IT clips on your middle finger, can be bought on the internet, and measures Covid-19 respiratory symptoms.
But while people are buying pulse oximeters to have in their first-aid box, in case they have coronavirus symptoms, self-monitoring at home is best advised only in conjunction with your doctor.
Devices bought online may vary in quality and reliability of data — to be of medical standard, they should bear the CE mark, a European safety and performance guarantee that is a legal requirement for any medical device placed on the EU market.
The pulse oximeter has been used by medics for several years on patients who have respiratory issues, as it measures oxygen saturation — the percentage of our red blood cells that carries oxygen — and pulse rate.
While Covid-19 symptoms generally include a persistent, dry cough, fever, and fatigue, for some patients the virus can multiply ‘silently’ in the respiratory tract, causing breathing problems that escalate to pneumonia.
The pulse oximeter’s role in the detection of Covid-19 was highlighted recently by an American emergency physician, Dr Richard Levitan, in aarticle.
Dr Levitan had noticed that Covid-19 pneumonia initially presents as a form of oxygen deprivation called ‘silent hypoxia’ — silent, because when it first strikes, patients don’t feel the usual distress and shortness of breath, even as their oxygen levels fall dramatically.
Detection of hypoxia, early treatment, and close monitoring apparently worked for British prime minister, Boris Johnson.
Dr Levitan made a convincing case for owning an oximeter, which he claimed saved the lives of two emergency physicians he knows, alerting them early on to the need for treatment.
And he argued that “all persons with cough, fatigue, and fevers should also have pulse oximeter monitoring, even if they have not had virus testing”.
But should we all be investing in an oximeter?
Google searches for ‘pulse oximeter coronavirus’ in Ireland began to spike in mid-March and continued on upwards in April, according to Google Trends. And, at the time of checking, prices online varied from €13 to €39.99.
Only five of 10 pharmacists rung in Cork said they had received an increase in enquiries for the devices, which they either stock for €59.99 or could order if needed. The others, including leading pharmaceutical chain store Boots, have never stocked them.
Aware that pulse oximeters can detect silent hypoxia, a Cork GP practice invested in 60 of them at the beginning of the Covid-19 outbreak, prior to the introduction of testing hubs, but has, thankfully, not needed to use them yet.
Dr Nick Flynn, of mycorkgp.ie, a large practice with 15,000 patients around the city, says: “We bought them with the intention that if there was a high level of community Covid-19 and we had patients who were sick, but didn’t need to go to hospital, that we could loan them a pulse oximeter and could keep in touch with them,” Dr Flynn says.
“We thought it would be a way of adding objective, meaningful information from the patient about their state, after our initial assessment, rather than subjective information, as in, ‘how do they feel?’,” he says.
Should we all be investing in oximeters? “Yes, in the same way every house should have a blood-pressure monitor and a thermometer,” Dr Flynn says.
Dr Killian Hurley, respiratory consultant at Beaumont Hospital, in Dublin, has been giving a finger pulse oximeter to coronavirus patients he is discharging because they are not sick enough to be in hospital. The oximeter links up by Bluetooth to an app on their phone.
The patient not only measures their own oxygen saturation levels — Dr Hurley says it helps them feel more confident and safer — but those numbers are also monitored daily by the healthcare team, over the following two weeks.
“In Beaumont, we have treated nearly 200 patients, and with the Covid-19 oximetry, we have already identified probably 20 or 30 patients and called them back in, based on what we found on the app,” Dr Hurley says.
The Bluetooth-oximeter monitoring service being used by the HSE, and which is CE-approved, is provided by a company called PatientMpower. Its CEO, Eamonn Costello, says that, so far, 850 Covid-19 patients in Ireland have used it within the larger hospitals with which he has worked.
While the Bluetooth links the oximeter to the phone app, Costello’s company’s application collects the data, so that it can be relayed back to the healthcare facility prescribing the solution.
He’s in discussions about linking up also with the community hubs and for GPs to be able to prescribe the oximeter service to patients.
“Oxygen levels for a normal, healthy person should be over 95% and when it goes less than 90%, that would be worrying and a sign for us to call that person back into the hospital to take a look at them, or they can talk to their GP and discuss it with them,” says respiratory consultant Dr Hurley.
For those of us thinking of investing, Dr Hurley also refers to the CE standard and says that if we are healthy and don’t have other Covid-19 symptoms, such as fever or cough, we would not benefit from monitoring at home — it might cause a lot of anxiety.
“The biggest use I would see for them is for people who have Covid and who are spotting that they don’t deteriorate, because they may be feeling OK, but their oxygen levels are a lot lower than they should be,” Dr Hurley says.
“Very, very few patients would present feeling absolutely normal, but have oxygen levels that are low — they’re going to have some other symptoms.”