Predictors of Acute Renal Failure During Extracorporeal Membrane Oxygenation in Pediatric Patients After Cardiac Surgery

Hemolysis Index Correlations with Plasma-Free Hemoglobin and Plasma Lactate Dehydrogenase in Critically Ill Patients under Extracorporeal Membrane Oxygenation or Mechanical Circulatory Support-A Single-Center Study

Monitoring for thrombosis and hemolysis is crucial for patients under extracorporeal or mechanical circulatory support, but it can be costly. We investigated correlations between hemolysis index (HI) and plasma-free hemoglobin (PFH) levels on one hand, and between the HI and plasma lactate dehydrogenase (LDH) levels on the other, in critically ill patients with and without extracorporeal or mechanical circulatory support. Additionally, we calculated the cost reductions if monitoring through HI were to replace monitoring through PFH or plasma LDH. In a single-center study, HI was compared with PFH and plasma LDH levels in blood samples taken for routine purposes in critically ill patients with and without extracorporeal or mechanical circulatory support. A cost analysis, restricted to direct costs associated with each measurement, was made for an average 10-bed ICU. This study included 147 patients: 56 patients with extracorporeal or mechanical circulatory support (450 measurements) and 91 patients without extracorporeal or mechanical circulatory support (562 measurements). The HI correlated well with PFH levels (r = 0.96; p < 0.01) and poorly with plasma LDH levels (r = 0.07; p < 0.01) in patients with extracorporeal or mechanical circulatory support. Similarly, HI correlated well with PFH levels (r = 0.97; p < 0.01) and poorly with plasma LDH levels (r = -0.04; p = 0.39) in patients without extracorporeal or mechanical circulatory support. ROC analyses demonstrated a strong performance of HI, with the curve indicating excellent discrimination in the whole cohort (area under the ROC of 0.969) as well as in patients under ECMO or mechanical circulatory support (area under the ROC of 0.988). Although the negative predictive value of HI for predicting PFH levels > 10 mg/dL was high, its positive predictive value was found to be poor at various cutoffs. A simple cost analysis showed substantial cost reduction if HI were to replace PFH or plasma LDH for hemolysis monitoring. In conclusion, in this cohort of critically ill patients with and without extracorporeal or mechanical circulatory support, HI correlated well with PFH levels, but poorly with plasma LDH levels. Given the high correlation and substantial cost reductions, a strategy utilizing HI may be preferable for monitoring for hemolysis compared to monitoring strategies based on PFH or plasma LDH. The PPV of HI, however, is unacceptably low to be used as a diagnostic test.

Short-Term Mortality Among Pediatric Patients With Heart Diseases Undergoing Veno-Arterial Extracorporeal Membrane Oxygenation: A Systematic Review and Meta-Analysis

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation serves as a crucial mechanical circulatory support for pediatric patients with severe heart diseases, but the mortality rate remains high. The objective of this study was to assess the short-term mortality in these patients.

METHODS AND RESULTS

We systematically searched PubMed, Embase, and Cochrane Library for observational studies that evaluated the short-term mortality of pediatric patients undergoing veno-arterial extracorporeal membrane oxygenation. To estimate short-term mortality, we used random-effects meta-analysis. Furthermore, we conducted meta-regression and binomial regression analyses to investigate the risk factors associated with the outcome of interest. We systematically reviewed 28 eligible references encompassing a total of 1736 patients. The pooled analysis demonstrated a short-term mortality (defined as in-hospital or 30-day mortality) of 45.6% (95% CI, 38.7%-52.4%). We found a significant difference (P<0.001) in mortality rates between acute fulminant myocarditis and congenital heart disease, with acute fulminant myocarditis exhibiting a lower mortality rate. Our findings revealed a negative correlation between older age and weight and short-term mortality in patients undergoing veno-arterial extracorporeal membrane oxygenation. Male sex, bleeding, renal damage, and central cannulation were associated with an increased risk of short-term mortality.

