Abstract
EDAC is defined by an abnormal expiratory reduction of the tracheal lumen leading to an elevation of airflow resistance. No data supports the clinical threshold of 50% closure. The aim of our study was to develop an experimental model of EDAC in order to assess the consequences of airway collapse on the work of breathing (WOB) and evaluate the impact of CPAP.
We have modelled and manufactured a realistic 3D silicon trachea and a static compression system to simulate tracheal collapse. The trachea was linked to a dummy head with realistic upper airways and to an artificial lung (ASL 5000, IngMar Medical) which simulated tidal breathing (TB) from three lung models (normal, COPD and restrictive). We simulated tracheal compressions (length 4 or 8 centimeters, closure of 0,31,49,63 and 87%) at rest and on exercise, without and with CPAP (PEP 5, 10, 15 and 20cmH2O). We measured pressure on both sides of collapse and computed expiratory resistance Rexp, flow Qexp and pressure time product (PTPexp which reflects WOB).
There was a significant impact of the degree of collapse on Rexp, Qexp and PTPexp for a closure ≥49%. During TB, median Rexp was 8,05 [6,60;9,90]cmH2O.s/L at 87% collapse versus 0,12 [0,11;0,14]cmH2O.s/L without collapse (p<0,001). Rexp and PTPexp were also correlated with the length of stenosis (respectively rho=0,38, p=0,004 and rho=0,34, p=0,012). All indicators were different between rest and exercise (p=0,001). At 87% collapse, the average PTPexp was 80,2±35,8 cmH2O.s during TB versus 0,8±0,6 cmH2O.s if the collapse was corrected by a 5 cmH2O PEP.
Our experimental model supports the 49% closure threshold associated with significant consequences on WOB.
Footnotes
Cite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA3219.
This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2021