Preoperative cerebral and renal oxygen saturation and clinical outcomes in pediatric patients with congenital heart disease

We examined the predictability of preoperative cerebral and renal rSO₂ values for outcomes in pediatric patients undergoing cardiac surgery under cardiopulmonary bypass (CPB). Patients who underwent pediatric cardiac surgery under CPB between September 2015 and September 2017 were enrolled in this study. Patients monitored with both cerebral and renal rSO₂ at the beginning of surgery were included. The primary outcome was the prediction of outcomes after pediatric cardiac surgery. Outcome was defined as any of: (1) death within 30 days after surgery, or the need for (2) renal replacement therapy or (3) extracorporeal membrane oxygenation, (4) shorten mechanical ventilator-free day,(5) shorten ICU-free survival day. We included 59 patients: cyanotic n = 31; non-cyanotic n = 28. Among all patients, 15 (25%) had poor outcomes, including three deaths. The cerebral and renal rSO₂ values were significantly lower in the cyanotic patients with poor outcomes compared to those without poor outcomes (cerebral: 59 ± 11 vs. 50 ± 5, p = 0.021; renal: 59 ± 15 vs. 51 ± 14, p = 0.015) but only the renal rSO₂ value was significantly lower in the non-cyanotic patients (77 ± 10 vs. 61 ± 14, p = 0.011). The cut-off value (51%) of cerebral rSO₂ were associated with risk of mechanical ventilator-free day and ICU-free survival day [ORs of 22.8 (95% CI 2.21–235.0, p = 0.0087) and 15.8 (95% CI 1.53–164.0, p = 0.0204), respectively] in the cyanotic patients. The cut-off value (66%) of cerebral rSO₂ value was associated with risk of mechanical ventilator-free day [OR of 11.3 (95% CI 1.05–25.3, p = 0.0456)] and the cut-off value (66%) of renal rSO₂ value was associated with risk of ICU-free survival day [ORs of 33.0 (95% CI 2.25–484.0, p = 0.0107)] in the noncyanotic patients. The preoperative low rSO₂ values were associated with outcomes including 30-day mortality and might be reflective of the severity of cardiopulmonary function. Further studies are needed to confirm our results.