Pediatric Cardiopulmonary Bypass Research Articles

Normoxic Management during Cardiopulmonary Bypass Does Not Reduce Cerebral Mitochondrial Dysfunction in Neonatal Swine.

Optimal oxygen management during pediatric cardiopulmonary bypass (CPB) is unknown. We previously demonstrated an increase in cortical mitochondrial reactive oxygen species and decreased mitochondrial function after CPB using hyperoxic oxygen management. This study investigates whether controlled oxygenation (normoxia) during CPB reduces cortical mitochondrial dysfunction and oxidative injury. Ten neonatal swine underwent three hours of continuous CPB at 34 °C (flow > 100 mL/kg/min) via cervical cannulation targeting a partial pressure of arterial oxygen (PaO2) goal < 150 mmHg (normoxia, n = 5) or >300 mmHg (hyperoxia, n = 5). The animals underwent continuous hemodynamic monitoring and serial arterial blood sampling. Cortical microdialysate was serially sampled to quantify the glycerol concentration (represents neuronal injury) and lactate-to-pyruvate ratio (represents bioenergetic dysfunction). The cortical tissue was analyzed via high-resolution respirometry to quantify mitochondrial oxygen consumption and reactive oxygen species generation, and cortical oxidized protein carbonyl concentrations were quantified to assess for oxidative damage. Serum PaO2 was higher in hyperoxia animals throughout CPB (p < 0.001). There were no differences in cortical glycerol concentration between groups (p > 0.2). The cortical lactate-to-pyruvate ratio was modestly elevated in hyperoxia animals (p < 0.03) but the values were not clinically significant (<30). There were no differences in cortical mitochondrial respiration (p = 0.48), protein carbonyls (p = 0.74), or reactive oxygen species generation (p = 0.93) between groups. Controlled oxygenation during CPB does not significantly affect cortical mitochondrial function or oxidative injury in the acute setting. Further evaluation of the short and long-term effects of oxygen level titration during pediatric CPB on cortical tissue and other at-risk brain regions are needed, especially in the presence of cyanosis.

Performance Evaluation of Geometrically Different Pediatric Arterial Cannulae in a Pediatric Cardiopulmonary Bypass Model.

To define a reference chart comparing pressure drop vs. flow generated by a set of arterial cannulae currently utilized in cardiopulmonary bypass conditions in pediatric surgery. Cannulae from two manufacturers were selected considering their design and outer and inner diameters. Cannula performance was evaluated in terms of pressure drop vs. flow during simulated cardiopulmonary bypass conditions. The experimental circuits consisted of a Jostra HL-20 roller pump, a Quadrox-i pediatric oxygenator (Maquet Cardiopulmonary AG, Rastatt, Germany), and a custom pediatric tubing set. The circuit was primed with lactated Ringer's solution only (first condition) and with human packed red blood cells added (second condition) to achieve a hematocrit of 30%. Cannula sizes 8 to 16 Fr were inserted into the cardiopulmonary bypass circuit with a "Y" connector. The flow was adjusted in 100 ml/min increments within typical flow ranges for each cannula. Pre-cannula and post-cannula pressures were measured to calculate the pressure drop. Utilizing a pressure drop limit of 100 mmHg, our results suggest a recommended flow limit of 500, 900, 1400, 2600, and 3100 mL/min for Braile arterial cannulae sizes 8, 10, 12, 14, and 16 Fr, respectively. For Medtronic DLP arterial cannulae sizes 8, 10, 12, 14, and 16 Fr, the recommended flow limit is 600, 1100, 1700, 2700, and 3300 mL/min, respectively. This study reinforces discrepancies in pressure drop between cannulae of the same diameter supplied by different manufacturers and the importance of independent translational research to evaluate components' performance.

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

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. This was a retrospective analysis of patients under 1year 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. 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%). 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.

