Could a light cap save infant brains after cardiac arrest?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria Subjects must meet ALL of the following criteria to be eligible for participation in the study: * In advance of the IHCA, a consent form signed by the Legally Authorized Representative (LAR) such as a parent/guardian will be attained. * Age greater than 48 hours and less than 1 year (with a corrected gestational age of at least 38 weeks). * Greater than or equal to 2.5 kg body weight. * Acquired or congenital heart disease. * Society of Thoracic Surgeons- European Association for Cardio-Thoracic Surgery (STAT) categories 4 and 5" and those patients with medical cardiac conditions with an admission diagnosis of acute heart failure, if blood lactate levels are greater than 3 mmol/L, or if mechanically ventilated within 4 hours of admission. * Chest compressions for at least 2 minutes (120 seconds) during IHCA with ROC; Modified Glasgow Coma Scale for Infants and Children will be used to determine eligibility. * Coma or encephalopathy after ROC. Coma or encephalopathy after ROC, Modified Glasgow Coma Scale for Infants and Children will be used to determine eligibility. * Requires mechanical ventilation (i.e., via endotracheal tube or tracheostomy). * The cardiac arrest was unplanned (i.e., not part of cardiac surgical procedure). * A patient with a condition in which direct contact with the scalp is contraindicated such as decubitus ulcers, cellulitis, cuts, nicks, scratches, or other conditions with disrupted scalp integrity, will not be eligible for treatment, but will be eligible for the study and data collected will be used as control data. Exclusion Criteria: Subjects must be EXCLUDED from participation in this study if ANY of the following criteria are met: * The Legally Authorized Representative does not speak English or Spanish * The LUCID cap is impossible to place within two (2) hours of ROC. * Preterm neonates (with a corrected gestational age of less than 38 weeks) due to the potential incompatibility with cap sizes, lack of information on depth of targeted brain structures, potential for waveguide overlap, and increased skin frailty. * Patients with a head size outside of the range of cap requirements: 32-49cm. * Modified Glasgow Coma Scale for Infants and Children motor response of six (infants, normal spontaneous movement) prior to treatment. * Duration of chest compressions greater than 60 minutes inclusive of ECMO deployment. * Pre-existing severe neurodevelopmental deficits with PCPC = 5 or progressive degenerative encephalopathy. * Central nervous system tumor with ongoing chemotherapy or radiation therapy. * Pre-existing terminal illness with life expectancy \< 3 months. * Progressive degenerative encephalopathy. * Cardiac arrest was associated with severe brain, thoracic, or abdominal trauma * Active and refractory severe bleeding prior to treatment. * Continuous infusion of epinephrine or norepinephrine at very high doses (≥ 2 μg/kg/minute). * Patient is newborn with acute birth asphyxia. * Patient cared for in a neonatal intensive care unit (NICU) after arrest (i.e., would not be admitted to PICU). * Patient has sickle cell anemia. * Patient known to have pre-existing cryoglobulinemia. * Patient known to have progressive degenerative encephalopathy. * Patient is known to have neurological issues including convulsions/epileptic seizures, intraventricular hemorrhage, Hypoxic-ischemic encephalopathy, periventricular leukomalacia, and retinopathy of prematurity. * Patient is known to have a recorded temperature at treatment/LDU site out of range. * Lack of commitment to aggressive intensive care therapies including do not resuscitate orders and other limitations to care. * History of a prior cardiac arrest with chest compressions for at least two minutes during the current hospitalization but outside the 2-hour window for treatment. * Patient cared for in a neonatal intensive care unit (NICU) after arrest (i.e., not admitted to pediatric ICU (PICU)/CICU). * Patients with prior or concurrent enrollment in any other neurotherapeutic trial, which may confound this study's results and expose patients to the unknown risks of multiple investigational treatments. * Patient participation in a concurrent interventional trial whose protocol, in the judgment of the LUCID investigators, prevents effective application of LUCID, or otherwise significantly interferes with carrying out the LUCID protocol. We will use the Neonatal Adverse Event Severity Scale. * Previous enrollment in or termination from LUTICA trial.