Critical Care Medicine, National Center for Child Health and Development, Tokyo, Japan.
Department of Intensive Care Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Int J Chron Obstruct Pulmon Dis. 2021 Feb 12;16:301-304. doi: 10.2147/COPD.S296343. eCollection 2021.
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.
虽然慢性阻塞性肺疾病（COPD）的病理生理学是多因素的，但中央气道塌陷被报道对症状严重程度有很大影响。在 COPD 患者中，由于呼气起始时快速呼气流速导致的气道内静态压力的负向变化和过度充气的肺压迫气管壁形成的正压使气管塌陷。这一现象可以用流体动力学理论来解释。我们的假设是，专注于最小化呼气流速的通气策略可能对接受 COPD 机械通气的患者有利。如果能够在呼气时施加适当的对抗压力，患者可能能够以较低的呼气流速缓慢呼气，从而防止气道内静态压力的负向变化。我们设计了一种新的通气模式“最小化呼气流速通气（MExV）”，它在呼气时施加调节后的对抗压力。显示了包括流量、容量和气道压力在内的“最小化呼气流速通气”的概念性波形，并与传统通气模式的典型波形进行了比较。