Plasmalyte and Ringer Lactate as Priming Solutions in Pediatric Cardiopulmonary Bypass: A Comparative Study

Background: Pediatric heart surgery, particularly for cyanotic congenital heart conditions, commonly requires the utilization of cardiopulmonary bypass (CPB) to assist with surgical interventions. The choice of priming solution for the CPB circuit can influence postoperative outcomes. This study aimed to assess the impact of two different priming solutions, Plasmalyte and Ringer's Lactate, on postoperative outcomes, blood biochemistry, pulmonary and renal function, bleeding, and hemostasis in children undergoing open cardiac surgery with CPB. Methods: This randomized prospective study was conducted on 80 pediatric patients aged 1 to 10 years, undergoing elective cardiac surgery with CPB. Patients were randomly assigned to receive either Plasmalyte (Group A) or Ringer's Lactate (Group B) as their CPB circuit priming solution. Standardized protocols for anesthesia, CPB circuit components, and surgical techniques were maintained. Postoperative parameters including blood chemistry, perfusion indicators, and physiological measurements were recorded and analyzed. Results: After CPB initiation, lactate levels were significantly higher in Group B (Ringer's Lactate) compared to Group A (Plasmalyte) (P-value &lt;0.001). Calcium levels also showed a significant difference between the two groups (P-value &lt;0.001). Postoperative lactate levels remained higher in Group B (P-value &lt;0.001), while bicarbonate, calcium, urine output, urea, and creatinine levels at 6th hour postoperatively were statistically significant (p&lt;0.05). Conclusions: Priming the CPB circuit with Plasmalyte may be associated with favorable outcomes in terms of lactate and calcium levels compared to Ringer Lactate in pediatric patients undergoing cardiac surgery.

Serum soluble triggering receptor levels expressed on myeloid cells2 identify early acute kidney injury in infants and young children after pediatric cardiopulmonary bypass.

Acute kidney injury (AKI) is a potential complication after cardiopulmonary bypass (CPB) of pediatric cardiac surgery and contributes to a certain amount of perioperative mortality. Serum soluble triggering receptor expressed on myeloid cells2 (sTREM2) is an inflammation-associated cytokine in circulation. Alterations of sTREM2 level have been reported in Alzheimer's disease, sepsis, and some other pathologic conditions. This study aimed to investigate the role of sTREM2 as a forecasting factor for AKI in infants and young children and other factors associated with early renal injury after pediatric CPB. A prospective cohort study with consecutive infants and young children ≤ 3 years old undergoing CPB from September 2021 to August 2022 was conducted in an affiliated university children's hospital. These patients were divided into an AKI group (n = 10) and a non-AKI group (n = 60). Children's characteristics and clinical data were measured. Perioperative sTREM2 levels were analyzed with enzyme-linked immunosorbent assay (ELISA). In children developing AKI, the sTREM2 levels significantly decreased at the beginning of CPB compared to the non-AKI group. Based on binary logistic regression analysis and multivariable regression analysis, risk-adjusted classification for congenital heart surgery (RACHS-1), operation time, and the s-TREM2 level at the beginning of CPB (AUC = 0.839, p = 0.001, optimal cut-off value: 716.0 pg/ml) had predictive value for post-CPB AKI. When combining the sTREM2 level at the beginning of CPB and other indicators together, the area under the ROC curve enlarged. Operation time, RACHS-1 score, and sTREM2 level at the beginning of CPB were independent prognosis factors of post-CPB AKI in infants and young children ≤ 3 years old. Decreased sTREM2 identified post-CPB AKI, and ultimately hampered the outcomes. Our findings indicated that sTREM2 may be a protective factor for AKI after CPB in infants and young children ≤ 3 years old.

