Indexed oxygen delivery during pediatric cardiopulmonary bypass is a modifiable risk factor for postoperative acute kidney injury.

BACKGROUND: Acute kidney injury after pediatric cardiac surgery is a common complication with few established modifiable risk factors. We sought to characterize whether indexed oxygen delivery during cardiopulmonary bypass was associated with postoperative acute kidney injury in a large pediatric cohort. METHODS: This was a retrospective analysis of patients under 1 year old undergoing cardiac surgery with cardiopulmonary bypass between January 1, 2013, and January 1, 2020. Receiver operating characteristic curves across values ranging from 260 to 400 mL/min/m2 were used to identify the indexed oxygen delivery most significantly associated with acute kidney injury risk. RESULTS: We included 980 patients with acute kidney injury occurring in 212 (21.2%). After adjusting for covariates associated with acute kidney injury, an indexed oxygen delivery threshold of 340 mL/min/m2 predicted acute kidney injury in STAT 4 and 5 neonates (area under the curve = 0.66, 95% CI = 0.60 - 0.72, sensitivity = 56.1%, specificity = 69.4%). An indexed oxygen delivery threshold of 400 mL/min/m2 predicted acute kidney injury in STAT 1-3 infants (area under the curve = 0.65, 95% CI = 0.58 - 0.72, sensitivity = 52.6%, specificity = 74.6%). CONCLUSION: Indexed oxygen delivery during cardiopulmonary bypass is a modifiable variable independently associated with postoperative acute kidney injury in specific pediatric populations. Strategies aimed at maintaining oxygen delivery greater than 340 mL/min/m2 in complex neonates and greater than 400 mL/min/m2 in infants may reduce the occurrence of postoperative acute kidney injury in the pediatric population.

International Survey of Perfusion Practice for Pediatric and Congenital Heart Surgery: 2021 Results.

The conduct of cardiopulmonary bypass in neonatal, infant, and pediatric patients continuously evolves as new devices and innovative techniques are introduced. Since 1989, periodic pediatric perfusion surveys have been conducted to ascertain practice patterns involving demographics, equipment, and perfusion techniques. The goal of this current project is to provide an updated perspective on international pediatric and congenital perfusion practice since the last survey conducted in 2016. In July 2021, a 100-question perfusion survey was distributed to 284 pediatric cardiac surgery centers using a secure web browser-based data application. Each center was given a unique survey hyperlink to ensure one response per institution and to monitor the response rate. Centers were given 1 month to complete the survey and electronic reminders were sent weekly to nonrespondents. After the survey was closed, information from completed surveys was exported to a software program for analysis. Responses were received from 153 of 284 pediatric centers for a response rate of 54%. Sixty respondents (39%) were from North American (NA) centers while 93 respondents (61%) were from non-North American (NNA) centers. The vast majority of centers use a roller head arterial pump (93%), hollow fiber oxygenators with open reservoirs (86%), and integrated arterial line filters (73%). The use of modified ultrafiltration was reported by 76% of centers. Ninety-two percent of centers reported the use of selective antegrade cerebral perfusion for aortic arch repairs. The N + 1 staffing model was most prevalent (52%), followed by two perfusionists per case (33%). Periodic surveys continue to be a useful modality in assessing regional variation in pediatric perfusion practice. This survey marked the first time the majority of responses came from non-North American institutions. Identifying these practice patterns may aid in the development of, and adherence to, regional standards and guidelines. This would foster the reduction of variation in practice and potentially improve patient safety.

Higher total ultrafiltration volume during cardiopulmonary bypass-assisted infant cardiac surgery is associated with acute kidney injury and fluid overload.

BACKGROUND: Ultrafiltration (UF) is used for fluid removal during and after infant cardiopulmonary bypass (CPB) surgery to reduce fluid overload. Excessive UF may have the opposite of its intended effect, resulting in acute kidney injury (AKI), oliganuria, and fluid retention. METHODS: This is a single-center, retrospective review of infants treated with conventional and/or modified UF during CPB surgery. UF volume was indexed to weight. AKI was defined using serum creatinine "Kidney Disease Improving Global Outcome (KDIGO)" criteria. Fluid balance was defined according to: [Formula: see text]. Peak fluid overload was determined on postoperative day 3. Multivariable logistic regression adjusted for multiple covariates was used to explore associations with UF, AKI, and fluid overload. RESULTS: Five hundred thirty subjects < 1 year of age underwent CPB-assisted congenital heart surgery with UF. Sixty-four (12%) developed postoperative AKI. On multivariable regression, higher indexed total UF volume was associated with increased AKI risk (OR 1.11, 95% CI=1.04-1.19, p = 0.003). UF volume > 119.9 mL/kg did not reduce peak fluid overload. Subjects with AKI took longer to reach a negative fluid balance (2 vs. 3 days, p = 0.04). Those with more complex surgery were at highest AKI risk (STAT 3 [25-75 percentile: 3-4] in AKI group versus STAT 3 [25-75 percentile: 2-4] in non-AKI group, p = 0.05). AKI was reduced in subjects undergoing more complex surgery and treated with UF volume < 119.9 mL/kg. CONCLUSIONS: Judicious use of UF in more complex congenital cardiac surgery reduces the risk of AKI.

Comparison of three autotransfusion devices for utilization in the pediatric population.

