High-exchange ULTrafiltration to enhance recovery after paediatric cardiac surgery (ULTRA): study protocol for a Canadian double-blinded randomised controlled trial

INTRODUCTION

Surgical repair is the standard of care for most infants and children with congenital heart disease. Cardiopulmonary bypass (CPB) is required to facilitate these operations but elicits a systemic inflammatory response, leading to postoperative organ dysfunction, morbidity and prolonged recovery after the surgery. Subzero-balance ultrafiltration (SBUF) has been shown to extract proinflammatory cytokines continuously throughout the CPB exposure. We hypothesize that a high-exchange SBUF (H-SBUF) will have a clinically relevant anti-inflammatory effect compared with a low-exchange SBUF (L-SBUF).

METHODS AND ANALYSIS

The ULTrafiltration to enhance Recovery After paediatric cardiac surgery (ULTRA) trial is a randomised, double-blind, parallel-group randomised trial conducted in a single paediatric cardiac surgery centre. Ninety-six patients less than 15 kg undergoing cardiac surgery with CPB will be randomly assigned to H-SBUF during CPB or L-SBUF during CPB in a 1:1 ratio with stratification by The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) score 1 and STAT score 2-5. The primary outcome is peak postoperative vasoactive-ventilation-renal score. Time series and peak values of vasoactive-ventilation renal score, vasoactive-inotrope score, ventilation index and oxygenation index will be collected. Secondary clinical outcomes include acute kidney injury, ventilator-free days, inotrope-free days, low cardiac output syndrome, mechanical circulatory support, intensive care unit length of stay and operative mortality. Secondary biomarker data include cytokine, chemokine and complement factor concentrations at baseline before CPB, at the end of CPB exposure and 24 hours following CPB. Analyses will be conducted on an intention-to-treat principle.

ETHICS AND DISSEMINATION

The study has ethics approval (#1024932 dated August 31, 2021) and enrolment commenced in September 2021. The primary manuscript and any subsequent analyses will be submitted for peer-reviewed publication.

TRIAL REGISTRATION NUMBER

NCT04920643.

Strategies to attenuate maladaptive inflammatory response associated with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) initiates an intense inflammatory response due to various factors: conversion from pulsatile to laminar flow, cold cardioplegia, surgical trauma, endotoxemia, ischemia-reperfusion injury, oxidative stress, hypothermia, and contact activation of cells by the extracorporeal circuit. Redundant and overlapping inflammatory cascades amplify the initial response to produce a systemic inflammatory response, heightened by coincident activation of coagulation and fibrinolytic pathways. When unchecked, this inflammatory response can become maladaptive and lead to serious postoperative complications. Concerted research efforts have been made to identify technical refinements and pharmacologic interventions that appropriately attenuate the inflammatory response and ultimately translate to improved clinical outcomes. Surface modification of the extracorporeal circuit to increase biocompatibility, miniaturized circuits with sheer resistance, filtration techniques, and minimally invasive approaches have improved clinical outcomes in specific populations. Pharmacologic adjuncts, including aprotinin, steroids, monoclonal antibodies, and free radical scavengers, show real promise. A multimodal approach incorporating technical, circuit-specific, and pharmacologic strategies will likely yield maximal clinical benefit.

Machine Learning Analysis of Predictors for Inhaled Nitric Oxide Therapy Administration Time Post Congenital Heart Disease Surgery: A Single-Center Observational Study

