The numbers are quite starkly grim, based on an epidemiological simulation model. They conclude that mitigation strategies (only isolating symptomatic people, social distancing only at-risk people) will at best reduce the load on the healthcare system to “only” 8x current surge capacity in UK/US, leading to estimated 1.1M deaths from COVID-19 alone (i.e., not considering possible deaths from other causes due to an overloaded healthcare system). Instead, suppression strategies (everyone socially isolating) need to be followed for 12-18 months to ensure that the load from COVID-19 stays within surge capacity, minimizing total deaths to the low hundreds of thousands, and buying time for a vaccine / treatment to help beat back a second epidemic after relaxing suppression measures.
I am curious about a few assumptions in their model (wish it was open-sourced!), and how this might change the estimate.
1) They assume a fixed ICU capacity (where I think the main limit is ventilators, not just beds). Does anyone have any models/estimates of how much UK/US can expand intensive care capacity (e.g., with “wartime” style all hands on deck manufacturing and innovation)?
2) I don’t see any modeling of social network effects in the mitigation scenarios. I’m thinking of the conjecture in this preprint (https://osf.io/fd4rh/?view_only=c2f00dfe3677493faa421fc2ea38e295) that intergenerational interactions, co-residence, and commuting patterns in Italy might have unique effects on the transmission and mortality rates.
Has anyone seen discussion of these points from experts? Or done some modeling themselves that could speak to these issues?
They assume a fixed ICU capacity (where I think the main limit is ventilators, not just beds). Does anyone have any models/estimates of how much UK/US can expand intensive care capacity (e.g., with “wartime” style all hands on deck manufacturing and innovation)?
My understanding is that the treatment requires significant monitoring and skill; the ventilation is often invasive (they have to get the tube into your lung, rather than just into your mouth).
But for a while people have been suggesting compartmentalizing the medical system further. If you just want someone to be a ‘ventilator nurse’, able to intubate a patient and then manage a ventilator for that patient, could you do that with a 30-day training program? Seems likely and worthwhile, but will require some sort of emergency legislation to authorize in most places, and some rapid development of curricula and testing.
Similarly, expanding production runs into legal issues. You may have heard about the volunteers who 3D printed ICU valves; they asked the company for blueprints, and the company threatened to sue for the IP violation. You might also have heard about the patent troll who sued the makers of a COVID19 test for infringement; they dropped the case once it was public that the use was a COVID19 test. It seems like a potentially sensible government action here is to nationalize (or otherwise force licensing) of technology that’s useful in a disaster, with the government paying for the IP after-the-fact based on actual usage out of the overall disaster response fund.
But in general, our ‘peacetime’ standards for medical devices are very high. If you want to take your toaster factory (or w/e) and start spitting out ventilators instead, there’s a lengthy approval process because this is complicated stuff with many ways things can go wrong. When the alternative is nothing, it’s probably good to have rush jobs available, but there’s nothing in place (that I’m aware of) to allow this sort of rapid ramping.
The first hard part is getting the tube past the vocal cords in the larynx. This requires the correct positioning of the patient to be able to see the vocal cords. (fibreoptic scope sometimes necessary) and to align structures for easier insertion.
Laryngospasm where the vocal cords come together to block the airway is a major concern. (the vocal cords coming together is a normal part of swallowing to prevent things going into the airways and contacting the cords will induce a spasm.) This can be reduced by using a local anaesthetic spray on the cords—essential if the patient is conscious (a rare situation).
Correct placement of the endotracheal tube is critical. It must be within the trachea, above the carina (where the trachea splits into the main bronchi and definitely not into a lung). If the tube goes into a bronchus it means one lung gets air, the other doesn’t. A bad intubation is worse than no intubation.
For ventilation:
Fancy equipment
or
Someone squeezing a ventilation bag. (+ oxygen supplementation)
But ultimately, nurses/EMTs/medical students can be trained to do all this in a few days. If someone’s competent and confident and has adequate back-up in-case of issues.
But ultimately, nurses/EMTs/medical students can be trained to do all this in a few days. If someone’s competent and confident and has adequate back-up in-case of issues.
I think we might want to be in the world where we train a substantial fraction of the recently unemployed, or the National Guard, or whoever to do this, which requires starting from a lower point than nurses/EMTs/medical students.
There’s a big difference between the process of intubation and maintaining a patient once intubated.
Someone with no prior knowledge of anatomy and physiology intubating patients (even after intense training) would increase the risks to patients. A mistake could be fatal. Time is a crucial factor—less than 4 minutes to correct an issue (brain needing oxygen).
Sedation/paralytic drugs need to be given. Dangerous in themselves. (an old saying re intravenous anaesthetics—dead easy, easily dead)
Adequate supervision/ back-up would be essential.
Aptitude of the trainee would also be very important. No room for getting stressed. 1st rule emergency medicine—breathe.
Better for the more experienced to intubate and then training people on ventilator management / how to squeeze a bag at the right pressure and timing (when ventilators aren’t available).
