Ellmauer S, Rindfleisch F, Landauer B
Abteilung für Anaesthesiologie und Operative Intensivmedizin, Städtisches Krankenhaus München-Bogenhausen.
Anaesthesist. 1993 Jul;42(7):470-2.
During aorto-coronary bypass surgery acute expiratory airway obstruction occurred in two patients during controlled ventilation with a Servo D ventilator (Siemens Elema) in combination with a Servo EVAC 180 gas evacuation system. In this system expiratory volume passes from the ventilator to the reservoir bag. Distension of the bag will open the valve to the receiving unit by vertical dislocation of the valve spring. The mechanism relies on free mobility of the valve spring within the reservoir bag. We observed an increase in mean expiratory and inspiratory airway pressure above 40 mmHg due to blockage of the expiratory gas outlet by external lateral dislocation of the valve spring. In conclusion, while free mobility of the valve spring within the hanging Evac bag has to be ascertained at all times for safe application of the EVAC 180 system, the manufacturer should provide some appropriate mechanical shelter around the bag.
在主动脉冠状动脉搭桥手术期间，两名患者在使用Servo D呼吸机（西门子Elema）联合Servo EVAC 180气体排出系统进行控制通气时发生了急性呼气气道梗阻。在该系统中，呼气量从呼吸机传至贮气囊。贮气囊膨胀会通过阀弹簧的垂直移位打开通向接收装置的阀门。该机制依赖于阀弹簧在贮气囊内的自由移动。我们观察到，由于阀弹簧向外侧移位导致呼气气体出口堵塞，平均呼气和吸气气道压力升高至40 mmHg以上。总之，为了安全应用EVAC 180系统，必须始终确保阀弹簧在悬挂的Evac贮气囊内能够自由移动，同时制造商应在贮气囊周围提供一些适当的机械防护措施。
