需要机械通气的患者通常存在严重的呼吸力学异常。应用机械通气时，首先需要对基础疾病的呼吸力学异常进行评估，然后根据相应的特点应用机械通气。通过合理应用吸气和呼气相压力、呼吸流量、容量和时间节律，调控相关患者的呼吸努力、吸气末与呼气末的肺容量位置和呼吸中枢驱动，达到优化机械通气应用的目的。急性呼吸窘迫综合征（acute respiratory distress syndrom，ARDS）作为肺氧合功能异常性疾病的代表，其机械通气的主要目标是维持肺的开放与氧合功能，避免肺过度牵张与呼吸机相关肺损伤。慢性阻塞性肺疾病作为气流受限性疾病的代表，其机械通气的主要目标是维持合适的通气的同时，避免导致肺动态过度充气和内源性呼气末正压的进一步恶化，调控合适的呼吸中枢驱动水平。临床日常工作中常态化开展呼吸力学监测，对优化机械通气应用有重要的意义。

Abnormalities of respiratory mechanics are commonly present in patients who require mechanical ventilation. Monitoring and evaluating respiratory mechanics is the first step in mechanical ventilation. An appropriate manipulation of inspiratory pressure, expiratory pressure, inspiratory flow, tidal volume, and cycling, as well as patient?s respiratory effort, lung volume at end of inspiration and expiration, should be adjusted according to the patient?s respiratory mechanic abnormalities. ARDS is characterized of severe oxygenation disorder. The main targets of mechanical ventilation for ARDS patients are to open the lung and to keep the lung open, thus improving oxygenation while avoiding the over-distension of the lungs and ventilator induced lung injury (VILI). Chronic obstructive pulmonary disease (COPD) is characterized of expiratory flow restriction. The main targets of mechanical ventilation for COPD patients are to ensure adequate ventilation while avoiding dynamic hyperinflation and increase of intrinsic PEEP, as well as keeping respiratory drive appropriate. Monitoring respiratory mechanics in a daily clinical practice is crucially important for optimization of mechanical ventilation.