Subjective assessment using still bronchoscopic images misclassifies airway narrowing in laryngotracheal stenosis.

OBJECTIVES Severity of airway narrowing is relevant to management decision-making processes in patients with laryngotracheal stenosis. Airway lumen is frequently assessed subjectively based on still images obtained during airway examinations or objectively using image analysis software applied to radiological or bronchoscopic images. The purpose of this study was to determine whether strictures classified as mild, moderate or severe degrees of airway narrowing based on subjective assessments by a group of experienced bronchoscopists using still images, matched the classifications derived from morphometric bronchoscopy measurements and whether the results of subjective assessments correlated with the level of bronchoscopic experience. METHODS Thirty-five bronchoscopic doublet still images of benign causes of laryngotracheal stenosis containing normal and abnormal airway cross-sectional areas were objectively analysed using morphometric bronchoscopy and classified as mild (<50%), moderate (50-70%) or severe (>70%). These images were then subjectively assessed by 42 experienced bronchoscopists participating in an interventional bronchoscopy course. Descriptive statistics were used to explore the accuracy of the participants' classifications. Correlation coefficients were used to study the relationship between participants' subjective assessments and bronchoscopy experience. RESULTS Only 47% of strictures were correctly classified by study participants (mean 16.48 ± 2.8). Of the 1447 responses included in this analysis, 755 were incorrect: 71 (9%) were over-classifications of strictures' severity and 684 (91%) were under-classifications. There was no correlation between number of strictures correctly classified and number of lifetime bronchoscopies or number of strictures seen by bronchoscopists in an average month. CONCLUSIONS Experienced bronchoscopists often misclassify the degree of airway narrowing when using still bronchoscopic images to subjectively assess strictures of benign aetiology.

[1]  S. Murgu,et al.  Morphometric bronchoscopy in adults with central airway obstruction: Case illustrations and review of the literature , 2009, The Laryngoscope.

[2]  T. Miyazawa,et al.  Assessing the site of maximal obstruction in the trachea using lateral pressure measurement during bronchoscopy. , 2012, American journal of respiratory and critical care medicine.

[3]  J. T. Fisher,et al.  Quantitative videobronchoscopy: a new technique to assess airway caliber. , 1996, American journal of respiratory and critical care medicine.

[4]  L. Forkert,et al.  A new method to perform quantitative measurement of bronchoscopic images. , 2001, The European respiratory journal.

[5]  R Polverosi,et al.  [Evaluation of tracheobronchial lesions with spiral CT: comparison between virtual endoscopy and bronchoscopy]. , 2001, La Radiologia medica.

[6]  S. Nagataki.  Computed tomography and radiation exposure. , 2008, The New England journal of medicine.

[7]  C Lacor,et al.  Influence of glottic aperture on the tracheal flow. , 2007, Journal of biomechanics.

[8]  S Takanashi,et al.  New method for quantitative assessment of airway calibre using a stereovision fibreoptic bronchoscope. , 2012, British journal of anaesthesia.

[9]  Martin Sonnenschein,et al.  Multidetector CT virtual bronchoscopy to grade tracheobronchial stenosis. , 2002, AJR. American journal of roentgenology.

[10]  R Wootton,et al.  A new method for objective identification and measurement of airway lumen in paediatric flexible videobronchoscopy , 2005, Thorax.

[11]  T. Upile,et al.  A proposed system for documenting the functional outcome of adult laryngotracheal stenosis , 2007, Clinical otolaryngology : official journal of ENT-UK ; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery.

[12]  Adnan Majid,et al.  Comparison of Dynamic Expiratory CT With Bronchoscopy for Diagnosing Airway Malacia: A Pilot Evaluation. , 2007, Chest.

[13]  R. Platt,et al.  Ultrasonography and videobronchoscopy to assess the subglottic diameter in the paediatric population: a first look. , 2002, The Journal of otolaryngology.

[14]  M. Tubiana,et al.  Computed tomography and radiation exposure. , 2008, The New England journal of medicine.

[15]  P. Andersen,et al.  Modern Management of Laryngotracheal Stenosis , 2006, The Laryngoscope.

[16]  Jerzy Soja,et al.  Assessment of Airway Caliber in Quantitative Videobronchoscopy , 2006, Respiration.

[17]  M. Lipton,et al.  Varying tracheal cross‐sectional area during respiration in infants and children with suspected upper airway obstruction by computed cinetomography scanning , 1990, Pediatric pulmonology.

[18]  C. Myer,et al.  Proposed Grading System for Subglottic Stenosis Based on Endotracheal Tube Sizes , 1994, The Annals of otology, rhinology, and laryngology.

[19]  L. F. Black,et al.  The flow-volume curve. A current perspective. , 1973, The American review of respiratory disease.

[20]  R. Hyatt,et al.  Evaluation of obstructing lesions of the trachea and larynx by flow-volume loops. , 2015, The American review of respiratory disease.

[21]  R. Ware,et al.  Airway sizes and proportions in children quantified by a video-bronchoscopic technique , 2006, BMC pulmonary medicine.

[22]  J. Verschakelen,et al.  Multidetector CT-generated virtual bronchoscopy: an illustrated review of the potential clinical indications , 2004, European Respiratory Journal.

[23]  Hyatt Re,et al.  The flow-volume curve. A current perspective. , 1973 .

[24]  K Neumann,et al.  Real-time interactive virtual endoscopy of the tracheo-bronchial system: influence of CT imaging protocols and observer ability. , 2000, European journal of radiology.

[25]  Chris Lacor,et al.  Tracheal stenosis: a flow dynamics study. , 2007, Journal of applied physiology.

[26]  H J Rozycki,et al.  Quantitative assessment of intrathoracic airway collapse in infants and children with tracheobronchomalacia , 1996, Pediatric pulmonology.

[27]  Soon-Cheang Quah,et al.  A Current Perspective , 2007 .