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 and 9/2021. As PBUF was performed at the perfusionists' discretion, a natural grouping of patients that received PBUF vs. those that did not occur. 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 the 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.

Predictors of Increased Lactate in Neonatal Cardiac Surgery: The Impact of Cardiopulmonary Bypass.

OBJECTIVE: Hyperlactatemia develops intraoperatively during cardiac surgery and is associated with postoperative mortality. This study aimed to determine the factors that lead to an increase in lactate during cardiopulmonary bypass (CPB) in neonates undergoing cardiac surgery. DESIGN: Retrospective study from July 2015 to December 2018. SETTING: Academic tertiary children's hospital. PARTICIPANTS: The study comprised 376 neonates. INTERVENTIONS: No interventions were performed. MEASUREMENTS AND MAIN RESULTS: Lactate measurements at prebypass, upon initiation of CPB and before coming off CPB, last in the operating room, and first in the cardiac intensive care unit were collected. The changes in lactate levels were compared using the nonparametric Wilcoxon signed rank test for paired data. Univariate and multivariate median regression models of the change during CPB were determined. The cohort characteristics were male (60%), median age 5 days (range 1-30), and weight 3.2 kg (range 1.5-4.7). Most patients had a STAT score of 4 (45%) or 5 (23%). Significant increases in lactate were observed from pre-CPB to start of CPB (p < 0.001) and from start to end of CPB (p < 0.001). In the multivariate regression analysis, duration of circulatory arrest (coefficient = 1.216; 95% confidence interval [CI] 0.754-1.678; p < 0.001), duration of mean arterial pressure < 25 mmHg (coefficient = 0.423; 95% CI 0.196-to- 0.651; p < 0.001), and duration of mean arterial pressure between 35 and 39 mmHg (coefficient = -0.246; 95% CI -0.397 to -0.095; p = 0.001) were identified as significant independent predictors of the lactate change per 30- minutes duration. CONCLUSION: These results emphasized the importance of blood pressure management during CPB and the importance of the duration of circulatory arrest.

A red cell preservation strategy reduces postoperative transfusions in pediatric heart surgery patients.

BACKGROUND: Blood transfusion has well-documented adverse effects. As part of a blood conservation initiative at our center, we began routine use of cell saver for all congenital heart surgery performed on cardiopulmonary bypass since 2014. AIMS: This study aimed to compare transfusion rates prior to, and in the first and second year after this initiative. We hypothesized that cell saver use would decrease transfusion requirements in second year after use of the cell saver compared to the pre cell saver group. METHODS: Consecutive patients under 18 years undergoing congenital heart surgery on cardiopulmonary bypass were retrospectively analyzed as 3 one-year cohorts defined above. We excluded patients who required mechanical support or reoperation at index admission. Baseline characteristics, and use of blood intraoperatively and postoperatively were compared between groups. RESULTS: The 3 groups had similar baseline characteristics. Blood use was significantly lower in year 2 after cell saver initiation as compared to the pre cell saver group both intra- and postoperatively. The median difference in volume of intraoperative blood transfusion was lower by 138 mL/m2 (-266, -10 mL/m2 ) in year 2 when compared to the pre cell saver group. Similarly, the proportion of subjects requiring red blood cell transfusion postoperatively on day of surgery was lower by 10% (-15%, -6%). CONCLUSION: Standardized use of cell saver significantly decreased perioperative blood use in children undergoing cardiac surgery at our center. A risk-adjusted transfusion threshold for children undergoing heart surgery needs to be developed to further decrease exposure to blood products and associated costs.

Massive air embolism in a Fontan patient.

Most institutions performing cardiopulmonary bypass for congenital heart disease patients use an integrated hard shell cardiotomy and venous reservoir attached to an oxygenator. It is of paramount importance that the integrated reservoir be vented so as not to cause pressurization. A pressurized sealed cardiotomy has been reported to occur secondary to issues with vacuum assisted venous drainage systems as well as improper venting in general. We report a case of air embolus caused by retrograde propulsion of air through the venous line secondary to a pressurized cardiotomy reservoir in a patient with Fontan circulation. The mechanism of cardiotomy pressurization is described, and the scenario simulated in a mock circuit.

The Children's Hospital Boston non-routine event reporting program.

Several authors have described methods to track perfusion and cardiac surgical morbidity and mortality as well as perfusion accidents. There is currently not a standard definition of a perfusion accident nor is there a standard reporting threshold for events which do not directly cause known morbidity. We propose the term non-routine events (NREs) instead of accidents, and provide a working definition and reporting threshold for such. This paper describes the program which we developed to track perfusion NREs within the Cardiovascular Program at Children's Hospital, Boston. NREs are categorized by type (technique, equipment, or patient-related) and bypass period (pre-cardiopulmonary bypass, bypass, or post-cardiopulmonary). NRE outcomes are also classified by the level of discussion or change in perfusion practice after multidisciplinary review. We have documented during a 44 month interval that 42% (29/69) of reported NREs occur during the bypass period and are equipment related and thus, efforts to improve practice should focus there. We have also seen a generally decreasing incidence of NREs requiring either a change in perfusion practice or a new protocol during this time period. We believe that our regular multidisciplinary meetings to discuss NREs have increased awareness among the entire team about potential problems in the program and that intuitively, it has improved patient safety.