The Emperor's New PPE... or pointing out what might be missing
As a physician and responder, I am concerned about the guidance and implementation we are seeing across the landscape of US healthcare and public health in reaction to the COVID-19 pandemic. In various settings and situations, I have encountered confusion and misunderstanding regarding the healthcare worker’s personal protective equipment or PPE.
The greatest disparity is related to head coverage. It is not the fault of the practitioner. One has but to review the recommendations given alternatively by WHO, CDC, and Medicens Sans Frontieres or Doctors Without Borders (MSF) and you see some distinction.
Internationally we are seeing head-to-toe coverage. In the US we often are not. The questions are: Why not, and are we getting the best guidance for the protection of both the provider and the patient?
The provider, if not properly covered, decontaminated (washed or rinsed off), or both, risks carrying contaminated material or virus to the next patient or to their clean home, or familial environment.
Precedents
We have seen this before. During the Ebola outbreak, initial guidelines from CDC differed significantly from those from MSF, which recommended complete coverage and an exact process for donning, doffing, and decontamination.
Changes were made as outlined in the article cited above, but only after a US healthcare worker had been infected. Currently CDC guidelines for proper healthcare worker PPE don’t include covering the hair. Internationally and according to WHO, a bonnet and head coverage is included in the consideration. Operating room personnel are required to wear the same.
CDC
WHO
Putting PPE on
Taking PPE off
MSF
Criteria for infectivity and PPE
Disparity on the ground
We have already seen confusion among some responders. Some have voiced concerns about distinction in the instruction, implementation and use in the response to COVID-19.
Questioning the verification or science behind a recommendation is often viewed as oppositional, but it can also be viewed as raising attention when an issue is critical. This is a challenging situation, but where potential endangerment takes place, speaking up is also an act of public service. In a complaint filed with the independent Office of Special Counsel, a whistleblower alleges that workers with the HHS Administration for Children and Families were sent to air force bases from January 28 to 31 and again from February 2 to 7 to meet with American evacuees from Wuhan, China, where COVID-19 first originated. The whistleblower charges that HHS broke protocol and ignored the whistleblower’s concerns about having the workers exposed to the coronavirus.
According to the complaint, workers from CDC, with whom the HHS employees worked side-by-side, were in “full gown, gloves and hazmat attire.”
Cough and sneeze aerosol dynamics
A typical cough starts with a deep breath, followed by a compression of air in the lungs. A crackling burst follows as that air is forced out in a fraction of a second.
Respiratory particles from a cough or sneeze are dispersed in what has been called a multiphase turbulent cloud. This cloud is the description of the way in which respiratory particles from a cough or sneeze are dispersed. This dispersion has been studied extensively. Relatively large droplets tend to travel less than 6 feet; hence the current social distancing recommendation. However, smaller droplets from a cough or sneeze may travel up to 200 times as far if not part of a cloud and may be capable of transmitting more infectious particles, according to an article in MIT News. The study reveals that droplets 100 micrometers in diameter can travel five times farther than previously estimated, that droplets 10 micrometers in diameter can travel 200 times farther, and that “droplets less than 50 micrometers in size can remain airborne long enough to reach ceiling ventilation units.”
What this means
The average human cough would fill about three-quarters of a two-liter soda bottle with air—air that shoots out of the lungs in a jet several feet long. Coughs also force out thousands of tiny droplets of saliva. About 3,000 droplets are expelled in a single cough, and some of them fly out of the mouth at speeds of up to 50 miles per hour.
A sneeze is even worse.
It starts at the back of the throat and produces even more droplets—as many as 40,000—some of which rocket out at speeds greater than 200 miles per hour. The vast majority of the droplets have diameters of less than 100 microns—the width of a human hair. Many of them are so tiny that they cannot be seen with the naked eye.
Most of the larger, heavier drops fall quickly to the floor under the influence of gravity. The smaller and lighter particles (those five microns or less across) are less affected by gravity and can stay airborne almost indefinitely as they are caught up in and dispersed by the room's airflow.
Movements in a room can cause the heavier droplets to become airborne again after they have fallen to the ground or another surface. Making a hospital bed can kick up viruses on the covers. Opening a door can dramatically alter the airflow in the room and pull up viruses on the floor. Even walking through a room can spread droplets in a person's wake.
One might reasonably ask if hair and hair extensions and wigs should also be considered in terms of droplet spread, and if there is data to support that it is not.
If a person is sick, the droplets in a single cough may contain as many as two hundred million virus particles. The number varies dramatically and changes over the course of an infection as the immune system clears out the virus. Generally, a sick person is most infectious as soon as the first symptoms appear and less infectious as his or her immune system clears the virus.
Airborne and ready to infect
Once airborne, viruses in these tiny droplets can survive for hours. Even if the droplets hit a surface, the viruses can survive and still spread disease if the droplets become airborne later. When a droplet lands on paper, its virus particles can survive for hours. On steel or plastic, they can survive far longer.
Assurances of safety and guidance
Unfortunately, it is difficult to have immediately applicable data for an ongoing novel situation, but given the differences in guidance one might consider the analyses that applied in the aftermath of the Ebola crisis. In an evaluation, Effectiveness of Personal Protective Equipment for Healthcare Workers Caring for Patients with Filovirus Disease: A Rapid Review, Thirty non-comparative studies (8 related to Ebola virus disease) were located, and 27 provided data on viral transmission. The conclusion was that reporting of personal protective equipment components and infection prevention and control protocols was generally poor.
Look to the OR
On April 26, 2018, the Association of periOperative Nurses, AORN released a statement as a result of its joint meeting with the American College of Surgeons, ACS, the American Society of Anesthesiologists (ASA), the Association for Professionals in Infection Control and Epidemiology (APIC), the Association of Surgical Technologists (AST), the Council on Surgical and Perioperative Safety (CSPS) and The Joint Commission (TJC). The meeting took place in February to "review and discuss the literature related to recommendations for OR attire, specifically ear and hair covering."
The conclusions from the meeting, issued in the statement, included, “Evidence-based recommendations on surgical attire developed for perioperative policies and procedures are best created collaboratively, with a multi-disciplinary team representing surgery, anesthesia, nursing and infection prevention.”
At present, available scientific evidence does not demonstrate any association between the type of hat or extent of hair coverage and surgical-site infection (SSI) rates. One recent study on head coverings (disposable bouffant or skullcap, cloth cap), identified that the commonly available disposable bouffant hat is the least effective barrier to transmission of particles.”
AORN's "Guideline for Surgical Attire" was published in April 2019.
What can we do with a lack of consensus in a novel situation?
We can intellectually exercise the greatest discretion with a do no harm philosophy and follow a hierarchy of controls. In a hazardous materials situation, that means more coverage and protection until data indicates you can back off or resort to less comprehensive protections. Unfortunately given that we are dealing with a virus whose long-term effects, therapeutics, vaccination protocol, and physical properties are not yet fully understood, it seems that in the interest of sustainment of healthcare personnel and protection of patients and the public, we might act more conservatively to protect everyone and recommend that additional coverage, along with a post care decontamination. At the very least, where individual health is concerned we really should act as conservatively in their interest as possible. Until we have research that supports an assurance that the lack of coverage is safe, we should consider advising that they cover up completely.
Matthew Minson, MD is a physician and has served as a senior health official at the local, state and federal level. He is the author of a series of books championing individual health and social advocacy published by Texas A&M University press and has been a contributor to C-Span, NPR, and PBS. His website is www.preparetodefendyourself.com
Ref:
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