Con: Modified Ultrafiltration Should Not Be Routinely Used in Adult Cardiac Surgery

CARDIOPULMONARY BYPASS (CPB) is known to induce a systemic proinflammatory state and may contribute to postoperative organ dysfunction, primarily through complement activation secondary to blood passing through an artificial extracorporeal circuit. 1 Hall RI Smith MS Rocker G. The systemic inflammatory response to cardiopulmonary bypass: Pathophysiological, therapeutic, and pharmacological considerations. Anesth Analg. 1997; 85: 766-782 Crossref PubMed Google Scholar , 2 Wang W Huang HM Zhu DM et al. Modified ultrafiltration in paediatric cardiopulmonary bypass. Perfusion. 1998; 13: 304-310 Crossref PubMed Scopus (39) Google Scholar , 3 Thapmongkol S Masaratana P Subtaweesin T et al. The effects of modified ultrafiltration on clinical outcomes of adult and pediatric cardiac surgery. Asian Biomedicine. 2015; 9: 591-599 Crossref Scopus (4) Google Scholar Ultrafiltration may minimize some of the impact of the CPB-induced systemic inflammatory response. 4 Huang H Yao T Wang W et al. Continuous ultrafiltration attenuates the pulmonary injury that follows open heart surgery with cardiopulmonary bypass. Ann Thorac Surg. 2003; 76: 136-140 Abstract Full Text Full Text PDF PubMed Scopus (85) Google Scholar Traditionally, ultrafiltration may be conventional (CUF) or modified (MUF). Conventional ultrafiltration has been employed extensively during CPB, and involves hemoconcentration of both the priming volume and patient's blood volume at any point during CPB. 5 Darup J Bleese N Kalmar P et al. Hemofiltration during extracorporeal circulation (ECC). Thorac Cardiovasc Surg. 1979; 27: 227-230 Crossref PubMed Scopus (30) Google Scholar ,6 Klineberg PL Kam CA Johnson DC et al. Hematocrit and blood volume control during cardiopulmonary bypass with the use of hemofiltration. Anesthesiology. 1984; 60: 478-480 Crossref PubMed Scopus (19) Google Scholar In the early 1990s, Naik et al. introduced the concept of MUF 7 Elliott MJ. Ultrafiltration and modified ultrafiltration in pediatric open heart operations. Ann Thorac Surg. 1993; 56: 1518-1522 Abstract Full Text PDF PubMed Scopus (205) Google Scholar ,8 Andreasson S Gothberg S Berggren H et al. Hemofiltration modifies complement activation after extracorporeal circulation in infants. Ann Thorac Surg. 1993; 56: 1515-1517 Abstract Full Text PDF PubMed Scopus (88) Google Scholar ,9 Naik SK Knight A Elliott MJ. A successful modification of ultrafiltration for cardiopulmonary bypass in children. Perfusion. 1991; 6: 41-50 Crossref PubMed Scopus (164) Google Scholar in which the patient's blood volume is hemoconcentrated after separation from CPB. 10 Wang S Palanzo D Undar A. Current ultrafiltration techniques before, during and after pediatric cardiopulmonary bypass procedures. Perfusion. 2012; 27: 438-446 Crossref PubMed Scopus (40) Google Scholar Naik et al. postulated it may permit blood-free cardiac surgery. 11 Naik SK Knight A Elliott M. A prospective randomized study of a modified technique of ultrafiltration during pediatric open-heart surgery. Circulation. 1991; 84 (III422-31) PubMed Google Scholar Blood is typically removed from the arterial cannula and returned through the venous cannula. Others employ a modified technique in which blood is removed from the right atrium and infused into the aorta, potentially reducing concerns about cerebral shunting. 12 Myers GJ Leadon RB Mitchell LB et al. Simple modified ultrafiltration. Perfusion. 2000; 15: 447-452 Crossref PubMed Scopus (16) Google Scholar

Impact of Pandemic Response on Training Experience of Anesthesiology Residents in an Academic Medical Center: A Retrospective Cohort Study.

