PART 21. April 23, 2020. CORONAVIRUS. “We need to ask, are we using ventilators in a way that makes sense for other diseases but not for this one?”

April 24, 2020

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CORONOVIRUS TRACKING Links to Parts 1-21

“President Trump on Saturday cited “positive signs” in the fight against the coronavirus pandemic, claiming that he inherited “broken junk” from the prior administration but has since turned the U.S. into the “king of ventilators.”” (A)

“Just about a month ago, people stricken with the new coronavirus started to arrive in unending ranks at hospitals in the New York metropolitan area, forming the white-hot center of the pandemic in the United States.

Now, doctors in the region have started sharing on medical grapevines what it has been like to re-engineer, on the fly, their health care systems, their practice of medicine, their personal lives.

Medicine routinely remakes itself, generation by generation. For the disease that drives this pandemic, certain ironclad emergency medical practices have dissolved almost overnight.

The biggest change: Instead of quickly sedating people who had shockingly low levels of oxygen and then putting them on mechanical ventilators, many doctors are now keeping patients conscious, having them roll over in bed, recline in chairs and continue to breathe on their own — with additional oxygen — for as long as possible.

The idea is to get them off their backs and thereby make more lung available. A number of doctors are even trying patients on a special massage mattress designed for pregnant women because it has cutouts that ease the load on the belly and chest.

Other doctors are rejiggering CPAP breathing machines, normally used to help people with sleep apnea, or they have hacked together valves and filters. For some critically ill patients, a ventilator may be the only real hope.” (B)

“Even as hospitals and governors raise the alarm about a shortage of ventilators, some critical care physicians are questioning the widespread use of the breathing machines for Covid-19 patients, saying that large numbers of patients could instead be treated with less intensive respiratory support.

If the iconoclasts are right, putting coronavirus patients on ventilators could be of little benefit to many and even harmful to some.

What’s driving this reassessment is a baffling observation about Covid-19: Many patients have blood oxygen levels so low they should be dead. But they’re not gasping for air, their hearts aren’t racing, and their brains show no signs of blinking off from lack of oxygen.

What is making critical care physicians suspect that blood levels of oxygen, which for decades have driven decisions about breathing support for patients with pneumonia and acute respiratory distress, might be misleading them about how to care for those with Covid-19. In particular, more and more are concerned about the use of intubation and mechanical ventilators. They argue that more patients could receive simpler, noninvasive respiratory support, such as the breathing masks used in sleep apnea, at least to start with and maybe for the duration of the illness.

“I think we may indeed be able to support a subset of these patients” with less invasive breathing support, said Sohan Japa, an internal medicine physician at Boston’s Brigham and Women’s Hospital. “I think we have to be more nuanced about who we intubate.”..

An oxygen saturation rate below 93% (normal is 95% to 100%) has long been taken as a sign of potential hypoxia and impending organ damage. Before Covid-19, when the oxygen level dropped below this threshold, physicians supported their patients’ breathing with noninvasive devices such as continuous positive airway pressure (CPAP, the sleep apnea device) and bilevel positive airway pressure ventilators (BiPAP). Both work via a tube into a face mask.

In severe pneumonia or acute respiratory distress unrelated to Covid-19, or if the noninvasive devices don’t boost oxygen levels enough, critical care doctors turn to mechanical ventilators that push oxygen into the lungs at a preset rate and force: A physician threads a 10-inch plastic tube down a patient’s throat and into the lungs, attaches it to the ventilator, and administers heavy and long-lasting sedation so the patient can’t fight the sensation of being unable to breathe on his own.

But because in some patients with Covid-19, blood-oxygen levels fall to hardly-ever-seen levels, into the 70s and even lower, physicians are intubating them sooner. “Data from China suggested that early intubation would keep Covid-19 patients’ heart, liver, and kidneys from failing due to hypoxia,” said a veteran emergency medicine physician. “This has been the whole thing driving decisions about breathing support: Knock them out and put them on a ventilator.”..

