Mysterious COVID-19 Condition Dubbed ‘Happy Hypoxia’ Puzzles Doctors

There’s a new — and odd — development in the symptoms of COVID-19.

Doctors are puzzled by a new phenomenon dubbed “happy hypoxia,” in which coronavirus patients appear comfortable and at ease despite extremely low oxygen levels that would normally leave them unconscious, or even dead, according to new reports.

“A healthy person would be expected to have an oxygen saturation of at least 95%. But doctors are reporting patients attending A&E with oxygen percentage levels in the 80s or 70s, with some drastic cases below 50%,” The Guardian writes.

“It’s intriguing to see so many people coming in, quite how hypoxic they are,” said Dr Jonathan Bannard-Smith, a consultant in critical care and anaesthesia at Manchester Royal Infirmary. “We’re seeing oxygen saturations that are very low and they’re unaware of that. We wouldn’t usually see this phenomenon in influenza or community-acquired pneumonia. It’s very much more profound and an example of very abnormal physiology going on before our eyes.”

The “happy hypoxics” have been seen scrolling through their phones and casually chatting with doctors and nurses. They describe themselves as generally comfortable, Science Magazine reported.

“There is a mismatch [between] what we see on the monitor and what the patient looks like in front of us,” says Reuben Strayer, an emergency physician at Maimonides Medical Center in New York City. Speaking from home while recovering from COVID-19 himself, Strayer says he was first struck by the phenomenon in March as patients streamed into his emergency room. He and other doctors are keen to understand this hypoxia, and when and how to treat it.

A normal blood-oxygen saturation is at least 95%. In most lung diseases, such as pneumonia, falling saturations accompany other changes, including stiff or fluid-filled lungs, or rising levels of carbon dioxide because the lungs can’t expel it efficiently. It’s these features that leave us feeling short of breath—not, counterintuitively, low oxygen saturation itself, says Paul Davenport, a respiratory physiologist at the University of Florida. “The brain is tuned to monitoring the carbon dioxide with various sensors,” Davenport explains. “We don’t sense our oxygen levels.”

The new development is puzzling doctors, who are working to figure out how COVID-19, the disease caused by SARS-CoV-2, affects the lungs.

Dr. Jonathan Bannard-Smith, a critical care specialist at the Manchester Royal Infirmary in Britain, told The Guardian that some COVID-19 patients have no idea their oxygen saturations are so low.

“We wouldn’t usually see this phenomenon in influenza or community-acquired pneumonia,” he said. “It’s very much more profound and an example of very abnormal physiology going on before our eyes.” He added: “It’s intriguing to see so many people coming in, quite how hypoxic they are.”

And the doctor said no one knows why.

“I don’t think any of us expect that what we’re seeing can be explained by one process,” he said.