Background Congenital heart disease (CHD) is a structural deformity of the heart present at birth. Pulmonary hypertension (PH) may arise from increased blood flow to the lungs, persistent pulmonary arterial pressure elevation, or the use of cardiopulmonary bypass (CPB) during surgical repair. Inhaled nitric oxide (iNO) selectively reduces high blood pressure in the pulmonary vessels without lowering systemic blood pressure, making it useful for treating children with postoperative PH due to heart disease. However, reducing or stopping iNO can exacerbate postoperative PH and hypoxemia, necessitating long-term administration and careful tapering. This study aimed to evaluate, using machine learning (ML), factors that predict the need for long-term iNO administration after open heart surgery in CHD patients in the postoperative ICU, primarily for PH management. Methods We used an ML approach to establish an algorithm to predict 'patients with long-term use of iNO' and validate its accuracy in 34 pediatric postoperative open heart surgery patients who survived and were discharged from the ICU at Kagoshima University Hospital between April 2016 and March 2019. All patients were started on iNO therapy upon ICU admission. Overall, 16 features reflecting patient and surgical characteristics were utilized to predict the patients who needed iNO for over 168 hours using ML analysis with AutoGluon. The dataset was randomly classified into training and test cohorts, comprising 80% and 20% of the data, respectively. In the training cohort, the ML model was constructed using the important features selected by the decrease in Gini impurity and a synthetic oversampling technique. In the testing cohort, the prediction performance of the ML model was evaluated by calculating the area under the receiver operating characteristics curve (AUC) and accuracy. Results Among 28 patients in the training cohort, five needed iNO for over 168 hours; among six patients in the testing cohort, one needed iNO for over 168 hours. CPB, aortic clamp time, in-out balance, and lactate were the four most important features for predicting the need for iNO for over 168 hours. In the training cohorts, the ML model achieved perfect classification with an AUC of 1.00. In the testing cohort, the ML model also achieved perfect classification with an AUC of 1.00 and an accuracy of 1.00. Conclusion The ML approach identified that four factors (CPB, in-out balance, aortic cross-clamp time, and lactate) are strongly associated with the need for long-term iNO administration after open heart surgery in CHD patients. By understanding the outcomes of this study, we can more effectively manage iNO administration in postoperative open heart surgery in CHD patients with PH, potentially preventing the recurrence of postoperative PH and hypoxemia, thereby contributing to safer patient management.

Heparin consumption and inflammatory response according to the coating of cardiopulmonary bypass circuits in cardiac surgery: A retrospective analysis

INTRODUCTION

There are several types of surface treatments (coatings) aimed at improving the biocompatibility of cardiopulmonary bypass (CPB) circuit. Some coatings appear to require higher doses of heparin to maintain anticoagulation goals, and some of them might induce postoperative coagulopathy. In this study, we compared the amount of heparin required, postoperative bleeding, and inflammatory response according to three types of coatings.

METHOD

We retrospectively included 300 consecutive adult patients who underwent cardiac surgery with CPB and received one of three coatings (Phisio®, Trillium®, and Xcoating™). Our primary objective was to compare, according to coating, the amount of heparin required to maintain an ACT > 400s during CPB. Our secondary objectives were to compare postoperative bleeding for 48 h and CRP rate.

RESULTS

Baseline characteristics were comparable between groups except for age and preoperative CRP. We did not find a significant difference between the 3 coatings regarding the amount of heparin reinjected. However, we found less postoperative bleeding with the Xcoating™ circuit compared to the Phisio® circuit (-149 mL [-289; -26.5]; p = 0.02) and a lower elevation of CRP with the Phisio® circuit (2.8 times higher than preoperative CRP) compared to Trillium® (4.9 times higher) and Xcoating™ (6.4 times higher); p < 10-3.

CONCLUSION

The choice of coating did not influence the amount of heparin required during CPB; however, the post-CPB inflammatory syndrome may be impacted by this choice.

Risk factors associated with prolonged intensive care unit stay following surgery for total anomalous pulmonary venous connection: a retrospective study

BACKGROUND

Prolonged intensive care unit (ICU) stays consume medical resources and increase medical costs. This study identified risk factors associated with prolonged postoperative intensive care unit (ICU) stay in children with total anomalous pulmonary venous connection (TAPVC).

METHODS

The medical records of 85 patients who underwent surgical repair of TAPVC were retrospectively analyzed. The patients were divided into prolonged-stay and standard-stay groups. The prolonged stay group included all patients who exceeded the 75th percentile of the ICU stay duration, and the standard stay group included all remaining patients. The effects of patient variables on ICU stay duration were investigated using univariate and logistic regression analyses.

RESULTS

Patient median age was 41 (18-103) days, and median weight was 3.80 (3.30-5.35) kg.Postoperative duration of ICU stay was 11-68 days in the prolonged stay group (n = 23) and 2-10 days in the standard stay group (n = 62). Lower preoperative pulse oximetry saturation (SpO2), higher intraoperative plasma lactate levels, and prolonged postoperative mechanical ventilation were independent risk factors for prolonged ICU stay. Preoperative SpO2 < 88.5%, highest plasma lactate value > 4.15 mmol/L, and postoperative mechanical ventilation duration was longer than 53.5 h, were associated with increased risk of prolonged ICU stay. Young age, low body weight, subcardiac type, need for vasoactive drug support, emergency surgery, long anesthesia time, low SpO2 after anesthesia induction, long cardiopulmonary bypass (CPB) and aortic clamp times, high lactate level, low temperature, large volume of ultrafiltration during CPB, large amounts of chest drainage, large red blood cells (RBCs) and plasma transfusion, and postoperative cardiac dysfunction may be associated with prolonged ICU stay.

