A Heart-Lung Machine for Babies Born Too Soon

What a Chinese study of 22 premature infants supported on ECMO tells families about survival, brain injury, and life after the machine

Doctors in China followed 22 premature babies who were placed on a heart-lung support machine called ECMO after every other treatment had failed. Seventeen of them — just over three in four — survived to go home, and about six in ten were developing normally by their second birthday. The findings suggest that carefully chosen premature babies can be helped by a machine long thought too dangerous for them [1].

The Problem That Led to This Research

Some newborn babies reach a point where a ventilator can no longer do the job. Their lungs are too damaged, or the blood vessels in their lungs are so tightly constricted that oxygen cannot get through. For those babies there is one last option: extracorporeal membrane oxygenation, usually shortened to ECMO. Blood is drained from a large vein in the neck, passed through an artificial lung that adds oxygen and removes carbon dioxide, and returned to the body through an artery. The machine takes over the work of the heart and lungs so that the baby's own organs can rest and, with luck, recover.

ECMO was first used successfully on a newborn in the 1970s, in a baby who has become well known in the medical literature as Esperanza — Spanish for hope [2], [3]. It saved lives, but it came with a serious cost. The first large report of 100 newborns on ECMO found that among the smallest and most premature babies, bleeding into the brain happened in as many as 89% of cases [4]. Later work on babies weighing between 2,000 and 2,500 grams confirmed the same pattern: the smaller and earlier the baby, the higher the danger [5].

That is where the rule came from. Premature babies are fragile in two specific ways. Their blood vessels are tiny — sometimes barely wider than a strand of spaghetti — which makes it hard and risky to place the tubes the machine needs. And their blood does not clot normally, while the medication that keeps the machine from clotting makes bleeding more likely still. Because bleeding into the developing brain can cause lasting harm, hospitals worldwide adopted a simple boundary: no ECMO for babies born before about 34 weeks or weighing under about 2 kilograms. For decades, families of very premature babies with failing lungs were told that this last option was not available to them.

Why Doctors Started Asking Again

The boundary was drawn using machines and methods from the 1980s. Since then the pumps have become gentler, the tubing smaller, the blood-thinning medicines better controlled, and brain scanning far more routine. Doctors began to argue that the old numbers described old technology rather than what happens today [6]. A review that gathered together all the published experience of ECMO in premature babies concluded that a blanket ban could no longer be justified and that the international guidelines should be rewritten [7]. A companion article put the real question directly: not whether prematurity rules a baby out, but how premature is too premature [8].

In China the question was harder to answer because ECMO for newborns started much later there than in Europe or North America. Only scattered reports from single hospitals existed [9], and the national guidance for using ECMO in newborn breathing failure had been written with full-term babies in mind [10]. One hospital had described its own experience with newborns [11], but nobody had pooled results across the country for premature infants. That is the gap this study set out to fill.

What the Researchers Did

The team looked back through the records of a national network of hospitals — the Pediatric Extracorporeal Life Support Alliance of China — covering January 2018 to November 2025 [1]. They found every premature baby (born before 37 weeks) who had been placed on ECMO because conventional intensive care was not working. A baby became a candidate when oxygen levels stayed dangerously low despite the strongest ventilator settings and inhaled nitric oxide, when the pressure in the lung blood vessels was straining the heart, or when blood pressure could not be sustained [11].

The doctors were deliberately cautious about whom they accepted, and this matters enormously when reading the results. No baby under 32 weeks was considered. No baby under 1.8 kilograms was cannulated. Every baby had a head ultrasound scan every single day while on the machine, and any baby who already had significant bleeding in the brain was not started on ECMO at all. Babies with untreatable birth defects were also excluded. In other words, the study did not test ECMO on the riskiest premature babies — it tested it on the most promising ones. All the babies were supported through tubes placed in the artery and vein on the right side of the neck. After the machine was removed, the artery was tied off permanently rather than repaired, a choice the doctors made because these vessels are so small that attempting repair carries its own risks. Survivors had a detailed brain scan (MRI) after coming off the machine, and their development was checked between 18 and 24 months of age using a standard assessment called the Bayley Scales. Weaning off the machine followed international guidance [12].

