Fouke J M, Wolin A D
Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106.
Crit Care Med. 1989 Mar;17(3):265-8. doi: 10.1097/00003246-198903000-00013.
For patients requiring PEEP during ventilation, e.g., patients with respiratory distress syndrome, performing traditional tests of lung function is a complicated problem. The pulmonary mechanics of these patients can change rapidly with potential for a negative impact on oxygenation. In an effort to address these problems, we designed a system with a three-way valve that permits the patient to be switched from the ventilator to a data collection system for the assessment of changes in the disease state. The short periods required for data collection (20 to 30 sec) do not interfere with patient care and are well within the limits of safety. A unique feature of the valved system is that it serves to maintain positive airway pressure during data collection. Tests show that, within the frequency range of interest, the mechanics of the measurement system are not altered by the DC pressures applied to the speaker and the valve itself does not contribute significantly to the serial impedance of the system.
对于通气期间需要呼气末正压（PEEP）的患者，例如患有呼吸窘迫综合征的患者，进行传统的肺功能测试是一个复杂的问题。这些患者的肺力学可能会迅速变化，对氧合产生潜在的负面影响。为了解决这些问题，我们设计了一个带有三通阀的系统，该系统允许将患者从呼吸机切换到数据采集系统，以评估疾病状态的变化。数据采集所需的短时间（20至30秒）不会干扰患者护理，并且完全在安全范围内。带阀系统的一个独特之处在于，它在数据采集期间有助于维持气道正压。测试表明，在感兴趣的频率范围内，施加到扬声器的直流压力不会改变测量系统的力学性能，并且阀门本身对系统的串联阻抗贡献不大。
