Ultrasound may diagnose transient tachypnea in newborns

The double lung point is an ultrasound sign that may help diagnose transient tachypnea of the newborn, a respiratory disorder currently diagnosed mainly by excluding other disorders. A recent study identified the double lung point in newborns already diagnosed with transient tachypnea.

Dr. Roberto Copetti and Dr. Luisa Cattarossi in the emergency department at S. Antonio Abate Hospital in Tolmezzo, Italy, did ultrasound exams on 137 infants in an effort to define the ultrasonographic appearance of transient tachypnea and determine clinical applications.

Thirty-two of the infants showed clinical signs of transient tachypnea and radiological indications of fluid in the lungs. All these ultrasound exams showed very compact comet-tail artifacts in the upper lung area and very few of these artifacts in the lower lung area. The authors called this the "double lung point." These ultrasound results were compared with exams on 60 normal infants, 29 infants with respiratory distress syndrome, six with pneumonia, five with pulmonary hemorrhage, and five with atelectasis. None of these showed the same double lung point sign.

Copetti and Cattarossi claimed 100% sensitivity and specificity for their double lung point sign in the diagnosis of transient tachypnea, although they acknowledged further studies should be done using better blinding.

The March issue of Neonatology, which published their study, also included a commentary by pediatricians Dr. Waldemar Carlo from the University of Alabama at Birmingham, and Eduardo Bancalari from the University of Miami in Florida. They are concerned the newborns identified as having transient tachypnea may actually have had respiratory distress syndrome, underscoring the difficulty of identifying this disorder. They were also concerned the ultrasonographers may have been influenced by being able to see which infants were on ventilators or oxygen assistance and encourage researchers to do a prospective study with masked ultrasound readers. They do agree that ultrasound could be a cost-effective, useful tool in diagnosing respiratory distress in infants, and encouraged researchers to investigate the ultrasonographic appearance of other lung problems in newborns.