Background The impact of the coronavirus disease 2019 (COVID-19) pandemic substantially altered operations at hospitals that support graduate medical education. We examined the impact of the pandemic on an anesthesiology training program with respect to overall case volume, subspecialty exposure, procedural skill experience, and approaches to airway management. Methods Data for this single center, retrospective cohort study came from an Institutional Review Board approved repository for clinical data. Date ranges were divided into the following phases in 2020: Pre-Pandemic (PP), Early Pandemic (EP), Recovery 1 (R1), and Recovery 2 (R2). All periods were compared to the same period from 2019 for case volume, anesthesia provider type, trainee exposure to Accreditation Council for Graduate Medical Education (ACGME) index case categories, airway technique, and patient variables. Results 15,087 cases were identified, with 5,598 (37.6%) in the PP phase, 1,570 (10.5%) in the EP phase, 1,451 (9.7%) in the R1 phase, and 6,269 (42.1%) in the R2 phase. There was a significant reduction in case volume during the EP phase compared to the corresponding period in 2019 (-55.3%; P < .001) that improved but did not return to baseline by the R2 phase (-17.6%; P < .001). ACGME required minimum cases were reduced during the EP phase compared to 2019 data for pediatric cases (age < 12 y, -72.1%; P < .001 and age < 3 y, -53.5%; P < .006) and cardiopulmonary bypass cases (52.3%, P < .003).Surgical subspecialty case volumes were significantly reduced in the EP phase except for transplant surgery. By the R2 phase, all subspecialty volumes had recovered except for plastic surgery (14.9 vs. 10.5 cases/week; P < .006) and surgical endoscopy (59.2 vs. 40 cases/week; P < .001). Use of video laryngoscopy (VL) and rapid sequence induction and intubation (RSII) also increased from the PP to the EP phase (24.6 vs. 79.6%; P < .001 and 10.3 vs. 52.3%; P < .001, respectively) and remained elevated into the R2 phase (35.2%; P < 0.001 and 23.1%; P < .001, respectively). Conclusions The COVID-19 pandemic produced significant changes in surgical case exposure for a relatively short period. The impact was short-lived, with sufficientremaining time tomeet the annual ACGME program minimum case requirements and procedural experiences. The longer-term impact may be a shift towards the increased use of VL and RSII, whichbecame more prevalent during the early phase of the pandemic.

Factor XIII levels, clot strength, and impact of fibrinogen concentrate in infants undergoing cardiopulmonary bypass: a mechanistic sub-study of the FIBCON trial

BackgroundAcquired factor XIII (FXIII) deficiency after major surgery can increase postoperative bleeding. We evaluated FXIII contribution to clot strength and the effect of fibrinogen concentrate administration on FXIII activity in infants undergoing cardiac surgery using cardiopulmonary bypass. MethodsWe conducted a prospectively planned, mechanistic sub-study, nested within the Fibrinogen Concentrate Supplementation in the Management of Bleeding During Paediatric Cardiopulmonary Bypass: A Phase 1B/2A, Open-Label Dose Escalation Study (FIBCON) trial, which investigated fibrinogen concentrate supplementation during cardiopulmonary bypass (ISRCTN: 50553029) in 111 infants (median age 6.4 months). The relationships between platelet number, fibrinogen concentration, and FXIII activity with rotational thromboelastometry clot strength (EXTEM-MCF) in blood taken immediately before cardiopulmonary bypass and after separation from bypass were estimated using multivariable linear regression. Changes in coagulation variables over time were quantified using a generalised linear model comparing three groups: fibrinogen concentrate-supplemented infants, placebo, and a third cohort with lower bleeding risk. ResultsOverall, 48% of the variability (multivariable R2) in EXTEM-MCF clot strength was explained by three factors: the largest contribution was from FXIII activity (partial R2=0.21), followed by platelet number (partial R2=0.14), and fibrinogen concentration (partial R2=0.095). During cardiopulmonary bypass, mean platelet count fell by a similar amount in the three groups (–36% to –41%; interaction P=0.98). Conversely, fibrinogen concentration increased in all three groups: 132% in the fibrinogen concentrate-supplemented group, 26% in the placebo group, and 51% in the low-risk group. A similar increase was observed for FXIII activity (61%, 23%, and 25%, respectively; interaction P<0.0001). ConclusionsFXIII contribution to clot strength is considerable in infants undergoing cardiac surgery. Fibrinogen concentrate supplementation also increased FXIII activity, and hence clot strength. Clinical trial registrationISRCTN: 50553029.

