Since the onset of the pandemic, the most daunting task in health care has been seen as a doctor inserting a breathing tube into the trachea of a critically ill Covid patient.
Those who perform such “aerosol-generating” procedures, often in an intensive care unit, have been provided with the best protective equipment, even if there would not be enough to go around, according to the Centers for Disease Control and Prevention. And for anyone else working with Covid patients, a surgical mask until a month ago is considered adequate.
A new wave of research now shows that several of the procedures were not the most dangerous. Recent studies have determined that a basic cough produces about 20 times more particles than intubation.
Other new studies show that patients with Covid, simply by talking or breathing, even in a well-ventilated room, can make workers sick in the CDC-sanctioned surgical masks. The studies suggest that the greatest risk of infection was among the frontline workers – many of whom were colored – who spent most of their time earlier in their illnesses and patients with the patients, not those working in the Covid ICU.
“The whole thing is upside down as it is currently set up,” said Dr. Michael Klompas, associate professor at Harvard Medical School. The term “aerosol-generating procedure” referred to a “misnomer” in a recent article in the Journal of the American Medical Association.
“It’s a big mistake,” he said.
The growing number of studies showing the distribution of Covid-19 aerosol during choir rehearsals, in a bus, in a restaurant and at gyms, has attracted the public’s attention and led to a wide interest in better masks and ventilation.
Yet the topic was very controversial in the healthcare industry. For more than a year, international and U.S. nurses’ union leaders have called on health workers who care for or confirm Covid patients to have the highest level of protection, including N95 masks.
But many experts, backed by national and California hospital associations, have long insisted that N95s be reserved for those performing aerosol-generating procedures, saying other frontline workers can safely care for Covid patients while wearing less protective surgical masks.
According to the guidelines, a worker will not be considered ‘exposed’ to Covid-19 after caring for a sick Covid patient while wearing a surgical mask. Yet, in recent months, Klompas and researchers in Israel have documented cases where workers using surgical masks and face masks became ill with Covid after providing routine care.
The CDC said in an email that N95 “respirators remained preferred over face masks when caring for patients or residents with suspected or confirmed” Covid, “but unfortunately respirators were not always available to health care workers due to supply shortages. not.”
Other new research by Harvard and Tulane scientists has found that so-called Covid super-distributors – the 20% of the people who emit 80% of the small particles – tend to be obese or older, a population more likely to be in parental care or be hospitalized.
When highly contagious, such patients emit three times as many small aerosol particles (about a billion a day) as younger or non-obese people. An infected super-distributor who simply breathes can pose as many risks to health care workers as a cough patient, said David Edwards, a Harvard associate in bioengineering and an author of the study.
According to the study, nursing home workers, of whom more than 546,000 Covid contracted and 1,590 died, are facing serious risks, according to reports submitted to the Centers for Medicare and Medicaid since mid-May.
Collectively, the research suggests that exposure to the workplace in health care was “much greater” than what the CDC defined when it prioritizes those who prioritize ‘aerosol-generating’ procedures, says Dr. Donald Milton, who reviewed the studies. but was not involved in any of them. .
‘The result is that it’s inhalation’ of small particles into the air that leads to infection, says Milton, a professor at the University of Maryland School of Public Health studying the spread of respiratory viruses, ‘which means loose surgical masks is not sufficient. . ”
On February 10, the CDC updated its guidelines to health workers by removing a proposal that wearing a surgical mask while caring for Covid patients be acceptable and urging workers to wear an N95 or a to wear ‘well-fitting face mask’, which includes a snug cloth mask over a looser surgical mask.
However, the update came after nearly 3,500 U.S. health workers had already died from Covid, as documented by the Guardian / KHN in the Lost on the Frontline project.
The project is more comprehensive than the U.S. government’s death toll. Current CDC data show 1,391 deaths in health care workers, which is 200 less than the total staff who reported Covid deaths nursing homes to the U.S. Centers for Medicare and Medicaid.
More than half of the deceased workers whose occupation was known were nurses or in roles in health care. Such staff members often have the most extensive patient contact, caring for their IVs and turning into hospital beds. brush their hair and sponge them in nursing homes. Many of them – two out of three – were workers of color.
Two UK anesthetists – doctors who do intubations in the ICU – have seen data showing non-ICU employees dying from excessive deaths, and have begun to question the idea that ‘aerosol-generating’ procedures are the most dangerous.
Dr Tim Cook, an anesthetist at Royal United Hospitals Bath, said the guidelines for the procedures were based on research from the first Sars outbreak in 2003. A widely cited study in 2012 warned that earlier studies was ‘very low’ and said there was a ‘significant research gap’ that needed to be filled.
But the research never took place before Covid-19 emerged, Cook said, and the main differences arose between Sars and Covid-19. In the first Sars outbreak, the patients were infected at the moment they arrived at a hospital in need of intubation. Yet studies of Covid patients in early summer began to show that peak infection occurred days before.
Cook and his colleagues discovered in October that the dreaded practice of intubation emits about 20 times fewer aerosols than a cough, said Dr Jules Brown, a British anesthetist and another author of the study. Extubation, also considered an “aerosol-generating” procedure, generated slightly more aerosols, but only because patients sometimes coughed when the tube was removed.
Since then, researchers in Scotland and Australia have validated these findings in a paper published on February 10, showing that two other aerosol-generating procedures were not as dangerous as talking, breathing heavily or coughing.
Brown said the initial shortage of PPE led to rationing and sent the best respiratory protection to anesthetists and intensivists like him. Now that it is known that emergency and nursing home workers are also at extreme risk, he said, he cannot understand why the old guidelines largely exist.
“It was all a big house of cards,” he said. “The foundation was shaky and I think it all fell apart.”
A CDC spokesman asked in an email about the research: “We are encouraged by the publication of new studies aimed at addressing this issue and better identifying what procedures in healthcare settings can cause aerosol. As studies accumulation and findings are repeated, CDC will update its list of procedures under consideration [aerosol-generating procedures]. ”
Cook also found that doctors who do intubations and work in the ICU have a lower risk than those who worked on general medical floors and encountered patients in earlier stages of the disease.
In Israel, doctors in a children’s hospital went viral from the mother of a three-year-old patient to six staff members, although all were masked and removed. The mother was pre-symptomatic and the authors said in the January 27 study that the case may be ‘evidence of an airborne transmission’.
Klompas, of Harvard, made a similar finding after leading an in-depth investigation into a September outbreak among patients and staff at Brigham and Women’s Hospital in Boston.
There, a patient who tested negative Covid developed the virus two days in a row and infected numerous staff members and patients. Among them were two patient care technicians who treated the patient while wearing surgical masks and face shields. Klompas and his team used genome sequencing to connect the sick workers and patients with the same outbreak.
CDC guidelines do not consider the care of a Covid patient in a surgical mask as a source of ‘exposure’, but for the in-depth study, the technician cases and others may not be considered work-related.
The seriousness of the guidelines on the dangers of “aerosol-generating” procedures has led hospital administrators to assume that those in the ICU become ill at work and that those who work elsewhere are exposed in the community, Tyler Kissinger, a organizer of the National Union, said. health workers in northern California.
“What plays out there is the difference in whose exposure is taken seriously,” he said. ” A phlebotomy or environmental service worker or nursing assistant with patient contact – only a surgical mask and not an N95 – is not considered exposed. They had to keep coming to work. ”
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KHN (Kaiser Health News) is a national news agency that provides in-depth journalism on health issues. Together with policy analysis and survey, KHN is one of the three most important operational programs at KFF (Kaiser Family Foundation). KFF is a non-profit organization that provides information on health issues to the country