See 'Pulse oximeter'.

The scan machine used is similar to that used to scan mothers during pregnancy. The most common scan is of the head. This is done with a small probe on the fontanelle (the soft spot on top of the baby's head). There can be many reasons for doing scans, but usually it will be to check the preterm baby, as they are at risk of bleeding into the brain. Other parts of the body that may need scanning are usually the abdomen or the heart. A scan of the heart is often called an echocardiograph, shortened to an 'echo'.

Special care baby unit.

A baby whose birth weight is lower than that of 90% of babies of the same gestational age.

This is a test done on babies who have been on oxygen for a long time and is often performed a short time before the baby is due to go home. The test establishes whether the baby can keep his or her own oxygen levels in a safe range. If the baby is to go home on oxygen, then the test is used to set the amount of oxygen that the baby will need. Usually the sleep study will take place over a period of 12 hours and must include a period when the baby is in quiet sleep, as this is the time that the body's oxygen levels are at their lowest.

Steroids (or corticosteriods) are given antenatally to mothers where the birth seems likely to occur early. The drug crosses the placenta and causes the baby's lungs to mature for breathing. In babies with chronic lung disease, it may be difficult for the baby to come off mechanical ventilatory support. Low doses of steroids may be given to reduce any inflammation in the lung. Repeated courses of steroids are now usually avoided because there is concern that they may be contributing to some of the developmental problems occurring later in some of these babies' lives.

A mixture of chemicals that prevent the lungs from collapsing when the baby breathes out. Production of surfactant in the lungs starts at about 24 weeks but is not well developed before 36 weeks' gestation. This can be the cause of respiratory distress syndrome (RDS ? see above). Replacement surfactant can be given as a liquid into the lungs of the premature baby.

A syringe driver is used to gradually and continuously give small amounts of fluids (with or without medication) to patients.