The use of the tidal breathing flow volume loop in laryngotracheal disease of neonates and infants

Flow volume loops have been valuable in the diagnosis of upper airway obstruction in adults; however, the use of this technique in neonates has been limited because of their inability to perform a forced exhalation. We have used the tidal breathing flow volume loop (TBFV) to evaluate upper airway function in 100 neonates and infants. Eleven of the neonates and infants tested with this method were found to have laryngotracheal abnormalities such as tracheal stenosis, innominate artery compression, subglottic hemangioma, and unilateral vocal cord paralysis. Normal neonates and infants demonstrate a round or oval TBFV loop pattern, while those with upper airway obstruction show a flat inspiratory or expiratory curve. Tidal breathing flow volume loops offer a new, rapid and noninvasive method for evaluating the upper airway function in neonates and infants, and may play an important role in diagnosing upper airway dysfunction and evaluating the need for therapeutic intervention.