ABC of preterm birth: Immediate care of the preterm infant

Preparing appropriately for the delivery and immediate care of the preterm infant is essential when time permits and may impact on the eventual outcome for the infant. This article describes the skills and equipment needed for the care and possible resuscitation of these vulnerable babies.  The support and advice needed by parents and families at this time is also explored.

Preparation for preterm delivery

When preterm delivery can be anticipated there may be an opportunity for paediatric staff to discuss intrapartum and postnatal care with prospective parents and colleagues from midwifery and obstetrics. Even if detailed discussion is not possible, relevant historical details should be taken to anticipate problems and prepare appropriately for the arrival of the preterm infant.

Broadly, the level of resuscitation that may be needed is inversely related to the gestation of the preterm infant. Usually, the approach taken in resuscitating preterm infants of > 32 completed weeks' gestation is the same as that taken for term infants. Most need only basic measures such as drying and stimulation. Infants of gestation < 32 weeks (or birth weight < 1500 g) require more active support. For infants of < 28 weeks' gestation, this support will probably include endotracheal intubation and assisted ventilation.

Ideally, two members of staff who are experienced in the early care of preterm infants should be present at the delivery of each anticipated infant. A senior paediatrician with extensive experience in dealing with preterm babies should be at the delivery of infants of < 28 weeks' gestation. Before delivery, the attending staff should recheck essential equipment for resuscitation.

The "inverted triangle" shows how commonly
certain interventions are needed

Assessment and resuscitation

Preterm infants get cold quickly because of their relatively large surface area. Resulting hypothermia reduces surfactant production, may hasten hypoglycaemia and acidaemia, and is associated with increased mortality. Preterm infants should be delivered into warm towels, dried, and transferred to a dedicated neonatal resuscitation platform or trolley with an integral radiant heater. Alternatively, immediate occlusive wrapping in polythene may be at least as effective in reducing evaporative heat loss, especially in extremely preterm infants.

As with all acute resuscitation, the aims are to ensure airway patency and support the breathing and circulation. Colour, respiratory effort, tone, and heart rate can be assessed to determine the response of the infant to interventions.

Airway

To obtain a patent airway, the infant's head should be maintained in a neutral position and the chin should be supported while applying gentle forward traction to the mandible (jaw thrust). Careful suction under direct vision may be used to clear secretions that can obstruct the airway.

Breathing

Failure to establish regular breathing in the first minute after birth is an indication for assisted ventilation. The aim is to inflate the newborn's poorly compliant, fluid filled lungs to recruit alveoli for gas exchange. About five initial "inflation" breaths of 2-3 seconds' duration followed by ventilation at a rate of around 40 breaths per minute using pressures of 20-25 cm H₂O is appropriate while checking for spontaneous respiration every 30 seconds. Occasionally, higher inflation pressures, up to 30 cm H₂O, may be needed. Commonly, 100% oxygen is used, but no evidence exists that this achieves better outcomes than lower concentrations of oxygen.

Preterm infants should be moved to a neonatal resuscitation trolley
with radiant heater after delivery as they could get cold quickly

Inflation breaths, and subsequent ventilation if spontaneous respiration is not established, can be delivered via a facemask attached to a Y piece system with a blow-off valve or via a bag valve mask. A range of masks should be available to fit over the infant's mouth and nose (but not the orbital margin). Staff caring for newborn infants in all centres, including community maternity units, should be trained to deliver facemask ventilation effectively.

Infants of >32 weeks' gestation

For infants of gestation > 32 weeks, failure to respond to appropriately delivered facemask ventilation in the first 2-3 minutes is rare, and may be an indication for endotracheal intubation.

Infants of 28-32 weeks' gestation

Infants born at < 32 weeks' gestation have an increased risk of surfactant deficiency and of developing respiratory distress syndrome. In addition, they have less developed respiratory muscles than term infants and are less able to cope with the increased work of breathing associated with poorly compliant lungs.

