Scatter plot of the gap index versus the degree of bronchial obstruction.

<p><i>Closed circles, before-intervention; open circles, after-intervention.</i> This figure shows the correlations between the gap index and the degree of bronchial obstruction in the bronchial obstruction group. The gap index more than 0.06 sec was observed only when the degree of bronchial obstruction was more than 80%. The gap index of cases with 80% or more unilateral bronchial obstruction (0.18±0.18 seconds) was significantly higher than cases with less than 80% obstruction (0.02±0.02 seconds, p<0.05).</p

Left and Right Lung Asynchrony as a Physiological Indicator for Unilateral Bronchial Obstruction in Interventional Bronchoscopy

<div><p>Background</p><p>In patients with bronchial obstruction, pulmonary function tests may not change significantly after intervention. The airflow asynchrony in both lungs due to unilateral bronchial obstruction may be applicable as a physiological indicator. The airflow asynchrony is reflected by the difference in the left and right lung sound development at tidal breathing.</p><p>Objectives</p><p>To investigate the usefulness of left and right lung asynchrony due to unilateral bronchial obstruction as a physiological indicator for interventional bronchoscopy.</p><p>Methods</p><p>Fifty cases with central airway obstruction were classified into three groups: tracheal, bronchial and extensive obstruction. The gap index was defined as the absolute value of the average of gaps between the left and right lung sound intensity peaks for a 12-second duration.</p><p>Results</p><p>Before interventional bronchoscopy, the gap index was significantly higher in the bronchial (p<0.05) and extensive obstruction groups (p<0.05) than in the tracheal group. The gap index in cases with unilateral bronchial obstruction of at least 80% (0.18±0.04 seconds) was significantly higher than in cases with less than 80% obstruction (0.02±0.01 seconds, p<0.05). After intervention for bronchial obstruction, the dyspnea scale (p<0.001) and gap index significantly improved (p<0.05), although no significant improvements were found in spirometric assessments. The responder rates for dyspnea were 79.3% for gap indexes over 0.06 seconds and 55.6% for gap indexes of 0.06 seconds or under.</p><p>Conclusions</p><p>Assessment of left and right lung asynchrony in central airway obstruction with bronchial involvement may provide useful physiological information for interventional bronchoscopy.</p></div

Bronchoscopic and CT findings, flow-volume loops and lung sound recordings for bronchial obstruction (before, A–E; after, F–J).

<p>The left bronchus was severely stenotic as a result of lung adenocarcinoma. The development of lung sound intensity in the left lung lagged behind the right lung (right, red; left, blue). After intervention, these asynchronies were mostly resolved.</p

Characteristics of patients with central airway obstruction.

<p>Characteristics of patients with central airway obstruction.</p

Pulmonary function tests and lung sound recordings of patients with central airway obstruction.

<p>Comparisons between tracheal obstruction group and CAO with bronchial involvement (bronchial and extensive obstruction group) were performed by one-way ANOVA with Dunnett adjustment.</p><p>Values are represented as mean ± standard error *p<0.05, **p<0.01, ***p<0.001.</p

Box-and-whisker plots showing the IMS signal intensity of peak-2 in adenocarcinoma patients positive and negative for EGFR.

<p>Fourteen patients with EGFR mutation displayed a significantly higher n-Dodecane peak with a sensitivity of 85.7% and a specificity of 78.6% (p<0.01) than in 14 adenocarcinoma patients without the EGFR mutation.</p

Characteristics of patients.

<p>Characteristics of patients.</p

Receiver operating characteristic (ROC) validation of the gap index in the diagnosis of bronchial involvement in patients with central airway obstruction (CAO).

<p>ROC validation of the gap index revealed that a cut-off point of 0.06 seconds showed 76.3% sensitivity, 91.7% specificity, and 80% accuracy in the differentiation between CAO with bronchial involvement (bronchial = 18 and extensive = 20) and tracheal obstruction (n = 12).</p

Dyspnea scale, pulmonary function tests and lung sound recordings before and after intervention.

<p>Definition of abbreviation: MMRC  =  modified Medical Research Council Scale.</p><p>Continuous valuables before and after intervention were tested by Wilcoxon signed-rank test.</p><p>Values are represented as mean ± standard error. *p<0.05, **p<0.01, ***p<0.001.</p><p>MMRC responder  =  improvement in MMRC scale grade by 1 or more.</p

A decision tree algorithm could separate small cell carcinoma, squamous cell carcinoma and adenocarcinoma.

<p>A decision tree algorithm could separate small cell carcinoma, squamous cell carcinoma and adenocarcinoma.</p