[Extracorporeal membrane oxygenation in critically ill neonates and children]

Performance Assessment of Anti-Xa Assay-Based Heparin Dosing Protocol in Pediatric Patients on Extracorporeal Membrane Oxygenation

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) in the postoperative cardiac critical care setting is evolving. Anticoagulation monitoring is among the most challenging aspects of pediatrics. However, there is no consensus on the optimal dosing and monitoring of unfractionated heparin in this setting. To address this, we developed an anti-Xa assay-based protocol derived from the best available clinical and anecdotal evidence of ECMO use and assessed its effectiveness in achieving the anti-Xa assay therapeutic target.

METHODS

This prospective single-arm study was conducted in the pediatric carcardiac-surgery intensive care unit of a large tertiary hospital. We used two different anti-Xa assay intensity levels based on the patients' bleeding status.

RESULTS

The median patient age was 7 (interquartile range [IQR]: 5-11.25) months, and the median weight was 5.7 (IQR: 3.8-13.82) kg. The median ECMO duration was 6 (IQR: 4.5-7.5) days. The bleeding protocol was used for most patients. Seventy percent achieved the anti-Xa assay therapeutic target during the study period (median: 75.5 h, IQR: 60.5-117.5 h). Hemorrhagic complications were reported in 40% of the patients, and thrombotic complications were reported in 25%. The median length of stay was 37 (IQR: 22-43) days, with a survival-to-discharge rate of 75%.

CONCLUSIONS

Despite a failure to achieve the anti-Xa assay target within the first ECMO days, most patients achieved the target by the median ECMO duration. Moreover, using two different anti-Xa assay levels reduced thrombotic complications.

Mobile Extracorporeal Membrane Oxygenation: 5-Year Experience of a French Pediatric and Neonatal Center

OBJECTIVES

Extracorporeal membrane oxygenation is an established therapy for refractory cardiac and/or pulmonary failure that is not available in all centers. When infants and children require extracorporeal membrane oxygenation, they are sometimes placed on extracorporeal membrane oxygenation support in peripheral centers where extracorporeal membrane oxygenation is not available and then transferred on extracorporeal membrane oxygenation to specialized centers. The objective of this study is to first describe one of the largest cohorts of infants and children transported by a mobile unit while on extracorporeal membrane oxygenation.

DESIGN

We undertook a single-center retrospective study that included patients transported while on extracorporeal membrane oxygenation between November 1, 2014, and May 31, 2019.

PATIENTS

All patients transported by our mobile extracorporeal membrane oxygenation unit during the study period were included. Computerized data collection was approved by the French Data Protection Authority (Commission nationale de l'informatique et des libertés n° 2121127V0).

MAIN RESULTS

Over the study period, our extracorporeal membrane oxygenation mobile team transported 80 patients on extracorporeal membrane oxygenation among which 20 were newborns (25%) and 60 were children of 1 month to 17 years old (75%); 57 patients were on venoarterial-extracorporeal membrane oxygenation (71%) and 23 on venovenous-extracorporeal membrane oxygenation (29%). The average duration of transport was 8.4 hours with a median of 8 hours; the average distance travelled was 189 ± 140 km. Transport was by air and then ground for 50% of the patients and by ground for 42%. We observed a significant decrease in the Vasoactive-Inotropic Score (125 vs 99; p = 0.005) and PaCO2 levels (67 vs 49 mm Hg; p = 0.0005) after arrival in our unit. Survival rate 6 months after PICU discharge was 46% (37). There was a statistically significant relationship between initial lactate level and mortality (p = 0.02). We observed minor adverse events in 39% of the transports and had no mortality during transport.

CONCLUSIONS

We describe one of the largest cohorts of infants and children transported by a mobile unit while on extracorporeal membrane oxygenation. Our findings confirm that it is safe to start extracorporeal membrane oxygenation in a referring center and to transport patients using an extracorporeal membrane oxygenation mobile team. The only risk factor associated with higher mortality was an initially elevated lactate level.

Extracellular histones indicate the prognosis in patients undergoing extracorporeal membrane oxygenation therapy

Introduction:

Extracellular histones have been recently identified as damage-associated molecular-pattern (DAMP) molecules involved with the pathogenesis of various inflammatory diseases. This study intended to investigate whether extracellular histones can indicate the prognosis in critically ill patients supported by extracorporeal membrane oxygenation (ECMO) therapy.

Methods:

A total of 56 patients undergoing ECMO were analysed retrospectively. Median concentrations of extracellular histones in patients before ECMO were assessed and used to divide the patients into two groups (Group 1 <48 µg/ml and Group 2 ⩾48 µg/ml). Mortality rate, Sequential Organ Failure Assessment (SOFA) scores and systemic inflammation were compared between the groups.

Results:

There were relatively higher concentrations of extracellular histones in Group 2 patients (57.78 µg/ml [48.4, 71.3]) than in Group 1 patients (36.76 µg/ml [28.5, 39.3], p<0.0001). The hospital mortality rate was 55.4% for the entire study subjects, with significantly worsened mortality in Group 2 in contrast to Group 1 (58.8% vs. 50%, p=0.031). Moreover, Group 2 patients had significantly higher SOFA scores and more pronounced systemic inflammation than Group 1 patients prior to ECMO initialization.

Conclusions:

Extracellular histones are known contributors to cell damage and organ injury. Our study showed that extracellular histones have a predictive value in the assessment of outcome of patients undergoing ECMO therapy and may be helpful for risk stratification in clinical settings.

The Role of Echocardiography in Neonates and Pediatric Patients on Extracorporeal Membrane Oxygenation

Indications for extracorporeal membrane oxygenation (ECMO) and extracorporeal cardiopulmonary resuscitation (ECPR) are expanding, and echocardiography is a tool of utmost importance to assess safety, effectiveness and readiness for circuit initiation and separation. Echocardiography is key to anticipating complications and improving outcomes. Understanding the patient's as well as the ECMO circuit's anatomy and physiology is crucial prior to any ECMO echocardiographic evaluation. It is also vital to acknowledge that the utility of echocardiography in ECMO patients is not limited to the evaluation of cardiac function, and that clinical decisions should not be made exclusively upon echocardiographic findings. Though echocardiography has specific indications and applications, it also has limitations, characterized as: prior to and during cannulation, throughout the ECMO run, upon separation and after separation from the circuit. The use of specific and consistent echocardiographic protocols for patients on ECMO is recommended.