Quantitative assessment of intrathoracic airway collapse in infants and children with tracheobronchomalacia

Abstract

Summary. Tracheobronchomalacia (TBM) is increasingly recognized in infants, children, and adults with acquired chronic lung diseases as the use of flexible bronchoscopy has become widely established in spontaneously breathing patients. However, the lack of a reliable method to quantify the severity of the airway collapse has made serial studies, evaluation of therapies, and comparisons between patients difficult. The purpose of this study was to describe a method of quantifying airway collapse in TBM. The degree of airway collapse was quantitated by measuring the ratio of the smallest to the largest airway area during a respiratory cycle. The videotape of flexible bronchoscopy was run through a video monitor and frozen at the appropriate times. The airway circumference was then traced onto plastic overlays and the area measured. The videotapes of seven infants and children with TBM and eight with normal airways were reviewed by investigators who did not know the diagnosis. Intra-observer variability was 2.2%, and interobserver variability was 1.4%. The mean smallest/largest airway ratio was 0.34 ? 0.14 (SD) in the subjects with known TBM, compared with a ratio of 0.82 2 0.08 (SD) in children with a normal airway (P < 0.0001). The range in the children with TBM was 0.22-0.61, whereas for the control children it was 0.73-0.93. In this series, there was no overlap in the ratios between affected and unaffected patients. In addition to the manual method of calculating airway area ratios, a computer-assisted method is described that could be adapted to real-time use. This way of analyzing the degree of airway collapse could be used to assess patients with TBM quantitatively and reproducibly.

Current management and outcome of tracheobronchial malacia and stenosis presenting to the paediatric intensive care unit

“…The median age at diagnosis was 137 days (interquartile range 62±213 days). The number of patients in each group was as follows: isolated primary airway pathology (7), ex-premature infants (11), vascular rings (9), complex cardiac and/or syndromic pathology (17) and tracheooesophageal fistulae (4). The overall mortality was 14/48 (29 %).…”

“…It is simple to perform in infants who are already intubated and is also useful in diagnosing fixed airway stenosis. Methods have been suggested for quantitative severity scoring of bronchographic data [17] but, in our experience, clinical assessment of the child is still paramount in determining which infants should be referred for long-term ventilation and/or surgical management. Bronchoscopy is still necessary to identify complete tracheal rings and examination of the airway under direct vision by the surgeon at operation has been more useful than imaging in deciding which surgical approach is most suitable for several patients.…”

Measuring Central Airway Obstruction: What Do Bronchoscopists Do?

“…This technique has primarily been used to measure airway sizes in pediatric patients. As an alternative to quantitative approaches, semiquantitative techniques without calibration markers have been used by some researchers (7,8). Semiquantitative methods rely upon software, such as ImageJ, to measure the CSA of the stenosis and normal airway distal to the stenosis in pixels.…”

“…Murgu and Colt (7) have been proponents of morphometric bronchoscopy, which uses image software processing techniques that enable analysis of still digital images to measure airway lumen caliber. Studies in normal patients and patients with tracheobronchomalacia and benign strictures have demonstrated that morphometric bronchoscopy reliably measured airway caliber, had high intraand interobserver agreement, and correlated well with measurements performed by CT (4,8,9). However, this method has disadvantages in terms of providing real-time measurements, and has not been widely adopted (10).…”

Conservative Management of Canine Tracheal Collapse with Stanozolol: A Double Blinded, Placebo Control Clinical Trial

“…The overall impression of stanozolol administration to the owners, and subsequently to us, was enthusiastic. DISCUSSION TM is a rare disorder, although its true incidence is unknown, because it is generally considered underdiagnosed (4,(12)(13). Its severity varies and it is classified as congenital (primary) and acquired (secondary) (14).…”