectable after 32 minutes of a 1-hour period of circulatory arrest. However, they returned to baseline within 3 hours of reperfusion as did cerebral blood flow and metabolism determined by microsphere studies. Piglets undergoing 1 hour of circulatory arrest showed more rapid recovery of cerebral adenosine triphosphate content and intracellular pH when managed with the pH-stat strategy during hypothermic bypass than with the more alkaline alpha-stat strategy. Other laboratory studies have examined pharmacologic methods of reducing cerebral injury associated with circulatory arrest including aprotinin, anti-CD18, neuronal receptor antagonists (MK801, NBQX), and blockade of glutamate release with adenosine in a cerebroplegia solution. These studies have suggested a number of promising approaches to improving the technique of circulatory arrest.
authors.affiliation: Department of Cardiac Surgery, Children's Hospital, Boston, Massachusetts 02115.
authors.forename: R A
authors.initials: RA
authors.lastname: Jonas
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology; D003402:Creatine Kinase / Q000378:metabolism; D006324:Heart Arrest, Induced / Q000009:adverse effects*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007527:Isoenzymes; D011446:Prospective Studies; D012106:Research; D012189:Retrospective Studies; D012640:Seizures / Q000201:enzymology / Q000209:etiology*; D013552:Swine
chemical_list: D007527:Isoenzymes; D000255:Adenosine Triphosphate; D003402:Creatine Kinase