Bleeding and Thrombosis in Pediatric Extracorporeal Membrane Oxygenation. Can We Improve Anticoagulation Strategies?

Use of Inhaled Tranexamic Acid for Pulmonary Hemorrhage in Pediatric Patients on Extracorporeal Membrane Oxygenation Support

Bleeding is a common complication of extracorporeal membrane oxygenation (ECMO), is multifactorial, and results in significant morbidity and mortality. Pulmonary hemorrhage represents a serious adverse event in pediatric patients on ECMO and remains a challenging complication to manage. Its occurrence highlights the importance of identifying treatments that address bleeding complications in this population. This retrospective cohort study, from January 2018 to August 2022, explores the use of inhaled tranexamic acid (TXA), a clot-stabilizing agent, in 53 pediatric ECMO patients with new pulmonary hemorrhage. Primary diagnoses included respiratory failure (34%) and structural abnormalities (34%), such as congenital heart defects, congenital diaphragmatic hernia, and tracheal stenosis, with viral pneumonia being the leading cause of respiratory failure (47%). Results indicated that 48 of 53 (91%) patients showed cessation of pulmonary hemorrhage within 48 hours of inhaled TXA administration as measured by a decrease in our institution-specific bleeding scale from moderate to minor or no bleeding. In ECMO-managed pediatric patients with pulmonary hemorrhage, treatment with inhaled TXA demonstrated safety, with no observed adverse effects, and showed promising signs of contributing to the cessation of bleeding.

Fibrinolysis as a Causative Mechanism for Bleeding Complications on Extracorporeal Membrane Oxygenation: A Pilot Observational Prospective Study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is associated with a high risk of bleeding complications. The specific impact of ECMO on fibrinolysis remains unexplored. The objective of the current pilot observational prospective study was to investigate the longitudinal dynamics of fibrinolytic markers-i.e., changes over time-in the context of bleeding events in patients on ECMO.

METHODS

Longitudinal dynamics of contact phase components (kininogen and bradykinin) and fibrinolysis markers (tissue plasminogen activator [tPA], plasminogen activator inhibitor-1 [PAI-1], their complexes [tPA•PAI-1], plasmin-antiplasmin complexes, plasminogen, and D-dimer) were measured in patients undergoing venovenous and venoarterial ECMO, before implantation, at 0, 6, and 12 h after implantation, and daily thereafter.

RESULTS

The cohort consisted of 30 patients (214 ECMO days). The concentrations of tPA, D-dimer, plasmin-antiplasmin complexes, PAI-1, and tPA•PAI-1 complexes were increased, whereas plasminogen decreased compared to normal values. A noteworthy divergence was observed between hemorrhagic and nonhemorrhagic patients: in bleeding patients, D-dimer, plasmin-antiplasmin, tPA, PAI-1, and tPA•PAI-1 followed an increasing kinetics before hemorrhage and then decreased to their baseline level; conversely, nonbleeding patients showed a decreasing kinetics in these markers. Also, D-dimer and tPA followed an increasing kinetics in bleeding patients compared to nonbleeding patients (median values for D-dimer dynamics: 1,080 vs. -440 ng/ml, P = 0.05; tPA dynamics: 0.130 vs. 0.100 nM, P = 0.038), and both markers significantly increased the day before hemorrhage. A tPA concentration above 0.304 nM was associated with bleeding events (odds ratio, 4.92; 95% CI, 1.01 to 24.08; P = 0.049).

CONCLUSIONS

Contact activation induces fibrinolysis in ECMO patients, especially in patients experiencing bleeding. This finding supports the role of this mechanism as a possible causal factor for hemorrhages during ECMO and open new avenues for novel therapeutic perspectives.

EDITOR’S PERSPECTIVE

Research progress on nutritional support in the neonatal and pediatric populations receiving extracorporeal membrane oxygenation

Nutritional support is crucial for the prognosis of children supported by extracorporeal membrane oxygenation (ECMO). This article discusses the latest research progress and guideline recommendations for nutritional support during ECMO. We summarize the nutritional status and evaluation of ECMO patients, nutritional support methods and timing, trace elements, the impact of continuous renal replacement therapy (CRRT), and energy requirements and algorithms. The article shows that malnutrition is high in ECMO patients compared to other critically ill patients, with nearly one-third of patients experiencing a decrease in nutritional indicators. The timing of the initiation of nutrition is very important for the nutritional status of the child. Early enteral nutrition can improve patient prognosis, which is the most commonly used, with parenteral nutrition as a supplement. However, the proportion of enteral nutrition is relatively low, and a stepwise nutrition algorithm can determine when to initiate early enteral nutrition and parenteral nutrition. Malnourishment during critical illness have been associated with increased morbidity as well as increased mortality. Nutritional status should be evaluated at admission by screening tools. In addition, changes in the levels of several metabolites in vivo, such as blood lipids, carnitine, and thiamine, can also reflect the degree of nutritional deficiency in critically ill children. This article provides a reference for the implementation of nutrition of pediatric ECMO patients and further research on nutritional support.