What They Found

Only 6 of the 23 hospitals in the network had ever done this — 22 babies in about eight years. This is rare, specialised care. The typical baby was born at 34 weeks weighing 2.5 kilograms, and weighed about 2.2 kilograms when the tubes were placed. Half of them (11 babies) needed ECMO because of severe high blood pressure in the lungs; three had blood infections, two had severe oxygen deprivation at birth, two had air leaking from the lungs, and the remaining four each had a different birth defect of the lungs, heart, or diaphragm. Babies stayed on the machine for a median of about 112 hours — roughly four and a half days.

Eighteen babies (81.8%) came off the machine successfully, and 17 (77.3%) survived to go home. Five babies died: one when the machine itself failed, and four after families and doctors together decided to stop treatment that could no longer help. Complications from the machine were remarkably few — one baby bled at the site where the tube entered, one developed a blood clot, and none had kidney failure.

The brain findings need to be read carefully. Of the 17 survivors, 9 (52.9%) had some abnormality on their MRI scan — 5 had bleeding in the brain (29.4%) and 4 had signs of injury from low oxygen. Yet when those children were assessed at 18 to 24 months, 10 of the 17 (58.8%) were developing normally, and 7 (41.2%) had some delay. Importantly, the scan and the child's actual development did not line up neatly. Among the eight most premature babies, three had developmental delay — but only one of those three had had bleeding in the brain.

The researchers also compared the eight babies born at or before 34 weeks with the fourteen born later. The earlier group did slightly worse on every measure: 75% versus 78.6% survived, 33.3% versus 27.3% had brain bleeding. But with only eight babies in the smaller group, none of these differences means anything statistically, and the authors say so explicitly in their own report. The smallest baby they treated was born at 33 weeks and weighed 1.8 kilograms.

What This Means for Families

If your baby is premature and critically ill, the honest summary is this: ECMO is no longer automatically off the table simply because a baby was born before 34 weeks. But this study does not show that prematurity has stopped mattering. It shows that in experienced hospitals, for babies who are at least 32 weeks and 1.8 kilograms, whose underlying problem is likely to get better, and whose brain scans are clear before starting, ECMO can work about as well as it does in full-term babies. Survival of 77.3% is close to the roughly 76% reported in a large study of infants on ECMO [13], and the rate of brain bleeding is much lower than the historic figure, close to the 38% reported in recent experience with babies under 34 weeks [14]. Results from European hospitals point to the same conclusion: outcomes depend heavily on which babies are chosen [15].

Two things are worth holding onto. An abnormal brain scan is common after ECMO and does not predict a child's future as reliably as parents fear — the developing brain is remarkably adaptable. But a normal check-up at two years is not the end of the story either. Children who had ECMO as newborns can show difficulties with attention, learning and behaviour that only appear at school age [16]. Long-term follow-up is not a formality; it is part of the treatment.

What Researchers Are Working on Next

The next step is a study that follows babies forward rather than looking backward, with every hospital using the same blood-thinning targets, the same brain scans, brainwave monitoring to catch seizures that cause no visible signs, and follow-up that continues into the school years [16]. Whether the limit can move below 32 weeks and 1.8 kilograms depends on making the tubes and pumps smaller still, and eventually on an entirely different idea — an artificial placenta that would support a very premature baby the way the womb does, which is now moving toward its first human trials [17]. For the very smallest and sickest babies, published attempts remain sobering [18]. For now, the message is one of cautious, specific hope rather than a general change in what is possible.

