Usefulness of bilateral cerebral regional oxygen saturation measurements in determining selective cerebral perfusion flow rate in a pediatric patient with aortic arch stenosis: a case report

We report a pediatric case where bilateral regional oxygen saturation (rSO2) measurements were useful in determining the selective cerebral perfusion (SCP) flow rate. A 9-year-old Japanese boy, 128 cm tall and weighing 25.6 kg, was scheduled for aortic arch reconstruction due to a 90–100 mmHg pressure gradient. Pediatric-sized oximetry sensors were attached to the bilateral forehead area. The rSO2 levels were 70–80% on the right and 80–90% on the left during cardiopulmonary bypass. Immediately following deep hypothermic circulatory arrest with the body temperature cooled to 25 °C, SCP was initiated from the right brachiocephalic artery at 10 mL/kg/min. As the rSO2 decreased steeply to 43–45% on the right and to 32–38% on the left, the SCP flow was increased to 15 mL/kg/min. The right rSO2 increased promptly to 50–60%, but the left rSO2 remained at 30–40%. After the SCP flow was increased to 20 mL/kg/min, bilateral rSO2 levels of 50–60% were obtained, and the SCP flow rate was maintained. The patient was transferred to the ICU postoperatively and extubated on the second postoperative day with no neurological abnormalities. Bilateral rSO2 measurements are essential even for a pediatric patient undergoing SCP, despite the limited forehead area.