Tachypnea is rapid shallow breathing, a phenomenon which in itself is often harmless. This type of breathing can be caused by physical exertion and exercise, and in these cases is not dangerous, since breathing soon returns to normal. Tachypnea can also be a symptom of a serious medical condition such as heart disease, emphysema, meningitis, or respiratory system trauma. When this occurs, treating the cause of the breathing may be prioritized over treating the symptom.
Tachypnea may be caused by a variety of respiratory or cardiac conditions, including mild asthma and allergies in addition to potentially life-threatening illnesses. The rapid breathing occurs because the respiratory system is either not getting enough oxygen, or is unable to transport oxygen to the heart. Often this is due to lung disease such as emphysema, or a cardiac condition that limits blood and oxygen flow to the heart.
This type of breathing is relatively common in infants, occurring in around 1% of all babies. It is more likely to occur in male babies. In addition to rapid breathing, babies with this condition may need an additional oxygen supply, and may have abnormal blood gas readings. When it occurs in newborns the condition is called transient tachypnea, or wet lungs.
When this condition occurs, it is usually due to the presence of fluid in the infant’s lungs. This fluid is present in the baby’s lungs during gestation, and is there to help promote normal lung development. During labor, chemical signals stimulate the lungs into removing the fluid. For various reasons, these chemical signals may be weak in some babies, and as a result these babies may be born with excess fluid still remaining in the lungs. Babies are at risk if their mothers have diabetes or asthma, if they are born small for their age, or if they are delivered by Cesarean.
Rapid breathing develops soon after birth, but is usually transient and lasts only two or three days. Transient tachypnea of newborn babies is, by definition, not a harmful condition and is not fatal. The most common side effect of the condition is simply that the infant requires a slightly longer stay in hospital.
There is some evidence, however, that the condition also increases the risk that the infant may develop asthma during childhood. If the rapid breathing lasts longer than five days, there is cause to search for an underlying reason for the condition. Possible diagnoses include anemia, pneumonia, and congenital heart disease.