Am. J. Respir. Crit. Care Med.,
Volume 162, Number 5, November 2000, 1795-1800
Functional Approach to Infants and Young
Children with Noisy Breathing
Validation of Pneumotachography by Blinded Comparison with Bronchoscopy
MARCO
FILIPPONE,
SURENDRA
NARNE,
ANDREA
PETTENAZZO,
FRANCO
ZACCHELLO,
and
EUGENIO
BARALDI
Department of Pediatrics, University of Padua, Padua, Italy
Flow-volume loop evaluation yields considerable diagnostic information about adult patients with upper airway obstruction. No
conclusive data support the reliability of this method in young children with noisy breathing. We used analysis of flow-volume loops
at tidal breathing (TB-FV) as a first diagnostic approach to young
children presenting with persistent noisy breathing (chronic stridor and/or wheezing). Flexible fiberoptic bronchoscopy was performed to establish a conclusive diagnosis and was used to verify
the accuracy of the preliminary functional localization of the airway
obstruction causing noisy breathing. The physician conducting
pneumotachography was blinded to the bronchoscopic findings in
the study, and the investigators conducting bronchoscopy were
blinded to the pneumotachographic findings. Through a 6-yr period, 113 consecutive young children (ranging in age from 15 to 48 mo) with noisy breathing were enrolled in the study. Three morphologically abnormal TB-FV patterns, as compared with the normal round-shaped TB-FV loops obtained with 15 healthy children, were identified in 110 patients. A TB-FV pattern of inspiratory fluttering was found in 26 subjects and in the first 3 yr of the study was
always associated with an endoscopic diagnosis of isolated laryngomalacia. Subsequently, this pattern was used to diagnose isolated laryngomalacia in 18 other infants, in whom endoscopy was
avoided. Of infants with endoscopic evidence of airway obstruction ranging from the glottis to the mainstem bronchi (49 subjects), all
but three showed a TB-FV loop pattern characterized by expiratory-limb flattening. A concave expiratory loop, with early expiratory peak flow and low flow at low volume, was invariably associated with peripheral bronchoconstriction, without endoscopic
evidence of anatomic abnormalities (20 cases). In conclusion, TB-
FV loop analysis is a noninvasive, accurate method of establishing
the site of airway obstruction in young children with recurrent stridor and/or wheezing. Clinical use of this method may provide interesting pathophysiologic information and may be useful in addressing the diagnostic management of such children.
