Medtronic open-source Ventilator does not meet UK’s Rapidly Manufactured Ventilator System Standard

I am not a doctor.

Dave Empey, Registered Respiratory Therapist (RRT), brought this to my attention.

The UK has released an influential standard for a Rapidly Manufactured Ventilator System(s). It sets a standard of minimal features for treating COVID-19 patients. It says 100% oxygen is required as a minimum requirement.

Medtronic has released, under a license strictly limited to the pandemic, open source plans and software for a ventilator, the Puritan Bennett (PB) 560. In theory this would allow 3rd parties to produce this ventilator to address the current and expected shortage of critical care ventilators for the huge numbers of COVID-19. However, the Puritan Bennett (PB) 560 specifically cannot deliver more than 50% oxygen, according to the user manual.

Clinicians may have differing opinions about treatment regimes. I would love to see the ventilator shortfall solved, but I think anyone attempting to mass produce the Medtronic (or other) ventilators should be aware of this inconsistency or limit.

To quote the Puritan Bennet (PB) 560 user manual, on page 28 in the pdf, labeled page 1–9 in the document, in the warnings:

*) The Puritan Bennett™ 560 Ventilator is designed to deliver a percentage of oxygen equal or lower than 50%. Do not exceed this value as this may cause the ventilator to malfunction and put the patient at risk.

*) Ensure that the oxygen supply pressure to the machine never exceeds 7 psi (50 kPa) or a flow of 15 lpm. Refer to Table A-8 on page A-3 for volume and sensitivity tolerances.

whereas the RMVS says:

3. Gas supply to patient.

a. User must be able to control inspired oxygen proportion (FiO2). The percentage of oxygen in the gas being breathed in by the patient. Room air is 21% oxygen.

b. Must provide a (50% or 60%) and 100% options

c. Should provide control variable between 30–100 % in 10% steps.

and, under “Gas and Electricity”, the RMVS states:

Must connect to wall pipeline oxygen supply via BS 5682:2015 compatible probes (Schrader). If hose not permanently fixed to machine, then must connect with NIST (Non-Interchangeable Screw Thread to ISO 18082:2014/AMD 1:2017). Oxygen pipeline pressure is approximately 3.7–4.5 bar [53.6 psi to 65.3].

These two statements are inconsistent.

To quote Dave Empey:

“Ensure that the oxygen supply pressure to the machine never exceeds 7 psi or a flow of 15 lpm” makes the machine a non-critical care ventilator. Ventilators like these are more often used in ventilator step down hospitals and home care settings.

The pandemic requires urgency, but this inconsistency requires clarification. Could medical professionals please comment on this?