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postoperative neonates and employs a probe that emits a near-infrared spectrum of light that is placed on the forehead and measures venous oxygen saturations Low cerebral oxygen saturations in the 48-hour period following the Norwood operation have been associated with brain MRI abnormalities and poor neurodevelopmental outcomes.133,134 It is not clear if low saturations are the cause of brain injury or a marker for infants with reduced physiologic reserve Centers that routinely use NIRS target interventions to keep cerebral NIRS saturations greater than 50%; these measures include sedation, mechanical ventilation, paralysis, packed red blood cell transfusion, and inotropic support A large limitation of NIRS is that it has poor reproducibility and poor intersubject reliability, which have limited recommendations for its routine use.135 Continuous Electroencephalography Postoperative seizures have been detected in one-quarter to one-third of neonates with hypoplastic left heart syndrome undergoing surgery with cardiopulmonary bypass.136 Seizures are largely subclinical and have been associated with mortality and neurodevelopmental dysfunction.136–138 Routine postoperative continuous EEG monitoring has been recommended by the American Neurophysiology Society; however, the widespread implementation of EEG monitoring is limited by the intense utilization of resources associated with this strategy.139 Head Ultrasonography Ultrasonography of the head is widely used to screen for preoperative and postoperative brain injury, although there are few data to support routine use Head ultrasonography can detect structural abnormalities of the brain and large hemorrhages and is used routinely to monitor neonates and infants on extracorporeal membrane oxygenation However, it is insensitive for the detection of strokes and has a high false-positive rate for hemorrhage that is not substantiated by MRI of the brain.140 Brain Magnetic Resonance Imaging The current gold standard imaging modality is MRI with MR angiography coupled with diffusion-weighted imaging and perfusion imaging; these modalities play a critical role in evaluation of the pathophysiology of brain injury In the postoperative period identified risk factors include hypoxemia, diastolic hypotension, cardiopulmonary bypass with regional cerebral perfusion, and decreased hemoglobin during bypass.141,142 Data on the association of brain MRI abnormalities in this population with long-term neurodevelopmental outcome are limited, but recent work suggests that perioperative white matter injury is associated with worse scores on neurodevelopmental testing at ages 2 and 6 years.143 Pain, Sedation, and Neurodevelopmental Care Pain control, appropriate levels of sedation, and emphasis on neurodevelopmental care are imperative components of postoperative management Uncontrolled pain has been shown to adversely affect central nervous system development in premature infants; however, the medications most frequently utilized may have adverse consequences as well The hemodynamic effects of uncontrolled pain and distress include tachycardia and hypertension, which may be particularly deleterious for fragile infants with a multidistribution circulation For the early postoperative neonate with a fUVH, increases in VO2 at a period when DO2 may be borderline, as well as fluctuations in systemic and pulmonary vascular tone, may lead to cardiac arrest Endotracheal tube suctioning, in particular, results in particularly noxious stimulation at a point when myocardial function is at its lowest and systemic and pulmonary vascular tone are at their most labile Ideally, analgesic and sedative medications will be titrated in a manner similar to vasoactive infusions targeting the minimal effective dose Additional as-needed doses may be used prior to anticipated painful or noxious stimulation As the neonate progresses in recovery, optimization of nonpharmacologic interventions and developmentally appropriate care will complement, medical management, thus limiting the need for excessive sedation These points are summarized in Table 71.7 A more complete review of the topic of neurodevelopmental care and nonpharmacologic interventions has recently been published by Lisanti and colleagues.144 Table 71.7 Interventions for Pain and Agitation: Risks and Benefits Risk PHARMACOLOGIC Neuromuscular blockade Global deconditioning and myopathy (especially with Benefit Decreased VO2 steroid use) Masks seizure activity Benzodiazepines Cerebral apoptosis Increased risk of delirium Hypotension Narcotics Feeding intolerance (bowel immobility) Dependence syndrome Respiratory depression Nonsteroidal antiinflammatory Renal dysfunction drugs Platelet dysfunction Reye syndrome (