CONCLUSIONS

The short-term mortality among pediatric patients undergoing veno-arterial extracorporeal membrane oxygenation for severe heart diseases was 45.6%. Patients with acute fulminant myocarditis exhibited more favorable survival rates compared with those with congenital heart disease. Several risk factors, including male sex, bleeding, renal damage, and central cannulation contributed to an increased risk of short-term mortality. Conversely, older age and greater weight appeared to be protective factors.

Hemostatic complications and systemic heparinization in pediatric post-cardiotomy veno-arterial extracorporeal membrane oxygenation failed to wean from cardiopulmonary bypass

BACKGROUND

Hemostatic complications and the need for large amounts of blood products are major obstacles during veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Additionally, the occurrence of coagulopathy after cardiopulmonary bypass (CPB) affects systemic heparinization in pediatric post-cardiotomy patients. This study compares hemostatic complications in pediatric post-cardiotomy VA-ECMO patients for failure to wean from CPB with those who received post-cardiotomy VA-ECMO for other indications, while also exploring the relationship between different stages-hemostatic complications and the timing of systemic heparinization.

METHODS

We retrospectively analyzed 146 pediatric patients who received post-cardiotomy VA-ECMO support (CPB-ECMO, n=96 vs. non-CPB-ECMO, n=50) from January 2005 to June 2020. Patients were divided into survivors (n=46) and non-survivors (n=50) according to in-hospital mortality in the CPB-ECMO group. We compared clinical outcomes between the groups, then examined the associations between the timing of systemic heparinization after ECMO implantation and different stages-hemostatic complications, in the CPB-ECMO group.

RESULTS

We found that the risk of early bleeding was significantly increased in patients who failed to wean from CPB. The presence of early bleeding was accompanied by the higher demand for blood products transfusion in the CPB-ECMO group, and for treatment the patients received a longer delayed continuous heparin infusion. As a result of using delayed systemic heparinization to avoid early bleeding, early hemolysis increased in the CPB-ECMO group. A delayed systemic heparinization of 9.5 hours showed the best Youden index results and the overall greatest accuracy in predicting early hemolysis.

CONCLUSIONS

A direct transition from CPB to ECMO in pediatric post-cardiotomy patients significantly increases early bleeding. Delayed systemic heparinization to reduce early bleeding has good discrimination for predicting early hemolysis in the CPB-ECMO group. Coagulopathy is complex in pediatric post-cardiotomy VA-ECMO patients who failed to wean from CPB, and, as such, it is extremely important to monitor coagulation-related indicators in multiple dimensions to determine the timing of systemic heparinization.

Mortality prediction in pediatric postcardiotomy veno-arterial extracorporeal membrane oxygenation: A comparison of scoring systems

Background

Pediatric postcardiotomy veno-arterial extracorporeal membrane oxygenation (VA-ECMO) patients have high mortality and morbidity. There are currently three scoring systems available to predict mortality: the Pediatric Extracorporeal Membrane Oxygenation Prediction (PEP) model, Precannulation Pediatric Survival After VA-ECMO (Pedi-SAVE) score, and Postcannulation Pedi-SAVE score. These methods provide risk stratification scores for pediatric patients requiring ECMO for cardiac support. However, comparative validation of these scoring systems remains scarce. We aim to assess the ability of these models to predict outcomes in a cohort of pediatric patients undergoing VA-ECMO after cardiac surgery, and identify predictors of in-hospital mortality.

Methods

A retrospective analysis of 101 children admitted to Fuwai Hospital who received VA-ECMO from January 1, 2010 to December 31, 2020 was performed. Patients were divided into two groups, survivors (n = 49) and non-survivors (n = 52) according to in-hospital mortality. PEP model and Pedi-SAVE scores were calculated. The primary outcomes were the risk factors of in-hospital mortality, and the ability of the PEP model, Precannulation Pedi-SAVE and Postcannulation Pedi-SAVE scores to predict in-hospital mortality.

