AFRL supports trial of closed-loop ventilator for COVID-19 patients
Under a cooperative agreement with the University of Cincinnati (UC), the Air Force Research Laboratory’s (AFRL) 711th Human Performance Wing is supporting a first-of-its-kind clinical trial involving closed-loop control of oxygenation during mechanical ventilation. In the long-term, findings from this trial could improve ventilator technology, a key treatment tool for COVID-19 patients hospitalized with severe acute respiratory distress.
“For the medical community, closed-loop devices would cut down on exposure, but also maintain, if not elevate, the standard of care [provided to patients],” said Dario Rodriquez, Jr, a senior research health science officer with the 711 HPW and a registered respiratory therapist. “This technology would reduce the time healthcare workers spend with patients adjusting ventilator settings.”
While this type of mechanical ventilator is not available on the US market, the technology is of great interest amid the current pandemic as hospitals treat patients with COVID-19. With closed-loop control oxygen, automatic adjustments are quicker than manual changes. Additional benefits include fewer instances of unnecessary oxygen delivery and fewer patients experiencing oxygen deficiencies.
Rodriquez, who also serves as the director of clinical research within UC’s Division of Trauma/Critical Care, said that a closed-loop system functions similarly to a thermostat, which regulates temperature by turning on the air conditioner or the heater to maintain the desired setting inside a home.
“Closed-loop ventilators do not employ artificial intelligence," he said. "Essentially, these devices incorporate an automated rule set by [clinicians] based on the desired parameters for a patient.”
The ventilator automatically adjusts the oxygen level that a patient requires based on a signal from a pulse oximeter, a finger probe that measures relevant levels in the blood. The system works as follows: an acceptable range for the patient’s oxygen saturation is set. Then, based on a signal that the pulse oximeter gives, if the reading goes above that number, the ventilator automatically brings the oxygen level down. However, if the level falls too low, it automatically instructs the ventilator, through an algorithm, to increase oxygen delivery.
The first trial, led by 711 HPW and UC researchers, began in 2006 and focused on the IMPACT 754 Ventilator. After acquiring IMPACT Instrumentation Inc., ZOLL Medical produced a new device, the ZOLL 731 EMV+. Rodriquez explained that the US Food and Drug Administration (FDA) required additional data on the new device since the technology had changed.
Rodriquez said that the latest trial aims to secure enough patients to provide efficacy and safety data so that ZOLL Medical can submit the trial data to the FDA. To date, the latest trial has reached 88% enrollment, with data collected from 184 patients.
Participating hospitals use these devices only on patients who consent to be part of the trial, which is permissible under an investigational device exemption, issued by the FDA for medical devices. As the host center, UC partnered with the University of Texas Health Science Center-Houston; Los Angeles County Medical Center, affiliated with the University of Southern California; and Regions Hospital in St Paul, Minnesota.
The research team he leads is also looking for other university or corporate scientists with experience developing a similar system that would allow full closed-loop oxygen control. Rodriquez said two closed-loop control devices exist outside of the US, including a device made by a European company and one for noninvasive approaches from Canada.
AFRL’s 711 HPW has a significant and long-standing partnership with UC researchers from various disciplines and departments working together under cooperative agreements. The Department of Surgery within the UC College of Medicine oversees this particular project.
Read more: https://afresearchlab.com/news/afrl-supports-study-of-advanced-ventilati...