Physiologic-range three/two-way valve for respiratory circuits.

A 3D-printed three/two-way valve compatible with respiratory circuits is presented. It is actuated by a servo motor (HXT12K), which is able to be controlled by any PWM-capable micro controller. The valve sufficiently isolates respiratory circuits to deliver fully customisable mechanical ventilation breathing cycles, with differences in driving and end-expiratory pressures of up to successfully demonstrated. It is suitable for multiplexing ventilators for in-series breathing, or providing separate ventilation to each individual lung in a single patient. Each switching valve costs approximately $16USD, $10 of which is the servo motor which can be reused, allowing subsequent devices for only $6USD of 3D printing and common engineering components. The valve has proven reliable for at least 50,000 state changes over at least one month.