Assessment of Extensive Airway Obstruction Using Point-by-Point Lateral Pressure Measurements during Bronchoscopy.

BACKGROUND: The positioning of the stent at the flow-limiting segment is crucial for patients with extensive airway obstruction to relieve dyspnea. However, CT and flow-volume curves cannot detect the area of maximal obstruction. OBJECTIVES: The aim of this study is to physiologically evaluate extensive airway obstruction during interventional bronchoscopy. METHODS: We prospectively measured point-by-point lateral airway pressure (Plat) at multiple points from the lower lobe bronchus to the upper trachea using a double-lumen catheter in 5 patients. The site of maximal obstruction was evaluated continuously to measure point-by-point Plat at multiple points when the airway catheter was withdrawn from the lower lobe bronchus to the upper trachea. RESULTS: Remarkable pressure differences occurred at the site of maximal obstruction assessed by point-by-point Plat measurements. After initial stenting in 1 case, migration of the maximal obstruction to a nonstented segment of the weakened airway was seen with extensive stenosis from the trachea to the bronchi. In the second case, in addition to radiological analysis, point-by-point Plat measurements could identify the location of the maximal obstruction which contributed to dyspnea. CONCLUSIONS: Point-by-point Plat measurement could be used to detect the site of maximal obstruction physiologically. Furthermore, Plat measurement could assess the need for additional procedures in real time in patients with extensive airway obstruction.

Assessment of Bronchial Obstruction Using Lateral Pressure Measurement during Bronchoscopy.

BACKGROUND: In patients with bronchial obstruction estimating the location of the maximal obstruction is crucial for guiding interventional bronchoscopy. However, flow-volume curves cannot discriminate between the right and left lungs. OBJECTIVES: The aim of this study was to physiologically evaluate bronchial obstruction during interventional bronchoscopy. METHODS: We prospectively measured lateral airway pressure (Plat) at either side of the obstruction using a double-lumen catheter (pressure-pressure [P-P] curve) simultaneously to assess the degree of bronchial obstruction in 22 patients. The shape of the P-P curve was assessed to confirm the site of maximal obstruction. RESULTS: In the experimental study, Plat was uniform between both bronchi in the normal model. For the unilateral and bilateral obstruction models, a phase shift was only seen for the more obstructed side. In healthy subjects, the angle of the P-P curve was close to 45° and linear in shape. In patients with bronchial obstruction, the angle was much smaller but approached 45° after the bronchoscopic procedure. The degree of bronchial obstruction was significantly correlated with the angle of the P-P curve (r = -0.51, p < 0.01). Dyspnea significantly increased when the airway lumen was obstructed by more than 60% (p < 0.0001), and when the P-P curve appeared loop-shaped (p < 0.01). CONCLUSIONS: The shape of the P-P curve could be used to detect the site of maximal obstruction for the optimal positioning of the stent and assess the need for additional procedures in real time in patients with bronchial obstruction.

Quantitative computed tomography assessment of air trapping in relapsing polychondritis: correlations with spirometric values.

OBJECTIVE: The purpose of this study was to evaluate the relationship between quantitative computed tomography (CT) parameters of air trapping obtained with inspiratory and expiratory CT and pulmonary function tests (PFTs) in patients with relapsing polychondritis (RP). MATERIALS AND METHODS: This study included 23 patients with RP who underwent both CT and PFTs. In each patient, the mean lung density (MLD) was obtained by averaging CT attenuation of the lung parenchyma on both inspiratory and expiratory CT. The ratio of expiratory MLD to inspiratory MLD (E/I ratio) was also calculated. Correlations between those quantitative CT measurements and the results of PFTs were evaluated using Spearman rank correlation. RESULTS: The expiratory MLD and E/I ratio were significantly correlated with forced expiratory volume in 1 second (FEV1) %predicted, ratio of FEV1 to FVC (FEV1/FVC), and the mid expiratory phase of forced expiratory flow (FEF25%-75%) %predicted (expiratory MLD: FEV1 %predicted, r = 0.764, P < 0.0001; FEV1/FVC, r = 0.764, P < 0.0001; FEF25%-75% %predicted, r = 0.674, P < 0.001, respectively; the E/I ratio: FEV1 %predicted, r = -0.689, P < 0.001; FEV1/FVC, r = -0.689, P < 0.001; FEF25%-75% %predicted, r = -0.586, P < 0.01, respectively). The correlation between inspiratory MLD and PFTs did not reach statistical significance. CONCLUSIONS: In RP patients, air trapping demonstrated on expiratory CT correlated with airway obstruction. This study may assist further refinement of the use of CT as quantitative evaluation for small and large airway obstruction in RP.

