Extracorporeal membrane oxygenation (ECMO) is the use of prolonged extracorporeal circulation and gas exchange via a modified heart-lung machine to provide temporary life support in patients with cardiac or respiratory failure who are refractory to maximum ventilatory and medical management. ECMO allows the lungs to rest and recover while avoiding the damaging effects of aggressive mechanical ventilation, including barotrauma and oxygen toxicity. The first successful use of extracorporeal support in a newborn was reported in 1976 by Dr. Robert Bartlett.1 Subsequent data suggested that ECMO provided improved survival when compared with historical controls2,3; however, only 2 small trials with adaptive designs were performed prior to widespread use of ECMO.4,5 The UK Collaborative ECMO Trial, published in 1996, confirmed that ECMO significantly reduced mortality when compared with standard medical care (32% vs 59%, relative risk 0.55; 95% confidence interval 0.36–0.80) with improved survival in all diagnostic categories.6
The Extracorporeal Life Support Organization (ELSO), established in 1989, maintains a patient registry to collect data from more than 200 ECMO centers around the world. ELSO Registry data as of July 2013 included 27,000 newborns placed on ECMO for respiratory support.7 Approximately 800 neonatal respiratory cases are performed annually, with a cumulative survival of 75%. Review of the neonatal ELSO Registry data demonstrated ongoing demographic changes. ECMO use for neonatal respiratory failure has declined over the last 2 decades, likely related to the increasing use of high-frequency ventilation (HRV), surfactant replacement, and inhaled nitric oxide (iNO).8, 9, and 10 There have also been significant changes in the diagnostic categories of those receiving ECMO. Dramatic decreases in the use of ECMO for respiratory distress syndrome and sepsis/pneumonia have occurred. There has also been a downward trend in the use of ECMO for meconium aspiration syndrome; it is no longer the most common indication for ECMO. In recent years, congenital diaphragmatic hernia (CDH) has become the most common indication for ECMO; however, the survival rate continues to decline for this and the other diagnostic categories. Most ECMO centers are treating fewer patients annually; however, the length of bypass is longer, and survival is lower. These changes challenge ECMO centers to maintain their expertise with a complex technology despite lower patient volumes.
Hypoxemic Respiratory Failure
Hypoxemic respiratory failure (HRF) frequently occurs in association with persistent pulmonary hypertension of the newborn (PPHN). PPHN is characterized by markedly elevated pulmonary vascular resistance and pulmonary arterial pressure, in conjunction with striking pulmonary vasoreactivity. This produces right-to-left shunting at the patent ductus arteriosus (PDA) and patent foramen ovale (PFO). It results in hypoxemia from extrapulmonary shunting, which can be poorly responsive to medical management. PPHN is felt to represent failure of the pulmonary circulation to adapt to postnatal conditions and as such is sometimes called “persistent fetal circulation.” The pulmonary vascular bed is abnormal, with extension of the ...