Effect of Red Blood Cell Transfusion on Regional Tissue Oxygenation in Pediatric Cardiac Surgery Patients.

BACKGROUND: Red blood cell (RBC) transfusions are used frequently in pediatric patients admitted to the intensive care unit (ICU) after cardiac surgery. To improve data-driven transfusion decision-making in the ICU, we conducted a retrospective analysis to assess the effect of RBC transfusion on cerebral and somatic regional oxygenation (rSO2). METHODS: We evaluated post- versus pre-RBC transfusion cerebral rSO2 and somatic rSO2 in all consecutive pediatric patients (age >28 days to <18 years) who underwent biventricular cardiac surgery at a single center between July 2016 and April 2020. RESULTS: The final data set included 263 RBC postoperative transfusion events in 75 patients who underwent 83 surgeries. The median pretransfusion hemoglobin was 10.6 g/dL (25th-75th percentile, 9.3-11.6). The median pretransfusion cerebral and somatic rSO2 were 63% (54-71) and 69% (55-80), which increased by a median of 3 percentage points (-2 to 6) and 2 percentage points (-3 to 6), respectively, after transfusion. After adjusting for pretransfusion hemoglobin, change in hemoglobin posttransfusion versus pretransfusion, and potential confounders (age, sex, and STAT surgical mortality risk score), the posttransfusion versus pretransfusion change in cerebral or somatic rSO2 was not statistically significant. Pretransfusion cerebral rSO2 (crSO2) was ≤50%, a previously described threshold for increased risk for unfavorable neurological outcome, for 22 of 138 (16%) transfusion events with complete pre- and post-crSO2 data. Sixteen of these 22 (73%) transfusions resulted in a posttransfusion crSO2 >50%. When restricting analysis to the first (index) transfusion after arrival to the ICU from the operating room (administered at a median of 1.15 postoperative days [25th-75th percentile, 0.84-1.93]), between-patient pretransfusion hemoglobin was not associated with pretransfusion crSO2 but within-patient posttransfusion versus pretransfusion hemoglobin difference was significantly associated with posttransfusion versus pretransfusion crSO2 difference (mean posttransfusion versus pretransfusion crSO2 difference, 2.54; 95% confidence interval, 0.50-4.48). CONCLUSIONS: In this study, neither cerebral nor somatic rSO2 increased significantly post- versus pre-RBC transfusion in pediatric cardiac surgery patients admitted to the ICU after biventricular repairs. However, almost three-quarters of transfusions administered when pretransfusion crSO2 was below the critical threshold of 50% resulted in a posttransfusion crSO2 >50%. In addition, the significant within-patient change in crSO2 in relation to the change in posttransfusion versus pretransfusion hemoglobin in the immediate postoperative period suggests that a personalized approach to transfusion following within-patient trends of crSO2 rather than absolute between-patient values may be an important focus for future research.

Implementation of a Regional Oxygen Saturation Thought Algorithm and Association with Clinical Outcomes in Pediatric Patients Following Cardiac Surgery.

Near infrared spectroscopy is routinely used in the noninvasive monitoring of cerebral and somatic regional oxygen saturation (rSO2) in pediatric patients following surgery for congenital heart disease. We sought to evaluate the association of a bedside rSO2 thought algorithm with clinical outcomes in a cohort of pediatric patients following cardiac surgery. This was a single-center retrospective cohort study of patients admitted following cardiac surgery over a 42-month period. The intervention was the implementation of an rSO2 thought algorithm, the primary goal of which was to supply bedside providers with a thought aide to help identify, and guide response to, changes in rSO2 in post-operative cardiac surgical patients. Surgical cases were stratified into two 18-month periods of observation, pre- and post-intervention allowing for a 6-month washout period during implementation of the thought algorithm. Clinical outcomes were compared between pre- and post-intervention periods. There were 434 surgical cases during the period of study. We observed a 27% relative risk reduction in our standardized mortality rate (0.61 to 0.48, p = 0.01) between the pre- and post-intervention periods. We did not observe differences in other post-operative clinical outcomes such as ventilator free days or post-operative ICU length of stay. Providing frontline clinical staff with education and tools, such as a bedside rSO2 thought algorithm, may aide in the earlier detection of imbalance between oxygen delivery and consumption and may contribute to improved patient outcomes.

Cerebral regional oxygen saturation variability in neonates following cardiac surgery.

BACKGROUND: Reduced cerebral regional oxygen saturation (crSO2) variability in neonates, as measured by near-infrared spectroscopy, following cardiac surgery with deep hypothermic circulatory arrest (DHCA) is associated with poor neurodevelopmental outcomes. We sought to evaluate the variability of crSO2 in a cohort of neonates following cardiac surgery with brief or no exposure to DHCA. METHODS: Variability of averaged 1-min crSO2 values was calculated for the first 48 h following cardiac surgery in consecutive neonates over a 30-month period. Neonates requiring aortic arch repair underwent antegrade cerebral perfusion with either brief or no exposure to DHCA. RESULTS: There were 115 neonates included in the study. Reduced crSO2 variability was observed in neonates with aortic arch obstruction (p = 0.02) and non-survivors (p = 0.02). Post hoc analysis demonstrated that the reduction in crSO2 variability was not as marked as in previously studied neonates with aortic arch obstruction who received DHCA alone (p < 0.001). CONCLUSIONS: Neonates with aortic arch obstruction have reduced crSO2 variability following cardiac surgery. The reduction in crSO2 variability observed in aortic arch obstruction is likely influenced by a number of factors, including perioperative perfusion technique. The impact of interventions on crSO2 variability and resultant influence on neurodevelopmental outcomes requires further study. IMPACT: Neonates with aortic arch obstruction have reduced crSO2 variability following cardiac surgery, which has been associated with poor neurodevelopmental outcomes, and is likely influenced by a number of factors, including perioperative perfusion technique. The contribution of perioperative perfusion technique to crSO2 variability following neonatal cardiac surgery is significant. Monitoring of crSO2 variability may provide insights into the adequacy of cerebral perfusion in neonates following cardiac surgery.