Coronavirus: Could one ventilator be used to treat multiple patients?

Study suggests ventilators could be modified to meet demand in disaster scenario

Conrad Duncan
Monday 23 March 2020 19:05 GMT
Coronavirus: 1.5 million 'vulnerable people' in UK will be asked at home for at least 12 weeks

The limited supply of ventilators in the UK is one of the most serious issues facing the NHS as it responds to the ongoing coronavirus pandemic.

Patients who become critically ill due to Covid-19 will need a ventilator to help them breathe and if hospitals are overwhelmed with cases, as has already happened in Italy, doctors may be forced to choose which patients get access to one.

The UK government is hoping to avoid this problem by manufacturing more ventilators, with Boris Johnson calling on companies to shift their production towards building the machines in the coming weeks.

Matt Hancock, the health secretary, said on Monday that 12,000 ventilators were now available, up from 5,000 previously, but the government has said up to 20,000 machines could be needed to meet the demand from coronavirus cases.

With this shortage in mind, some people have looked to research from more than a decade ago which suggested ventilators could be quickly modified to treat four patients simultaneously.

The 2006 study by St John's Hospital and Medical Centre in Detroit investigated whether ventilators could be adapted to meet a surge in cases in a disaster scenario.

Using test lungs rather than live patients, researchers found there was “significant potential” for expanding a ventilator for multiple patients for a limited time by using plastic tubing to split the oxygen flow four ways.

The study found the four test lungs could be ventilated for 12 hours using just one machine so long as the lungs were of the same size.

The findings received renewed attention this month after Dr Charlene Babcock, a co-author of the original study, posted a video on YouTube explaining how the research could work in practice.

Dr Babcock said the modification had not been tested in humans in a study, but it had been used effectively in the aftermath of the 2017 Las Vegas shooting, when a physician used the research to treat multiple patients for hours until additional ventilators arrived at the scene.

However, she also noted that the modification should only be used in dire circumstances.

“This is off-label use of the ventilator. The ventilator is made for one person and I’m using it here in a simulation of four patients,” Dr Babcock said.

“I always hope that you would never need to use it in this way but you can never predict what is going to happen in a disaster.”

She added: “This is clearly off label and likely would only be used in a dire circumstance, which we may see with Covid-19.”

Another potential problem with applying the research to Covid-19 cases is seriously ill patients are likely to need ventilators for days rather than just hours.

Professor Mark Tooley, from the Royal Academy of Engineering, told MailOnline earlier this month that he had never heard of ventilators being shared between patients simultaneously.

“The process of ventilation is very personal – the controls and sensors are set to satisfy an individual patient’s needs and wellbeing,” Mr Tooley said.

“The risk of infection would also be high if used for seriously ill patients. In theory it could be possible, but it would be a very complex procedure, fraught with issues.”

Dr Alain Gauthier, an anaesthetist in Canada, said last week he was prepared to use the research if necessary and had already set up a system to modify his hospital’s ventilators for two patients.

“At one point we may not have other options,” he told CBC News.

“The option could be well, we let people die or we give that a chance."

As of 9am on Sunday, 5,683 cases of coronavirus have been confirmed in the UK, with 281 deaths.

However, as the UK government is only testing suspected cases in hospital, the number of Covid-19 cases in the country is likely to be significantly higher than that figure.

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