For infants of gestation 28-32 weeks who do not establish adequate spontaneous respiration in 30-60 seconds, other options to sustain respiration exist. These options include supporting ventilation with continuous positive airway pressure via nasal prongs or facemask, intubating and providing intermittent positive pressure ventilation, and administering prophylactic surfactant.

Infants of < 28 weeks gestation

Not all infants of < 28 weeks' gestation need intubation at birth. Unless the infant is pink and active, however, immediate endotracheal intubation at birth should be considered. In these infants there is evidence that early prophylactic replacement of natural surfactant is more effective than delayed "rescue" treatment in reducing the incidence of acute lung injury and mortality. For infants born outside the labour ward, resuscitative efforts should concentrate on keeping the infant warm, maintaining a clear airway, administering oxygen, and applying facemask ventilation.

Circulation

Chest compression is indicated if, despite adequate artificial ventilation, the infant's heart rate remains < 60 beats per minute and is not improving. Apply around 90 compressions per minute with lung reinflation after every three chest compressions.

Correct head position for newborn
resuscitation - the neutral position

Drugs

If there is no improvement in clinical condition after adequate ventilation and chest compression, then certain drugs may be useful in the acute resuscitation of preterm infants. Persistent bradycardia may respond to adrenaline (epinephrine) and sometimes intravenous sodium bicarbonate can be used to correct acidosis. Dextrose may also be useful during prolonged resuscitation to correct hypoglycaemia. The use of intravenous fluids (normal saline, plasma, and blood) for volume expansion in preterm infants should be limited to those infants known to have volume depletion - for example, after antepartum haemorrhage.

All drugs are best delivered via an umbilical venous catheter. Adrenaline (epinephrine) may be given via the endotracheal route although its efficacy is unknown when given this way. Sadly, infants who do not respond to appropriate "basic" resuscitation and merit drug intervention will probably have a poor prognosis.

Stopping intensive resuscitation efforts If the heart rate does not improve despite 15-20 minutes of appropriate efforts, then it may be appropriate to stop resuscitation and to provide palliative care. A decision to stop active intervention should be made by senior staff in consultation with the parents. If an experienced member of staff is not available resuscitation should be continued until a senior colleague is present

Jaw thrust for maintaining a patent
airway in a newborn infant

Infants born at the threshold of viability

Although interventions (such as prophylactic antenatal steroids and exogenous surfactants) have improved certain outcomes for extremely preterm infants, recent data indicate that the overall prognosis for infants born at < 26 weeks' gestation remains poor. When delivery at < 26 weeks' gestation is anticipated, the most experienced paediatrician available must counsel the parents and inform them of the potential outcomes for mother and infant.

If possible, the parents should then be allowed to reflect on the implications of this information before it is decided how to care for the newborn infant. Some parents and carers may feel that aggressive perinatal interventions are not in the best interests of the infant and family. Such discussions and any decisions reached should be documented and conveyed to all staff who are caring for the mother or infant. The parents should be assured that any decision to withhold or start resuscitation can be revised at any time depending on clinical circumstances.

Laryngoscope and endotrachealtubes for intubating preterm infants

Bag valve mask can be used to deliver inflation breaths and subsequent ventilation if necessary

Palliative care of the newborn infant

If resuscitation is unsuccessful, or if active resuscitation is felt to be inappropriate, then palliative care should be provided for the infant and family. The parents can spend time with their baby, and should be aware that their baby may show signs of life, such as occasional gasps, after birth. Privacy and sensitive support for parents and family with subsequent follow up are essential.

The potential importance of postmortem examination should be discussed at an appropriate time.

Audit and review

All deliveries of extremely preterm infants should be reviewed by the neonatal service as part of training and good practice. Particular attention should be given to aspects of care that have been shown to affect outcome. Regular perinatal meetings are an ideal opportunity to examine these episodes of care and should be mandatory for any neonatal service.

Peter W Fowlie, consultant paediatrician, Perth Royal Infirmary and Ninewells Hospital and Medical School, Dundee

William McGuire, senior lecturer in neonatal medicine, Tayside Institute of Child Health, Ninewells Hospital and Medical School, Dundee


studentBMJ 2005;13:221-264 June ISSN 0966-6494