Government chooses design of ventilators that UK urgently needs
The government has chosen the medical ventilators it believes can be rapidly produced to equip the NHS with 30,000 machines needed to cope with an upsurge in Covid-19 patients.
Amid concern that the 8,175 devices available will not be sufficient, manufacturing giants have been looking at designing a model that could be mass-produced, based on criteria issued by the Department for Health and Social Care (DHSC).
But sources familiar with the discussions said the government has opted for existing designs and could harness the power of UK industry to scale up production massively.
Smiths Group already makes one of the designs, its portable “paraPac” ventilator, at its Luton site, and said it was in discussions with the government to help make 5,000 ventilators in the next two weeks.
Andrew Reynolds Smith, chief executive, said: “During this time of national and global crisis, it is our duty to assist in the efforts being made to tackle this devastating pandemic, and I have been inspired by the hard work undertaken by our employees to achieve this aim.
“We are doing everything possible to substantially increase production of our ventilators at our Luton site and worldwide. Alongside this, we are at the centre of the UK consortium working to set up further sites to materially increase the numbers available to the NHS and to other countries impacted by this crisis.”
Oxfordshire-based Penlon is the designer of the other ventilator, according to the Financial Times. Penlon’s product chief has previously warned that asking non-specialist manufacturers to make ventilators would be “unrealistic” and the company has said its own Nuffield 200 Anaesthetic Ventilator presented a “quick and simple” solution.
In an effort that some have likened to British industry’s role in making Spitfires during the second world war, manufacturers such as Airbus and Nissan are expected to lend support by offering to 3D-print parts or assemble machines themselves.
HSBC said on Monday that it would offer companies working on the project fast-track loan applications, cheaper interest rates and extended repayment terms to support the unprecedented demand on UK hospitals.
The DHSC had been weighing up whether manufacturers could come up with new designs, issuing specifications for a “minimally acceptable” rapidly manufactured ventilator system (RMVS).
Its specifications included: Ventilators must be reliable and able to keep working 100% of the time for at least 14 days.
They should be small and light enough to fix to a hospital bed, but robust enough to survive falling from bed to floor.
The machines must be able to provide both mandatory ventilation – breathing on behalf of the patient – as well as a pressure support mode that assists those who can breathe independently to some extent.
The machine should be able to sense when a patient stops breathing and switch from the assisted breathing mode to a mandatory setting.
Ventilators will have to connect to hospital gas supplies and will also need at least 20 minutes of backup battery in case of mains power failure. The batteries should be swappable in case of a longer outage, or a patient transfer that could last two hours.
Buried at the end of the government’s specification document is a warning that requiring backup batteries will mean 30,000 large batteries being sourced quickly. The government admits it will “need the advice of an electronic engineer with military/resource-limited experience before specifying anything here. It needs to be got right first time.”
All of the ventilator’s parts need to be detachable so they can be disinfected manually.
They must also be fitted with an alarm that alerts medical staff in case of a fault or some other interruption or inadequacy of oxygen supply.
Doctors must be able to monitor the ventilator’s performance, for instance the oxygen percentage it is providing, via clear displays.
Operating the machine must be intuitive, requiring no more than 30 minutes of training for a medical professional who already has some ventilator experience. Some of the instructions should also be included on the external labelling.
Specifications include the ability to support a range of 10 to 30 breaths per minute, rising in increments of two, with the settings adjustable by medical professionals. They should also be able to change the ratio of the length of time for inhalations to exhalations.
The document includes a minimum for the amount of oxygen the ventilator should be able to pump into a patient’s lungs. Tidal volume – the amount of air someone inhales during a normal breath – is typically about six or seven millilitres per kilogram of body weight, or about 500ml for someone weighing 80kg (12 stone 8lb). The minimum requirement for a RMVS is a single setting of 450. Ideally, it could move on a spectrum between 250 and 800 in increments of 50, or be set to a ml/kg setting.
The average proportion of oxygen in the air is 21%. The ventilator should offer 50% and 100% at the very least and ideally 30% to 100%, rising in increments of 10 percentage points.
The Medicines and Healthcare Products Regulatory Agency (MHRA) is the UK body that approves medical equipment for use. It will have to give the green light to any ventilators used in the Covid-19 response. Manufacturers must show their supply chain is contained within the UK, to ensure no disruption in the event that crossborder freight movements are interrupted. The supply chain must also be transparent so that the MHRA can ensure suitability of parts.
Ventilators must meet certain existing standards for MHRA approval. However, the DHSC said it was considering whether these can be “relaxed” given the urgency of the situation.