Use of maximal expiratory flows to evaluate central airways obstruction in infants

Partial expiratory flow-volume (PEFV) curves obtained by the rapid compression technique were employed to assess airway function in three infants with three different lesions of the central airways (vascular ring, congenital tracheal stenosis, subglottic polyp). Preoperatively, all three demonstrated severe flow limitation with a relatively constant forced expiratory flow over the tidal volume range. Postoperatively the PEFV curves changed to a normal convex shape, and the maximal expiratory flows at functional residual capacity (VmaxFRC) returned to normal. The PEFV curve adds to our physiologic assessment of the severity of the central airway obstruction in infants and to the efficacy of our therapeutic intervention.