42 | New Scientist | 13 February 2021
A
S MUCH as the gloves and N95
masks, Devan Kansagara’s constant
companion early last February was a
sense of gnawing anxiety. As a physician at
the Oregon Health Sciences University, he
braced himself for a tidal wave of covid-19
cases. A few weeks later, it arrived. Like
doctors around the world, Kansagara found
himself having to care for patients with a
deadly disease he knew very little about.
“Everyone was grasping at straws,” he says.
Ideas flooded in from all corners, ranging
from the medically plausible to the utterly
crackpot. Various clinical insights began to
emerge from cities hit early by the outbreak
such as Wuhan in China and Milan in Italy.
Doctors and researchers had to decide in real
time which strategies to pursue and what
warranted further testing.
It all happened at a blistering pace. Doctors
swapped advice over WhatsApp, Facebook
and Twitter, changing clinical practice in hours
instead of years. Scientists launched clinical
trials, enrolled participants, analysed data
and rapidly disseminated results.
Some pinned their hopes on new, life-saving
medicines. Yet while thousands of drugs are
being tested or are in development, few have
yet proven to make much difference (see
“Where are the medicines?”, page 44).
In spite of this, we have made
tremendous progress since those early
days. Although outcomes vary by location,
and new variants pose new challenges, people
hospitalised with covid-19 now are much more
likely to survive than they would have been at
the start of the pandemic. This is largely thanks
to three major changes.
The vast majority of people infected with
SARS-CoV-2, the virus that causes covid-19,
won’t need hospital care, says Anita Simonds,
a respiratory physician at the National Heart
and Lung Institute at Imperial College London.
But about 3.5 per cent will need to be looked
after in hospital, according to data from the
COVID Tracking Project and the Johns Hopkins
University COVID-19 Dashboard.
A wide array of measures, from better
protective gear and greater test availability,JEFF^ PAC
HOUD/AFP^ VIA^ GET
TY
IMAGESto improved understanding of transmission
and the first roll-out of vaccines, have affected
care for those who go to hospital. But there has
been a major change in how doctors deliver
oxygen. One of the big dangers that covid-19
poses is lung damage, which prevents enough
oxygen from reaching the rest of the body.
Most healthy people should have an oxygen
saturation in their blood of between 95 and
100 per cent. In some people with covid-19,
it can dip as low as 50 per cent.
That is why official policies from around
the world say that people who show signs of
significant hypoxia – which include shortness
of breath, headache, fast heartbeat and a
bluish tint to the skin – should go to hospital.
Early in the pandemic, the staggeringly low“ People hospitalised
with covid-19 now
are far more likely
to survive than at the
start of the pandemic” >
oxygen levels seen in covid-19 patients sent
doctors into panic, especially as they noticed
that some people could crash into critical
illness within minutes to hours, says Lewis
Kaplan, a critical care physician at the
University of Pennsylvania. So putting
patients on mechanical ventilators early in
their hospital stay seemed like the best option.
“We believed that we were doing exactly the
right thing,” says Kaplan. “If you got really sick
and were about to die, we would have to rescue
you—and we would rather treat than rescue.”
With experience, they began to discover that
even people with worryingly low oxygen levels
can sometimes manage with less invasive
kinds of ventilation. Early on, nearly three
quarters of patients in critical care were put on
ventilators – often very soon after admission.
Now it is about half that. Making the shift
required many doctors to defy what they knew.
Research suggests that using less-invasive
oxygen delivery methods, such as nasal
cannulas and continuous positive airway
pressure masks, helped doctors to reduce the
number of people who needed to be sedated.
But perhaps most crucially, it reserved
mechanical ventilators for the very sickest