Key Considerations and Topics in Pediatric ECMO

ECMO as Bridge to Transplantation in Pediatric Pulmonary Hypertension

ECMO provides critical cardiopulmonary support for children with pulmonary hypertension (PH) who are bridging to lung transplantation, with survival rates demonstrating feasibility when properly implemented. 1

Indications and Patient Selection

ECMO sustains life in children with PH experiencing critical illness, allowing bridging to medical therapy optimization, palliative shunt creation, or transplantation 1
VA (venoarterial) or VV (venovenous) ECMO modes provide cardiac, pulmonary, or combined cardiopulmonary support depending on the severity of right ventricular dysfunction 1
When used as bridge to transplantation, pharmacotherapies treating PH must be optimized and prolonged endotracheal intubation avoided when possible 1

Outcomes in PH Patients

Among children with PH on ECMO before lung transplantation (n=14), early mortality was 7% (within 30 days) and late mortality was 29% 1
Average duration on ECMO before transplantation was 18.6 days (range 1-60+ days) 1
Active rehabilitation with physical therapy, minimized sedation and neuromuscular blockade, and improved nutrition status are essential during ECMO support 1

Technical Considerations

VA ECMO cannula configuration and securement can be challenging when facilitating rehabilitation and ambulation, often requiring unique configurations 1
The approach to ECMO mode and configuration is dictated by severity of RV dysfunction and need to offload the failing right ventricle 1

ECMO for Pediatric Cardiac Arrest (ECPR)

ECPR may be considered for infants and children with cardiac diagnoses who have in-hospital cardiac arrest (IHCA) in settings with appropriate expertise, resources, and systems, but evidence remains insufficient for routine use in non-cardiac patients. 1

Recommendations by Patient Population

Cardiac patients with IHCA: ECPR may be considered in settings that optimize ECMO use during and after resuscitation (weak recommendation, very-low-quality evidence) 1
Non-cardiac patients with IHCA: Insufficient evidence to suggest for or against routine ECPR use (weak recommendation, very-low-quality evidence) 1
Out-of-hospital cardiac arrest (OHCA) has not been adequately studied for ECPR application 1

Resource and Expertise Requirements

Significant expertise and resource implications exist for appropriate ECPR implementation 1
Selection of patients and local practice is highly variable across institutions 1
All reports to date are heavily influenced by selection bias of ECPR candidates 1
The expense incurred and intensity of resources necessary for universal deployment must be weighed against improved survival in select populations 1

Critical Knowledge Gaps in Pediatric ECMO

Timing and Technique

Optimal timing of ECMO initiation during pediatric resuscitation has not been established—neither minimal nor maximal intervals are defined 1
Quality of CPR (cerebral and systemic perfusion) before and during ECMO cannulation remains unstudied in pediatrics 1
Optimal anatomic vascular access (neck versus femoral versus central) for neuro- and cardio-protection during resuscitation is unknown 1

Special Populations Requiring Study

Deep hypothermic out-of-hospital arrest 1
Pulmonary emboli 1
High-risk complex congenital heart disease (e.g., single-ventricle physiology) 1

Co-Interventions and Management

Effect of therapeutic hypothermia during ECMO initiation and support in pediatric IHCA is unstudied 1
Interventions requiring evaluation include: targeted temperature management and rewarming rate, blood flow rate on reperfusion, pulsatile versus nonpulsatile flow, oxygenation and CO2 targets, hemodilution, hemofiltration, concurrent mechanical ventilation, inotropes and vasoactive strategies, thrombolytics, and steroids 1

Research Design Challenges

Comparative studies in pediatric IHCA or OHCA receiving resuscitation with versus without ECMO are lacking 1
Alternative study designs (cluster-randomized trials, prospective observational with Bayesian methodology) may be needed given challenges with patient-level randomization 1
Perceived utility of ECMO in some healthcare settings creates absence of equipoise, making traditional RCTs difficult 1
Studies incorporating functional outcomes are urgently needed 1

ECMO for Postcardiotomy Support in Congenital Heart Disease

ECMO provides effective cardiac support for children with postcardiotomy ventricular dysfunction, with survival rates of 54-70% in appropriately selected patients. 2, 3, 4

Indications for Postcardiotomy ECMO

Failure to wean from cardiopulmonary bypass (most common indication, 69.7% of cases) 3
Low cardiac output syndrome (12.1% of cases) 3
Isolated right or left ventricular failure (13.6% combined) 3
Malignant arrhythmia and pulmonary hypertension (4.6% combined) 3

Cannulation Strategies

Transthoracic right atrium-ascending aorta cannulation is commonly used in postcardiotomy patients 2
Right internal jugular vein-right common carotid artery cannulation through cervical incision is an alternative 2
Right internal jugular vein-left axillary artery cannulation may be employed 2

Outcomes and Survival

Overall survival to hospital discharge ranges from 22% to 54.5% depending on indication 2, 3, 4
45-54% of patients can be successfully weaned from ECMO 2, 3
Mean duration of ECMO support is 5.1 days (range 15-144 hours) 2, 3
Recovery of cardiac function occurs within the first week of ECMO support if at all—longer support beyond 6 days without recovery does not result in survival without transplantation 4