References

  1. Cao J, Wang F, Zhao Z, et al. Application of extracorporeal membrane oxygenation in respiratory and circulatory support of preterm infants: a multicenter retrospective study in China. Front Cardiovasc Med. 2026;13:1885674. doi:10.3389/fcvm.2026.1885674 ↩
  2. Bartlett RH. The story of ECMO. Anesthesiology. 2024;140:578–84. doi:10.1097/ALN.0000000000004843 ↩
  3. Bartlett RH. Esperanza: the first neonatal ECMO patient. ASAIO J. 2017;63:832–43. doi:10.1097/MAT.0000000000000697 ↩
  4. Bartlett RH, Gazzaniga AB, Toomasian J, et al. Extracorporeal membrane oxygenation (ECMO) in neonatal respiratory failure. 100 cases. Ann Surg. 1986;204:236–45. doi:10.1097/00000658-198609000-00003 ↩
  5. Revenis ME, Glass P, Short BL. Mortality and morbidity rates among lower birth weight infants (2000 to 2500 grams) treated with extracorporeal membrane oxygenation. J Pediatr. 1992;121:452–8. doi:10.1016/S0022-3476(05)81804-981804-9) ↩
  6. Wild KT, Hedrick HL, Rintoul NE. Reconsidering ECMO in premature neonates. Fetal Diagn Ther. 2020;47:927–32. doi:10.1159/000509243 ↩
  7. Burgos CM, Frenckner B, Broman LM. Premature and extracorporeal life support: is it time? A systematic review. ASAIO J. 2021;68:633–45. doi:10.1097/MAT.0000000000001555 ↩
  8. Wild KT, Burgos CM, Rintoul NE. Expanding neonatal ECMO criteria: when is the premature neonate too premature. Semin Fetal Neonatal Med. 2022;27:101403. doi:10.1016/j.siny.2022.101403 ↩
  9. Tang SH, Hong XY, Feng ZC, Li QP. Extracorporeal membrane oxygenation in preterm infants: current status and future perspectives. Chin J Pediatr. 2023;61:82–5. doi:10.3760/cma.j.cn112140-20221021-00892 ↩
  10. Neonatologist Branch of the Chinese Medical Doctor Association, Editorial Board of the Chinese Journal of Pediatrics. Consensus on extracorporeal membrane oxygenation support for neonatal respiratory failure. Chin J Pediatr. 2018;56:327–31. doi:10.3760/cma.j.issn.0578-1310.2018.05.003 ↩
  11. Wang G, Li Q, Zhou G, et al. Veno-arterial extracorporeal membrane oxygenation for respiratory and cardiac support in neonates: a single center experience. Front Cardiovasc Med. 2024;11:1322231. doi:10.3389/fcvm.2024.1322231 ↩
  12. Brown G, Moynihan KM, Deatrick KB, et al. Extracorporeal Life Support Organization (ELSO): guidelines for pediatric cardiac failure. ASAIO J. 2021;67:463–75. doi:10.1097/MAT.0000000000001431 ↩
  13. Schueller M, Greenberg RG, Smith PB, Laughon MM, Clark RH, Hornik CP. In-hospital outcomes following extracorporeal membrane oxygenation in a retrospective cohort of infants. Am J Perinatol. 2017;34:1347–53. doi:10.1055/s-0037-1603593 ↩
  14. Olutoye OO 2nd, Lee T, Todd HT, King A, Keswani SG. Extracorporeal membrane oxygenation before 34 wks' gestation: a single-center experience. J Surg Res. 2024;301:302–7. doi:10.1016/j.jss.2024.06.012 ↩
  15. Amodeo I, Di Nardo M, Raffaeli G, et al. Neonatal respiratory and cardiac ECMO in Europe. Eur J Pediatr. 2021;180:1675–92. doi:10.1007/s00431-020-03898-9 ↩
  16. Madderom MJ, Reuser JJCM, Utens EMWJ, et al. Neurodevelopmental, educational and behavioral outcome at 8 years after neonatal ECMO: a nationwide multicenter study. Intensive Care Med. 2013;39:1584–93. doi:10.1007/s00134-013-2973-1 ↩
  17. Spencer BL, Mychaliska GB. Updates in neonatal extracorporeal membrane oxygenation and the artificial placenta. Clin Perinatol. 2022;49:873–91. doi:10.1016/j.clp.2022.07.002 ↩
  18. Hon KL, Fung GPG, Chen RH, et al. Extracorporeal membrane oxygenation for pulmonary hypoplasia and prematurity: any chance of survival? Hong Kong Med J. 2023;29:561–2. doi:10.12809/hkmj219831 ↩