Handling medical waste. Photo courtesy of ourtesy of John Lowe, PhD, assistant professor in the Department of Environmental, Agricultural and Occupational Health at University of Nebraska Medical Center (UNMC).
By Karin Lillis
It’s usually the small things that are overlooked, emphasizes John Lowe, PhD, assistant professor in the Department of Environmental, Agricultural and Occupational Health at University of Nebraska Medical Center (UNMC). Lowe’s facility was among a handful in the United States that treated patients infected with Ebola virus in 2014. Healthcare systems such as UNMC and Emory University Hospital in Atlanta have well-established biocontainment units and expert staff that helped stop the spread of the deadly pandemic pathogen.
It’s clear that healthcare facilities that treat patients with infectious disease are focused on the broader picture—policies, procedures and regulations for disposing of infectious medical waste. The “why” behind these practices is always clear—protecting patients and the community from harm. But sometimes seemingly minute details can fall through the cracks, Lowe notes.
“It’s usually the small things you have to work through ahead of time—they are simple fixes that will vastly improve the safety of those involved,” Lowe says.
For example, UNMC had to consider how much waste was disposed into each biocontamination bag. That meant changing out the size of the trash cans on the unit and patient rooms—per hospital protocol, trash bags are only filled two-thirds of the way. That protects employees in two ways—there is less risk of contaminated waste spilling out of the bag, and staff are less likely to sustain an injury from a bag that is too heavy.
“We made sure that the trash cans equal two-thirds of the bag. If we overfill them, someone has to adjust the contents of the bag,” Lowe says. “We also identified the potential for occupational injury.”
Lowe and his colleagues say other healthcare facilities can learn from the experiences of organizations like UNMC and Emory. Ebola, they note, is only a small part of a larger picture.
UNMC’s biocontainment unit is a five-room, 10-bed unit that was “designed to provide a full spectrum of care, from quarantine to intensive care treatment. It is designed to handle everything from smallpox, SARS, avian influenza and the Ebola virus,” says the hospital’s website. “It is staffed by highly trained medical professionals who have special training in disaster management, cardiac life support and bioterrorism.”
“Early on—about seven or eight years ago—we decided that all environmental cleaning, infection control and waste management would be done by our unit staff,” Lowe says. “It’s easier to maintain things like proper PPE protocol and infection control competency.”
In order to most effectively prevent pathogens from spreading—and protecting the community at large—UNMC’s unit is self-contained. Staff—including nurses, technologists and other clinicians—handle cleaning and disinfecting patient rooms and the unit and treating contaminated waste and linens to render them safe for transport.
“On our biocontainment unit, we adopted onsite sterilization and onsite inactivation of waste. We want our unit to be standalone—with no perception of increasing risk in the hospital or community as a result of waste being moved,” Lowe says. “A major point of restriction of our clinical operation was managing this waste. This is a huge issue for all facilities—not just those with biocontainment units.”
On UNMC’s biocontainment unit, healthcare workers double-bag all solid waste in clear autoclaved bags. Healthcare workers don full personal protective equipment (gown, booties, triple gloves, head covering, face shield and mask). Once the bag is secured, a staff member (in full PPE) places the bag in a pass through autoclave located within the isolation unit and/or to a waste holding container. Once sterilized, the waste is placed in a red biohazard bag, bag top twisted, goose necked and placed inside a medical waste shipping box for incineration, according to Lowe, 2014.
Emory University Hospital’s biocontainment unit has an equally meticulous procedure for treating and handling medical waste: Standard operating procedures dictate that the solid waste collected from patient rooms is placed in biohazard bags—the waste is actually double-bagged in the patient rooms (Lowe, 2014).
“At time of passing into the anteroom, the double-bagged waste is placed inside a third autoclave-specific bag. An autoclave rubber band is used to secure the opening. The bag is not twisted, goose necked, or taped to ensure the bag is able to breathe for proper autoclaving. The autoclave bag is externally wiped with bleach wipes prior to being placed in a covered waste container outside the anteroom. Once the bag is placed inside a barrel and the top is secured, the outside of the barrel is wiped down with bleach wipes (Lowe, 2014).
