Everyone will know someone that was born prematurely, with approximately 10% of all births being early. The rates of extremely preterm birth (<29 weeks gestation at birth) are increasing at a greater rate. Fortunately, now most extremely preterm babies survive, but with increased risk of lung damage that can occur throughout life. This lung damage can occur from birth; thus, it is important that clinicians support preterm babies’ lungs from the very first breaths if we are to give them a healthy start to life.
The POLAR trial aims to establish how to best, and safely, support the fragile lungs of premature babies at birth. The trial will compare two commonly used strategies that both use gentle pressure to open the lungs. The trial will assess whether a brief period of higher pressure, called PEEP (positive end expiratory pressure) at birth (up to 12 cmH2O), which is adjusted to the oxygen and breathing needs of the baby, helps premature babies immediately after birth, and improves their survival without chronic lung disease, compared with the current typical newborn resuscitation practice of a using a lower, unchanging level of PEEP.
Through this we hope to give guidance to clinicians that can be easily, rapidly, and cheaply be translated into everyday practice.
Premature birth is essentially a respiratory problem. Babies have to start breathing air well before their lungs are fully developed to do so. Not only does this make it hard for preterm babies to do, but it also places these very fragile lungs at great risk of injury. Once lung injury begins, it is a slippery slope, causing many breathing issues until chronic (long-term) lung damage occurs. It is this chronic lung injury, called bronchopulmonary dysplasia (BPD), that we know increases the risk of neurological problems and carries a lifelong risk of lung impairment. The POLAR Trial is aiming to improve the survival of extremely preterm infants and do so with less chronic lung problems.
A large number of previous clinical trials investigating novel methods of assisting the lungs of preterm infants have involved therapies in the Newborn Intensive Care Unit (NICU), where sophisticated technology can be applied. However, the risk of lung injury begins as soon as a baby is born, before babies get access to these therapies.
How is the POLAR Trial going to assist Preterm Babies?
It has been shown that the cascade of lung injury can begin within minutes of birth. The POLAR trial addresses this and is unique for three reasons:
- It is the largest respiratory trial so far to be performed in the delivery room, aiming to enrol 906 very premature babies from their first breath of life
- The new treatment our team has developed does not require complicated technology but can be delivered with the simple breathing and oxygen systems used in virtually every delivery room across the globe; and
- Unlike previous lung therapies for preterm babies, our new treatment (dynamic PEEP) is individualised to the needs of the baby; i.e. it is a form of ‘personalised’ or ‘tailored’ medicine whereby the clinician administers the therapy that the individual baby needs at that time.
It is well known that the lungs need to have enough air within them to provide oxygen to the body. Preterm infants also lack a critical chemical needed to allow their lungs to ‘open’ or ‘fill’, and the muscles of their chest wall are weaker than those of a full-term baby. Together this makes breathing difficult, and the lungs often lack the volume of air needed to support the body, complicated further by the fact that the at birth their lungs are still full of liquid.
To help the lungs achieve enough volume, the medical team provide gentle pressure to the lungs via a face mask or prongs in the nose - similar to how one would blow up a balloon. In preterm babies, we and others have shown that the amount of pressure, and how it is applied to the lungs as is critical to getting enough oxygen in and to minimising lung injury. This pressure is called PEEP. Both too little and too much PEEP can harm the fragile lining of the lungs.
There is a fine balance between too little, too much and just right and clinicians lack guidance on how to much PEEP to deliver at birth.
We are hopeful that this promising clinical trial will be able to provide just these answers.
The POLAR Trial team includes nine researchers from Australia, Europe and North America, all of whom are international leaders in neonatal respiratory research. The team is supported by the Murdoch Children’s Research Institute (MCRI), Australia’s leading paediatric research institute and the MCRI’s Melbourne Children’s Trials Centre (MCTC) who are centrally coordinating the International clinical trial.