CONCLUSIONS

Lower preoperative SpO2, higher intraoperative plasma lactate levels, and prolonged postoperative mechanical ventilation were independent risk factors for prolonged ICU stay in children with TAPVC. When SpO2 was lower than 88.5%, the highest plasma lactate value was more than 4.15 mmol/L, and the postoperative mechanical ventilator duration was longer than 53.5 h, the risk of prolonged ICU stay increased. Improved clinical management, including early diagnosis and timely surgical intervention to reduce hypoxia time and protect intraoperative cardiac function, may reduce ICU stay time.

Novel inflammatory mediator profile observed during pediatric heart surgery with cardiopulmonary bypass and continuous ultrafiltration

BACKGROUND

Cardiopulmonary bypass (CPB) is associated with systemic inflammation, featuring increased levels of circulating pro-inflammatory cytokines. Intra-operative ultrafiltration extracts fluid and inflammatory factors potentially dampening inflammation-related organ dysfunction and enhancing post-operative recovery. This study aimed to define the impact of continuous subzero-balance ultrafiltration (SBUF) on circulating levels of major inflammatory mediators.

METHODS

Twenty pediatric patients undergoing cardiac surgery, CPB and SBUF were prospectively enrolled. Blood samples were collected prior to CPB initiation (Pre-CPB Plasma) and immediately before weaning off CPB (End-CPB Plasma). Ultrafiltrate effluent samples were also collected at the End-CPB time-point (End-CPB Effluent). The concentrations of thirty-nine inflammatory factors were assessed and sieving coefficients were calculated.

RESULTS

A profound increase in inflammatory cytokines and activated complement products were noted in plasma following CBP. Twenty-two inflammatory mediators were detected in the ultrafiltrate effluent. Novel mediators removed by ultrafiltration included cytokines IL1-Ra, IL-2, IL-12, IL-17A, IL-33, TRAIL, GM-CSF, ET-1, and the chemokines CCL2, CCL3, CCL4, CXCL1, CXCL2 and CXCL10. Mediator extraction by SBUF was significantly associated with molecular mass < 66 kDa (Chi² statistic = 18.8, Chi² with Yates' correction = 16.0, p < 0.0001). There was a moderate negative linear correlation between molecular mass and sieving coefficient (Spearman R = - 0.45 and p = 0.02). Notably, the anti-inflammatory cytokine IL-10 was not efficiently extracted by SBUF.

CONCLUSIONS

CPB is associated with a burden of circulating inflammatory mediators, and SBUF selectively extracts twenty of these pro-inflammatory factors while preserving the key anti-inflammatory regulator IL-10. Ultrafiltration could potentially function as an immunomodulatory therapy during pediatric cardiac surgery. Trial registration ClinicalTrials.gov, NCT05154864. Registered retrospectively on December 13, 2021. https://clinicaltrials.gov/ct2/show/record/NCT05154864 .

Association of Conventional Ultrafiltration on Postoperative Pulmonary Complications

BACKGROUND

Postoperative pulmonary complications increase mortality after cardiac surgery. Conventional ultrafiltration may reduce pulmonary complications by removing mediators of bypass-induced inflammation and countering hemodilution. We tested the primary hypothesis that conventional ultrafiltration reduces postoperative pulmonary complications, and secondarily, improves early pulmonary function assessed by the ratio of PaO2 to fractional inspired oxygen concentration.

METHODS

This retrospective analysis compared the incidence of postoperative pulmonary complications in adult patients who underwent cardiac surgery, with and without the use of conventional ultrafiltration, by using logistic regression with adjustment for confounding variables. The primary outcome was a composite of reintubation, prolonged ventilation, pneumonia, or pleural effusion. Secondarily, we examined early postoperative lung function using a quantile regression model. We also explored whether red blood cell transfusion differed between groups.

RESULTS

Of 8026 patients, 1043 (13%) received conventional ultrafiltration. After adjustment for confounding variables, the incidence of the composite primary outcome was higher in the conventional ultrafiltration group (12.1% vs 9.9%; P = .03), with an estimated odds ratio of 1.25 (95% CI, 1.02-1.53; P = .03). The median (quantiles) PaO2-to-fractional inspired oxygen concentration ratio was 373 (303-433) vs 368 (303-428), with the estimated adjusted difference in medians of 5 (95% CI, -5.9 to 16; P = .37). The estimated odds ratio of intraoperative transfusion was 1.38 (95% CI, 1.19-1.60; P < .0001) and for postoperative transfusion was 1.30 (95% CI, 1.14-1.49; P = .0001).