Results

Postcannulation Pedi-SAVE score accessing the entire ECMO process had the greatest area under receiver operator curve (AUROC), 0.816 [95% confidence interval (CI): 0.733–0.899]. Pre-ECMO PEP model could predict in-hospital mortality [AUROC = 0.691 (95% CI: 0.565–0.817)], and Precannulation Pedi-SAVE score had the poorest prediction [AUROC = 0.582(95% CI: 0.471–0.694)]. Lactate value at ECMO implantation [OR = 1.199 (1.064–1.351), P = 0.003] and infectious complications [OR = 5.169 (1.652–16.172), P = 0.005] were independent risk factors for in-hospital mortality.

Conclusion

Pediatric cardiac ECMO scoring systems, including multiple risk factors before and during ECMO, were found to be useful in this cohort. Both the pre-ECMO PEP model and the Postcannulation Pedi-SAVE score were found to have high predictive value for in-hospital mortality in pediatric postcardiotomy VA-ECMO.

Extracorporeal Life Support Organization (ELSO): Guidelines for Pediatric Cardiac Failure

These guidelines are applicable to neonates and children with cardiac failure as indication for extracorporeal life support. These guidelines address patient selection, management during extracorporeal membrane oxygenation, and pathways for weaning support or bridging to other therapies. Equally important issues, such as personnel, training, credentialing, resources, follow-up, reporting, and quality assurance, are addressed in other Extracorporeal Life Support Organization documents or are center-specific.

Hemolysis and Plasma Free Hemoglobin During Extracorporeal Membrane Oxygenation Support: From Clinical Implications to Laboratory Details

Venovenous and venoarterial extracorporeal membrane oxygenation (ECMO) are lifesaving supports that are more and more frequently used in critically ill patients. Despite of major technological improvements observed during the last 20 years, ECMO-associated hemolysis is still a complication that may arise during such therapy. Hemolysis severity, directly appreciated by plasma free hemoglobin concentration, may be present with various intensity, from a nonalarming and tolerable hemolysis to a highly toxic one. Here, we propose a review dedicated to extracorporeal membrane oxygenation (ECMO)-associated hemolysis, with a particular emphasis on pathophysiology, prevalence, and clinical consequences of such complication. We also focus on laboratory assessment of hemolysis and on the limits that have to be known by clinicians to prevent and manage hemolytic events.

Outcomes and factors associated with early mortality in pediatric postcardiotomy veno-arterial extracorporeal membrane oxygenation

Mortality and morbidity of children received veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support after cardiac surgery remain high despite remarkable advances in medical management and devices. The purpose of this study was to describe outcomes and risk factors of applying VA-ECMO in the surgical pediatric population. We retrospectively analyzed 85 consecutive pediatric patients (aged <18 years) who received postcardiotomy VA-ECMO from January 2010 to December 2018. Median (IQR) age at ECMO implantation in this cohort was 12.7 (6.4, 43.2) months, median weight was 8.5 (6.0, 12.8) kg, mean ECMO duration was 143.2 ± 81.6 hours and mean hospital length of stay was 48.4 ± 32.4 days. Seventy-five patients (88.2%) were indicated for postcardiotomy cardiogenic shock. The successful ECMO weaning rate was 70.6% and in-hospital mortality was 52.9%. The most common diagnosis was transposition of great arteries (n = 18, 21.2%), while acute kidney injury occurred most often (n = 64, 75.3%). Multivariate logistic regression analysis showed that thrombocytopenia, hemolysis, and nosocomial infection were positively correlated with in-hospital mortality. Multivariate Cox proportional hazard regression analysis presented that thrombocytopenia significantly increased the 180-day mortality in patients with successful weaning. Therefore, multiple factors had adverse effects on prognosis. Patient selection and procedures from ECMO implantation to weaning need to be closely monitored and performed in a timely manner to improve outcome.

Use of extracorporeal membrane oxygenation in postcardiotomy pediatric patients: parameters affecting survival

AIM

We aimed to investigate the risk factors affecting survival after extracorporeal membrane oxygenation use in pediatric postcardiotomy patients.

METHODS

One hundred thirty-three consecutive patients who underwent surgery for congenital heart disease who needed extracorporeal membrane oxygenation support were retrospectively analyzed.

