Analysis: How 'virtual wards' care for COVID-19 patients at home
11 November 2020
Professor Naomi Fulop, Dr Cecilia Vindrola (both UCL Epidemiology & Health Care) and Professor Trish Greenhalgh (University of Oxford) explain how oximeters and 'virtual wards' are caring for COVID-19 patients at home and could help save lives.
Do you own an oximeter? If so, do you know how and when to use it? It could save your life.
COVID-19 has killed at least 60,000 people in the UK. Many who die have a sudden drop in their blood oxygen levels a day or two before their lungs fail. Unlike in many other chest diseases (asthma, for example), COVID-19 can cause a severe drop in blood oxygen level without any associated breathlessness.
Because of this, people with this “silent hypoxia” are unlikely to seek the urgent help they need, unless they regularly measure their blood oxygen level or their condition deteriorates. If they realise something is wrong, they may reach hospital just in time to receive oxygen therapy (and, if necessary, ventilation). Others are admitted too late to save – or die at home.
The blood oxygen level is one of the strongest predictors of death in COVID-19, and early oxygen improves survival. So it’s time to learn to measure yours and to know what to do if it’s low.
Oxygen is carried in the blood attached to haemoglobin (the large, iron-containing protein that makes blood red). Haemoglobin exists in two forms – oxygenated and deoxygenated – which reflect light slightly differently. An oximeter works by bouncing a beam of light against blood vessels close to the skin, typically in a fingertip, and using the reflected light to estimate the proportion of oxygenated to total haemoglobin.
To measure your blood oxygen level, turn on the oximeter and clip it on a warm fingertip (one without nail varnish). Wait five minutes until the reading has stabilised. Record the result and the time (either on paper or using an app).
You can buy an oximeter online for £15-£35 – though if you live in England, you may not need to because NHS England has just purchased 200,000 of them for distribution to eligible NHS patients as part of a new model of care.
If you’re sick enough to be using an oximeter, you may not be thinking clearly. That’s why it’s best to share your oximeter readings with a healthcare professional. This is the rationale behind this new model of care called the “virtual ward”: a system for supporting patients using home oximeters through phone or video calls. The aim of the virtual ward is twofold: to fast-track you to hospital if you need to be there, and to keep you out of hospital if you don’t.
If you are a patient on a virtual ward, you’ll be given an oximeter and shown how to use it. You’ll also be asked to record your pulse, temperature and symptoms, such as breathlessness. A health professional will phone you to check these readings every day – more often if you need it.