Pulse Oximeters – what are they and should we be using them to combat coronavirus?

A pulse oximeter is a medical device which is used to monitor a person’s oxygen saturation and pulse rate. They are small, matchbox sized things which clip over a fingertip to detect any potential problems in these areas.

They are used extensively in hospitals in normal times, to allow doctors and nurses to monitor these important signs, but there are also versions which are available on the commercial market. Prices vary, but Amazon UK has a range from about £23 at the lower end to £70 for its recommended, Prime product.

Normally, these pulse oximeters will be prescribed by doctors for patients with chronic lung diseases, such as emphysema or pulmonary hypertension, who also need to monitor their oxygen saturation at home. These home patients regularly need to supplement their oxygen remotely, outside of a hospital setting.

In a recent article for the New York Times, Dr Richard Levitan, who is volunteering as an emergency medic in the city’s Bellevue hospital, has urged that pulse oximeter’s should be used more extensively to combat Covid-19 and help patients suffering from the disease caused by the SARS-CoV-2 virus.

In a revealing, if anecdotal, insight into the frontlines of this global health emergency, Levitan explained that high numbers Covid-19 patients in this central New York hospital have been suffering from “Covid pneumonia”. This is an infection of the lungs in which the air sacs fill with fluid or pus. It is associated with Covid-19 and develops gradually, but then suddenly provides patients with pain when breathing and breathing problems. It leads to their normal oxygen saturation to plummet below the 94-100% range which is considered normal in healthy people.

Levitan wrote: “To my amazement, most patients I saw said they had been sick for a week or so with fever, cough, upset stomach and fatigue, but they only became short of breath the day they came to the hospital. Their pneumonia had clearly been going on for days, but by the time they felt they had to go to the hospital, they were often already in critical condition.” This is known as “silent hypoxia”, where Covid pneumonia causes a form of Oxygen deprivation without a person notcing it.

The problem with Covid-19, writes Levitan, is that by the time those who have contracted the virus realise they have it, and begin experiencing breathing difficulties, the “Covid pneumonia” has already been able to advance. This, according to Levitan, puts a significant minority of Covid pneumonia patients at risk of serious damage to their lungs, and even “acute respiratory failure”.

One way of arresting this situation would involve a closer monitoring of oxygen saturation in potential Covid patients, using pulse oximeters. It could allow people, hospitals and health authorities to detect the signs of silent hypoxia, catching it before it can progress to respiratory failure.

So does this mean that we should all be getting online to order our own personal pulse oximeters? Should everyone be constantly monitoring their oxygen saturation on a daily basis?

This might be counterproductive. According to a report by Quartz, there is doubt among experts in the US that it would be helpful for otherwise healthy people to get their own pulse oximeters. There would be no obvious benefit, since non-vulnerable people are likely to suffer only mild symptoms, and it could be harmful to someone’s mental wellbeing, causing users to obsess unhealthily about small fluctuations in saturation levels. Commercial kits may also be unverified and unreliable.

Where the use of pulse oximeters is likely to be useful, is in hospital settings and in community testing centres. Alongside testing for the virus and CT scans, these could add another tool in the arsenal when detecting signs of infection. Considering that this is equipment that hospitals in the UK already have, it is likely that they are already doing this to some extent.

Finally, pulse oximeters could also be helpful for those who are at home, but who suffer from underlying health conditions. Here, the NHS and Public Health England could conceivable send pulse oximeters to those struggling at home with anything from asthma to pulmonary disease (if they aren’t doing so already).

As the epidemic continues, hospitals and health authorities will need all the devices they can muster in order to combat the virus, and keep further outbreaks under control.