RESULTS

In all, 3,082 patients were operated, of which 140 patients (4.54% of the total number of operations) needed extracorporeal membrane oxygenation. Eighty (60.1%) patients were successfully weaned and 51 (38.3%) patients were discharged. Of the 50 patients discharged during the mean follow-up period of 34.8 (0-192.4) months, 6 (12%) patients died. The extracorporeal membrane oxygenation support was instituted in 29 (21.8%) patients for extracorporeal membrane oxygenation cardiopulmonary resuscitation, in 44 (33.1%) patients due to the inability to be separated from cardiopulmonary bypass, in 19 (14.3%) patients due to respiratory failure, and in 41 patients due to low cardiac output syndrome. Eighty patients (60.2%) were successfully weaned from extracorporeal membrane oxygenation support. The remaining 53 (39.8%) patients died on extracorporeal membrane oxygenation. Mortality was observed in 29 (21.8%) of the 80 patients in the successful weaning group, while the remaining 51 (38.3%) patients were discharged from the hospital. Multivariate analysis showed that double-ventricular physiology increased the rate of successful weaning (odds ratio: 3.4, 95% confidence interval lower: 1.5 and upper: 8, p = 0.004) and prolonged extracorporeal membrane oxygenation durations were a risk factor in successful weaning (odds ratio: 0.9, 95% confidence interval lower: 0.8 and upper: 0.9, p = 0.007). The parameters affecting mortality were the presence of syndrome (odds ratio: 3.8, 95% confidence interval lower: 1.0 and upper: 14.9, p = 0.05), single-ventricular physiology (odds ratio: 5.3, 95% confidence interval lower: 1.8 and upper: 15.3, p = 0.002), and the need for a second extracorporeal membrane oxygenation (odds ratio: 12.9, 95% confidence interval lower: 1.6 and upper: 104.2, p = 0.02). While 1-year survival was 15.2% and 3-year survival was 12.1% in patients with single-ventricular physiology, the respective survival rates were 43.9% and 40.8%.

CONCLUSION

Parameters affecting mortality after extracorporeal membrane oxygenation support in pediatric postcardiotomy patient group were the presence of a syndrome, multiple runs of extracorporeal membrane oxygenation, and single-ventricular physiology. Timing of extracorporeal membrane oxygenation initiation, appropriate patient selection, appropriate reintervention or reoperation for patients with correctable pathology, the use of an appropriate cannulation strategy in single-ventricle patients, management of shunt flow, and appropriate interventions to reduce the incidence of complications play key roles in improving survival.

Renal function in children assisted with extracorporeal membrane oxygenation

Acute kidney injury is a frequent complication in patients requiring extracorporeal membrane oxygenation. A single-center retrospective analysis from a prospective observational database assessing the incidence of acute kidney injury in children undergoing extracorporeal membrane oxygenation, the use of continuous renal replacement therapy and its association with outcomes was performed. One hundred children were studied. Creatinine was normal in 33.3% of children at the beginning of extracorporeal membrane oxygenation, between 1.5 and 2 times its baseline levels in 18.4% of children (stage I acute kidney injury), between 2 and 3 times baseline levels (stage II) in 20.7%, and over 3 times baseline levels or requiring continuous renal replacement therapy (stage III) in 27.6% of the patients. Eighteen patients were on continuous renal replacement therapy before the beginning of extracorporeal membrane oxygenation, 81 required continuous renal replacement therapy during extracorporeal membrane oxygenation, and 38 after weaning from extracorporeal membrane oxygenation, but none of them did at discharge from the pediatric intensive care unit. Fifty-one children survived to pediatric intensive care unit discharge. Mortality was lower in children with normal kidney function or with stage I acute kidney injury at the beginning of extracorporeal membrane oxygenation than in those with stage II or III acute kidney injury (33.3% vs 58.3%, p = 0.021). Mortality in children requiring continuous renal replacement therapy during extracorporeal membrane oxygenation was 54.3% and 21.1% in the rest of patients (p < 0.01). We conclude that kidney function is significantly impaired in a high percentage of children undergoing extracorporeal membrane oxygenation and many of them are treated with continuous renal replacement therapy. Patients treated with continuous renal replacement therapy have a higher mortality than those with normal kidney function or stage I acute kidney injury at the beginning of extracorporeal membrane oxygenation. Most patients surviving to pediatric intensive care unit discharge recover normal renal function after weaning from extracorporeal membrane oxygenation.

