The best explanation to understand how Covid-19 threatens the State’s ability to offer an intensive care bed to the seriously ill is the riddle of the doubling lily pads.
The lily pad doubles every day. On day one there is a single lily pad; on day two there are two; day three there are four, and so on. If it takes 30 days to cover the pond, on what day is it half-covered?
The answer is day 29. Even on day 24 the pads cover only a small part of the pond.
"The key is slowing the doubling time of the lily pad," says infectious diseases consultant in St Vincent's hospital Dr Paddy Mallon. "At the same time you start developing pesticides that can kill the lily pads. The two things happen in parallel," says Mallon, adding that the analogy perfectly explains the challenges.
“Identify outbreaks, isolate people and don’t give the virus an opportunity to propagate. The key to strangling or suffocating the virus and mini-outbreaks across the country is that you stop new ones coming.”
Time is short. Eleven days ago 13 Covid-19 patients occupied beds in the State’s hospital intensive care units (ICU). Last Saturday, the number had risen to 88, a near-seven-fold increase in just nine days. On one day alone the numbers had jumped by 47 per cent.
Another seven-fold increase over two weeks, if there is one, could overwhelm the State’s health system.
The HSE is bracing for a possible peak of cases in mid-April – specifically between April 10th and April 14th – right at the point when the “stay-at-home” measures are due, for now, to lapse on Easter Sunday, April 12th.
The fear that ICUs could be stretched beyond breaking, despite the efforts made in recent weeks to increase the number of such beds, is " a very significant concern", said HSE chief executive Paul Reid.
‘We don’t know’
His colleague HSE chief operations officer Anne O’Connor, said just 167 critical care beds were free on Sunday. In any one day there is 1,200, no more.
Asked how many the State could be short of at peak, she said “we don’t know”.
Such numbers made compliance with the lockdown critical. Keeping older and sick people “cocooned” for a fortnight will reduce the number of them needing ICU beds.
The drop from 20 to five in the average number of contacts that Covid-19 patients have had in two weeks is an early encouraging sign that the restrictions on public movement may be working.
However, if the number of Covid-19 patients heading to ICU continues to rise at the current curve then it will not have been “flattened” enough to bring it below the 1,200 ICU bed limit.
Ireland's ICU numbers are already the lowest in Europe, and will be the quickest across the EU to be overwhelmed unless people heed the warnings now given.
Managing the surge is a numbers game. Hospitals must put people through: treating the positive cases – along with the negatives - and discharge them safely in a constant rotation.
For now it is a day-to-day battle that is being won, or at least not lost.
“We have got to try and prevent people going to ICU,” says Mallon. “A hospital is like a motor factory production line: cars are made piece by piece by piece. What we have to be able to do is to continue pushing cars out the other end, and if any part of that chain falls down the whole factory could close.”
Swamped
Lombardy's hospitals in northern Italy were swamped by early waves of very sick, older people infected with Covid-19.
“We haven’t seen that,” says Mallon. “We said at the very beginning that the key to riding this epidemic out is protecting your elderly and protecting the vulnerable. If you do that well, then you don’t get that tidal wave that ends up breaking the system.”
The danger with surging, exponential growth curves – the ones that sweep upwards sharply on graphs – is that everything looks manageable until it suddenly is not.
This is why the Government is imposing new measures now when less than a quarter of ICU beds are filled with Covid-19 cases. When you are dealing with exponential growth, the time to act is when it feels too early.
