Schönhofer B, Mang H, Köhler D
Krankenhaus Kloster Grafschaft, Zentrum für Pneumologie und Allergologie, Schmallenberg-Grafschaft.
Anasthesiol Intensivmed Notfallmed Schmerzther. 1995 Nov;30(7):403-11. doi: 10.1055/s-2007-996517.
Long-term mechanical ventilation implies a significant number of weaning failures. The basis of this unweanability is chronic fatigue of the inspiratory muscles which is due to depletion of energy store (e.g. glycogen). Considering this pathophysiological principle, the decisive therapeutic option during weaning from long-term mechanical ventilation consists of resting the respiratory muscles. The commonly used assisted ventilation modes only partially relieve the respiratory muscles because the work of breathing is done both during the trigger phase and during the inspiratory cycle. The essential characteristic of our weaning concept includes the repeated determination of the spontaneous breathing frequency in awake patients, which is followed by controlled intermittent positive pressure ventilation with a slightly higher respiratory rate. Ideally, this results in total suppression of the activity of the breathing centre, and in subsequent relief and recovery of the respiratory muscles by replenishing the energy stores. The close succession of relief and training periods avoids inactivity-induced atrophy of the respiratory muscles and permits regeneration. Additionally, our weaning concept avoids increases in inspiratory work during the phases of spontaneous breathing. This means that high-resistance small-caliber endotracheal tubes have to be replaced by large tubes. Moreover, transtracheal oxygen insufflation during spontaneous breathing decreases anatomic dead space. This reduces minute ventilation and, therefore, the work of breathing. In patients still exhibiting chronic fatigue of the respiratory muscle pump after successful weaning, intermittent home ventilation is initiated via a breathing mask. Apart from the concept described above, successful weaning from the respirator after long-term ventilation is based upon dedicated patient care and depends on the architectural characteristics of the intensive care unit.
长期机械通气意味着大量撤机失败。这种无法撤机的根本原因是吸气肌慢性疲劳，这是由于能量储备（如糖原）耗竭所致。考虑到这一病理生理原理，长期机械通气撤机过程中的决定性治疗选择是让呼吸肌休息。常用的辅助通气模式只能部分减轻呼吸肌负担，因为呼吸功在触发阶段和吸气周期都存在。我们撤机理念的基本特征包括反复测定清醒患者的自主呼吸频率，随后以略高的呼吸频率进行控制性间歇正压通气。理想情况下，这会导致呼吸中枢活动完全受抑制，随后通过补充能量储备使呼吸肌得到缓解和恢复。缓解期和训练期紧密衔接可避免因不活动导致的呼吸肌萎缩并促进再生。此外，我们的撤机理念可避免自主呼吸阶段吸气功增加。这意味着必须将高阻力小口径气管插管更换为大口径插管。而且，自主呼吸时经气管给氧可减少解剖死腔。这会降低分钟通气量，从而减少呼吸功。对于成功撤机后仍存在呼吸肌泵慢性疲劳的患者，通过呼吸面罩启动间歇性家庭通气。除上述理念外，长期通气后成功脱离呼吸机还基于专门的患者护理，并取决于重症监护病房的结构特点。
