Respiratory Pressure and Flow Data Collection Device Providing a Framework for Closed-Loop Mechanical Ventilation
Description
Patient response to mechanical ventilation is highly variable, and not patient specific. Furthermore, current weaning best-practice relies on clinical experience which can lead to variability and inequity in both care and health outcomes. This device offers a framework through which personalized mechanical ventilator support can be established. This device offers improvements on previous respiratory data collection devices. This design of this device is optimized for the invasive mechanical ventilation use case, with improved data resolution and equally high-quality inhalation and exhalation measurements. Furthermore, this device is integrated into a framework that provides freedom to implement a closed-loop control system for mechanical ventilation. Systems such as hysteresis loop analysis and rapid exhalatory occlusion can be implemented to form a digital twin model. Therefore, digital twin models can be both designed and tested within this framework, improving development workflows. This device is formed from two 3D printed custom Venturis that measure pressure data in collaboration with two ESP32-S3 development boards, integrated with custom printed circuit boards. The digital twin framework is implemented in Microsoft Excel. Overall, this device allows the future development and validation of personalised mechanical ventilation treatment.
Files
Steps to reproduce
1. Place an order for the printed circuit boards and appropriate parts for population (Control PCB, Gauge PCB and Sensor PCBs). With manufacturing and shipping times this step is often slow so it should be completed first. The differential pressure sensors should also be ordered at this time. 2. Populate the PCBs in accordance with the Altium project files. To populate the PCBs solder on the capacitors, resistors, female wire connectors and sensors. Solder female socket headers into the through holes for the ESP32, before mounting it. 3. If a switch with LED is not available, a basic Switch, LED, and 3POS MOLEX Female Connector can be wired together to act in a similar manner. 4. Print the Housing Top and Housing Base on the same print plate. The parts were printed in PLA on a BambuLab Printer with automatic tree support and an extra fine layer height of 0.08 mm. All other 3D printed parts should be printed on a separate plate, with normal support and a layer height of 0.12 mm. 5. Remove support material from components and attach barbs to venturis and y-piece using biocompatible resin. Remove membrane from Hudson One-Way Valve and attach to 3D printed One-way Valve. Insert into Y-piece and Inhalatory Venturi with membrane facing out. Tap the four small holes on each of Housing Top and Housing Base with a M3 x 0.5 mm tap. 6. Connect inhalatory and exhalatory venturis. The inhalatory barbs should lay in the horizontal plane. The exhalatory barbs should be at a 45o angle down from the horizontal and the Y-piece barb should face directly downwards. 7. Connect the inhale and exhale Sensor PCBs to the Control PCB using 3-pin connectors. Connect the Gauge PCB to the Control PCB using the 4-pin connector. 8. Attach a short length of Silicone Tubing to the sensor ports. The lengths are dependent on the positioning of each sensor and should be adjusted by trial. Each sensor has two ports, one that sits higher than the other. The higher port should be connected to the low-pressure barbs of the venturis and the Y-piece barb from each of their three respective sensors. The lower port should connect to the high-pressure barb on the venturis. The lower port on the gauge sensor should be left disconnected. Figure 8 shows the connection of all components within the device, spaced out for clarity. 9. Attach the Gauge Sensor PCB to the Base Plate using M2 screws. Attach Control PCB to the 3D printed Base Plate with M3 screws. Leave the inhale and exhale Sensor PCBs loose. Do not attach the Switch, LED and 3POS MOLEX Connector at this stage. 10. Slide Base Plate into Housing Base and connect the Switch and LED. Align Inhalatory Venturi, Exhalatory Venturi and Y-piece above the system and connect the end of the silicone tube to the free barbs. 11. Attach Housing Top to Housing Base and insert 4 M3 grub screws into the tapped holes to secure the external housing shut. Refer to the README.md file for operation instructions.
Institutions
- University of Canterbury