Produced by the Royal College of Physicians of Edinburgh and Royal College of Physicians and Surgeons of Glasgow

BREAKTHROUGH IN NEONATAL TRANSPORT INCUBATOR DESIGN

  • Dr IA Laing, Consultant Neonatologist, Simpson Centre for Reproductive Health, Royal Infirmary of Edinburgh, Scotland

Summary

Away from the relative safety of a Neonatal Intensive Care Unit, infants can come to harm rapidly if deterioration occurs during transports to such units. Dr Ian Laing reports on an innovative approach to developing a more effective transport incubator.

Key Points

  • Ill neonates frequently need to be transported to Neonatal Intensive Care Units for management. Incubators are central to safe transport.
  • The problems of incubator design are many:
    • Protection of the neonate physically and from elements such as cold
    • Vibration from the incubator, ventilation machine, monitoring equipment and the transport impairs monitoring, particularly of oxygenation
    • Noise is distressing to the neonate
    • Weight of the neonate, incubator, trolley and ancillary equipment are today frequently around 225kg and there is a strong need for this unwieldy mass to be reduced to under 140Kg
    • Energy must be sustainable from the incubator itself and batteries are heavy
  • A new ventilator originating from a student at the Glasgow College of Art using carbon fibre, lighter batteries, and a new suspension design with a total weight of 90kg looks set to meet current demands.
  • A Swedish company has also recently produced an incubator compatible with use in CT and MRI scanners.
  • Benefits to patients can come from looking beyond the traditional sources of medical supply.

Declaration of interests: No conflict of interests declared

In Scotland there are almost 1,000 neonatal transports carried out annually. Many of these infants require maximum intensive care en route. They are commonly extreme preterm neonates, infants with congenital abnormalities or those suffering from perinatal asphyxia or severe infections. The UK is currently undergoing a dramatic revolution in the way neonatal transports are organised.1

Away from the relative safety of a Neonatal Intensive Care Unit the infants can come to harm rapidly if deterioration occurs during transports.2 In Scotland, particularly during winter nights, these children can become cold during ambulance journeys, and hypothermia is causally associated with neonatal mortality. The babies can be difficult to monitor because of vibration of equipment3 and such vibration involves the ambulance or aircraft, the incubator, the ventilator and all monitoring devices: pulse oximetry is particularly prone to provide unreliable estimates of oxygenation during transport. Excessive noise can also make monitoring difficult and can be distressing for the baby.4

For decades designers have striven to plan the perfect incubator to maximise the safety of the sick neonate. Designers have a strong imperative to produce a combined incubator and trolley which weighs less than 140kg to fulfill health and safety requirements of staff including paramedics. Until recently the combined weight of the infant, trolley and essential ancillary equipment have weighed around 225kg. In addition incubators should have the approval of the Civil Aviation Authority, and be entirely compatible with the fixation systems of Scottish ambulances and aircraft.

It may be that a Scottish company has recently contributed substantially to these goals. Approximately two years ago Neil Tierney, a student at Glasgow Art College, approached paediatricians to ask them what their top requirements for the ideal neonatal incubator might be. Armed with the responses he began to construct an incubator that was light, durable and which reduced vibration compared to current incubators. The use of carbon fibre was central to the idea, and lighter batteries were introduced.

Tierney was then joined by a colleague, Neil Farish and together they set up a business called Lightweight Medical, l, and, assisted by a grant, began to explore production of the projected incubator. Heat retention was given priority, but Tierney and Farish also concentrated on a sophisticated suspension method to reduce noise and vibration caused by the trolley. The latter is achieved by a spring damping system. Such damping could be particularly important during helicopter flights when noise and vibration can be distressing for the infant and monitoring can be exceedingly difficult.

The incubator itself is described as a clear cylindrical container with a small mattress for the infant, access ports for the nurses and a top which opens completely, allowing the baby to be removed easily either electively or in an emergency. Tierney and Farish claim now to have a system weighing just over 90kg in total, and thus well within the demands of the European Directive on this issue. There are many other companies who have been working in the same field. Paraid (Birmingham) are interested in the work of Lightweight Medical, and it is possible that a collaboration may prove fruitful.

One of the further challenges that face designers is to produce a self-contained incubator which could house the sick neonate even when imaging, including computerised tomography (CT) and Magnetic Resonance Imaging (MRI) scanning, is being carried out. The incubator should therefore detach easily from the trolley without disruption of the infant’s intensive care. A Swedish company, Koala Systems, has a website which states

Our main development project is a novel transport incubator fulfilling all the requirements for safe ground and air transport of the fragile newborn infant and compatible with the demanding environments of medical imaging such as MRI as well as X-ray and CT.

In practice the incubator module should be released from its base and the infant and incubator are then inserted together into such a scanner.

When an incubator is travelling from one neonatal unit to another, its energy depends on three principal sources: its own 12 volt DC batteries, a petrol generated source within the ambulance, and the 240 volt cable extension system intrinsic to the ambulance itself. To maximise safety, the incubator’s own source should be capable of a battery life sufficient to reach the destination even in the event of breakdown of the ambulance energy systems. Most transports in Scotland last less than two hours, but there must be a clear plan to ensure that flights from Lerwick to Aberdeen, Stornoway to Glasgow and Birmingham to Edinburgh can be safely achieved.

Tierney and Farish unveiled their plans recently at the Lighthouse, Scotland’s national centre for architecture and design. Dr Skeoch, Consultant Neonatologist at Princess Royal Maternity Hospital in Glasgow, is clearly very impressed with the innovative system. Aspects of the design remain confidential but Lightweight Medical claim that journey times during neonatal transport can now be doubled because of their work on lighter battery systems.

In 2004 three neonatal transport teams are taking responsibility for all neonatal transports in Scotland. Advances such as those made by Tierney and Farish may prove to be vital to our neonatal transport plans. We hope that their work will decrease neonatal morbidity and mortality in the coming years. What else might the Nation’s Art Colleges do for us?

References

  1. Field D, Milligan D, Skeoch C et al. Neonatal transport: time to change? Arch Dis Child Fetal Neonatal Ed 1997; 76(1):F1–2.
  2. Jaimovitch DG, Vidyasagar D. Handbook of Pediatric and Neonatal Transport Medicine. Lippincott Williams and Wilkins; 1993.
  3. Task Force on Interhospital Transport. Guidelines for Air and Ground Transport of Neonatal and Pediatric Patients. Chicago: American Academy of Pediatrics; 1993.
  4. Buckland L, Austin N, Jackson A et al. Excessive exposure of sick neonates to sound during transport. Arch Dis Child Fetal Neonatal Ed 2003; 88(6):F513–16.