Why preterm lungs need help

Bliss describes respiratory distress syndrome as the condition caused by not having enough surfactant, the natural substance that coats the inside of the lungs and stops the tiny air sacs collapsing between breaths. Surfactant production ramps up late in pregnancy, which is why the earlier a baby is born the more likely they are to need help. Steroid injections given to the mother before a preterm birth work by accelerating that process, which is why they are offered rather than optional.

The ladder, from most to least support

Conventional ventilator. Air, with or without added oxygen, blown gently into the lungs through a tube passed into the windpipe. NICE guideline NG124 says that for babies who need invasive ventilation, teams should use volume-targeted ventilation combined with synchronised ventilation as the primary mode.
High frequency oscillator. Bliss describes this as blowing small amounts of air into the lungs hundreds of times a minute, so the chest looks like it is vibrating. NG124 lists it as the option to consider if volume-targeted ventilation is not effective. It looks alarming and works well for some lung problems.
CPAP. Continuous positive airway pressure, delivered through two thin prongs in the nose or a small mask, holding the lungs slightly open between breaths. Your baby is doing the breathing.
Nasal high flow. Warmed, humidified air through smaller prongs. Less pressure, more comfort, easier feeding.
Low-flow oxygen. A trickle of extra oxygen through fine nasal prongs.
Air. The last rung.

Why CPAP comes first

NICE NG124 says that when stabilising preterm babies who need respiratory support soon after birth and before admission to the neonatal unit, teams should use CPAP where clinically appropriate rather than invasive ventilation. For babies on the unit needing non-invasive support, it says to consider nasal CPAP or nasal high flow as the primary mode. The reasoning is that a tube and a ventilator, while sometimes unavoidable, carry their own costs for immature lungs.

Surfactant

Surfactant is given directly into the lungs. NG124 says to give it to preterm babies who need invasive ventilation for stabilisation in the early postnatal period, and that when giving it to a baby who does not need invasive ventilation, a minimally invasive administration technique should be used — and where that is not possible, a tube should be placed and removed early afterwards. In plain terms, teams try hard to give surfactant without committing a baby to a ventilator. It is named here as a treatment only; doses are a matter for your baby's team.

Caffeine's part in this

Caffeine citrate is not sedation and not a stimulant in the coffee sense; it steadies an immature breathing drive and reduces pauses. NG124 says to use it routinely in preterm babies born at or before 30 weeks, starting as early as possible and ideally before three days of age, and to consider stopping it at 33 to 35 weeks corrected gestational age if the baby is clinically stable. It is often the thing that makes coming off CPAP possible.

Why the oxygen number is not 100

NG124 says that after initial stabilisation, teams should aim for an oxygen saturation of 91 to 95 per cent in preterm babies. Too little oxygen is obviously harmful; too much is also harmful to immature eyes and lungs. So the alarm limits are set as a window with a top as well as a bottom, and a nurse turning the oxygen down is doing the same job as turning it up. NG124 also notes that pulse oximeters can under- or overestimate saturation, with overestimation reported in people with dark skin, which is one reason the number is read alongside the baby rather than instead of them.

Steps backwards are part of the pattern

Almost no baby comes down this ladder in a straight line. Infection, a patent ductus arteriosus, tiredness, a large feed or simply a bad night can all move a baby up a rung for a day or two. NG124 explicitly tells teams not to treat low blood pressure on a number alone, and the same spirit applies here: your team is watching a trend, not a moment. A step back after a good week is discouraging and is not a lost fortnight.

Chronic lung disease

If a baby still needs oxygen or support after several weeks, the team may use the term chronic lung disease — also called bronchopulmonary dysplasia. Bliss describes it as a lung condition that can follow a long period on a ventilator, where a baby needs more oxygen and finds breathing harder, and which takes time to improve. Some babies go home on low-flow oxygen because of it. That is a planned route, arranged in advance with equipment installed and training given, and it is what allows a baby who no longer needs a hospital to stop living in one.

What to ask at the cot side

Two questions cover most of it: what rung is my baby on today, and what would have to happen for the next step down? Ask them at ward rounds. They convert a wall of settings into a direction of travel.

What the settings on the screen refer to

You do not need to interpret them, but knowing what they are stops them looking like a verdict. FiO2 is the percentage of oxygen in the gas being given — air is 21 per cent, so a baby "in 25 per cent" is on barely any extra oxygen. PEEP and the pressure numbers describe how hard the machine is working to hold the lungs open. Rate is breaths per minute. Flow, on high flow, is litres per minute. NICE NG124 says oxygen should be humidified when given at higher flow rates, which is why there is a warm water chamber in the circuit.

The most useful number to watch is the oxygen percentage, because it reflects most directly how much help your baby's lungs currently need, and it tends to creep up quietly before anything else changes.

Feeding while on breathing support

Babies can feed on CPAP and on high flow, and units increasingly support breastfeeding with prongs in place, although the prongs make latching harder and the tubing gets in the way. Tube feeds continue throughout, and ventilated babies are fed entirely by tube. If your baby tires or dips during feeds, that is a recognised pattern rather than a sign of failure, and the team may shorten feeds, run them more slowly, or use a combination of tube and mouth for a while.

Breathing Support for Preterm Babies