BackgroundThe objective of this study was to evaluate mean cerebral blood flow velocity, gaseous microemboli (GME) counts, regional cerebral oxygen saturation (rSO2), and clinical outcomes using multimodality neuromonitoring in risk-stratified congenital cardiac surgery patients and by cyanotic and acyanotic heart disease.MethodsA total of 377 pediatric patients undergoing congenital cardiac surgery with cardiopulmonary bypass (CPB) were stratified by the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) mortality categories and by classification of cyanotic and acyanotic heart disease. Intraoperative mean cerebral blood flow velocity, GME counts, and rSO2 were assessed at multiple time points. Clinical outcomes were compared between patients of each STAT mortality category and cyanotic classification.ResultsMean cerebral blood flow velocities of STAT Mortality Category 5 patients decreased drastically from baseline values after cross-clamp (down to 56%) and after off-bypass (down to 32%), while rSO2 values increased significantly during CPB. Patients in STAT mortality category 5 experienced higher GME counts (1.3- to 4.4-fold greater) compared with patients in all other STAT categories. When compared with acyanotic patients, cyanotic patients experienced significantly lower mean blood flow velocity, significantly greater rSO2 during CPB, and greater GME counts than acyanotic patients (1.3-fold greater). Although 29 patients experienced neurological injury confirmed by electroencephalogram and magnetic resonance imaging, instances of injury were not correlated with GME counts among risk-stratified and cyanotic versus acyanotic patients.ConclusionsUtilization of intraoperative transcranial Doppler, in addition to near-infrared spectroscopy, may help to identify other parameters for cerebral protection, such as drastically decreased cerebral blood flow velocity and increased cerebral microemboli counts, particularly in STAT Mortality Category 5 and cyanotic patients.
Keywords: cardiopulmonary bypass; cerebral hemodynamics; clinical outcomes; congenital heart surgery; gaseous microemboli; near-infrared spectroscopy; transcranial Doppler.