INTRODUCTION: A device that may help attenuate the amount of homologous blood product given to pediatric cardiac surgical patients is the autotransfusion device. Three separate autotransfusion devices were selected for evaluation. The Sorin Xtra, Fresenius Continuous Autotransfusion System Plus (CATS*plus), and the Fresenius Continuous Autotransfusion System Smart (CATSmart) were evaluated based on the mechanical processes of each device, hematocrit value of the salvaged packed red cell product, time of processing, and the advantageous accessories with each device. METHODS: Each of the autotransfusion devices were used to collect salvageable blood from the surgical field as well as to process residual blood from the cardiopulmonary bypass circuit after decannulation. The cell salvage process was performed in accordance with the manufacturer's instructions for use and the recommended settings for processing and washing. The Sorin Xtra device had the 55 mL bowl set up for all cases, while the Fresenius continuous autotransfusion systems utilized the standard disposable for each device. RESULTS: Each cell salvage device was employed during 30 pediatric cardiac surgery procedures, and data for each device, was broken down into four groups based on patient weight (0-10, 10-20, 20-40, and >40 kg). For all patient sizes, the Sorin Xtra tended to produce the greatest volume of cell saver product (55-825 mL) as compared to the CATS*plus and CATSmart devices (7-550 mL and 0-860 mL, respectively). The Continuous Autotransfusion System Smart tended to produce the highest hematocrit product, ranging from 44 to 81%. DISCUSSION: Through this evaluation, it was determined the continuous autotransfusion systems provided the highest hematocrit with the lowest recovered packed red cell volume, while the Sorin Xtra packed red cell product showed to have a lower hematocrit with a larger packed red cell volume. Each device proved effective within our pediatric population.

A Single-Center Analysis of Methylprednisolone Use during Pediatric Cardiopulmonary Bypass.

Cardiac surgery with the use of cardiopulmonary bypass (CPB) is known to induce an inflammatory response in patients. This response may be even more pronounced in pediatric patients given their small body size compared to adults. Several interventions have been instituted in an effort to attenuate this response, including the use of corticosteroids in the pump prime. However, the clinical effectiveness and potential harmful effects of steroid use have been the source of recent debate. Therefore, our institution made the decision to evaluate the use of methylprednisolone in our CPB prime. This evaluation was performed as a formal quality improvement project at The Children's Hospital of Philadelphia. Methylprednisolone was eliminated from the CPB prime for 6 months. At the end of this time period, The Society of Thoracic Surgeons Congenital Heart Surgery Database was used to evaluate clinical outcomes of patients (n = 222). These outcomes were then compared to patients operated on during the 6 months prior to elimination of methylprednisolone (n = 303). No significant clinical benefit was identified in the group of patients who received methylprednisolone. When compared to the group who did not receive methylprednisolone, significantly more patients in the steroids group had a postoperative wound infection (p = .037) or respiratory failure requiring tracheostomy ( p = .035). No other differences in clinical outcomes were identified between the two groups. No significant differences in clinical outcomes were identified between neonates who received methylprednisolone (n = 55) and neonates who did not receive steroids (n = 58). Due to the lack of clinical benefit seen with its use, as well as its potential contribution to the incidence of wound infection, methylprednisolone continues to be excluded from the CPB prime at our institution. Methylprednisolone is still given intraoperatively at the request of the attending anesthesiologist and on bypass during orthotopic transplant procedures according to institutional protocol.

Increased cerebral mitochondrial dysfunction and reactive oxygen species with cardiopulmonary bypass.

OBJECTIVES: Neurodevelopmental injury after cardiac surgery using cardiopulmonary bypass (CPB) for congenital heart defects is common, but the mechanism behind this injury is unclear. This study examines the impact of CPB on cerebral mitochondrial reactive oxygen species (ROS) generation and mitochondrial bioenergetics. METHODS: Twenty-three piglets (mean weight 4.2 ± 0.5 kg) were placed on CPB for either 1, 2, 3 or 4 h (n = 5 per group) or underwent anaesthesia without CPB (sham, n = 3). Microdialysis was used to measure metabolic markers of ischaemia. At the conclusion of CPB or 4 h of sham, brain tissue was harvested. Utilizing high-resolution respirometry, with simultaneous fluorometric analysis, mitochondrial respiration and ROS were measured. RESULTS: There were no significant differences in markers of ischaemia between sham and experimental groups. Sham animals had significantly higher mitochondrial respiration than experimental animals, including maximal oxidative phosphorylation capacity of complex I (OXPHOSCI) (3.25 ± 0.18 vs 4-h CPB: 1.68 ± 0.10, P < 0.001) and maximal phosphorylating respiration capacity via convergent input through complexes I and II (OXPHOSCI+CII) (7.40 ± 0.24 vs 4-h CPB: 3.91 ± 0.20, P < 0.0001). At 4-h, experimental animals had significantly higher ROS related to non-phosphorylating respiration through complexes I and II (ETSCI+CII) than shams (1.08 ± 0.13 vs 0.64 ± 0.04, P = 0.026). CONCLUSIONS: Even in the absence of local markers of ischaemia, CPB is associated with decreased mitochondrial respiration relative to shams irrespective of duration. Exposure to 4 h of CPB resulted in a significant increase in cerebral mitochondrial ROS formation compared to shorter durations. Further study is needed to improve the understanding of cerebral mitochondrial health and its effects on the pathophysiology of neurological injury following exposure to CPB.