Impact of Pre-Bypass Ultrafiltration on Prime Values and Clinical Outcomes in Neonatal and Infant Cardiopulmonary Bypass

Background: A standard blood prime for cardiopulmonary bypass (CPB) in congenital cardiac surgery may possess non-physiologic values for electrolytes, glucose, and lactate. Pre-bypass Ultrafiltration (PBUF) can make these values more physiologic and standardized prior to bypass initiation. We aimed to determine if using PBUF on blood primes including packed red blood cells and thawed plasma would make prime values more predictable and physiologic. Additionally, we aimed to evaluate whether the addition of PBUF had an impact on outcome measures. Methods: Retrospective review of consecutive patients ≤ 1 year of age undergoing an index cardiac operation on CPB between 8/2017-9/2021. As PBUF was performed at the perfusionists’ discretion, a natural grouping of patients that received PBUF vs. those that did not occurred. Differences in electrolytes, glucose, and lactate were compared at specific time-points using Fisher’s exact test for categorical variables and the Wilcoxon rank sum test for continuous variables. Clinical outcomes were also assessed. Results: In both cohorts, the median age at surgery was 3 months and 47% of patients were female; 308/704 (44%) of PBUF group and 163/414 (39%) of the standard prime group had at least one preoperative risk factor. The proportion of PBUF circuits which demonstrated more physiologic values for glucose (318 [45%]), sodium (434, [62%]), potassium (688 [98%]), lactate (612 [87%]) and osmolality (595 [92%]) was significantly higher when compared to standard prime circuit levels for glucose (8 [2%]), sodium (13 [3%], potassium (150 [36%]), lactate (56 [13%]) and osmolality (23 [6%]) prior to CPB initiation. There were no differences in clinical outcomes or rates of major adverse events between the two cohorts. Conclusions: PBUF creates standardized and more physiologic values for electrolytes, glucose, and lactate before the initiation of bypass without significant impacts on in-hospital outcomes.