Doctors have launched a campaign calling for home devices that measure blood oxygen levels to be available on prescription.
They act as an early warning system for people at increased risk of a ‘silent pneumonia’ death due to coronavirus.
They want the matchbox-sized gadgets, known as pulse oximeters, to be given to those in most urgent need for free. They also advise against otherwise healthy people buying them, to avoid a shortage for those who need them most.
One sinister feature of Covid-19 is that it causes a catastrophic fall in oxygen levels without patients noticing. Intensive care specialists have seen people chatting normally on their phones when their blood oxygen is only at 50 per cent — it should be around 92 per cent. This deficit means they are close to dying, as their vital organs will not be getting enough oxygen.
Doctors are pointing out that more than one million people with chronic obstructive pulmonary disease (COPD), a smoking-related lung condition, and a further 250,000 with severe asthma, are particularly vulnerable to oxygen starvation.
A paper published in March by Dr Vageesh Jain, a senior public health specialist at University College London, showed that COPD was the ‘strongest predictor’ of severe disease. The review discovered COPD patients were six times more likely to develop severe Covid-19 infection and 17 times more likely to need intensive care treatment.
A silent drop in oxygen levels also means patients are at risk of dying before they even know they have been infected, but when it is already too late to save them. Those with COPD are especially vulnerable because their lungs have already been damaged by the underlying disease.
There is also a debate about whether millions who are vulnerable due to old age should also be issued with pulse oximeters, ahead of the anticipated second wave of coronavirus infections this winter.
Some are suggesting that people with Covid-19 should also be given the devices to help monitor them. As medical consultations are now taking place exclusively online or over the phone, the opportunity for a doctor to get an instant read-out of blood oxygen levels would help them decide whether a patient needs to go to hospital.
Apps that give GPs access to pulse oximeter readings taken at home have been developed.
Nearly 187,000 people have contracted Covid-19 in the UK, and 28,446 have died.
Dr Nick Summerton, a GP in Howden, East Yorkshire, who is a specialist in the use of diagnostic tools in primary care, says that up to one in 30 of these deaths is likely to have involved someone suffering from COPD. A smaller, unknown proportion may have been people with severe asthma who were unable to fight off the infection.
‘Blood oxygen is a fifth vital sign alongside pulse, temperature, blood pressure and breathing,’ he says. ‘One feature of this disease is that it can lower people’s blood oxygen levels and create this serious risk of patients dying before they get treatment.
‘With COPD, you might not be able to tell until it’s too late to save them [because their organs have already suffered irreversible damage due to a lack of oxygen].
In recent weeks, Dr Summerton has been helping to field calls for the NHS 111 urgent medical advice helpline.
‘We have to work out whether people can be managed at home, or need to be seen by a GP or sent to hospital,’ he says. ‘There is a big group who will be managed at home, and if we are going to do that pulse oximeters would make that process much safer.
‘Some of my patients have bought their own, but the ones most in need are those who can’t afford to buy them. This is why we think they should be available on the NHS.’ Dr Summerton will be writing to Health Secretary Matt Hancock to call for this. ‘They are inexpensive for the NHS to provide,’ he adds.
The devices clip onto the finger and send a beam of light through the finger to a sensor on the other side of the unit.
Oxygenated and deoxygenated blood absorb light differently. The oximeter uses this to provide a blood oxygen level reading, which is displayed on a screen. A healthy person should have a reading above 95 per cent.
It was a low reading from a pulse oximeter which alerted doctors to the severity of Prime Minister Boris Johnson’s condition and his need to go to hospital.
‘Normally, doctors would be more concerned about [other] symptoms, but Covid-19 is slightly odd,’ says Ian Pavord, a professor of respiratory medicine at the University of Oxford and chief medical adviser to Asthma UK.
‘Blood oxygen can go very low in a patient who is not symptomatic. If I am doing virtual consultations, I can see that kind of information would be very helpful.’
Lionel Tarassenko, a professor of electrical engineering at the University of Oxford, is also calling for pulse oximeters to be prescribed to those in high-risk groups. He has developed an app with Sensyne Health that can provide GPs with an instant reading from an oximeter used by a patient at home.
The CVm-Health app was formally launched late last month. It can be downloaded for free by NHS doctors and their patients.
Professor Tarassenko is in talks with the NHSX agency, set up to expand the use of remote and digital healthcare solutions, regarding the app.
‘People are starting to think more about a second wave of coronavirus infections hitting us,’ he says. ‘I would hope the recommendation to use pulse oximetry more widely will have gone through by then.’
Pulse oximeters can easily be bought online, costing from around £20. Professor Tarassenko warned there are dozens of devices on the market and, while price varies wildly, the basic function does not.
Consumers currently have no way of knowing if the device they buy has been fully approved and checked for accuracy.
Like many of the drugs and equipment in demand since the coronavirus crisis began, there are already signs of a shortage of pulse oximeters, with outlets such as Argos and Lloyds Pharmacy reporting limited or no stock.
Following recent suggestions that we should all have pulse oximeters at home, Dr Babak Javid, a consultant in infectious diseases at Cambridge University Hospitals NHS Trust, said that it’s important to preserve supply for those most at risk from Covid-19.
Dr Javid, who was one of the first to highlight the benefits of the devices, added: ‘They would be of very little value for young, healthy people. For the majority they really wouldn’t be that useful.’
He says people in low-risk groups should think twice about buying them, because there will be a finite number manufactured.
He suggests that we could address the shortage of pulse oximeters by giving them to the task forces set up to trace coronavirus cases.
‘If these task forces were issued with pulse oximeters, they would have a pretty simple five-second job of giving them to those who need them. This would avoid Britons buying millions of them and causing a global shortage,’ he tells Good Health.
Dr Andy Whittamore, clinical lead for the Asthma UK and British Lung Foundation Partnership, said: ‘The use of pulse oximeters in response to Covid-19 is still being examined.
‘Home-use oximeters, which are available for sale online and in chemists, can sometimes give poor or inaccurate measurements. It is important that, before testing at home, people talk to their healthcare professional.’