Validation and pilot clinical study of a new bronchoscopic method to measure collateral ventilation before endobronchial lung volume reduction

• Published in: Journal of applied physiology (1985) Vol. 106; no. 3; pp. 774 - 783
• Main Authors: Aljuri, Nikolai, Freitag, Lutz
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.03.2009; American Physiological Society
• Subjects: Adaptation, Physiological - physiology; Airway Resistance; Biological and medical sciences; Bronchoscopy; Clinical medicine; Emphysema; Female; Fundamental and applied biological sciences. Psychology; Humans; Lungs; Male; Methods; Middle Aged; Minimally Invasive Surgical Procedures; Pilot Projects; Pneumonectomy - instrumentation; Pneumonectomy - methods; Prostheses and Implants; Pulmonary Atelectasis - diagnostic imaging; Pulmonary Atelectasis - etiology; Pulmonary Atelectasis - physiopathology; Pulmonary Emphysema - diagnostic imaging; Pulmonary Emphysema - physiopathology; Pulmonary Emphysema - therapy; Respiratory Function Tests; Respiratory Mechanics; Respiratory System - diagnostic imaging; Respiratory System - physiopathology; Tomography, X-Ray Computed; Treatment Outcome; Validation studies; Human; Pilot; Validation; Lung disease; Respiratory disease; minimally invasive; collateral resistance; Respiratory system; Lung volume; Vertebrata; Absorption; Mammalia; Atelectasis; Bronchus disease; patient selection; Obstructive pulmonary disease; Pulmonary ventilation; Respiration; absorption atelectasis; Emphysema
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.91075.2008

1 Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts; and 2 Institute for Experimental Pneumology, Lungenklinik Hemer, Hemer, Germany Submitted 10 August 2008 ; accepted in final form 21 November 2008 Endobronchial lung volume reduction (ELVR) may be helpful in a selected group of patients with advanced stages of emphysema. However, collateral ventilation (CV) from adjacent lobes through collateral channels often prevents target lobe atelectasis, which presumably mediates clinical responses after ELVR. With the goal of identifying patients who are more or less likely to benefit, we propose endobronchial CV assessment (ECVA), a novel catheter-based endobronchial approach, to quantitatively determine the resistance of collateral channels ( R coll ). ECVA relies on the measurement of spontaneous airflow from the sealed and isolated target compartment during spontaneous respiration in an awake subject, thereby providing a direct, simple, and minimally invasive method of assessing R coll in lungs. In this study, we validated ECVA in a controlled laboratory setup and tested ECVA's clinical feasibility in 11 emphysematous human subjects undergoing ELVR treatment. To evaluate ECVA in a controlled laboratory setup with known CV levels, we built a benchtop model mimicking a simple one-compartment model of the lungs during temporary compartmental occlusion and spontaneous respiration, which could be adapted to hold restrictors of different sizes representing collateral airways, and applied ECVA to estimate the resistance of various benchtop model restrictors. We then rated ECVA's performance by direct comparison between estimated and actual restrictor resistance and found a correlation coefficient near one. To test ECVA's clinical performance, post-ELVR radiological assessments were made to determine the occurrence of atelectasis in the treated lobe, and interlobar R coll was estimated in the target lobe via ECVA pre-ELVR. ECVA could be completed in all patients with no adverse events, and a high R coll by ECVA predicted absorption atelectasis following ELVR ( P = 0.005). We believe that ECVA may be helpful to distinguish those patients with and without interlobar CV by identifying the critical value of R coll above which atelectasis is likely to occur. collateral resistance; minimally invasive; emphysema; absorption atelectasis; patient selection Address for reprint requests and other correspondence: N. Aljuri, Massachusetts Institute of Technology, 45 Carleton St., E25-335, Cambridge, MA 02142