The MADVent Ventilator

The COVID-19 pandemic has produced critical shortages of ventilators worldwide.

There is an unmet need for rapidly deployable, emergency-use ventilators with sufficient functionality to manage COVID-19 patients with severe Acute Respiratory Distress Syndrome. We have developed and validated a simple, portable, and low-cost ventilator that may be rapidly manufactured with minimal susceptibility to supply chain disruptions. This single-mode continuous, mandatory, closed-loop, pressure-controlled, time-terminated emergency ventilator offers robust safety and functionality absent in existing solutions to the ventilator shortage. Validated using certified test lungs over a wide range of compliances, pressures, volumes and resistances to meet U.S. Food and Drug Administration standards of safety and efficacy, an Emergency Use Authorization is in review for this system.

Recently accepted in Wiley's Medical Devices & Sensors (DOI: 10.1002/mds3.10106), the details of the ventilator are provided below; the capabilities are summarized here.

### Advantages of our approach

Our ventilator design offers novel advantages over the current panoply of commercial, emergency-use FDA-approved, and FDA-unapproved but widely publicized ventilator designs as follows:

1. The MADVent ventilator is tailored to treat COVID-19 patients as, formally (ISO 19223), a single-mode continuous, mandatory,
pressure-controlled, time-terminated design. Most low-cost ventilators function instead as volume-control ventilators,
delivering air into the lungs even to excessive pressure, which can lead to lung injury, especially in ARDS lung-compromised patients
typical in this COVID-19 pandemic.

2. The MADVent has a novel torque conversion mechanism via a simple pulley and lanyard system to convert the relatively low-torque, high speed rotation of the motor to a high-torque, reduced speed resuscitation bag compression mechanism. This is superior to the
ubiquitous geared rack-and-pinion mechanisms of other low-cost ventilators as it offers greater pressure, at least doubles the
maximum ventilation rate, has no backlash,, and is far quieter. It is also much more durable, as the nylon geared mechanisms used in
other systems are subject to wear and failure much faster than our approach.

3. Unlike all low-cost ventilators known to us, we offer a fully alarmed ventilation operation suitable for life support, commensurate with the strict requirements of the FDA for life-support ventilators, even in a pandemic.

4. We uniquely determine the volume of air delivered through knowledge of the resuscitation bag characteristics and a model of its compression based on the rotation angle of the motor. This obviates the need for expensive airflow sensors and the complex algorithms necessary to compute the volume from airflow. It also drastically reduces the cost of our ventilator, to about $300 in parts and less than $500 including assembly; an airflow sensor approved for use in ventilators is  $150 alone. This furthermore offers the possibility of offering other ventilation modes in the future, such as volume-control or patient-initiated ventilation.

5. We have pursued a comprehensive strategy of low cost, worldwide accessible parts in the design. In this pandemic, supply lines are disrupted and the complex designs of many ventilators, open source designs included, are simply not produceable due to parts shortages. Our design avoids this problem, from the ability to use 3.3 VDC or 5 VDC pressure sensors to the exclusion of valves and motors that are simply unavailable.