Cardiopulmonary bypass in neonates and infants

Using cardiopulmonary bypass (CPB), congenital cardiac surgeons have the ability to intervene earlier on complex lesions. As a result, definitive and palliative surgical options can be offered to neonates and infants. These populations have higher overall mortality than older children who undergo cardiac surgery. However, this measurement does not consider case-mix. Subsequently, means of mortality risk-adjustment have emerged, which allow for comparison of different surgical groups, quality improvement, and enhanced research. Another common finding postoperatively is vital organ injury, including acute kidney injury, cerebral injury, and myocardial injury. These morbidities have been associated with poor long-term outcomes as the patients age; neural injury is especially tied to poor development, suggesting the need for further neuroprotection in the intraoperative setting through multimodality neuromonitoring. Another major complication that neonates are especially susceptible to is severe inflammatory response secondary to hemodilution and transfusion due to relative circuit size. Using oxygenators with integrated arterial filters, smaller inner diameter tubing, shorter tubing length, mast-mounted pump heads, and lower venous reservoir levels are all ways to reduce priming volumes. However, the safety and hemodynamics of each component must be assessed through in vitro/in vivo evaluations as drastic miniaturization of the circuit could pose more risks than benefits. Additionally, utilizing modified ultrafiltration and optimizing each component of the CPB circuit may help reduce morbidity/mortality for the most fragile patient population.