To autoclave the waste, the bags are removed from the barrel and placed directly into the autoclave. The empty barrel is wiped down with bleach wipes, including both sides of the barrel lid. The inside of the barrel is then sprayed with a 1:10 dilution of bleach or other approved disinfectant. Environmental services personnel wear protective suits, booties, double gloves, head covering, face shield, and mask during the entire autoclaving process” (Lowe, 2014).
Notes Marshall Lyon, MD, associate professor of medicine at Emory University, “Before we place anything in the autoclave on the unit, any known contaminated waste goes into red bags. Nurses inside the unit wipe down the outside of the bag with a bleach-containing solution, put the bag into a second biohazard bag and repeat the process a third time. By the end of the process, employees have bagged the waste five times—including two more after the waste is autoclaved.”
While some might consider the process “overkill,” Lyon notes, it’s critical to have “an abundance of caution to ensure we’re not contaminating our staff. If we can protect our staff, we’re protecting the community at large.”
He says that Emory follows the same procedure any time the decontamination unit is activated—whether it’s a case of smallpox, anthrax, South American hemorrhagic fevers or any other potentially contagious pathogen.
Again, Lowe stresses that healthcare organizations need to focus on the smaller details of the larger policy. For example, he says, many factors need to be taken into account when it comes to moving infectious medical waste through the unit.
For instance, Lowe reports that “one hospital repurposed a dust cart and now uses it as an enclosed waste transport cart.” Staff hauling the waste can load the barrels and containers, close up the cart and transport the waste to the appropriate holding or disposal area. On Nebraska’s biocontainment unit, staff uses that method to transfer potentially infectious medical waste from the patient’s room to the on-unit autoclave.
“We really focused on how we’re moving that waste and where snags can occur,” Lowe says. “Is there an issue of stockpiling the waste while waiting to confirm or rule out a certain pathogen, or is there a bottleneck at the autoclave?”
Long before the outbreak of Ebola and other dangerous pathogens UNMC conducted sterilization mapping studies to determine what temperatures to heat waste in the autoclave, in order to kill biological indicators. “We prepared for this years ago,” Lowe says. “We would not have been able to test our processes with live Ebola. You have to prepare before it’s too late.”
“We have general procedures for medical waste—as all hospitals do—and those requirements for medical waste are pretty clean and consistent,” says Patty Olinger, executive director of the Emory Environmental Health and Safety Office. “Let’s say, for instance, in the case of patients with Ebola. We did a risk assessment. Our current procedures are to box medical waste and send it for incineration. In the case of medical waste contaminated with Ebola, for instance, we took a step back. We autoclaved the waste before shipping it out. Now, a lot of institutions, ours included, are faced with challenges handling waste contaminated with MERS. Do we need to handle the waste any differently, building upon what’s already in place? We have to ensure we’re protecting employees and the community at large.”
Notes infection preventionist Kelley Boston, MPH, CIC, “Whenever there is a new or emerging disease, there is always a confusion of information. A lot of times, hospital staff feel like there is not enough and too much information coming in at the same time—and it’s rapidly changing. One of the roles of infection preventionists is to help waste managers parse through this information.”
Boston, a member of the communications committee for APIC, continues, “We will need to keep in mind the need for rapid retraining of staff. You have to have good measures in place and rapid training of staff. Make sure EVS workers—who are a critical part of the healthcare team—are included in training.”
But what about those hospitals that don’t have a biocontainment unit—like smaller community facilities or suburban healthcare organizations?
“Most community hospitals are prepared to take care of diseases and pathogens like chicken pox, influenza and MRSA,” Lyon says. “They have the tools at their disposal—it’s just a matter of putting everything together. They need to think on a higher level. They need to be cognizant of biothreats that could show up. As long as you think about something you can address it.”
He points to the Centers for Disease Control and Prevention (CDC)’s network of facilities—regional and state hospitals—already approved to treat Ebola.
“Most smaller hospitals can be prepared (that network is there to support them. They don’t need to panic,” Lyon says.
“The network is critical—especially when a hospital is running into unfamiliar situations. Even if I am doing OK and someone can say that I’m headed in right direction,” Olinger says.
The bottom line, Olinger adds, is ensuring healthcare workers protect themselves in order to provide the best possible patient care. “In healthcare, we are very focused on patient-centered care. From the standpoint of biosafety and risk management, you still have to focus on the patient. But provider-centered care comes into play. You have to focus on providers, faculty, nurses, doctors, technicians, other clinicians and support staff. If we can’t protect them, we can’t provide care and we can’t protect the community.”
