Mobile Extracorporeal Membrane Oxygenation

Unité mobile d’assistance circulatoire et respiratoire de l’enfant et du nouveau-né : une revue narrative

Les unités mobiles d’assistance circulatoire et respiratoire de l’enfant et du nouveau-né se sont développées au cours des dix dernières années. En effet, la mise en place d’une suppléance extracorporelle respiratoire ou circulatoire nécessite une équipe expérimentée et n’est pas disponible dans tous les centres hospitaliers pédiatriques. Or, les enfants atteints d’une défaillance circulatoire ou respiratoire réfractaire ne sont, pour la plupart, pas déplaçables vers une unité délivrant ce type de traitement de sauvetage. Les unités mobiles ont donc pour objectif de mettre à disposition ces technologies d’exception sur l’ensemble du territoire afin de garantir une égalité d’accès aux soins. Cependant, la haute technicité de ces thérapeutiques nécessite une équipe entraînée sachant poser et régler une assistance extracorporelle, prendre en charge un patient en défaillance respiratoire et/ou hémodynamique réfractaire et aguerrie à ces transports à haut risque. Le territoire français était jusqu’en 2014 très mal couvert par les unités mobiles pédiatriques et néonatales. Depuis, la création de plusieurs unités a permis une couverture totale du territoire. L’objectif de cette revue narrative sur les unités mobiles pédiatriques et néonatales est de résumer les différentes modalités de suppléance respiratoire et hémodynamique extracorporelle, d’en illustrer leurs différentes missions et leurs modalités de fonctionnement. Nous finirons par une description de leur efficacité en termes de survie et de survenue d’incidents en cours de transport.

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.

Blade and balloon atrial septostomy for left heart decompression in patients with severe ventricular dysfunction on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is used as circulatory support or bridge to transplantation in patients with severe left ventricular (LV) dysfunction. Left heart decompression is needed to reduce pulmonary edema, prevent pulmonary hemorrhage, and reduce ventricular distention that may aid in recovery of function. We reviewed our experience from November 1993 to December 1997 with 10 patients having severe LV dysfunction (7 myocarditis, 3 dilated cardiomyopathy) who required circulatory support with ECMO and who underwent left heart decompression with blade and balloon atrial septostomy (BBAS). Patients ranged in age from 1 to 24 years (median, 3 years). Indications for BBAS included left atrial/left ventricular distension (10), pulmonary edema/hemorrhage (9), or severe mitral regurgitation (2). BBAS was performed electively in eight patients and urgently in two patients. BBAS was performed while on ECMO in seven patients and pre-ECMO in three. A femoral venous approach was used in all patients. ECMO patients were fully heparinized. Transseptal puncture was required in nine patients while one patient had a patent foramen ovale. Blade septostomy was performed in all patients. Enlargement of the defect was then performed by stationary balloon dilation in nine and Rashkind balloon atrial septostomy in one. Balloon diameters ranged from 10 to 20 mm. Sequential balloon inflations were performed in some patients. Adequacy of the atrial septal defect (ASD) was confirmed by pressure measurement and echocardiography. Adequate left heart decompression was achieved in all patients. Pulmonary edema improved in nine of nine patients. Left atrial mean pressure fell from a mean of 30.5 mm Hg, (range, 12-50 mm Hg) to 16 mm Hg (range, 9-24 mm Hg). Left atrial to right atrial pressure gradient fell from a mean of 20 mm Hg pre-BBAS to 3 mm Hg post-BBAS. ASDs ranged in size from 2.5 to 8 mm (mean, 5.9 mm). Complications included needle perforation of the left atrium without hemodynamic compromise (one), ventricular fibrillation requiring defibrillation (one), and hypotension following BBAS which responded to volume infusion (two). Duration of ECMO ranged from 41 hr to 704 hr (mean, 294 hr). Seven patients survived and four patients had recovery of normal LV function. Of those who recovered, two had no ASD at follow-up while two ASDs are patent 14 days and 3 months post-BBAS. Three patients underwent successful cardiac transplantation. Three patients died, all of whom had multisystem organ failure with or without sepsis. A patent ASD was noted at transplant (three) or autopsy (two). No patient required a second BBAS. BBAS alleviates severe left atrial hypertension and pulmonary edema. In addition, BBAS avoids the potential bleeding complications of surgical left heart decompression. Stationary balloon dilation of the atrial septum is an effective alternative to Rashkind balloon septostomy in older patients. BBAS achieves left heart decompression that may permit recovery of LV function or allow extended ECMO support as a bridge to transplant.