Assessment of central airway obstruction using impulse oscillometry before and after interventional bronchoscopy.

BACKGROUND: Spirometry is used to physiologically assess patients with central airway obstruction (CAO) before and after interventional bronchoscopy, but is not always feasible in these patients, does not localize the anatomic site of obstruction, and may not correlate with the patient's functional impairment. Impulse oscillometry may overcome these limitations. We assessed the correlations between impulse oscillometry measurements, symptoms, and type of airway narrowing, before and after interventional bronchoscopy, and whether impulse oscillometry parameters can discriminate between fixed and dynamic CAO. METHODS: Twenty consecutive patients with CAO underwent spirometry, impulse oscillometry, computed tomography, dyspnea assessment, and bronchoscopy, before and after interventional bronchoscopy. The collapsibility index (the percent difference in airway lumen diameter during expiration versus during inspiration) was calculated using morphometric bronchoscopic images during quiet breathing. Variable CAO was defined as a collapsibility index of > 50%. Fixed CAO was defined as a collapsibility index of < 50%. The degree of obstruction was analyzed with computed tomography measurements. RESULTS: After interventional bronchoscopy, all impulse oscillometry measurements significantly improved, especially resistance at 5 Hz, which decreased from 0.67 ± 0.29kPa/L/s to 0.38 ± 0.17kPa/L/s (P < .001), and reactance at 20 Hz, which increased from -0.09 ± 0.11 to 0.03 ± 0.08 (P < .001). Changes in dyspnea score correlated with resistance at 5 Hz, the difference between the resistance at 5 Hz and the resistance at 20 Hz, and the reactance at 5 Hz, but not with spirometry measurements. The type of obstruction also correlated with dyspnea score, and showed distinct impulse oscillometry measurements. CONCLUSIONS: Impulse oscillometry measurements correlate with symptom improvements after interventional bronchoscopy. Impulse oscillometry might be useful to discriminate variable from fixed central airway obstruction. (University Hospital Medical Information Network, http://www.umin.ac.jp/english, ID000005322).

Narrow band imaging applied to pleuroscopy for the assessment of vascular patterns of the pleura.

BACKGROUND: Narrow band imaging (NBI), which enhances blood vessels, is a new endoscopic technology for diagnosing malignancies, but it has not been investigated for pleuroscopy. OBJECTIVES: To evaluate the efficacy of NBI applied to pleuroscopy for detecting malignant lesions by assessing vascular patterns of the pleura. METHODS: From May 2006 to September 2008, 45 patients with undiagnosed pleural ef-fusion underwent pleuroscopy using a pleura-videoscope with white light (WL) and NBI under local anesthesia. For this prospective study, 73 biopsy specimens were obtained from sites where images under both WL and NBI were recorded and classified regarding vascular patterns. RESULTS: Of the 73 lesions, WL showed blood vessels in 32 lesions, and NBI in 52 lesions (WL vs. NBI; p = 0.0014). The accuracy, sensitivity and specificity in the detection of irregular vascular patterns, e.g. blood vessels with irregular caliber or punctate vessels indicating malignant lesions, were 60.3, 76.5 and 55.4% in WL, and 80.8, 85.3 and 76.9% in NBI, respectively, resulting in a significant increase in NBI (p = 0.0106 for accuracy and p = 0.0494 for specificity). For flat lesions, NBI revealed a higher accuracy rate (90.6%) in the detection of irregular vascular patterns indicating malignant lesions. CONCLUSION: Our study demonstrated that NBI applied to pleuroscopy displayed blood vessels significantly better than WL. NBI was useful to detect irregular vascular patterns suggesting malignant lesions, especially for flat lesions. Therefore, NBI was considered useful in the selection of optimal biopsy sites by assessing vascular patterns.

Vibration response imaging as a new tool for interventional-bronchoscopy outcome assessment: a prospective pilot study.

