Ebola and Medical Device Sterilization
In recent weeks there has been a lot of concern about Ebola viral disease and how to prevent the disease from spreading from one person to another. This has been especially focused on how do health care workers protect themselves and thus protect the public from becoming contaminated with the Ebola virus. Recent cases of Ebola in the USA have pointed up some issues with following the protocols for preventing the spread of infectious microorganisms. Because of issues with the virulence of this disease questions have also arisen on what precautions need to be taken when contacting a patient who has Ebola. Also, are there any special precautions that need to be taken by the surgical team when a patient with Ebola has surgery or by sterile processing technicians when instruments from an Ebola patient are cleaned? To answer the question about precautions that sterile processing personnel need to take let’s first review the Chain of Infection and the protocols for handling of materials contaminated with blood, body fluids or other potentially infectious material (OPIM).
A number of things need to happen before an infectious disease can be spread from one entity (person or animal) to another entity (person or animal). Infectious disease experts often describe this as the Chain of Infection. I think a brief review of the Chain of Infection and how infectious disease can be spread will be helpful to understand the precautions that need to be taken when contacting patients in the health care setting.
There are six links in the Chain of Infection:
- Causative agent - the microorganism or pathogen that is capable of causing a disease, e.g, Ebola virus.
- Reservoir of the agent - a place where the infectious agent can survive, e.g. animal or human carrier, bed linens, surgical instruments
- Portal of exit of the agent from the reservoir - the way in which an infectious agent leaves a reservoir, e.g. blood, mucous or wound drainage, vomit, stool
- Mode of transmission - the way in which an infectious agent moves from a reservoir to a susceptible host, e.g. direct or indirect contact with the infectious agent, contaminated food or water, airborne or vectors (insects or arthropods)
- Portal of entry - the way in which an infectious agent enters a susceptible host, e.g. respiratory, non-intact skin or mucous membrane, parenteral (needle punctures)
- Susceptible host - a person or animal that lacks the ability to resist infection by an infectious agent, many factors can increase a person’s susceptibility to an infectious agent, e.g. very young or elderly, underlying disease (diabetes, heart disease), inadequate nutrition, compromised immune status, and trauma
If any of the links in the Chain of Infection are broken then the disease cannot be transmitted and the disease will not occur in the new host. One of the ways in which health care workers can break the Chain of Infection is through the use of Standard Precautions. Standard Precautions are used to prevent an infectious agent from coming into contact with a portal of entry. If the infectious agent cannot enter a portal of entry because the portal has been blocked with protective attire then it will not be possible for the infectious agent to cause a disease.
Standard Precautions are to be used for any contact with a patient in a health care setting; these precautions are intended to reduce the risk of the spread of infection from known and unknown sources. These precautions require that all patients are treated as if they might have an infectious disease. The issue here is that one can’t always tell by looking at someone that they have an infectious disease. Standard Precautions include: 1) hand hygiene, 2) use of personal protective equipment (PPE) (e.g., gloves, gowns, masks), 3) safe injection practices, 4) safe handling of potentially contaminated equipment or surfaces in the patient environment, and 5) respiratory hygiene/cough etiquette. An assessment needs to be performed to determine the level of risk present when treating a particular patient. The level of risk for transmitting a disease increases in the presence of blood, body fluids or OPIM. A higher level of risk will require a higher level of protection. This means that gloves should always be worn whenever touching a patient’s skin or mucous membranes. Hand hygiene should always be performed before donning gloves and after removing those gloves. If there was any contact with blood, body fluids or OPIM then the hand hygiene should be with soap and water.
In the USA protective apparel for healthcare workers is classified by the level of protection provided. ANSI/AAMI PB70 “Liquid barrier performance and classification of protective apparel and drapes intended for use in health care facilities” describes four levels of protection that protective apparel could have. The highest level of protection, Level 4, is required when it is expected that there will be large amounts of blood, body fluids or OPIM and/or when it is expected that these fluids and the protective attire could be subjected to excessive pressure as when performing long surgical procedures or when performing cleaning and decontamination procedures on reusable medical devices (surgical instrumentation). This level of protection is required whether or not we know that the patient has Ebola or any other infectious disease. The patient could have an infectious disease that we don’t know about and that can be spread by contact with blood, body fluids or OPIM, e.g. MRSA, hepatitis B, hepatitis C, HIV, etc.
In the case of Ebola which can cause can cause exposure to large amounts of blood, body fluids or OPIM because of vomiting, diarrhea, and internal and external bleeding, Level 4 protection is required. In addition to deciding the level of protection required for a particular health care procedure it is also necessary to remove and dispose of the protective attire correctly. The blood, body fluid and OPIM that may now be present on the protective attire can cause an infection if contact with non-intact skin or mucous membranes occurs. This can happen if a person has contact with protective attire that has blood, body fluid or OPIM on it that contains an infectious agent. Contact with the protective attire can transmit the infectious agent from the attire to the person handling the attire (indirect contact). Though this type of transmission is rare it is very possible when dealing with a highly infectious agent like Ebola. For this reason it is necessary to follow strict protocols on removal of protective attire after use and for handling of that protective attire before it is disposed of or cleaned. For this reason it is necessary to follow recommended procedures for removal of protective attire. These procedures are intended to ensure that the health care worker does not contaminate themselves or the environment when removing the protective attire. When dealing with a patient that has Ebola the CDC recommends that a trained observer be used to ensure that the PPE is donned and doffed correctly. Correctly following procedures for donning and doffing of protective attire is critical to ensure that exposure to the Ebola virus does not occur.
In the event that surgery is performed on a patient with Ebola the sterile processing technician must follow all procedures for use of PPE when decontaminating the instrumentation. There should be no difference in the type of PPE required. Remember AAMI Level 4 protection is required for performing surgical instrumentation decontamination procedures. What is required is to ensure that the PPE is donned correctly so that there is no exposed skin and there is no chance of contamination occurring at the gown/glove interface. This means wearing 1) gowns that meet the AAMI Level 4 protection, 2) gloves that are long enough to fit over the gown cuff and up onto the arm and that fit tightly to the arm so that fluid cannot run down the gown, under the glove and onto the hand, 3) hair covers, 4) full facial protection, 5) surgical masks and 6) shoe or boot covers. When the PPE is removed the doffing must be done in such a way that the outside of the gown, shoe covers, gloves etc. that could be contaminated are placed into a disposal container and do not allow the outer surface to come into contact with other surfaces. Remember indirect contact can be a mode of transmission. For example, if the outside of a contaminated gown were to come into contact with the outside of a disposal container then contact with the outside of the disposal container could transmit the infectious agent.
Additional information on disposal of biohazardous waste that has been contaminated by the Ebola virus can be found in the Multisociety Statement on Processing Biohazardous Medical Waste. This statement was developed at the recent AAMI Sterilization Standards Committee Meetings and was approved by AAMI, AORN, APIC, AST and IAHCSMM. The statement can be found on the IAHCSMM web site at: https://www.iahcsmm.org/resources/ebola-resources.html or on the AAMI web site at: http://www.aami.org/hottopics/ebola/index.html
Basically if sterile processing technicians follow the current acceptable practices for decontaminating contaminated medical devices and surgical instrumentation there should be very little chance that the Ebola virus can be transmitted to them from a patient or contaminated medical device, including surgical instrumentation.
Donna Swenson, BS, CRCST, CHL, ACE, CSPDM, Co-chair AAMI PB70 Protective Barriers