What do the figures tell us about Boris Johnson’s chances of a full recovery after he was placed in intensive care?
Well, news that the prime minister hasn’t been put on a ventilator could be a crucial sign, according to the latest figures from an intensive care research centre.
Numbers won’t tell the full story, as every case depends on a multitude of extremely personal factors – but, like those now-famous charts showing the curve of cases and deaths – they can help us get a sense of the bigger picture.
For instance: like Boris Johnson, who is 55, the vast majority of patients in an intensive care unit (ICU) – almost three-quarters, or 73% – are men, mostly in older middle age.
The average age of admission to critical care is 60.
There are more men in critical care in their 50s than in their 70s.
That’s not to say that the disease is more fatal for people in this age range, as, sadly, many older sufferers may not even make it to the ICU – but it does send a crucial public health message to this group.
They may think they are self-isolating to protect older friends and relatives.
In fact, it is very important they act to protect themselves – not least because (the data tells us) they occupy critical care beds for a significant period of time.
These figures come from the Intensive Care National Audit & Research Centre (ICNARC) which releases reports on patients with COVID-19 admitted to ICUs.
The latest was published on Saturday and examines the experience of 2,249 patients.
Most are still receiving treatment so we must be careful about drawing conclusions, but there are currently outcomes for 690 patients, around half of whom have died.
This bare fact shows just how serious admission to critical care is for most patients.
But anyone wondering specifically about Mr Johnson can find hope in another statistic.
According to his official spokesperson, the prime minister has not been placed on a mechanical ventilator, instead receiving “standard oxygen treatment”, most likely using a device which blows air into the lungs.
Patients who don’t go on a ventilator in the first 24 hours in an ICU survive 83% of the time.
Those who are put on a ventilator in that period have a much lower survival rate – just 32%.
This is correlation, not causation, so we don’t know why that is, but while it’s worth stressing again the limited nature of the data, on an individual level, this is good news.
Of course, even if one person does recover, that doesn’t mean a visit to the ICU isn’t extremely serious.
One sign of that: the proportion of patients receiving support for organs other than the lungs.
Of the 690 patients whose outcome in an ICU is known, almost all received support for their heart, and 143 received what ICNARC calls “advanced cardiovascular support”.
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“You’re protecting the organs trying to maintain good kidney function, good heart function and so you’re giving fluids, nutrition, trying to prevent secondary complications like new infections, pressure sores,” says Mervyn Singer, professor of intensive care medicine at University College London.
“There’s a whole package of care that needs to be delivered to try and obviously help the patient get over their primary condition. So in this case, lung failure, respiratory failure, but also to try and prevent this domino effect of other organs being compromised.”
Without this dreaded domino effect, how long do patients stay in the ICU? The data suggests that, among survivors, five days is the average – although the range is from two to eight. What about full recovery?
There’s no data on that. “Unfortunately, that’s a bit of an unknown quantity,” said Professor Singer said.
“There’s something called post-intensive care syndrome, which is very, very well recognised. So patients who are critically ill have had the stuffing knocked out of them and it can take actually weeks or sometimes even months to fully recover.”