Hemolysis During Pediatric Extracorporeal Membrane Oxygenation: Associations With Circuitry, Complications, and Mortality

OBJECTIVES

To describe factors associated with hemolysis during pediatric extracorporeal membrane oxygenation and the relationships between hemolysis, complications, and mortality.

DESIGN

Secondary analysis of data collected prospectively by the Collaborative Pediatric Critical Care Research Network between December 2012 and September 2014.

SETTING

Three Collaborative Pediatric Critical Care Research Network-affiliated hospitals.

PATIENTS

Age less than 19 years and treated with extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Hemolysis was defined based on peak plasma free hemoglobin levels during extracorporeal membrane oxygenation and categorized as none (< 0.001 g/L), mild (0.001 to < 0.5 g/L), moderate (0.5 to < 1.0 g/L), or severe (≥ 1.0 g/L). Of 216 patients, four (1.9%) had no hemolysis, 67 (31.0%) had mild, 51 (23.6%) had moderate, and 94 (43.5%) had severe. On multivariable analysis, variables independently associated with higher daily plasma free hemoglobin concentration included the use of in-line hemofiltration or other continuous renal replacement therapy, higher hemoglobin concentration, higher total bilirubin concentration, lower mean heparin infusion dose, lower body weight, and lower platelet count. Using multivariable Cox modeling, daily plasma free hemoglobin was independently associated with development of renal failure during extracorporeal membrane oxygenation (defined as creatinine > 2 mg/dL [> 176.8 μmol/L] or use of in-line hemofiltration or continuous renal replacement therapy) (hazard ratio, 1.04; 95% CI, 1.02-1.06; p < 0.001), but not mortality (hazard ratio, 1.01; 95% CI, 0.99-1.04; p = 0.389).

CONCLUSIONS

Hemolysis is common during pediatric extracorporeal membrane oxygenation. Hemolysis may contribute to the development of renal failure, and therapies used to manage renal failure such as in-line hemofiltration and other forms of continuous renal replacement therapy may contribute to hemolysis. Hemolysis was not associated with mortality after controlling for other factors. Monitoring for hemolysis should be a routine part of extracorporeal membrane oxygenation practice, and efforts to reduce hemolysis may improve patient care.

Predictors of Poor Outcomes in Pediatric Venoarterial Extracorporeal Membrane Oxygenation

BACKGROUND

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides respiratory and hemodynamic support to pediatric patients in severe cardiac failure. We aim to identify risk factors associated with poorer outcomes in this population.

METHODS

A retrospective chart review was conducted of pediatric patients requiring VA-ECMO support for cardiac indications at our institution from 2004 to 2015. Data were collected on demographics, indication, markers of cardiac output, ventricular assist device (VAD) insertion, heart transplantation, or left atrial (LA) decompression. Univariate Cox proportional hazards models were used to calculate hazard ratios (HRs) for variables associated with the composite primary outcome of transplant-free survival (TFS).

RESULTS

Of the 68 reviewed patients, 65% were male, 84% were white, 38% had a prior surgery, 13% had a prior transplant, 10% had a prior ECMO support, and 87.5% required vasoactive support within six hours of cannulation. The ECMO indications included congenital heart disease repaired >30 days prior (12%), cardiomyopathy (41%), posttransplant rejection (7%), and cardiorespiratory failure (40%). The TFS was 54.5% at discharge and 47.7% at one year. Predictors of transplant and/or death include epinephrine use (hazard ratio [HR] = 2.269, P = .041), elevated lactate (HR = 1.081, P = 0005), and elevated creatinine (HR = 1.081, P = .005) within six hours prior to cannulation. Sixteen (23.6%) patients underwent LA decompression. Placement of VAD occurred in 16 (23.5%) patients, for which nonwhite race (HR = 2.94, P = .034) and prior ECMO (HR = 3.42, P = .053) were the only identified risk factors.

