Transient tachypnea, or TTN, occurs when a newborn has extra fluid in his lungs, causing him to have difficulty breathing. TTN is sometimes called "wet lung" or type II respiratory distress syndrome and occurs in approximately 1 to 2 percent of newborns.
While in utero, a baby's lungs are filled with amniotic fluid. Most of this fluid is squeezed out of the baby's lungs with each contraction during birth, and any remaining fluid is either coughed up shortly after birth or gradually absorbed into the bloodstream.
In a baby with TTN, the extra fluid in the lungs is absorbed too slowly, making it difficult for the baby to take in oxygen and the baby must breath harder and faster to compensate. Symptoms of TTN may be similar to other respiratory problems, so doctors will usually perform a chest x-ray to make an accurate diagnosis. Symptoms include:
Rapid, labored breathing (tachypnea) of more than 60 breaths a minute
Grunting or moaning sounds when the baby exhales
Flaring nostrils or head bobbing
Retractions (when the skin pulls in between the ribs or under the ribcage during rapid or labored breathing)
Cyanosis (when the skin turns a bluish color) around the mouth and nose
TTN occurs in both premature and full-term babies; although premature babies tend to develop TTN more frequently because their lungs are not fully developed. Newborns who are at higher risk of TTN include those who are:
Babies who are born via c-section or a very fast vaginal delivery are at higher risk because they do not experience the pressure of passing through the birth canal, which squeezes out some of the fluid. Some doctors believe that TTN may be the result of inhibited release of the hormone epinephrine, which facilitates the clearing of fluid from the lungs.
Babies with TTN may be placed in the NICU for observation and treatment to ensure their breathing rates slow and oxygen levels remain normal. Some may need to receive extra oxygen through a mask or under an oxygen hood. If a baby continues to struggle to breathe under an oxygen hood, doctors may use continuous positive airway pressure (CPAP), in which tubes are inserted in the baby's nose and a machine supplies a continuous stream of pressurized air.
Babies with TTN often cannot coordinate sucking, swallowing, and breathing at the same time, so they frequently require an IV to prevent dehydration and maintain their blood sugar levels.
TTN usually clears up within 24 to 48 hours and all symptoms disappear within 72 hours, leaving the child healthy and without any long-term effects. If fluid persists after that period of time, doctors will probably investigate other medical problems that may be causing the distress.