CONCLUSIONS

Use of conventional ultrafiltration was not associated with a reduction in the composite of postoperative pulmonary complications or improved early pulmonary function. We found no evidence of benefit from use of conventional ultrafiltration during cardiac surgery.

Continuous Ultrafiltration Enhances Recovery After Adult Cardiac Surgery With Cardiopulmonary Bypass: A Systematic Review and Meta-analysis

Background

Cardiac surgery with cardiopulmonary bypass is associated with systemic inflammation. Ultrafiltration used throughout the cardiopulmonary bypass time, continuously, is hypothesized to be an immunomodulatory therapy.

Methods

A systematic review and meta-analysis of randomized trials investigating continuous forms of ultrafiltration during adult cardiac surgery (CRD42020219309) was conducted and is reported following PRISMA guidelines. MEDLINE, Embase, CENTRAL, and Scopus were searched on November 3, 2021. The primary endpoint was operative mortality, and secondary outcomes included intensive care unit length of stay (ICU LOS), ventilation time, acute kidney injury or renal failure, and pneumonia. Each study was assessed for risk of bias using the Cochrane Risk-of Bias-Tool for Randomized Trials (RoB2) instrument. Outcomes were analyzed with inverse variance random-effects models and assessed for GRADE quality of evidence.

Results

Twelve randomized trials consisting of 989 adult patients undergoing coronary, valvular, or concomitant cardiac procedures were included. Compared to controls, patients receiving continuous ultrafiltration had no statistical difference in operative mortality; risk ratio of 0.32 (95% confidence interval [CI]: 0.10-1.03; P = 0.06). Reductions occurred in ICU LOS, by 7.01 hours (95% CI: 1.86-12.15; P = 0.008); ventilation time, by 2.11 hours (95% CI: 0.71-3.51; P = 0.003); and incidence of pneumonia, with a risk ratio of 0.33 (95% CI: 0.15-0.75; P = 0.008). There wasno difference in renal injury. The GRADE quality of evidence for these outcomes ranged from very low to low.

Conclusions

Continuous forms of ultrafiltration enhance recovery after adult cardiac surgery by reducing ICU LOS, ventilation time, and incidence of pneumonia. A multicentre randomized trial could confirm and generalize these findings.

Narrative review of systemic inflammatory response mechanisms in cardiac surgery and immunomodulatory role of anesthetic agents

Although surgical techniques and perioperative care have made significant advances, perioperative mortality in cardiac surgery remains relatively high. Single- or multiple-organ failure remains the leading cause of postoperative mortality. Systemic inflammatory response syndrome (SIRS) is a common trigger for organ injury or dysfunction in surgical patients. Cardiac surgery involves major surgical dissection, the use of cardiopulmonary bypass (CPB), and frequent blood transfusions. Ischemia-reperfusion injury and contact activation from CPB are among the major triggers for SIRS. Blood transfusion can also induce proinflammatory responses. Here, we review the immunological mechanisms of organ injury and the role of anesthetic regimens in cardiac surgery.

Do continuous forms of intra-operative ultrafiltration enhance recovery after adult cardiac surgery with cardiopulmonary bypass? A protocol for systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with a systemic inflammatory syndrome that adversely impacts cardiopulmonary function and can contribute to prolonged postoperative recovery. Intra-operative ultrafiltration during CPB is a strategy developed by pediatric cardiac specialists, aiming to dampen the inflammatory syndrome by removing circulating cytokines and improving coagulation profiles during the cardiac operation. Although ultrafiltration is commonly used in the pediatric population, it is not routinely used in the adult population. This study aims to evaluate if randomized evidence supports the use of continuous intra-operative ultrafiltration to enhance recovery for adults undergoing cardiac surgery with CPB.