The question is whether ICU physicians are moving patients to mechanical ventilators too quickly. “Almost the entire decision tree is driven by oxygen saturation levels,” said the emergency medicine physician, who asked not to be named so as not to appear to be criticizing colleagues…

“We need to ask, are we using ventilators in a way that makes sense for other diseases but not for this one?” Gillick said. “Instead of asking how do we ration a scarce resource, we should be asking how do we best treat this disease?”… (C)

“Some doctors are also concerned that ventilators could be further harming certain coronavirus patients, as the treatment is hard on the lungs, the AP reported.

Dr. Tiffany Osborn, a critical-care specialist at the Washington University School of Medicine, told NPR on April 1 that ventilators could actually damage a patient’s lungs.

“The ventilator itself can do damage to the lung tissue based on how much pressure is required to help oxygen get processed by the lungs,” she said.

Dr. Negin Hajizadeh, a pulmonary critical-care doctor at New York’s Hofstra/Northwell School of Medicine, also told NPR that while ventilators worked well for people with diseases like pneumonia, they don’t necessarily also work for coronavirus patients.

She said that most coronavirus patients in her hospital system who were put on a ventilator had not recovered.

She added that the coronavirus does a lot more damage to the lungs than illnesses like the flu, as “there is fluid and other toxic chemical cytokines, we call them, raging throughout the lung tissue.”

“We know that mechanical ventilation is not benign,” Dr. Eddy Fan, an expert on respiratory treatment at Toronto General Hospital, told the AP.

“One of the most important findings in the last few decades is that medical ventilation can worsen lung injury — so we have to be careful how we use it.”

Doctors are trying to find other solutions and reduce their reliance on ventilators

The lack of treatment options for coronavirus patients has caused much of the world to turn to ventilators for the worst-affected patients.

But the high death rates reported among patients on ventilators have prompted some doctors to seek alternatives and reduce their reliance on ventilators, the AP reported.

Dr. Joseph Habboushe, an emergency-medicine doctor in Manhattan, told the AP that until a few weeks ago, it was routine in the city to place particularly ill coronavirus patients on ventilators. Now doctors are increasingly trying other treatments.

“If we’re able to make them better without intubating them,” Habboushe said, “they are more likely to have a better outcome — we think.”

According to the AP, doctors are putting patients in different positions to try to get oxygen into different parts of their lungs, giving patients oxygen through nose tubes, and adding nitric oxide to oxygen treatments to try to increase blood flow.

Dr. Howard Zucker, the New York state health commissioner, said on Wednesday that officials were examining other treatments to use before ventilation but that it was “all experimental,” the AP reported.” (D)

“Only a few weeks ago in New York City, coronavirus patients who came in quite sick were routinely placed on ventilators to keep them breathing, said Dr. Joseph Habboushe, an emergency medicine doctor who works in Manhattan hospitals…

There are widespread reports that coronavirus patients tend to be on ventilators much longer than other kinds of patients, said Dr. William Schaffner, an infectious diseases expert at Vanderbilt University.

Experts say that patients with bacterial pneumonia, for example, may be on a ventilator for no more than a day or two. But it’s been common for coronavirus patients to have been on a ventilator “seven days, 10 days, 15 days, and they’re passing away,” said New York Gov. Andrew Cuomo, when asked about ventilator death rates during a news briefing on Wednesday…

Experts think most people who are infected suffer nothing worse than unpleasant but mild illnesses that may include fever and coughing.

But roughly 20% — many of them older adults or people weakened by chronic conditions — can grow much sicker. They can have trouble breathing and suffer chest pain. Their lungs can become inflamed, causing a dangerous condition called acute respiratory distress syndrome. An estimated 3% to 4% may need ventilators.

“The ventilator is not therapeutic. It’s a supportive measure while we wait for the patient’s body to recover,” said Dr. Roger Alvarez, a lung specialist with the University of Miami Health System in Florida…

“Needing to be ventilated might mean never getting off the ventilator,” he said.” (E)

“Acute respiratory distress syndrome, or ARDS, is the endgame for the unluckiest COVID-19 patients. By that point, the virus has begun to destroy the tiny compartments in the lungs where blood normally collects oxygen. Roaring inflammation, a response to infection, further deteriorates the lung’s ability to draw in air. Without help, these patients could drown.

More than a dozen medications that were developed to treat other diseases are now being tested on COVID-19 patients. Ideally, several of them would allow patients with mild to moderate symptoms recover before their illnesses reach the severe or critical stage.