CONCLUSIONS

Need for VA-ECMO for cardiac support carries high inpatient morbidity and mortality. Epinephrine use and elevated lactate and creatinine were associated with especially poor outcomes. Patients who survived to discharge had good short-term follow-up results.

Multicenter Experience With Mechanical Circulatory Support Using a New Diagonal Pump in 233 Children

Technological innovations in pediatric extracorporeal life support circuits can reduce system-related complications and may improve patients' outcome. The Deltastream DP3 (Medos Medizintechnik AG, Stolberg, Germany) is a novel rotational pump with a diagonally streamed impeller that can be used over a broad range of flows. We collected patient data from seven pediatric centers to conduct a retrospective cohort study. We examined 233 patients whose median age was 1.9 (0-201) months. The DP3 system was used for cardiopulmonary support as veno-arterial extracorporeal membrane oxygenation (ECMO) in 162 patients. Respiratory support via veno-venous ECMO was provided in 63 patients. The pump was used as a ventricular assist device in eight patients. Median supporting time was 5.5 (0.2-69) days and the weaning rate was 72.5%. The discharge home rate was 62% in the pulmonary group versus 55% in the cardiac group. Extracorporeal cardiopulmonary resuscitation was carried out in 24 patients (10%) with a survival to discharge of rate of 37.5%. About 106 (47%) children experienced no complications, while 33% suffered bleeding requiring blood transfusion or surgical intervention. Three patients suffered a fatal cerebral event. Renal replacement therapy was performed in 28% and pump or oxygenator exchange in 26%. Multivariable analysis identified system exchange (OR 1.94), kidney failure (OR 3.43), and complications on support (OR 2.56) as risk factors for dismal outcome. This novel diagonal pump has demonstrated its efficacy in all kinds of mechanical circulatory and respiratory support, revealing good survival rates.

Artificial Organs 2016: A Year in Review

In this Editor's Review, articles published in 2016 are organized by category and briefly summarized. We aim to provide a brief reflection of the currently available worldwide knowledge that is intended to advance and better human life while providing insight for continued application of technologies and methods of organ Replacement, Recovery, and Regeneration. As the official journal of The International Federation for Artificial Organs, The International Faculty for Artificial Organs, the International Society for Mechanical Circulatory Support, the International Society for Pediatric Mechanical Cardiopulmonary Support, and the Vienna International Workshop on Functional Electrical Stimulation, Artificial Organs continues in the original mission of its founders "to foster communications in the field of artificial organs on an international level." Artificial Organs continues to publish developments and clinical applications of artificial organ technologies in this broad and expanding field of organ Replacement, Recovery, and Regeneration from all over the world. We were pleased to publish our second Virtual Issue in April 2016 on "Tissue Engineering in Bone" by Professor Tsuyoshi Takato. Our first was published in 2011 titled "Intra-Aortic Balloon Pumping" by Dr. Ashraf Khir. Other peer-reviewed Special Issues this year included contributions from the 11th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion edited by Dr. Akif Ündar and selections from the 23rd Congress of the International Society for Rotary Blood Pumps edited by Dr. Bojan Biocina. We take this time also to express our gratitude to our authors for offering their work to this journal. We offer our very special thanks to our reviewers who give so generously of time and expertise to review, critique, and especially provide meaningful suggestions to the author's work whether eventually accepted or rejected. Without these excellent and dedicated reviewers the quality expected from such a journal could not be possible. We also express our special thanks to our Publisher, John Wiley & Sons for their expert attention and support in the production and marketing of Artificial Organs. We look forward to reporting further advances in the coming years.

Extracorporeal Life Support for Pediatric Heart Failure

Extracorporeal life support (ECLS) represents an essential component in the treatment of the pediatric patient with refractory heart failure. Defined as the use of an extracorporeal system to provide cardiopulmonary support, ECLS provides hemodynamic support to facilitate end-organ recovery and can be used as a salvage therapy during acute cardiorespiratory failure. Support strategies employed in pediatric cardiac patients include bridge to recovery, bridge to therapy, and bridge to transplant. Advances in extracorporeal technology and refinements in patient selection have allowed wider application of this therapy in pediatric heart failure patients.