Read the Imperial College COVID-19 Response Team report tonight. https://www.imperial.ac.uk/media/imperial-college/medicine/sph/ide/gida-fellowships/Imperial-College-COVID19-NPI-modelling-16-03-2020.pdf
The numbers are quite starkly grim, based on an epidemiological simulation model. They conclude that mitigation strategies (only isolating symptomatic people, social distancing only at-risk people) will at best reduce the load on the healthcare system to “only” 8x current surge capacity in UK/US, leading to estimated 1.1M deaths from COVID-19 alone (i.e., not considering possible deaths from other causes due to an overloaded healthcare system). Instead, suppression strategies (everyone socially isolating) need to be followed for 12-18 months to ensure that the load from COVID-19 stays within surge capacity, minimizing total deaths to the low hundreds of thousands, and buying time for a vaccine / treatment to help beat back a second epidemic after relaxing suppression measures.
I am curious about a few assumptions in their model (wish it was open-sourced!), and how this might change the estimate.
1) They assume a fixed ICU capacity (where I think the main limit is ventilators, not just beds). Does anyone have any models/estimates of how much UK/US can expand intensive care capacity (e.g., with “wartime” style all hands on deck manufacturing and innovation)?
2) I don’t see any modeling of social network effects in the mitigation scenarios. I’m thinking of the conjecture in this preprint (https://osf.io/fd4rh/?view_only=c2f00dfe3677493faa421fc2ea38e295) that intergenerational interactions, co-residence, and commuting patterns in Italy might have unique effects on the transmission and mortality rates.
Has anyone seen discussion of these points from experts? Or done some modeling themselves that could speak to these issues?
Also curious what others think of the report.
My understanding is that the treatment requires significant monitoring and skill; the ventilation is often invasive (they have to get the tube into your lung, rather than just into your mouth).
But for a while people have been suggesting compartmentalizing the medical system further. If you just want someone to be a ‘ventilator nurse’, able to intubate a patient and then manage a ventilator for that patient, could you do that with a 30-day training program? Seems likely and worthwhile, but will require some sort of emergency legislation to authorize in most places, and some rapid development of curricula and testing.
Similarly, expanding production runs into legal issues. You may have heard about the volunteers who 3D printed ICU valves; they asked the company for blueprints, and the company threatened to sue for the IP violation. You might also have heard about the patent troll who sued the makers of a COVID19 test for infringement; they dropped the case once it was public that the use was a COVID19 test. It seems like a potentially sensible government action here is to nationalize (or otherwise force licensing) of technology that’s useful in a disaster, with the government paying for the IP after-the-fact based on actual usage out of the overall disaster response fund.
But in general, our ‘peacetime’ standards for medical devices are very high. If you want to take your toaster factory (or w/e) and start spitting out ventilators instead, there’s a lengthy approval process because this is complicated stuff with many ways things can go wrong. When the alternative is nothing, it’s probably good to have rush jobs available, but there’s nothing in place (that I’m aware of) to allow this sort of rapid ramping.
For intubation:
The patient is usually sedated/unconscious. (drugs need to be administered)
correct insertion of endotracheal tube ( endo ~ inside trachea = windpipe)
The first hard part is getting the tube past the vocal cords in the larynx. This requires the correct positioning of the patient to be able to see the vocal cords. (fibreoptic scope sometimes necessary) and to align structures for easier insertion.
Laryngospasm where the vocal cords come together to block the airway is a major concern. (the vocal cords coming together is a normal part of swallowing to prevent things going into the airways and contacting the cords will induce a spasm.) This can be reduced by using a local anaesthetic spray on the cords—essential if the patient is conscious (a rare situation).
Correct placement of the endotracheal tube is critical. It must be within the trachea, above the carina (where the trachea splits into the main bronchi and definitely not into a lung). If the tube goes into a bronchus it means one lung gets air, the other doesn’t. A bad intubation is worse than no intubation.
For ventilation:
Fancy equipment
or
Someone squeezing a ventilation bag. (+ oxygen supplementation)
But ultimately, nurses/EMTs/medical students can be trained to do all this in a few days. If someone’s competent and confident and has adequate back-up in-case of issues.
I think we might want to be in the world where we train a substantial fraction of the recently unemployed, or the National Guard, or whoever to do this, which requires starting from a lower point than nurses/EMTs/medical students.
There’s a big difference between the process of intubation and maintaining a patient once intubated.
Someone with no prior knowledge of anatomy and physiology intubating patients (even after intense training) would increase the risks to patients. A mistake could be fatal. Time is a crucial factor—less than 4 minutes to correct an issue (brain needing oxygen).
Sedation/paralytic drugs need to be given. Dangerous in themselves. (an old saying re intravenous anaesthetics—dead easy, easily dead)
Adequate supervision/ back-up would be essential.
Aptitude of the trainee would also be very important. No room for getting stressed. 1st rule emergency medicine—breathe.
Better for the more experienced to intubate and then training people on ventilator management / how to squeeze a bag at the right pressure and timing (when ventilators aren’t available).
Tracheal intubation in the ICU: Life saving or life threatening?