Lung Re-transplantation after prolonged veno-venous extracorporeal membrane oxygenation (ECMO) in a child with chronic lung allograft dysfunction

BACKGROUND

Extracorporeal Membrane Oxygenation (ECMO) may be used as a bridge to lung transplantation in selected patients with end-stage respiratory failure. Historically, ECMO use in this setting has been associated with poor outcomes Puri V et.al, J Thorac Cardiovasc Surg, 140:427. More recently, technical advances and the implementation of rehabilitation and ambulation while awaiting transplantation on ECMO have led to improved surgical and post-transplant outcomes Kirkby S et.al, J Thorac Dis, 6:1024.

METHODS

We illustrate the case of a 6-year-old child who received prolonged ECMO support as a bridge to lung re-transplantation secondary to Chronic Lung Allograft Dysfunction (CLAD).

RESULTS

Early rehabilitation was key in improving the overall pre-transplant conditioning during ECMO.

CONCLUSIONS

Despite challenges associated with awake/ambulatory ECMO, the use of this strategy as a bridge to lung transplantation is feasible and has resulted in improved pre-transplant conditioning and post-transplant outcomes.

Awake veno-arterial extracorporeal membrane oxygenation in patients with perioperative period acute heart failure in cardiac surgery

Background

Extracorporeal membrane oxygenation (ECMO) is an effective extracorporeal life support technology that has been applied to treat cardiorespiratory failure patients. Some medical centers have started using ECMO on awake, non-intubated, spontaneously breathing patients, as this strategy offers several benefits over mechanical ventilation. However, most awake-ECMO methods focus on venovenous ECMO, and few cases of awake veno-arterial ECMO (V-A ECMO) have been reported, especially in perioperative acute heart failure. Therefore, our study aimed to examine awake—V-A ECMO cases that were not given continuous sedation or invasive mechanical ventilation (IMV) during perioperative heart failure.

Method

In total, 40 ECMO patients from December 2013 to November 2019 were divided into 2 groups (the awake-ECMO group and the asleep-ECMO group) according to the ventilation use. The demographics, patient outcomes, and ECMO parameters were collected and retrospectively analyzed.

Results

We identified 12 cases of awake ECMO without continuous ventilation, and 28 cases of simultaneous IMV and ECMO (asleep ECMO). Awake-ECMO patients showed fewer complications and better outcomes compared to ventilation patients. All patients in the awake group were successfully weaned off ECMO, while only 5 (18%) patients were weaned off ECMO in the asleep group. Furthermore, 9 (75%) patients survived until discharge in the awake group vs. 3 (11%) in the asleep group; 3 patients died of septic shock after weaning in the awake group, while 25 patients died of septic shock, hemodynamic disorder, bleeding, cerebral hemorrhage, etc., in the asleep group. These complications, including bleeding, pneumonia, hemolysis, and abdominal distension, etc., occurred less frequently in the asleep group compared to the awake group (P<0.05).

Conclusions

Awake V-A ECMO is an effective, feasible, and safe strategy in patients with perioperatively acute heart failure and can be applied as a bridge to cardiac function recovery or transplantation.

Bleeding, Thrombosis, and Transfusion With Two Heparin Anticoagulation Protocols in Venoarterial ECMO Patients

OBJECTIVE

To compare the incidence of bleeding and thrombosis between adult venoarterial (VA) extracorporeal membrane oxygenation (ECMO) patients managed with an activated clotting time (ACT)-guided heparin anticoagulation protocol and activated partial thromboplastin time (aPTT) protocol.

DESIGN

Retrospective cohort study.

SETTING

Tertiary care, academic medical center.

PARTICIPANTS

Consecutive adult VA ECMO patients during a 6-year period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Demographic, medical, transfusion, and ECMO data were collected for all patients. Primary study outcomes were bleeding and thrombosis. Secondary outcomes were stroke and in-hospital mortality. One hundred twenty-one patients were included in the cohort. Fifty patients had ACT monitoring, and 71 had aPTT monitoring. There was no difference in the incidence of bleeding or thrombosis between the 2 groups (78.0% v 67.6% for bleeding [p = 0.21] and 16.0% v 19.7% for thrombosis [p = 1.0]). After adjusting for age and total ECMO days, patients managed with ACT received approximately 30% more red blood cell, fresh frozen plasma, and platelet transfusion (all p < 0.05).

CONCLUSION

There is no apparent difference in the incidence rate of bleeding or thrombosis between VA ECMO patients managed with an ACT- or aPTT-guided heparin anticoagulation protocol. Patients managed with an ACT-guided protocol received more blood transfusion, which could reflect greater total bleeding. Future randomized controlled trials would help to elucidate optimal anticoagulation strategies for VA ECMO patients.