Anticoagulation Strategies in Pediatric Cardiopulmonary Bypass, Weight-Based vs. Concentration-Based Approaches

Pediatric patients undergoing cardiopulmonary bypass (CPB) require adequate anticoagulation to combat hemostatic activation. Heparin is used to bind and catalyze antithrombin III (ATIII) that works to inhibit clot formation. To dose heparin, a weight-based (WB) or patient-specific concentration-based (PSCB) method can be used. The WB protocol calculates the dose based on the patients’ weight and uses an activated clotting time (ACT) test to ensure anticoagulation. The ACT has limitations during CPB especially for pediatric patients who have immature hemostatic systems. The PSCB method predicts the patients’ response to heparin by projecting a heparin dose–response (HDR) curve. Some investigators have found benefit to using the PSCB method but further investigation into how well the HDR predicts the heparin response is needed. A literature review was conducted for studies that looked at heparin management strategies in pediatric CPB patients between 1992 and 2020. Articles that focused on pediatric physiology, heparin management strategies, and anticoagulation were included. Articles older than 1990 were excluded. The literature review highlights that utilizing the PSCB approach more adequately anticoagulated patients. The WB protocol was found to have several flaws due to its reliance on the ACT, especially in infants. The results show that further investigation is needed to understand why there is benefit to using the PSCB approach. Observing the association between the HDR curve and subsequent heparin concentrations could determine how accurately it predicts the patients’ response to heparin and why there is benefit to using this method.

Anticoagulation Strategies in Pediatric Cardiopulmonary Bypass, Weight-Based vs. Concentration-Based Approaches.

Pediatric patients undergoing cardiopulmonary bypass (CPB) require adequate anticoagulation to combat hemostatic activation. Heparin is used to bind and catalyze antithrombin III (ATIII) that works to inhibit clot formation. To dose heparin, a weight-based (WB) or patient-specific concentration-based (PSCB) method can be used. The WB protocol calculates the dose based on the patients' weight and uses an activated clotting time (ACT) test to ensure anticoagulation. The ACT has limitations during CPB especially for pediatric patients who have immature hemostatic systems. The PSCB method predicts the patients' response to heparin by projecting a heparin dose-response (HDR) curve. Some investigators have found benefit to using the PSCB method but further investigation into how well the HDR predicts the heparin response is needed. A literature review was conducted for studies that looked at heparin management strategies in pediatric CPB patients between 1992 and 2020. Articles that focused on pediatric physiology, heparin management strategies, and anticoagulation were included. Articles older than 1990 were excluded. The literature review highlights that utilizing the PSCB approach more adequately anticoagulated patients. The WB protocol was found to have several flaws due to its reliance on the ACT, especially in infants. The results show that further investigation is needed to understand why there is benefit to using the PSCB approach. Observing the association between the HDR curve and subsequent heparin concentrations could determine how accurately it predicts the patients' response to heparin and why there is benefit to using this method.

Extracorporeal Membrane Oxygenation in Congenital Heart Disease.

Mechanical circulatory support (MCS) is a key therapy in the management of patients with severe cardiac disease or respiratory failure. There are two major forms of MCS commonly employed in the pediatric population—extracorporeal membrane oxygenation (ECMO) and ventricular assist device (VAD). These modalities have overlapping but distinct roles in the management of pediatric patients with severe cardiopulmonary compromise. The use of ECMO to provide circulatory support arose from the development of the first membrane oxygenator by George Clowes in 1957, and subsequent incorporation into pediatric cardiopulmonary bypass (CPB) by Dorson and colleagues. The first successful application of ECMO in children with congenital heart disease undergoing cardiac surgery was reported by Baffes et al. in 1970. For the ensuing nearly two decades, ECMO was performed sparingly and only in specialized centers with varying degrees of success. The formation of the Extracorporeal Life Support Organization (ELSO) in 1989 allowed for the collation of ECMO-related data across multiple centers for the first time. This facilitated development of consensus guidelines for the use of ECMO in various populations. Coupled with improving ECMO technology, these advances resulted in significant improvements in ECMO utilization, morbidity, and mortality. This article will review the use of ECMO in children with congenital heart disease.

