International Journal of COPD (Feb 2021)
The Ventilatory Strategy to Minimize Expiratory Flow Rate in Ventilated Patients with Chronic Obstructive Pulmonary Disease
Abstract
Norihiko Tsuboi,1 Kaoru Tsuboi,1 Nobuyuki Nosaka,1,2 Nao Nishimura,1 Satoshi Nakagawa1 1Critical Care Medicine, National Center for Child Health and Development, Tokyo, Japan; 2Department of Intensive Care Medicine, Tokyo Medical and Dental University, Tokyo, JapanCorrespondence: Norihiko TsuboiCritical Care Medicine, National Center for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, JapanTel +81-334160181Fax +81-224162222Email [email protected]: Although the pathophysiology of chronic obstructive pulmonary disease (COPD) is multifactorial, central airway collapse is reported to have a great impact on symptom severity. In COPD patients, positive pressure formed by hyperinflated lungs compressing the tracheal wall and negative changes in intratracheal static pressure due to rapid expiratory flow velocity at the beginning of expiration collapse the trachea. This phenomenon can be explained by fluid dynamics theory. Our hypothesis is that ventilatory strategy focusing on minimization of expiratory flow rate may be advantageous for patients receiving mechanical ventilation for COPD. If appropriate counter pressure could be applied on exhalation, patients may be able to exhale slowly with reduced expiratory flow rates which may prevent negative changes of the intratracheal static pressure. We devised a new conceptual ventilation mode “minimized expiratory flow rate ventilation (MExV)” which applies regulated counter pressure on exhalation. The conceptual waveforms of “minimized expiratory flow rate ventilation” including flow rate, volume, and airway pressure are shown, compared with typical waveforms of the conventional ventilation modes.Keywords: COPD, tracheomalacia, fluid dynamics, minimized expiratory flow rate ventilation, flow-controlled ventilation
