Apnoea, bradycardia and desaturations

What is it?

Apnoea (pronounced Ap-knee-ah) is when a baby stops breathing for 15-20 seconds or more. Apnoea can occur in full-term babies, but is more common in premature babies, especially those born at less than 31 weeks gestation. It may occur while the baby is awake, but is more common during periods of sleep. The baby’s skin colour may become pale, purplish, or blue, and the apnoea may be followed by bradycardia. This is a slowing of the heart rate, usually to less than 100 beats per minute for a premature baby) because as breathing slows the heart rate also slows. You may find nurses often use the shorter “braddy” when talking about bradycardia. Some babies have “braddies” without any apnoea, but because the same things can cause both problems, the two conditions are often lumped together and referred to equally. A common term for apnoea with bradycardia is “As and Bs.”

Desaturation is a decrease in the percentage of oxygen found in the circulating blood supply. In premature babies a saturation below 85 is considered below normal. In most babies, oxygen is adjusted to keep the oxygen saturation at 92-96%. Desaturation is often the result of bradycardia.

Why does it occur?

The most common reason for apnoea and bradycardia in a premature baby is that the part of their brain which controls breathing (the respiratory centre) is immature and “forgets” to tell the baby to breathe. The baby may have a burst of big breaths followed by a period of shallow breathing or pauses. As the baby gets older, their breathing becomes more regular, and by the time they reach their due date this type of apnoea usually goes away.

Bradycardia will often follow apnoea, a period of rapid shallow breathing, insertion of a feeding tube, or an attempted bowel movement.

Less commonly, apnoea and bradycardia can also be caused (or increased in frequency) by other issues, such as infection, low blood sugar, patent ductus arteriosus (PDA), high or low body temperature, insufficient oxygen, etc. Bradycardia may also be caused by acid reflux. Medical staff will examine each baby to determine whether any of these issues are relevant to him/her.

How do I know if my baby has apnoea and/or bradycardia, or desaturations?
What happens if they do?

As apnoea and bradycardia are common conditions, premature babies (under 35 weeks gestation, or older if they are still on caffeine medication) are constantly monitored by machines that will sound an alarm if breathing stops or the heart rate drops below 100 beats per minute. Most babies will also have a device called an oximeter attached to a hand or foot to monitor oxygen saturation levels. If your baby has an instance of apnoea or bradycardia, this will be written in your baby’s notes, and the nurses will usually mention it to you if you were not near your baby at the time.

If the monitor sets off an alarm, a nurse will observe your baby to see if he/she is breathing, if there is a change in colour, or if the heart rate is falling. False alarms can occur in some babies. The nurse may stimulate your baby if they need a reminder to breathe, by patting or rubbing their arms, feet, back etc. If there is a change in colour, the nurse may give your baby extra oxygen.

How is it treated?

Apart from the continuous monitoring and patting/tickling as required, premature babies who experience apnoea and bradycardia may be given medication such as caffeine to stimulate breathing. In some cases a baby may require continuous positive airway pressure (CPAP) - a continuous flow of air and/or oxygen via small tubes in the baby’s nose to help keep tiny air passages in the lungs open. In very severe cases, the baby may need a breathing machine (ventilator or respirator) to help with breathing.

As babies mature, they are less likely to suffer from apnoea, bradycardia and desaturations. Cardiac (heart) and respiration (breathing) monitoring in the hospital will continue until medical staff are confident that your baby is no longer having any As and Bs. Some babies may require apnoea monitoring after coming home, and the hospital will advise you if your child falls into this category.

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This is one of a series of articles I’ve written for the L’il Aussie Prems newsletter under the heading of Premmie Health. Read my disclaimer here.