Protecting the Infant Brain During Cardiac Surgery: A Systematic Review

Abstract

Prevention of brain injury during congenital heart surgery has focused on intraoperative and perioperative neuroprotection and neuromonitoring. Many strategies have been adopted as “standard of care.” However, the strength of evidence for these practices and the relationship to long-term outcomes are unknown. We performed a systematic review (January 1, 1990 to July 30, 2010) of neuromonitoring and neuroprotection strategies during cardiopulmonary bypass (CPB) in infants of age 1 year or less. Papers were graded individually and as thematic groups, assigning evidence-based medicine and American College of Cardiology/American Heart Association (ACC/AHA) level of evidence grades. Consensus scores were determined by adjudication. Literature search identified 527 manuscripts; 162 met inclusion criteria. Study designs were prospective observational cohort (53.7%), case-control (21.6%), randomized clinical trial (13%), and retrospective observational cohort (9.9%). Median sample size was 43 (range 3 to 2,481). Primary outcome was evidence of structural brain injury or functional disability (neuroimaging, electroencephalogram, formal neurologic examination, or neurodevelopmental testing) in 43%. Follow-up information was reported in only 29%. The most frequent level of evidence was evidence-based medicine level 4 (33.3%) or ACC/AHA class IIB: level B (42%). The only intervention with sufficient evidence to recommend “the procedure or treatment should be performed” was avoidance of extreme hemodilution during CPB. Data supporting use of current neuromonitoring and neuroprotective techniques are limited. The level of evidence is insufficient to support effectiveness of most of these strategies. Well-designed studies with correlation to clinical outcomes and long-term follow-up are needed to develop guidelines for neuromonitoring and neuroprotection during CPB in infants.

Neurological Injury After Neonatal Cardiac Surgery

“…3,[5][6][7][8] There is an ongoing debate in regard to whether pH-stat strategy is superior to alpha-stat strategy, and, similarly, it is unclear whether a low (20%) or high (30%) hematocrit is preferable. 21 Finally, we do not know the effect of the preoperative administration of dexamethasone, which is routinely used at our institution, even though similar doses have been associated with delayed later development in premature infants with chronic lung disease. 22 It is known from studies in premature neonates that cerebral hypoperfusion, hypoxia, and inflammation are all considered to contribute to WMI.…”

Anesthesia for Cardiac Surgery in Neonates

“…In addition to the previously discussed neuroprotective strategies, other approaches have been explored in an effort to limit neurologic morbidity after cardiac surgery [ 275 ]. These strategies include specifi c anesthetic regimens (e.g., ketamine, dexmedetomidine), administration of drugs (e.g., erythropoietin, anti-infl ammatory agents, free radical scavengers, and neurotrophic factors), preconditioning (hypoxiaischemia and remote ischemia), and stem cell treatment [ 276 ].…”

Usefulness of Percutaneous Transluminal Pulmonary Artery Balloon Angioplasty after Bilateral Pulmonary Artery Banding: Prevention against Additional Surgical Interventions

“…Despite a significant improvement in mortality and morbidity rates associated with neonatal operations involving cardiopulmonary bypass, morbidity continues to occur to some extent owing to the immaturity and fragility of neonatal organs. Neonatal cardiopulmonary bypass can cause brain injury, which can result in severely impaired motor and cognitive neurodevelopmental outcomes, although notable advances and innovations have been made in cardiopulmonary bypass, surgical techniques, and instruments [3,4]. Moreover, patients with severe coronary heart disease (CHD) have significantly impaired early neurodevelopmental outcomes, although the mortality rate after a hybrid procedure is similar to that after the Norwood procedure [5].…”