A rapidly deployable individualized system for augmenting ventilator capacity

Abstract

Strategies to split ventilators to support multiple patients requiring ventilatory support have been proposed and used in emergency cases in which shortages of ventilators cannot otherwise be remedied by production or procurement strategies. However, the current approaches to ventilator sharing lack the ability to individualize ventilation to each patient, measure pulmonary mechanics, and accommodate rebalancing of the airflow when one patient improves or deteriorates, posing safety concerns to patients. Potential cross-contamination, lack of alarms, insufficient monitoring, and inability to adapt to sudden changes in patient status have prevented widespread acceptance of ventilator sharing. We have developed an individualized system for augmenting ventilator efficacy (iSAVE) as a rapidly deployable platform that uses a single ventilator to simultaneously and more safely support two individuals. The iSAVE enables individual-specific volume and pressure control and the rebalancing of ventilation in response to improvement or deterioration in an individual’s respiratory status. The iSAVE incorporates mechanisms to measure pulmonary mechanics, mitigate cross-contamination and backflow, and accommodate sudden flow changes due to individual interdependencies within the respiratory circuit. We demonstrate these capacities through validation using closed- and open-circuit ventilators on linear test lungs. We show that the iSAVE can temporarily ventilate two pigs on one ventilator as efficaciously as each pig on its own ventilator. By leveraging off-the-shelf medical components, the iSAVE could rapidly expand the ventilation capacity of health care facilities during emergency situations such as pandemics.

Rapid Ventilator Splitting During COVID-19 Pandemic Using 3D Printed Devices and Numerical Modeling of 200 Million Patient Specific Air Flow Scenarios

“…COVID-19 has brought renewed interest[ 12 ] and innovation[ 10 ], [ 13 ] in ventilator sharing, which has applications in future respiratory outbreaks, the battlefield, and in low resource ICU settings, as well as during the current global pandemic. However, current advances in ventilator splitting still require careful patient matching[ 14 ] or the use of complex medical equipment[ 10 ] that might not be feasible in all cases. The VSRS system implements simple 3D printed components that can be readily created in locations with a 3D printer and shipped to nearby hospitals, as well as a free mobile app that removes the guess work from pairing patients and determining what resistor size to use.…”

“…Ventilator splitting has been introduced as a strategy to support multiple patients on the same ventilator and has been implemented at a number of institutions during dire situations [5]- [7]. Recent advances, such as the addition of resistors [8], clamps [9], and valves [10], has allowed ventilator splitting to be useful for carefully matched patients [7]. However, ventilator splitting remains unable to be safely and rapidly implemented for patients with significantly differing pulmonary compliances [9] or minute ventilation requirements [10], as this could lead to volutrauma, barotrauma, and/or hypoventilation of one or both of the patients.…”

“…Recent advances, such as the addition of resistors [8], clamps [9], and valves [10], has allowed ventilator splitting to be useful for carefully matched patients [7]. However, ventilator splitting remains unable to be safely and rapidly implemented for patients with significantly differing pulmonary compliances [9] or minute ventilation requirements [10], as this could lead to volutrauma, barotrauma, and/or hypoventilation of one or both of the patients. Concerns related to the safety of ventilator splitting has prevented it from being recommended as a general solution for ventilator shortages in the most extreme of circumstances [11].…”

Fixed-time descriptive statistics underestimate extremes of epidemic curve ensembles

“…As a more general approach to the issues associated with fixed-time statistics as a summary of ensembles, we note that the expectation and probability distribution of any scenario can be explicitly evaluated by counting how often they occur in the ensemble of curves. For example, consistent large numbers of hospitalized patients for long periods places a serious burden on healthcare systems 11,12 . If half of the simulated curves predict that hospitals will get at least 300 new patients every day for at least 20 consecutive days, and all curves are considered equally likely, the probability of this scenario is estimated to be 50%.…”

Ventilator Sharing: The Good, the Bad, and the Ugly

“…This allowed them to successfully deliver similar ventilation to each simulated lung during volume control or pressure control ventilation. Srinivasan et al 11 developed a system for individualized shared ventilation using flow control valves, one-way valves, PEEP valves, and filters; they were able to successfully ventilate 2 pigs with shared ventilation using this system. Han et al 12 Through these studies and anticipated clinical applications, it has become clear that to successfully support multiple patients with a single shared ventilator requires either the patients to have similar respiratory mechanics or the ventilator circuit to be altered to distribute volume and pressure differently to each patient.…”