I’m going to tag this as a little tutorial for @MichaelYeadon3 who keeps saying that there’s no problem from the suppliers of medical ‘gasses’

Most hospitals in the U.K. run their O2 supply from a Vacuum Insulated Evaporator (VIE)

https://t.co/Lu9ktGFSSm

1/n

This VIE is essentially a large thermos flask/ vacuum insulated cylinder at -180C
O2 is supplied from (typically) BOC in liquid form; when required, allowed to evaporate into gas, & supplied to hospital outlets.

Most hospitals have a VIE big enough to meet their needs

2/n
The problem is the pipes

Most ~12 bed ICUs have pipes that allow ~400L/min flow

This is Ok because most ventilators don’t use >20l/min; giving useful buffer capacity

Modern non invasive ventilation systems- CPAP, NIV, and High flow nasal Oxygen (HFNO), however, need more
3/n
A typical patient on HFNO will have 60-80Lmin flow. If they’re on 90% O2, that’s 60L O2 for 1 patient

6 of these patients will come very close to triggering the O2 flow alarm for this 12 bed unit.

4/n
Aside from breaking walls and re engineering the O2 supply for the whole hospital there’s no easy way of solving this problem
5/n
The next question being asked is ‘can’t we use ‘oxygen bottles’

A typical F cylinder has 1360 litres Oxygen. And weighs 18KG.
That will last ~22 minutes for a patient on HFNO

That’s 72 cylinders per patient per day.

That’s not how you can run a service.

6/n
Then you come to cost.

These 72 cylinders cost approx £2000. That’s ~20x more than liquid O2 in a VIE.

Typical ICU tariff for a L2 patient is <£1500!

7/n
many hospitals (including mine) have had to plan around O2 supply (flow) and scatter patients- this leads to inefficiencies of dispersal if you have say 3-4 areas with 6-8 patients in them rather than one area with 30

Leads to problems with staffing and cover for safety

8/n
So what I’ve tried to explain is that when hospitals report they’re running out of O2, the problem doesn’t lie with suppliers of liquid O2. Don’t ask them if there’s a shortage.

The problem is infrastructure and old estate.

Please stop this misinformation.

9/n
TLDR: there isn’t a problem with O2 supply from manufacturers. It’s a problem with old estate and infrastructure in the hospital buildings

10/10
@iceman_ex @rupert_pearse @ShaunLintern @BBCHughPym @sbattrawden @charlot_summers @SepsisUK

More from Health

You gotta think about this one carefully!

Imagine you go to the doctor and get tested for a rare disease (only 1 in 10,000 people get it.)

The test is 99% effective in detecting both sick and healthy people.

Your test comes back positive.

Are you really sick? Explain below 👇

The most complete answer from every reply so far is from Dr. Lena. Thanks for taking the time and going through


You can get the answer using Bayes' theorem, but let's try to come up with it in a different —maybe more intuitive— way.

👇


Here is what we know:

- Out of 10,000 people, 1 is sick
- Out of 100 sick people, 99 test positive
- Out of 100 healthy people, 99 test negative

Assuming 1 million people take the test (including you):

- 100 of them are sick
- 999,900 of them are healthy

👇

Let's now test both groups, starting with the 100 people sick:

▫️ 99 of them will be diagnosed (correctly) as sick (99%)

▫️ 1 of them is going to be diagnosed (incorrectly) as healthy (1%)

👇

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