Avian Flu Diary: Ventilator Shortages And Pandemic Triage

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#15,094

While it is true that 80% of people who contract COVID-19 will recover, likely at home, without complications - for roughly 20% (mostly the elderly, or those with comorbidities) - this infection can require hospital care.

A significant portion of those will require an ICU bed, and some of those will require a ventilator (or ECMO).

It is very likely that the high number of fatal outcomes being reported in Iran and in Italy stem not from a more virulent strain of the virus, but from an overwhelmed healthcare system, and a shortage of ICU staff and ventilators.

Two days ago, CIDRAP news report by Lisa Schnirring entitled ECDC: COVID-19 not containable, set to overwhelm hospitals, described the situation in Italy:

Life-and-death decisions in Italy's inundated hospitals

In a Lancet report today, two authors from Italy said the percentage of COVID-19 patients needing ICU treatment has ranged from 9% to 11% and that ICUs will be at maximum capacity if that trend continues for 1 more week. They predicted that Italy will need 4,000 more ICU beds over the next month, a challenge given that the country has about 5,200 ICU beds.

In the hard-hit Lombardy region, healthcare workers have been working around the clock. About 350 (20%) have been infected, and some have died, according to the report. Italy's government is considering hiring 20,000 more medical workers and providing 5,000 more ventilators. Unless the measures are implemented in the next few days, they wrote, otherwise-avoidable deaths will occur.

"Intensive care specialists are already considering denying life-saving care to the sickest and giving priority to those patients most likely to survive when deciding who to provide ventilation to," they wrote. "In the near future, they will have no choice. They will have to follow the same rules that health-care workers are left with in conflict and disaster zones."

The Italian College of Anesthesia, Analgesia, Resuscitation and Intensive Care (SIAARTI) has published guidelines for doctors to use in triaging patients during this emergency, and there are reports (see The Atlantic's The Extraordinary Decisions Facing Italian Doctors) that some of these excruciating medical triage decisions are already being made.

While this is happening in Italy today, no country is capable of handling the kind of surge capacity a severe pandemic is expected to produce.

Three years ago, in Pandemic Realities: Ventilator Shortages, we looked at the number of ventilators and ICU beds available in the United States, and the impact that two different pandemic scenarios (one `high severity', the other `mild') would have on our ability to provide intensive care treatment to victims.

Estimates of the demand for mechanical ventilation in the United States during an influenza pandemic.
Meltzer MI1, Patel A2, Ajao A3, Nystrom SV4, Koonin LM5.

Abstract

An outbreak in China in April 2013 of human illnesses due to avian influenza A(H7N9) virus provided reason for US public health officials to revisit existing national pandemic response plans. We built a spreadsheet model to examine the potential demand for invasive mechanical ventilation (excluding "rescue therapy" ventilation).

We considered scenarios of either 20% or 30% gross influenza clinical attack rate (CAR), with a "low severity" scenario with case fatality rates (CFR) of 0.05%-0.1%, or a "high severity" scenario (CFR: 0.25%-0.5%).

We used rates-of-influenza-related illness to calculate the numbers of potential clinical cases, hospitalizations, admissions to intensive care units, and need for mechanical ventilation. We assumed 10 days ventilator use per ventilated patient, 13% of total ventilator demand will occur at peak, and a 33.7% weighted average mortality risk while on a ventilator.

At peak, for a 20% CAR, low severity scenario, an additional 7000 to 11,000 ventilators will be needed, averting a pandemic total of 35,000 to 55,000 deaths.
A 30% CAR, high severity scenario, will need approximately 35,000 to 60,500 additional ventilators, averting a pandemic total 178,000 to 308,000 deaths.

Estimates of deaths averted may not be realized because successful ventilation also depends on sufficient numbers of suitably trained staff, needed supplies (eg, drugs, reliable oxygen sources, suction apparatus, circuits, and monitoring equipment) and timely ability to match access to ventilators with critically ill cases. There is a clear challenge to plan and prepare to meet demands for mechanical ventilators for a future severe pandemic.

Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Worth noting, the `severe' scenario presented - a 30% attack rate and a CFR of .5% - is nowhere near the severity we've already seen with COVID-19. Even if the attack rate remained at 30%, we'll be lucky to see a 1% CFR from this virus.

But even this optimistic scenario finds that - without the unlikely rapid addition of 35,000 to 60,500 ventilators (and trained staff, oxygen, drugs, and electricity to run them) - 200,000 to 300,000 Americans that might otherwise be saved, would die for the lack of ventilator resources.

And this opens up the thorny problems of who gets a ventilator, and for how long? When do you withdraw ventilator support from one patient in order to give it to another? Who makes these decisions? And how will the public react to the heartbreaking realities of triage during a pandemic?

The CDC's 2011 document Ethical Considerations for Decision Making Regarding Allocation of Mechanical Ventilators during a Severe Influenza Pandemic or Other Public Health Emergency spends 27 pages looking at a myriad of legal and ethical considerations, but concludes that `policy decisions need to be set and implemented by the responsible public health officials.'

In 2015 the State of New York released a 266 page manual called VENTILATOR ALLOCATION GUIDELINES, which is broken up into Adult, Pediatric, and Neonatal sections. While this massive document probes deeply into the complexity of triage, it admits:

While the Adult Guidelines developed by the Task Force and the 2006 and 2009 Adult Clinical Workgroups assist a triage officer/committee as they evaluate potential patients for ventilator therapy, decisions regarding treatment should be made on an individual (patient) basis, and all relevant clinical factors should be considered.

A triage decision is not performed in a vacuum; instead, it is an adaptive process, based on fluctuating resources and the overall health of a patient. Examining each patient within the context of his/her health status and of available resources provides a more flexible decision-making process, which results in a fair, equitable plan that saves the most lives.

Adding to the confusion, standards and guidelines will vary from one state to the next, and none have the benefit of having ever been tested under real pandemic conditions. Not to disparage the work that has gone into them, but the old adage that `No battle plan survives contact with the enemy' comes to mind.

These are issues that as a society, we don't like to think about.

We assume there will be a hospital bed, or ventilator, or medicines available to treat us if we need it. But in a severe pandemic we could find our medical infrastructure seriously overwhelmed, and those things we take for granted quickly unavailable.

Which is why you will continue to hear - ad nauseum - about the importance of `flattening the curve' of this pandemic. To reduce the daily number of new cases our hospital system will have to absorb.

If we can stretch an 8 week pandemic wave into 16 or 20 weeks, we can can cut down the number of patients who will be denied an ICU bed or ventilator substantially, and in doing so, save lives.