Comparison between Del Nido and conventional blood cardioplegia in pediatric open-heart surgery.

Del Nido cardioplegia (DNc) was designed for superior myocardial protection during cardiopulmonary bypass (CPB). We conducted a retrospective review to explore if DNc was associated with increase in systemic ventricle dysfunction (sVD) following pediatric CPB. This single-center, retrospective study included 1534 patients undergoing CPB between 2013 and 2016, 997 prior to center-wide conversion to DNc and 537 following. The primary outcome was new postoperative ≥moderate sVD by echocardiogram. Secondary outcomes included sVD of any severity and right ventricular dysfunction. Data was evaluated by interrupted time-series analysis. Groups had similar cardiac diagnoses and surgical complexity. Del Nido cardioplegia was associated with longer median (IQR) CPB [117 (84-158) vs 108 (81-154), p = 0.04], and aortic cross-clamp [83 (55-119) vs 76 (53-106), p = 0.03], and fewer cardioplegia doses [2 (1-2) vs 3 (2-4), p < 0.0001]. Mortality was similar in both groups. Frequency of sVD was unchanged following DNc, including predetermine subgroups (neonates, infants, and prolonged cross-clamp). Logistic regression showed a significant rise in right ventricular dysfunction (OR 5.886 [95% CI: 0.588, 11.185], p = 0.03) but similar slope. Use of DNc was not associated with increased in reported sVD, and provided similar myocardical protection to the systemic ventricle compared to conventional cardioplegia but may possibly impact right ventricular function. Studies evaluating quantitative systolic and diastolic function are needed.

The Fundamental Skills and Deconstructed Sub-Steps of Pediatric Cardiopulmonary Bypass.

Perfusion education programs use simulation to provide students with clinical skills prior to entering the operating room. To teach the psychomotor execution of skills in a simulation lab requires a list of validated skills and deconstructed sub-steps to fully optimize adult learning. A list of the fundamental skills of adult cardiopulmonary bypass (CPB) was recently published; however, no defined list exists regarding pediatric CPB skills. The purpose of this survey is to form a definitive list of skills fundamental to pediatric CPB. A survey of 23 proposed pediatric CPB clinical skills and 291 proposed skill sub-steps was developed. Proposed pediatric CPB skills were evaluated using an established frequency and harm index. If the skill is performed >50% of the time (frequency), and if >50% believe that if the skill is performed incorrectly patient harm is probable (risk), then the skill is accepted as fundamental. The survey content was validated by subject matter experts and then distributed to practicing perfusionists between September 2020 and December 2020. Of the 125 survey respondents, 57.9% had 10 or more years in the field. 35.2% of respondents are American Society of Extracorporeal Technology (AmSECT) Fellows of Pediatric Perfusion (FPP) and pediatric CPB represents >50% of the annual caseload for 69.7% of respondents. 22 of the 23 proposed skills were accepted as fundamental in the conduct of pediatric CPB and 258 of the 291 proposed sub-steps associated with CPB skills were accepted as integral to skill performance. By surveying practicing pediatric perfusionists, this study identifies 22 skills as fundamental to the safe execution of pediatric CPB. In addition, skill sub-elements were identified as necessary for skill execution. This knowledge will assist perfusion programs in developing a pediatric simulation curriculum that matches current clinical execution of pediatric skills.

The Fundamental Skills and Deconstructed Sub-Steps of Pediatric Cardiopulmonary Bypass

The Fundamental Skills and Deconstructed Sub-Steps of Pediatric Cardiopulmonary Bypass

Association Between Hyperoxemia and Increased Cell-Free Plasma Hemoglobin During Cardiopulmonary Bypass in Infants and Children.

