Iotti G A, Braschi A
Rianimazione 1, I.R.C.C.S, Policlinico S. Matteo, Pavia, Italy.
Respir Care Clin N Am. 2001 Sep;7(3):441-64, ix. doi: 10.1016/s1078-5337(05)70043-5.
Conventional mechanical ventilation modes fail to provide a setting for direct control of a patient's ventilatory effort; however, with all modes clinicians may manipulate conventional controls to modulate the spontaneous respiratory activity of the patient. For instance, during pressure support ventilation the spontaneous respiratory activity can be decreased by increasing the pressure support level to achieve an adequate residual load for the respiratory muscles of the patient, neither too high nor too low. This choice is based on the clinical observation. A closed-loop controller can be envisaged to accomplish automatically, precisely, and on a breath-by-breath basis, this difficult task. The closed-loop controller should be based on the continuous and possibly noninvasive monitoring of a parameter that quantitatively reflects the patient's effort for ventilation. Occlusion pressure at 0.1 second (P0.1) can be the ideal parameter for that purpose. The authors have designed a noninvasive method for breath-by-breath monitoring of P0.1, and then a closed-loop control mode that automatically adapts the pressure support level to reach and maintain a user-set P0.1 and alveolar volume. This article discusses features and performance of this P0.1 control mode, fields of application, known limits, and possible future improvements.
传统的机械通气模式无法提供直接控制患者通气努力的设置；然而，在所有模式下，临床医生都可以通过操作传统控制装置来调节患者的自主呼吸活动。例如，在压力支持通气期间，可以通过增加压力支持水平来降低自主呼吸活动，从而为患者的呼吸肌实现适当的残余负荷，既不过高也不过低。这种选择基于临床观察。可以设想一种闭环控制器，以便在逐次呼吸的基础上自动、精确地完成这项艰巨任务。闭环控制器应基于对定量反映患者通气努力的参数进行连续且可能无创的监测。0.1秒时的阻断压力（P0.1）可能是用于此目的的理想参数。作者设计了一种用于逐次呼吸监测P0.1的无创方法，然后设计了一种闭环控制模式，该模式可自动调整压力支持水平，以达到并维持用户设定的P0.1和肺泡容积。本文讨论了这种P0.1控制模式的特点和性能、应用领域、已知局限性以及可能的未来改进。
