The coronavirus (COVID-19) pandemic has caused a surge of patients requiring mechanical ventilation in Intensive Care Unit (ICU) rooms. Consequently, the units now require increased staffing of trained respiratory therapists in addition to more ventilators. Every small change on a ventilator requires staff to enter a patient room, which risks potential exposure, and to frequently change personal protective equipment.
However, a collaboration between the Hopkins Hospital, Laboratory for Computational Sensing and Robotics and the University of Maryland led to the innovation of a robotic system to remotely control ventilators in COVID-19 patient rooms.
The robotic system is secured to the ventilator on a horizontal bar spanning the top of the ventilator touch screen. Two vertical bars are also attached, allowing a stylus to move in all directions across the screen. A camera captures an image of the current screen and sends it to the operating tablet, which can be used to control the robot outside of patient rooms. The respiratory therapist simply has to tap a screen and the robot will travel to that position on the screen of the ventilator.
Axel Krieger, a Hopkins assistant professor in the Department of Mechanical Engineering, was one of the team members who worked on the project.
In an email to The News-Letter, Krieger explained how the idea to use a robot to control ventilators originated from Zoom calls with frontline health-care workers like Dr. Sarah Murthi, a doctor in the University of Maryland Medical System who specializes in critical care medicine.
“Dr. Murthi showed us pictures of her ICU bay. She presented the difficult problem that nurses and respiratory techs must enter contaminated areas to make simple adjustments to equipment such as ventilators or infusion pumps,” Krieger wrote.
Over the next few months, Mikhail Khrenov, a University of Maryland computer science graduate student, and Balazs Vágvölgyi, a Hopkins research scientist, worked to develop the robotic system prototype.
Khrenov explained in an email to The News-Letter how two distinct system designs were originally considered. One design included the use of a Six Degree of Freedom (6-DoF) robotic arm, which would closely mimic a human hand operating the ventilator. However, the current system is a Cartesian robot fixed directly on the screen.
“The 6-DoF concept was appealing in that it in theory allows for greater flexibility,” Khrenov wrote. “It posed far greater challenges for the quick implementation that was necessary for this project to be of use for the COVID pandemic.”
In addition to considering how the robot would be implemented in ICU rooms, the team prioritize efficiency, weight and cost. They also evaluated how the robot could be sanitized in the future.
After carefully planning the design of the robot, Khrenov built the first working prototype in his basement. In April, due to strict COVID-19 research restrictions enforced by the University, Khrenov printed the parts on a consumer-grade FDM 3D-Printer (Prusa MINI) and bought stock components such as linear rods and motors.
Vágvölgyi, who helped build the prototype, worked on the robot’s controller algorithm. In an email to The News-Letter, he explained that the algorithm accounts for any possible errors the robot could make.
“I added an automatic error correction algorithm in the robot controller method, that tracks the position of the robot’s pointer in the camera image and if the pointer is not pointing accurately to the expected position, then it corrects the error by moving the robot to the right position,” Vágvölgyi wrote.
After creating a prototype, the robot moved into the testing phase. However, since ventilators were in short stock testing opportunities were limited. The system was eventually tested on a ventilated mannequin in the Hopkins Hospital’s Biocontainment Unit. Jonathan Cope, a respiratory therapist, operated the robot.
Cope used his expertise in mechanical ventilators to guide the design of the prototype.
“I was pleasantly surprised with the accuracy of the prototype in moving the stylus to where we tapped on the remote screen,” Cope wrote in an email to The News-Letter.
This groundbreaking project will unquestionably impact the safety and staffing of respiratory therapists in the future.
“With the ability to remotely control a ventilator from outside a patient room, we can save significant time and resources.” Cope said. “This robotic system has the potential to be a force multiplier for bedside clinicians to provide timely, detailed care to a larger number of patients.”
The team is currently working on making the robot more robust and adaptable to ventilators without touch screens. The robot will soon be tested in a clinical setting with real patients.