To determine potential risk factors for severe hemolysis during pediatric cardiopulmonary bypass and examine whether supraphysiologic levels of oxygen and cardiopulmonary bypass duration are associated with hemolysis. Prospective observational study. Cardiac ICU in a university-affiliated children's hospital. Greater than 1 month to less than 18 years old patients undergoing cardiopulmonary bypass for cardiac surgery. None. Plasma samples from 100 patients to assess cell-free plasma hemoglobin levels were obtained at start cardiopulmonary bypass, at the end of cardiopulmonary bypass, and 2 and 24 hours after reperfusion. Arterial blood gas samples were obtained before and every 30 minutes during cardiopulmonary bypass. Patient demographics and laboratory data were collected from the electronic medical record. Plasma hemoglobin levels peaked at the end of cardiopulmonary bypass and haptoglobin levels continued to fall throughout all time points. There were 44 patients with severe hemolysis (change in cell-free plasma hemoglobin > 50 mg/dL). Younger age (odds ratio/sd 0.45 [95% CI, 0.25-0.81]) and higher mean Pao2 × cardiopulmonary bypass duration (31.11 [1.46-664.64]) were identified as risk factors for severe hemolysis in multivariable analysis. Severe hemolysis was associated with longer hospital and ICU lengths of stay as well as acute kidney injury. We observed younger age and the exposure to both oxygen and duration of cardiopulmonary bypass as risk factors for hemolysis. Oxygen delivery through the cardiopulmonary bypass circuit is an easily modifiable risk factor. Its role in the production of reactive oxygen species that could alter the erythrocyte membrane deserves further examination in larger prospective studies.

S-Nitrosoglutathione Limits Apoptosis and Reduces Pulmonary Vascular Dysfunction After Bypass

BackgroundDuring hypoxia or acidosis, S-nitrosoglutathione (GSNO) has been shown to protect the cardiomyocyte from ischemia-reperfusion injury. In a randomized double-blinded control study of a porcine model of paediatric cardiopulmonary bypass (CPB), we aimed to evaluate the effects of 2 different doses (low and high) of GSNO. MethodsPigs weighing 15-20 kg were exposed to CPB with 1 hour of aortic cross-clamp. Prior to and during CPB, animals were randomized to receive low-dose (up to 20 nmol/kg/min) GSNO (n = 8), high-dose (up to 60 nmol/kg/min) GSNO (n = 6), or normal saline (n = 7). Standard cardiac intensive care management was continued for 4 hours post-bypass. ResultsThere was a reduction in myocyte apoptosis after administration of GSNO (P = .04) with no difference between low- and high-dose GSNO. The low-dose GSNO group had lower pulmonary vascular resistance post-CPB (P = .007). Mitochondrial complex I activity normalized to citrate synthase activity was higher after GSNO compared with control (P = .02), with no difference between low- and high-dose GSNO. ConclusionsIn a porcine model of CPB, intravenous administration of GSNO limits myocardial apoptosis through preservation of mitochondrial complex I activity, and improves pulmonary vascular resistance. There appears to be a dose-dependent effect to this protection.

Effects of Pulsatile and Non-Pulsatile Perfusion On Oxygenator Fibers During Pediatric Cardiopulmonary Bypass

In cardiopulmoner operations patients can be perfused with a pulsatile or nonpulsatile pump mode. The extra energy maintained by the pulsatile perfusion may have different effects on the patient and the oxygenator fiber rather than nonpulsatile perfusion. Especially the effect of pulsatile perfusion on the fibers isn’t clearly known. The purpose of this study is to investigate the effects of pulsatile and non-pulsatile blood flows on oxygenator fibers. 18 out of 32 patients that had an pediatric open heart surgery was chosen according to their aortic clamp times. 9 of 18 patients were perfused in a pulsatile mode, other 9 patients were perfused in a nonpulsatile mode. The patient blood was collected before the open heart surgery (T1), before aortic clamp (T2), after aortic clamp (T3), after 1st intensive care hour (T4) and after the 1st intensive care day (T5) in order to compare the results of whole blood and plasma proteins. At the end of the open heart operation 10 cm of oxygenator fiber was removed from the fiber bundle and taken into the phosfate buffer saline (PBS) solution after the patient had a stabile outcome. Whole blood and micro protein measurements were applied in both first fiber solution and sonicated solution. No harmful effect of pulsatile perfusion on blood cells and proteins was observed according to patient results. More blood cell aggregation and total protein adsorption was observed in nonpulsatile mode fibers results. In this study pulsatile perfusion maintained better blood compability over nonpulsatile perfusion and the extra energy in pulsatile perfusion caused better microcirculation.