BACKGROUND: In many patients, the benefit of interventional bronchoscopy cannot be appropriately objectified. OBJECTIVES: We investigated a new technique, vibration response imaging (VRI), for breathing sound mapping to determine whether it could provide additional, valuable objective qualitative and quantitative information in central airway obstruction (CAO) and patient outcome following interventional bronchoscopy. METHODS: VRI images from 83 patients with suspected central airway stenosis and 25 healthy volunteers were evaluated by two raters blinded to the subjects' status. Qualitative and quantitative dynamic and static features were documented for the final assessment of images as normal or abnormal and changes after the intervention. As a secondary goal, stenosis location was also evaluated and compared to bronchoscopic findings. Treatment outcome analysis (improved vs. not improved) was performed by comparing baseline and follow-up images in 64 evaluations of interventional bronchoscopy. VRI measurements of treatment outcome were compared to standard tests, i.e. dyspnea score, pulmonary function testing (PFT, i.e. FEV(1), FVC and FEV(1)/FVC), chest X-ray/computed tomography and bronchoscopy, the latter being considered the gold standard). RESULTS: There was 95% (115/121) agreement between raters and clinical assessment in distinguishing between normal and abnormal images. The sensitivity and specificity of VRI were 97 and 88%, respectively. The accuracy of VRI in locating the pathology compared to bronchoscopy was 85% (17/20) for tracheal and 88% (51/58) for bronchial obstruction; overall accuracy was 83%. Correct detection of the affected side in bronchial obstructions was 88%. The overall accuracy of VRI in defining the outcome of interventional bronchoscopy was 84%. CONCLUSIONS: Obstruction location and procedure outcome were reliably identified according to specific patterns of lung images. VRI proved at least as good as standard tests in locating CAO and has the potential for becoming a valuable complementary tool in evaluating treatment outcome in patients with CAO. If our results are confirmed by further studies, VRI may replace PFT or imaging procedures in cases in which such tests cannot be performed or are not readily available at the time of the intervention.

Endobronchial ultrasonography using a guide sheath increases the ability to diagnose peripheral pulmonary lesions endoscopically.

STUDY OBJECTIVE: To assess the ability of endobronchial ultrasonography (EBUS) using a guide sheath (EBUS-GS) to diagnose peripheral pulmonary lesions. METHOD: We devised a technique for EBUS-GS covering a miniature probe, and 150 lesions were evaluated in a prospective open study. In this procedure, the probe covered by a guide sheath is introduced into the lesion via the working channel of a bronchoscope. The probe is withdrawn, while the guide sheath is left in situ. A brush or biopsy forceps is introduced through the guide sheath into the lesion. RESULTS: One hundred sixteen of 150 EBUS-GS procedures (77%) were diagnostic. Cases in which the probe was located within the lesion had a significantly higher diagnostic yield (105 of 121 cases, 87%) than when the probe was located adjacent to it (8 of 19 cases, 42%) [p < 0.0001, chi(2)]. The diagnostic yield from EBUS-GS in lesions 10 to 15 to 20 to

Endobronchial ultrasonography in the assessment of centrally located early-stage lung cancer before photodynamic therapy.

To evaluate the utility of endobronchial ultrasonography (EBUS) in selecting appropriate candidates with centrally located early-stage lung cancer for photodynamic therapy (PDT) with curative intent, we performed EBUS before PDT in 18 biopsy-proven squamous cell carcinomas (including three carcinoma in situ) that had been considered to be appropriate candidates for PDT by conventional bronchoscopy and high-resolution computed tomography (HR-CT). Nine lesions were diagnosed as intracartilaginous by EBUS and subsequently PDT was performed. Long-term complete remission has been achieved in these patients with a median follow-up term after PDT of 32 months. The remaining nine lesions were diagnosed as extracartilaginous by EBUS and were considered candidates for other therapies such as surgical resection, chemotherapy, and radiotherapy, although two were invisible by HR-CT, three were superficial, and five were < or = 1 cm in diameter on observation by bronchoscopy. The depth of tumor invasion estimated by EBUS was proven to be accurate by histopathologic findings in six specimens after surgical resection. We conclude that EBUS is a useful technique that might be considered in addition to conventional bronchoscopy and HR-CT to improve the efficacy of PDT in patients with centrally located early-stage lung cancer.