Raemer D B, Ji X B, Topulos G P
Department of Anesthesia, Massachusetts General Hospital, Boston 02114, USA.
J Clin Monit. 1997 Mar;13(2):91-101. doi: 10.1023/a:1007384122804.
To develop an instrument to help prevent pulmonary O2 toxicity, a syndrome that manifests itself in adult intensive care patients.
We designed, built, and tested a device that controls FIO2 exposure using oxygen saturation measured with a pulse oximeter (SpO2) in a negative feedback control system. A target SpO2 is designated by the clinician and the system adjusts the FIO2 from a mechanical ventilator so as to minimize the difference between the measured SpO2 and the target. Important elements of the system include a conservative artifact rejection algorithm, a gainscheduled sampled-data proportional-integral-derivative (PID) controller, and a safety system to prevent inspired mixtures with undesirably low FIO2 due to device failure.
The control system was tuned in a series of animal experiments. Acceptable clinical response of the system was obtained using a gain-scheduled controller algorithm whereby the gain of the proportional term of a PID controller was adjusted based on the error signal and measured minute ventilation. Also, the artifact rejection algorithm and safety systems were successfully tested using simulation.
Testing the effectiveness of this instrument will require comparison with manual control of FIO2 in an appropriately designed trial.
开发一种有助于预防肺氧中毒的仪器，这种综合征在成人重症监护患者中表现出来。
我们设计、制造并测试了一种装置，该装置在负反馈控制系统中使用脉搏血氧仪测量的血氧饱和度（SpO2）来控制吸氧浓度（FIO2）暴露。临床医生指定目标SpO2，系统会调整机械通气机的FIO2，以尽量减小测量的SpO2与目标值之间的差异。该系统的重要组成部分包括保守的伪差剔除算法、增益调度采样数据比例积分微分（PID）控制器以及一个安全系统，以防止因设备故障导致吸入的混合气FIO2过低。
该控制系统在一系列动物实验中进行了调试。使用增益调度控制器算法获得了系统可接受的临床反应，即根据误差信号和测量的分钟通气量调整PID控制器比例项的增益。此外，伪差剔除算法和安全系统通过模拟成功进行了测试。
要测试该仪器的有效性，需要在适当设计的试验中与FIO2的手动控制进行比较。