Contemporary Trends and Risk Factors of Hemodynamic and Myocardial Mechanics Derived by the Pressure Recording Analytical Method After Pediatric Cardiopulmonary Bypass.

Objective: Adverse factors of postoperative hemodynamic and myocardial performance remain largely unexplored in children with congenital heart disease following cardiopulmonary bypass due to technical limitations. Pressure recording analytical method (PRAM) is a continuous hemodynamic and myocardial performance monitoring technique based on beat-to-beat arterial pressure waveform. Using PRAM, we examined the temporal trends and adverse factors, in clinical management, of these performances.Methods: We monitored blood pressure, cardiac index, cardiac cycle efficiency (CCE), dP/dTmax, and systematic vascular resistance index in 91 children (aged 186 ± 256 days) during their first 48 h after cardiopulmonary bypass. Above parameters, inotropic and vasoactive drug dosages, and serum lactate were recorded 3-hourly. NT-proBNP was measured daily.Results: CCE and dP/dTmax gradually increased (Ps < 0.0001), while systematic vascular resistance index, diastolic blood pressure and inotrope dosages decreased (Ps < 0.0001) over time. Cardiac index, systolic blood pressure, and heart rate did not change significantly (Ps ≥ 0.231). Patients undergoing deep hypothermic circulatory arrest had significantly higher heart rate and lower CCE (Ps ≤ 0.006) over time. Multivariate analyses indicated that epinephrine dose significantly correlated with systolic blood pressure, cardiac index, CCE, and dP/dTmax after polynomial transformation, with the peak ranging from 0.075 to 0.097.Conclusions: Systemic hemodynamic and myocardial performance gradually improved in the first 48 h after cardiopulmonary bypass without the “classic” nadir at 9–12 h. Deep hypothermic circulatory arrest and higher epinephrine doses were adversely associated with these performances. CCE, rather than cardiac index or other common-used parameters, was the most sensitive and consistent indicator.

Subzero balance - simple modified ultrafiltration (SBUF-SMUF) technique for pediatric cardiopulmonary bypass.

The use of cardiopulmonary bypass (CPB) can be associated with significant hemodilution, coagulopathy and a systemic inflammatory response for infants and children undergoing cardiac surgery. Intra-operative ultrafiltration has been used for decades to ameliorate these harmful effects. The novel combination of a continuous and non-continuous form of ultrafiltration, Subzero Balance Simple Modified Ultrafiltration (SBUF-SMUF) here described, seeks to enhance recovery from pediatric cardiac surgery and CPB.

Procalcitonin and Early Postoperative Infection After Pediatric Cardiopulmonary Bypass Surgery

Systemic inflammation and bacterial infections are critical occurrences after pediatric cardiac surgery. Elevated white blood cell count and C-reactive protein cannot discriminate between these two conditions in the early postoperative period. The aim of this study was to understand whether procalcitonin (PCT) values within 48 hours of surgery could be a useful marker of postoperative infection. Retrospective observational study. The study was performed in a teaching hospital. All patients ≤six years of age. Cardiac surgery on cardiopulmonary bypass from January 1, 2017 to January 1, 2020. PCT, white blood cell count, and C-reactive protein values were measured at intensive care unit admission and at 24 and 48 hours after surgery. All positive cultures in the first seven days after surgery were recorded. Out of 177 consecutive patients, 22 (12%) developed infections. PCT at 48 hours after surgery was the only laboratory predictor of infections in the first seven days after surgery (p=0.02). Receiver operating curve analyses on PCT values at 48 hours identified an optimal cut-off value of 1.85 ng/mL in the overall population. Area under the curve was 0.63, sensitivity 63%, and specificity 69%. In light of this preliminary result, the clinical relevance and predictive accuracy of PCT are promising in patients with increasing values of PCT but need to be confirmed in a larger sample.