METHODS

This systematic review and meta-analysis will include randomized controlled trials (RCT) that feature continuous forms of ultrafiltration during adult cardiac surgery with CPB, specifically assessing for benefit in mortality rates, invasive ventilation time and intensive care unit length of stay (ICU LOS). Relevant RCTs will be retrieved from databases, including MEDLINE, Embase, CENTRAL and Scopus, by a pre-defined search strategy. Search results will be screened for inclusion and exclusion criteria by two independent persons with consensus. Selected RCTs will have study demographics and outcome data extracted by two independent persons and transferred into RevMan. Risk of bias will be independently assessed by the Revised Cochrane Risk-of-Bias (RoB2) tool and studies rated as low-, some-, or high- risk of bias. Meta-analyses will compare the intervention of continuous ultrafiltration against comparators in terms of mortality, ventilation time, ICU LOS, and renal failure. Heterogeneity will be measured by the χ² test and described by the I² statistic. A sensitivity analysis will be completed by excluding included studies judged to have a high risk of bias. Summary of findings and certainty of the evidence, determined by the GRADE approach, will display the analysis findings.

DISCUSSION

The findings of this systematic review and meta-analysis will summarize the evidence to date of continuous forms of ultrafiltration in adult cardiac surgery with CPB, to both inform adult cardiac specialists about this technique and identify critical questions for future research in this subject area.

SYSTEMATIC REVIEW REGISTRATION

This systematic review and meta-analysis is registered in PROSPERO CRD42020219309  ( https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020219309 ).

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.

Modified ultrafiltration and postoperative course in patients undergoing repair of tetralogy of fallot

BACKGROUND

Expected benefits of modified ultrafiltration (MUF) include increased hematocrit, reduction of total body water and inflammatory mediators, improved left ventricular systolic function, and improved systolic blood pressure and cardiac index (CI) following cardiopulmonary bypass (CPB). This prospective randomized trial tested this hypothesis.

METHODS

Seventy-nine patients undergoing intracardiac repair of tetralogy of fallot were randomized to conventional ultrafiltration (CUF) + MUF (n = 39) or only CUF group (n = 40). The primary outcome was a change in hematocrit. Secondary outcomes were changes in peak airway pressures, ventilatory support, blood transfusions, time to peripheral rewarming, mean arterial pressure, central venous pressure, inotrope score (IS), and CI. Serum inflammatory markers were measured.

RESULTS

Baseline hematocrit was 50.6 ± 10.02 in the only CUF group whereas it was 43.9 ± 5.55 in the CUF + MUF group (p = .36). Following MUF, the CUF + MUF group had higher hematocrit (44.7 ± 0.50 g/dl) compared to the only CUF group (37.2 ± 0.49 g/dl), p ≤ .001 after adjusting for baseline hematocrit. Central venous pressure (mmHg) immediately following sternal closure was 9.27 ± 3.12 mmHg in the CUF + MUF group and 10.52 ± 2.2 mmHg in the only CUF group (p = .04). In the intensive care unit (ICU), they were 11.52 ± 2.20 mmHg in the only CUF group and 10.84 ± 2.78 mmHg in the CUF + MUF group (p = .02). Time to peripheral rewarming was 6.30 ± 3.91 h in the CUF + MUF group and 13.67 ± 3.91 h in the only CUF group (p = .06). Peak airway pressures in ICU were 17 ± 2 mmHg versus 20.55 ± 2.97 mmHg in CUF + MUF group & only CUF group, respectively, p < .001). Duration of mechanical ventilation was 6.3 ± 2.7 h in CUF + MUF group compared to 14.7 ± 3.5 h in the only CUF group (p = .002). IS was 11.52 ± 2.20 in the only CUF group compared to 10.84 ± 2.78 in CUF + MUFs group. Eight of 39 (20.5%) patients in the CUF + MUF group had IS > 10 compared to 22 of 40 (55%) patients in the only CUF group (p = .02). Serum Troponin-T and interleukin-6 levels were lower in the CUF + MUF group; TNF-α and CPK-MB were similar. ICU and hospital stay were similar.

CONCLUSION

Patients undergoing a combination of CUF and MUF had higher postoperative hematocrit, decreased duration of mechanical ventilation, lower need for inotropes and lower interleukin-6 and Troponin-T levels. This group had better postoperative outcomes. This study was registered with the Clinical trials registry of India (CTRI/2017/11/010512) before commencement.

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.