But researchers are not stopping there.

They are also using artificial intelligence to identify patients who are most likely to develop ARDS and need the gold standard treatment to survive. They’re devising ways to provide breathing assistance with techniques short of mechanical ventilation. If the ventilator shortage becomes desperate, as it has already in some New York City hospitals, doctors will likely try some of these alternatives to rescue dying patients.

Patients who are older, male and have underlying conditions such as heart disease, diabetes or asthma tend to have worse outcomes. But there are exceptions to that pattern. As they assess incoming COVID-19 patients, doctors need better ways to predict the courses their charges will likely take.

A team of researchers in China and at New York University turned to machine learning to see whether useful clues could be found through a massive scouring of symptoms, blood test results and patient characteristics.

Aided by artificial intelligence techniques, the researchers performed an exhaustive scrub of data from 53 patients who were treated in a hospital in Wenzhou, China. Their work identified the three top signs of a patient likely to develop critical illness, as well as their order of importance.

The resulting list amounts to a step-by-step “decision tree” to help doctors triage patients early and set aside scarce ventilators for the right ones.

At the top of the list: a slightly elevated level of the liver enzyme alanine aminotransferase, or ALT. It is one of 20 measures of metabolic and organ function, blood oxygenation and inflammation that’s routinely tested in all hospitalized patients.

In those who would go on to develop ARDS, ALT levels were so slightly above normal that “it would not necessarily set off alarm bells,” said Dr. Megan Coffee of NYU, who has been working on the research while treating COVID-19 patients. But in winnowing out patients most likely to need a respirator, it offers a powerful first clue.

Once that liver enzyme reading has tripped the alarm, a patient’s report of overall achiness appears to hold important information. After that, there’s a high likelihood of trouble ahead if sign No. 3 is present — an elevated hemoglobin level that looks like the opposite of anemia.

A patient’s male gender, higher temperature and abnormal sodium levels were measures 4, 5 and 6 on the list of predictors…

Coffee and her colleague Anasse Bari of NYU’s Courant Institute plan to refine their prediction tool by adding in the disease histories of more than 14,000 COVID-19 patients that have been admitted to New York City hospitals. Bari hopes a reliable decision tree will help guide healthcare workers in countries such as his native Morocco, where hospitals are expected to be overwhelmed in the pandemic.

Another approach is to find existing medical equipment that can function like a ventilator in certain circumstances.

A leading contender is the bilevel positive airway pressure device that is ordinarily used to help patients with breathing problems that have not progressed to the critical stage. BiPap machines could be used to wean some improving patients from the invasive mechanical ventilators, freeing them up for incoming patients, said Dr. Atul Malhotra, a lung specialist at UC San Diego. Already used widely in New York City, where COVID-19 patients are outstripping ventilators, BiPap machines deliver oxygen under pressure through a mask. Patients can readily pull them off to cough or because they are uncomfortable, so they pose extra infection risks to healthcare workers…” (F)

“For weeks, U.S. government officials and hospital executives have warned of a looming shortage of ventilators as the coronavirus pandemic descended.

But now, doctors are sounding an alarm about an unexpected and perhaps overlooked crisis: a surge in Covid-19 patients with kidney failure that is leading to shortages of machines, supplies and staff required for emergency dialysis.

In recent weeks, doctors on the front lines in intensive care units in New York and other hard-hit cities have learned that the coronavirus isn’t only a respiratory disease that has led to a crushing demand for ventilators.

The disease is also shutting down some patients’ kidneys, posing yet another series of life-and-death calculations for doctors who must ferry a limited supply of specialized dialysis machines from one patient in kidney failure to the next. All the while fearing they may not be able to hook up everyone in time to save them.

It is not yet known whether the kidneys are a major target of the virus, or whether they’re just one more organ falling victim as a patient’s ravaged body surrenders. Dialysis fills the vital roles the kidneys play, cleaning the blood of toxins, balancing essential components including electrolytes, keeping blood pressure in check and removing excess fluids. It can be a temporary measure while the kidneys recover, or it can be used long-term if they do not. Another unknown is whether the kidney damage caused by the virus is permanent…

Kidney specialists now estimate that 20 percent to 40 percent of I.C.U. patients with the coronavirus suffered kidney failure and needed emergency dialysis, according to Dr. Alan Kliger, a nephrologist at Yale University School of Medicine who is co-chairman of a Covid-19 response team for the American Society of Nephrology…

As the coronavirus spread rapidly in New York and in other cities, governors and mayors clamored for thousands more ventilators. But doctors have been surprised by the scarcity of dialysis machines and supplies, especially specialized equipment for continuous dialysis. That treatment is often used to replace the work of injured kidneys in critically ill patients.

