A new methodology for intra-breath control of mechanical ventilation

Recent improvements in digital control strategies are driving the implementation of innovative pulmonary ventilation modalities able to support the physician in the intensive care through a better management of the patient's respiratory pathologies. New control strategies, such as intra-breath ones, which guarantee successful patient-machine synchronization and dynamic adjustment to the patient, still require improvements in the control of the breathing process. Such improvements can be achieved by decreasing the response time of the actuation system driving the mechanical ventilators. This paper presents a new methodology of intra-breath control to generate traditional and high frequency ventilation techniques. The methodology is implemented through a custom-developed electro-mechanical system, which consists of on/off solenoid valves driven by a fast switching driver circuit. In vitro experimental trials show the system's ability to generate almost continuous flow-rate patterns in different shapes, a time resolution down to 20 ms, flow-rate resolution of 1L/min, and repeatability of 0.5L/min. Experimental results show that the proposed electro-mechanical system can be used as a stand-alone hardware solution for both intra-breath control techniques and high frequency ventilation.