International Pediatric Perfusion Practice: 2016 Survey Results

New cardiopulmonary bypass device techniques emerge and are reported in the scientific literature. The extent to which they are actually adopted into clinical practice is not well known. Since 1989, we have periodically surveyed pediatric cardiac centers to ascertain practice patterns. In December 2016, a 186-question perfusion survey was distributed to pediatric cardiac surgery centers all over the world using a Web-based survey tool. Responses were received from 93 North American (NA) centers (the United States and Canada) and 67 non-NA (NNA) centers, representing 19,645 cumulative annual procedures in NA and 27,776 in NNA centers on patients <18 years. Wide variation in practice was evident across geographic regions. However, the most common pediatric circuit consisted of a hard-shell (open) venous reservoir, an arterial roller pump, and a hollow-fiber membrane oxygenator with a separate or integrated arterial filter. Compared with our previous surveys, there was increased utilization of all types of safety devices. The use of an electronic perfusion record was reported by 50% of NA centers and 31% of NNA centers. There was wide regional variation in cardioplegia delivery systems and cardioplegia solutions. Seventy-nine percent of the centers reported the use of some form of modified ultrafiltration. The survey demonstrated that there remains variation in perfusion practice for pediatric patients. Future surveys will be useful to evaluate the adoption of emerging perfusion practice guidelines.

The Effect of Optimized Ultrafiltration on Perioperative Pulmonary Function During Cardiopulmonary Bypass in Infants Under 10 kg

Objective: This study aims to investigate the effect of optimized ultrafiltration on perioperative electrolytes, acid-base balance, and pulmonary function during cardiopulmonary bypass (CPB) in infants with low body weight (under 10 kg), using traditional balanced ultrafiltration and modified ultrafiltration. Methods: A total of 30 children who underwent surgical correction for congenital heart disease in Changzhou Children's Hospital between January 2018 and December 2019 were randomly divided into two groups. In the treatment group, ultrafiltration pre-treatment was carried out with blood-containing priming fluid prior to CPB. Balanced ultrafiltration was performed during the operation, and optimized and modified ultrafiltration were conducted before closing and extubation. In the control group, traditional balanced ultrafiltration was used during the operation, and a modified ultrafiltration combination was used before closing and extubation. Indexes such as blood gas analysis and electrolytes were measured perioperatively, and pulmonary function was observed. Results: No deaths were reported in either group. The ventilator-assisted breathing time was shorter in the treatment group than in the control group (P < 0.05). The indexes of the treatment group were closer than those of the control group to the optimal physiological values. The concentrations of potassium ion (K⁺), lactate (Lac), and blood glucose (Glu) decreased, and there was significant difference between the two groups (P < 0.05) at the end of CPB. Hemoglobin (Hb) and hematocrit (HCT) in the treatment group increased (P < 0.01). Alveolar-arterial differences for oxygen (A-aDO₂) and respiratory index (RI) increased significantly in both groups after operation. Children in the treatment group began to recover lung function earlier than children in the control group. Both A-aDO₂ and RI were lower in the treatment group than in the control group at each time point after operation (P < 0.05). Conclusion: Optimizing and modifying the traditional ultrafiltration combination method can effectively shorten the ultrafiltration time, reduce the adverse impacts of the ultrafiltration technique, and improve the lung function of infants after operation.

Association of postoperative fluid overload with adverse outcomes after congenital heart surgery: a systematic review and dose-response meta-analysis

BACKGROUND

Pediatric cardiac surgery is commonly associated with acute kidney injury (AKI) and significant fluid retention, which complicate postoperative management and lead to increased rates of morbidity. This meta-analysis aimed to accumulate current literature evidence and evaluate the correlation of fluid overload degree with adverse outcome in patients undergoing congenital heart surgery.

METHODS

Medline, Scopus, CENTRAL, Clinicaltrials.gov, and Google Scholar were systematically searched from inception. All studies reporting the effects of fluid overload on postoperative clinical outcomes were selected. A dose-response meta-analytic method using restricted cubic splines was implemented in R-3.6.1.

RESULTS

Twelve studies were included, with a total of 3111 pediatric patients. Qualitative synthesis indicated that fluid overload was linked to significantly higher risk of mortality, AKI, prolonged hospital, and intensive care unit (ICU) stay, as well as with increased duration of mechanical ventilation, inotrope need, and infection rate. Meta-analysis demonstrated a linear correlation between fluid overload and the risk of mortality (χ² = 6.22, p value = 0.01) and AKI (χ² = 35.84, p value < 0.001), while a positive curvilinear relationship was estimated for the outcomes of hospital (χ² = 18.84, p value = 0.0001) and ICU stay (χ² = 63.69, p value = 0.0001).

CONCLUSIONS

The present meta-analysis supports that postoperative fluid overload is significantly linked to elevated risk of prolonged hospital stay, AKI development, and mortality in pediatric patients undergoing cardiac surgery. These findings warrant replication by future prospective studies, which should define the optimal cutoff values and assess the effectiveness of therapeutic strategies to limit fluid overload in the postoperative setting.