Complications and Mortality Predictors

Major hemorrhage develops in up to 30% of patients on ECMO 2
Mediastinal bleeding complications are associated with nonsurvival 4
Renal failure requiring dialysis predicts poor outcome 4
Primary cause of death is multiorgan system failure (68%) 4
Other causes include cerebral hemorrhage, pulmonary failure, consumption coagulopathy, and therapy-resistant myocardial insufficiency 3

ECMO as Bridge to Cardiac Transplantation

ECMO as bridge to cardiac transplantation demonstrates superior outcomes compared to postcardiotomy support, with survival rates of 46-66%. 4

Outcomes by Indication

Bridge to first transplant: 46% survival to discharge (6 of 13 patients received transplant, 1 recovered spontaneously) 4
Bridge to second transplant after failed graft: 66% survival (2 of 3 received second transplant, 1 recovered graft function) 4
These outcomes significantly exceed the 22% survival for postcardiotomy ECMO support 4

Neonatal ECMO Considerations

Neonates on VA ECMO with elevated lactate and suspected ischemic bowel require immediate surgical consultation for exploratory laparotomy, as bowel necrosis represents a reversible cause of refractory shock that must be addressed before ECMO can be effective. 5

Critical Recognition Points

Lactate fails to clear despite adequate ECMO flows (optimize within safe parameters, avoid >110 mL/kg/min due to hemolysis risk) 5
Abdominal distension, bloody stools, or feeding intolerance during ECMO support 5
Intra-abdominal pressure >12 mmHg indicates abdominal compartment syndrome requiring decompression 5
Pneumatosis intestinalis, portal venous gas, or free air on imaging mandate urgent surgical exploration 5

Management Principles

Necrotic bowel is a nidus of ongoing shock that must be removed for ECMO to be effective—do not delay surgery waiting for "stability" 5
ECMO provides hemodynamic support necessary to tolerate surgery that would otherwise be impossible 5
Survival with ECMO for neonatal sepsis is 80%, but only if reversible causes like bowel necrosis are addressed 5
High lactate levels at ECMO cannulation are associated with severe complications including death and necrotizing enterocolitis 5

Hemodynamic Targets During Neonatal ECMO

Maintain central venous oxygen saturation (ScvO2) >70% to confirm adequate systemic oxygen delivery 5
Target mean arterial pressure (MAP) >70 mmHg to maintain adequate perfusion pressure 5
Monitor pulse pressure—values <20 mmHg in first 24 hours are associated with acute brain injury and likely reflect inadequate pulsatile flow to other organs including bowel 5

Renal Support Integration

In neonates with inadequate urine output and ≥10% fluid overload despite diuretics, perform CRRT on the ECMO circuit 5
CRRT combined with ECMO increases blood volume, enables larger cannula use, and improves hemodynamic stability 5
This is particularly important in neonates with ischemic bowel who may develop acute kidney injury from hypoperfusion 5

ECMO for Persistent Pulmonary Hypertension of the Newborn (PPHN)

ECMO is reserved for refractory PPHN with oxygenation index >25 despite inhaled nitric oxide and optimized ventilation. 6

Escalation Pathway

Inhaled nitric oxide (iNO) at 20 ppm is first-line treatment for PPHN 6
Optimize lung recruitment before or concurrent with iNO initiation, as lung recruitment strategies significantly improve iNO efficacy 6
ECMO is indicated when oxygenation index exceeds 25 despite iNO and optimized ventilation 6
Consider sildenafil as adjunctive therapy for iNO-refractory PPHN with oxygenation index >25 6
Inhaled prostacyclin analogs may be added for refractory cases with oxygenation index >25 6

Critical Pitfalls

Metabolic alkalinization remains critical during initial resuscitation as PPHN can reverse when acidosis is corrected 6
Any newborn with shock and hepatomegaly, cyanosis, cardiac murmur, or differential upper/lower extremity blood pressures must receive prostaglandin infusion immediately until complex congenital heart disease is excluded by echocardiography 6

Transfusion Support for Pediatric ECMO

Neonatal and pediatric ECMO patients require significant transfusion support both at cannulation and throughout ECMO support, necessitating multidisciplinary protocols for blood product availability. 7

Transfusion Requirements

Significant transfusion support is required at time of cannulation and after ECMO circuit establishment 7
Requests often occur with little advance notice, requiring streamlined ordering and communication processes 7
Close collaboration among critical care medicine, perfusion, and transfusion medicine services is essential 7

Protocol Development

Identify and stratify ECMO candidate patients in advance 7
Streamline ordering and communication processes between services 7
Improve blood product turnaround times and availability 7
Implement quality improvement measures for transfusion support 7

Emergency Department Considerations

ECMO therapy is transitioning from intensive care unit to emergency department settings, requiring emergency medicine physicians to understand fundamentals of pediatric ECMO support. 8

ECMO Modes and Indications in Emergency Settings

VA (venoarterial) ECMO supports oxygenation and perfusion in cardiac arrest, sepsis, and cardiogenic shock 8
VV (venovenous) ECMO supports oxygenation in respiratory failure 8
Environmental hypothermia may be an indication for ECMO support 8

Emergency Physician Responsibilities

Recognize critically ill pediatric patients who may benefit from ECMO 8
Understand fundamentals of ECMO therapy and its applications 8
Coordinate with ECMO teams for rapid deployment when indicated 8

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