Reference: Lowe, J, et al. (2014). Nebraska Biocontamination Unit perspective on Ebola Medical Waste. Journal of Infection Control. 42:1256-7.
The Persistence of Ebola Virus in Wastewater
The outbreak of Ebola virus disease in West Africa that began in March 2014 and has killed more than 11,000 people since, has raised new questions about the resilience of the virus and tested scientists' understanding of how to contain it.
John Lowe, PhD, at UNMC, says one of his facility's big concerns was handling liquid waste from Ebola. “Could you put liquid waste into the sewer? There is clear evidence that sewer treatment plants in the United States are capable of deactivating Ebola," Lowe says. "What we found out, as soon as we had a patient in the unit with Ebola, we had to work with the local public works and other groups about potential upstream exposures or what would happen if there was a sewer line or sewer main failure. We made the decision to pretreat our liquid waste with a hospital-grade EPA registered disinfectant prior to discharging it into the sewer system. That put the public works, interior and exterior plumbers groups at ease, knowing we were doing whatever we could to protect them.”
The latest discovery by a group of microbial risk-assessment and virology researchers suggests that the procedures for disposal of Ebola-contaminated liquid waste might underestimate the virus' ability to survive in wastewater.
Current epidemic response procedures from both the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) advise that after a period of days, Ebola-contaminated liquid can be disposed of directly into a sewage system without additional treatment. However, new data recently published by researchers from the University of Pittsburgh, Drexel University, and the National Institutes of Health indicate that Ebola can survive in detectable concentrations in wastewater for at least a week or longer.
"Initial research by the WHO and CDC recommended disposing of Ebola-contaminated liquid waste into a latrine or treatment system without disinfection because the virus wasn't expected to persist in wastewater," explains Kyle J. Bibby, assistant professor of civil and environmental engineering at Pitt's Swanson School of Engineering and principal investigator of the study "Persistence of Ebola Virus in Sterilized Wastewater," published in the journal Environmental Science & Technology Letters. "However, we found that the virus persisted over a period of at least eight days."
The researchers gathered their data by observing the change in viral particle concentration in two samples, spiked with different concentrations of the virus, over an eight-day period. The testing was performed in a secured lab at the NIH. While the researchers observed a 99 percent decrease in concentration after the first day, the remaining viral particles were detectable for the duration of the experiment.
"These results demonstrate a greater persistence of Ebola virus in wastewater than previously speculated," says co-author Charles Haas, head of the Department of Civil, Architectural, and Environmental Engineering; the LD Betz Professor of Environmental Engineering; and director of the Environmental Engineering Program. "While the Ebola virus was found to be generally less persistent than enteric viruses in wastewater, the identified survival period might suggest a potential of a wastewater exposure route."
Historically, it was believed that the virus could only be transmitted through direct contact with bodily fluids, but there have been cases where people contracted the disease without apparently coming in contact with infected fluids. This, the study suggests, could be an indication that large liquid droplets might be a vector for the virus--which means greater care should be taken when handling contaminated liquid waste. And given that an infected patient may produce up to nine liters of liquid waste per day, if infected liquid could carry the virus to someone else, this could be a significant risk factor.
The team also notes that the virus' seemingly early decay upon entry into wastewater might be due to the viral particles clumping together or latching onto other particles in the water, rather than the virus dying. These phenomena would actually make the viruses less susceptible to environmental factors, such as disinfectants, that would normally kill them off.
A proposed solution, already adopted by the WHO, would be to hold the contaminated liquid waste for a longer period of time before releasing it into the sewage system. Another might be to pretreat it with an antiviral agent, such as chlorine, although performance data on disinfectants is needed as well. These options would provide more time for the viral concentration to decay and for the remaining viruses to be inactivated.
"These results indicate that further research is needed with a more holistic approach to assessment of Ebola-infected wastewater, from storage to treatment to disposal and continued monitoring, including a precautionary approach to wastewater handling in all epidemic responses," Bibby says.
In addition to studying whether or not Ebola can actually be contracted from exposure to wastewater, the next step for this research thread would be to review variations in the wastewater composition, such as temperature, microbe population and pH level, the use of disinfectants, and the viral concentration's effect on the decay and inactivation of the virus.