Cooling for birth asphyxia, and what the HELIX trial means for India

Birth asphyxia means a baby's brain and body did not get enough oxygen or blood flow around the time of birth. When this injures the brain, it is called HIE. Cooling the baby helps in rich countries, but the HELIX trial found it did not help, and increased deaths, in babies in India, Sri Lanka and Bangladesh. Careful supportive care is what matters most here.

What is birth asphyxia?

Birth asphyxia is a lack of oxygen and blood flow to the baby before, during or just after birth. A baby affected by it may not breathe or cry at birth and may need help to start breathing.

Causes include problems with the placenta or cord, very long or blocked labour, heavy bleeding in the mother and a torn womb. Sometimes no clear cause is found. Many babies recover fully. Some develop brain injury.

What is HIE in a newborn?

HIE (hypoxic ischaemic encephalopathy) is brain injury caused by too little oxygen and blood flow around birth. It shows as abnormal alertness, tone, feeding or breathing, and sometimes fits.

The injury happens in two waves. The first is during the lack of oxygen itself. After a short recovery, a second wave follows over the next hours and days, as damaged cells swell, become inflamed and die. Treatments such as cooling were designed to soften that second wave.

How is HIE graded as mild, moderate or severe?

Doctors grade HIE by examining the baby's alertness, muscle tone, reflexes, breathing and fits. The usual system comes from a 1976 study by Sarnat and Sarnat.¹

• Mild (stage 1): jittery, very alert, lasts less than a day.
• Moderate (stage 2): sleepy, floppy, often with fits.
• Severe (stage 3): very hard to rouse, very floppy, with weak brainstem functions.

In that first study, babies who did not reach stage 3, and whose stage 2 signs settled within five days, seemed to develop normally later.¹

What is cooling therapy for babies?

Cooling, or therapeutic hypothermia, means keeping the baby's body at about 33 to 34 degrees C for 72 hours, starting within 6 hours of birth.²

The idea is to slow the brain's energy use and calm the second wave of injury. It is done with a machine that watches the baby's temperature all the time and adjusts the cooling, followed by slow rewarming.

Does cooling work for HIE?

In high income countries, yes. A Cochrane review of 11 trials found that cooling reduced death or major disability at 18 months.³

For every 7 babies cooled, one more survived without major disability.³ In the UK TOBY trial, more cooled children survived with a normal IQ at 6 to 7 years, 52 percent compared with 39 percent.² But nearly all these babies were born in rich countries with different patterns of birth injury.

What was the HELIX trial?

HELIX was the largest cooling trial in low and middle income countries. It found that cooling did not reduce death or disability, and it increased deaths.⁴

Published in the Lancet Global Health in 2021, it enrolled 408 babies with moderate or severe HIE in seven tertiary NICUs in India, Sri Lanka and Bangladesh. Babies were cooled with modern machines or given usual care. All units had ventilators and MRI scanners.⁴

• Death or moderate to severe disability at 18 months: 50 percent with cooling, 47 percent without.
• Death: 42 percent with cooling, 31 percent without.

The authors concluded that cooling should not be offered for HIE in low and middle income countries, even in tertiary NICUs.⁴

Why might cooling not work for babies in India?

Nobody knows for certain. One leading idea is that brain injury in our babies often starts earlier, or builds up over a longer time, so cooling comes too late to help.

The HELIX team has said that the benefit of cooling depends on the population, not only on the level of intensive care, and that research should look at when and how the injury begins.⁵ In a later analysis of HELIX, babies who needed longer resuscitation had more brain injury and worse outcomes, but this did not change the effect of cooling.⁶ Infection, poor growth in the womb and other illness may also play a part.

Should my baby be cooled in India?

For most babies in India, Dr Dutta does not recommend cooling. The best evidence from our region shows no benefit and more deaths.⁴

Some doctors still discuss cooling for selected babies, for example those born in hospital after a sudden event such as a cord accident. That question is not settled. If cooling is offered, it is fair to ask why the doctor thinks it suits your baby and what the unit's results are. The HELIX authors advise keeping the baby at normal temperature, and taking great care to avoid overheating.⁵

Is it safe to cool a baby with ice packs or cold water?

No. Never cool a baby at home or with ice packs, cold water or by switching off the warmer.

Low cost cooling methods spread across India before there was evidence that they were safe or useful.⁵ Without a machine that controls temperature, a baby's temperature can fall far too low, which is dangerous on its own. If cooling did not help even with the best machines in HELIX, it cannot be safe with crude methods.⁵

Why must a baby with HIE not get too hot?

Fever is harmful to an injured brain. A baby with HIE should be kept at a normal temperature, never overwrapped.

In an American study, among babies with HIE who were not cooled, each 1 degree C rise in the highest temperatures was linked to a 3.6 to 4 times higher chance of death or disability.⁷ In a hot Kolkata summer, a baby with HIE needs light clothing and careful temperature checks.

What treatment does a baby with HIE need?

The main treatment is careful supportive care that protects the brain from further harm.

• Breathing support if needed, keeping oxygen and carbon dioxide in a normal range.
• Steady blood pressure and blood sugar.
• Finding and treating fits.
• Careful fluids, because the kidneys are often affected.
• Normal temperature, with no overheating.^7,5
• Breast milk feeding and family involvement as the baby recovers.

Why does my baby need an EEG?

Many fits in newborns cannot be seen from the outside. An EEG (a recording of brain waves) shows fits that are otherwise missed.

In a study using video EEG, only about a third of newborn brain fits showed any visible sign. Experienced staff recognised and recorded only 9 percent of them.⁸ EEG monitoring helps doctors treat fits that matter and avoid treating movements that are not fits.

Will my baby need an MRI scan?

Usually yes. An MRI brain scan, often done at around two weeks, shows which parts of the brain are injured and helps predict the future.

In the HELIX babies, MRI at two weeks showed more injury in areas such as the deep grey matter and white matter in babies who had needed longer resuscitation, and these babies also did worse at 18 months.⁶ MRI is not perfect, but it helps us talk about the future more precisely.

Can birth asphyxia be prevented?

Much of it can. Good care in labour and skilled help in the first minute after birth save many babies.

Monitoring the baby during labour and acting quickly on warning signs prevents many cases. After birth, training for drying, stimulating and, if needed, breathing for the baby with a bag and mask makes a real difference. After Helping Babies Breathe training in Karnataka, stillbirths fell from 3.0 to 2.3 percent.⁹

What follow-up does a baby with HIE need?

Babies with moderate or severe HIE need regular checks of development, hearing and vision through the early years of childhood.

Physiotherapy and early stimulation work best when started early, while the brain is still very adaptable. Talk, sing and play with your baby every day. Keep every follow-up appointment, even if your baby seems fine.

When should I call the doctor after my baby comes home?

Contact your doctor promptly if you notice any of these.

• Jerking, stiffening, staring spells or repeated lip smacking.
• Trouble sucking or swallowing, or choking on feeds.
• A baby who seems unusually floppy or stiff.
• Fever or a baby who feels cold.
• No social smile, poor head control, or other milestones that seem late.
• Any worry about hearing or vision.