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An opinion piece by almostadoctor author, GP Registrar and Emergency doctor – Dr Tom Leach. For information about novel coronavirus (COVID-19) see the almostadoctor coronavirus encyclopaedia article.

I am worried

I am worried about coronavirus.

I am not a statistician, or an epidemiologist, nor am I involved in any public health planning or even hospital level planning for dealing with the coronavirus outbreak. I am just a regular front-line doctor, with an interest in the issues surrounding coronavirus. Many of my colleagues in the hospital, some of whom are involved in such planning decisions are having the same thoughts as I am.

We are worried.

Not clutching-hoards-of-toilet-roll-whilst-wearing-PPE-in-the-street kind of worried. But I’m concerned enough to warn all my patients to be diligent about basic hygiene measures, and if they are elderly or have comorbidites that they should be planning to isolate themselves.

I am also not overly worried about my own health. I am a relatively fit and well 30-something, with no serious health issues. I’m likely to catch it – and possibly early on in the outbreak – just due to the nature of my work. But I suspect I’ll have an illness somewhere between a bad flu and a mild cold – like the vast majority of cases, especially in young adults.

What really worries me is how health services around the world will cope if (more likely –¬†when) the disease becomes widespread. The point is perfectly illustrated by this tweet from Tim Steller:

Graph of the spread of novel coronavirus

Graph of the spread of novel coronavirus

If you want to understand more about how social distancing can help to slow the spread of an outbreak, take a look at this interactive simulator from The Washington Post.

Why I am worried

The UK government estimates that the outbreak will infect between 20-80% of the population, and that 50% of cases will occur within a 3-week window, with 95% of cases occurring in a 9-week period.

We also know that typically 80% of cases are mild and can be managed at home, whilst 20% require hospital admission, including about 5% of the total number of cases requiring ICU and ventilation. The typical ventilator requirement for a COVID-19 patient is 2-3 weeks.

If it really turns out like that, then the scale on the graph above might look quite conservative. Even looking at the low end of that estimate, that would mean 13 million cases in the UK, with over 2 million hospital admissions and over 500,000 ICU admissions. We just don’t have anything like the capacity required for that numbers of patients. There are about 4,000 ICU beds in England, and about 2,000 in Australia.

In Italy, already, even though they have “only” about 20,000 confirmed cases, tough decisions have had to made about who is treated, due to some services reaching capacity. Age-restrictions were placed on access to ventilators – to give those with the best chance of survival the best access to treatment. Patients over-65 have been excluded from ICU on the basis of age.

What are we going to do, when the next seriously unwell patient comes along and there is physically not another ventilator to use for them? How about when there are 200 such patients in your emergency department, and no beds to put them in? And another 500 people in the waiting room, who can’t even get into the emergency department. A lot of people are probably going to die, whom might otherwise survive if we had the resources.

Some governments have suggested novel approaches – like putting 2 patients on a single ventilator, or re-using typically disposable supplies – such as ventilator tubing.

The numbers

Let’s use a fictional example to look at the numbers.

Sarshampton is a medium sized city in a Western nation. It has a population of about 300,000. It has two main hospitals, which take about 55,000 admissions each year, and between them, they have 50 ICU beds.

Normally the hospitals run at about 90% capacity, and in winter, extra wards are opened to cope with winter-pressures.

Let’s imagine that 30% (the low end of the estimate) of the population are infected with coronavirus over a 9-week period. That’s 100,000 people. 5-10% of these might need ventilation. Let’s be conservative – and say 5,000 patients. Each of them could be in ICU for 2-3 weeks. Let’s be ambitious again, and say that on average this is just 2 weeks, and to make the maths more simple, we’ll stretch out our 9-week outbreak to 10-weeks.

  • 5,000 patients require ventilation for 2 weeks each, over a 10 week period
  • An average of 1,000 patients will have clinical need for ventilation at any given time during the outbreak
  • Sarshampton has 50 ventilated ICU beds.¬†Remember – about 40-45 of these already have ventilated patients who are sick from other diseases. So, Sarshampton has capacity for about 10 ventilated COVID-19 patients
  • This is a scenario at the lower end of the predicted scale of the outbreak
  • This is why I am worried

What can be done about it?

The approach taken by most nations is that of social distancing to spread the outbreak over a longer period.

Going back to our healthcare system capacity graph above (doesn’t that scale look a bit off now?) – the total number of cases would still be the same – in Sarshampton – 5,000 patients requiring ventilation. But let’s imagine we manage to spread it out over say 6 months – 24 weeks.

This means that ‘only’ about 420 patients would require ventilation at any given time during the course of the outbreak.

What else can we do?

We could close almost all of our operating theatres for all but the most urgent operations. We can then use their ventilators. Maybe that gives us an extra 50 ventilators. Because non-urgent surgery has been cancelled, we might also have fewer ventilated patients in ICU following their surgery. Maybe this gives us an extra 10 ventilators. So, maybe Sarshampton now has capacity to ventilate 70 COVID-patients at any given time

We could try running two patients to every ventilator – I’m not even sure how this would work but it could be possible.

Now we have capacity to ventilate about 140 patients at any given time. Perhaps we can use spare ventilators – Sarshampton has about 10 old ones in a storeroom. Maybe the local ambulance service has some spares too. Maybe we can get another 30 ventilators together. We can ventilate 200 patients at once. Still less than half. And remember – this is if only 30% of the population catch the virus.

BBC news reports today that UK manufacturers are being urged to switch manufacturing to assist the coronavirus pandemic – including for example by producing more ventilators. The longer we can stretch out the outbreak, the more helpful measures like this will be.

And we need the doctors and nursing staff to care for these ventilated patients. Its a pretty specialist role. And probably >30% of our medical staff in Sarshampton are off work with COVID-19 during the course of the outbreak.

Now what? This is where we have start rationing. But who decides? And on what criteria?

Conclusion

The peak is coming. It will be somewhere between 20-80% of the population. The longer we manage to spread it out, the more lives will be saved. Business should be urged to assist in fighting the pandemic. Social isolation restrictions are likely to be in place for months – the longer it goes on the better for our health (but the worse for our economy).

It is encouraging  as as an Australian resident to see Australia taking more-drastic social isolation measures than many European countries have done at the same point in the time line. But even these are not likely to be severe enough to slow the spread far enough to prevent health care systems reaching capacity.

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