The shortages involved not only the machines, but also fluids and other supplies needed for the dialysis regimen. Having enough trained nurses to provide the treatment has also been a bottleneck. Hospitals said they have called on the federal government to help prioritize equipment, supplies and personnel for the areas of the country that most need it, adding that manufacturers had not been fully responsive to the higher demand.

The fluids needed to run the dialysis machines are not on the Food and Drug Administration’s watch list of potential drug shortages, although the agency said it was closely monitoring the supply. The Federal Emergency Management Agency described the shortage of supplies and equipment as “unprecedented,” and said it was working with manufacturers and hospitals to identify additional supplies, both in the United States and overseas.

“Everybody thought about this as a respiratory illness,” said Dr. David Charytan, the chief of nephrology at N.Y.U. Langone Medical Center. “I don’t think this has been on people’s radar screen.”” (G)

“By using ventilators more sparingly on Covid-19 patients, physicians could reduce the more-than-50% death rate for those put on the machines, according to an analysis published Tuesday in the American Journal of Tropical Medicine and Hygiene.

The authors argue that physicians need a new playbook for when to use ventilators for Covid-19 patients — a message consistent with new treatment guidelines issued Tuesday by the National Institutes of Health, which advocates a phased approach to breathing support that would defer the use of ventilators if possible.

As the pandemic has flooded hospitals with a disease that physicians had never before seen, health care workers have had to figure out treatment protocols on the fly. Starting this month, a few physicians have voiced concern that some hospitals have been too quick to put Covid-19 patients on mechanical ventilators, that elderly patients in particular may have been harmed more than helped, and that less invasive breathing support, including simple oxygen-delivering nose prongs, might be safer and more effective.

The new analysis, from an international team of physician-researchers, supports what had until now been mainly two hunches: that some of the Covid-19 patients put on ventilators didn’t need to be, and that unusual features of the disease can make mechanical ventilation harmful to the lungs.

“This is one of the first coherent, comprehensive, and reasonably clear discussions of the pathophysiology of Covid-19 in the lungs that I’ve seen,” said palliative care physician Muriel Gillick of Harvard Medical School, who was one of the first to ask if ventilators were harming some Covid-19 patients, especially elderly ones. “There is mounting evidence that lots of patients are tolerating fairly extreme” low levels of oxygen in the blood, suggesting that such hypoxemia should not be equated with the need for a ventilator….

It’s important to highlight “aspects of Covid-19 that differ from other diseases that require respiratory support,” said Phil Rosenthal of the University of California, San Francisco, editor of the journal. Patients with Covid-19 pneumonia are often less breathless “compared to other patients with similar [blood oxygen] levels,” he said, adding that this difference “may allow physicians to avoid intubation/ventilator support in some patients.”

There is a growing recognition that some Covid-19 patients, even those with severe disease as shown by the extent of lung infection, can be safely treated with simple nose prongs or face masks that deliver oxygen.The latter include CPAP (continuous positive airway pressure) masks used for sleep apnea, or BiPAP (bi-phasic positive airway pressure) masks used for congestive heart failure and other serious conditions. CPAP can also be delivered via hoods or helmets, reducing the risk that patients will expel large quantities of virus into the air and endanger health care workers…

The Covid-19 treatment guidelines released by the NIH do not specifically address what criteria physicians should use for putting patients on a ventilator. But in a recognition of the damage that the ventilators can do, they recommend a phased approach to breathing support: oxygen delivered by simple nose prongs, escalating if necessary to one of the positive-pressure devices, and intubation only if the patient’s respiratory status deteriorates. If mechanical ventilation becomes necessary, the NIH said, it should be used to deliver only low volumes of oxygen, reflecting the risk of damaging healthy lung tissue” (H)