NHS handed Covid patients £20 oximeters — and triaged them by number, not feeling

One of the mysteries of Covid-19 was why blood oxygen could drop to dangerous levels without the patient noticing — “silent hypoxia”. Patients were arriving at hospital far sicker than they realised, sometimes too late to treat effectively. Normal oxygen saturation runs 95–100%; “with Covid, we were admitting patients with oxygen levels in the 70s or low-or-middle 80s”, said Dr Matt Inada-Kim, a consultant in acute medicine at Hampshire Hospitals who became national clinical lead of the Covid Oximetry@home project.

The scheme handed pulse oximeters — about £20 each — to high-risk Covid patients in England: anyone over 65, younger people with health problems, or anyone doctors were concerned about, with similar rollouts across the UK. Patients measured their oxygen three times a day under plain rules: 93–94% means speak to your GP or call 111; below 92% means A&E or 999 for an ambulance. NHS England supplied around 300,000 oximeters for home monitoring. At one practice, Dr Caroline O’Keefe was monitoring 44 patients on Christmas Day and 160 weeks later, quadrupling her team in a fortnight.

Chris Harris, 70, was one of the first patients through. After a positive Covid test during treatment for a urinary infection, his readings dipped a couple of points below the normal zone and his GP sent him to hospital while he still felt fine. The next day his breathing laboured and his oxygen fell into the 80s; he was treated, avoided intensive care and recovered fully. “It was the oxygen meter that forced me to go, I would have just sat it out thinking I would recover,” he said.

Feeling was the wrong signal for silent hypoxia: patients did not believe they were dangerously ill, so waiting for symptoms meant arriving too late.

The protocol is simple enough for home use — one number, three times a day, two thresholds, no specialist kit.

At about £20 a device the scheme scaled quickly, reaching around 300,000 oximeters across NHS England.

Admitting patients at 'a more salvageable point in their illness' shifts treatment earlier, before intensive care becomes necessary.

When the symptom is unreliable, move the sensor into the home and pre-agree the thresholds: cheap devices plus simple rules routinize early rescue.

Dr Inada-Kim cautioned there was not yet definitive proof the gadget saves lives — firm answers were expected by around April — but the early signs were all positive, including what he called the early seeds of a reduction in length of stay, and the home-monitoring schemes continued to roll out across the UK.