Man’s obsession for cleanliness is evident from the vast array of cleaning products available on the supermarket shelf. There is a cleaning product for practically everything man-made, no doubt fuelled by a growing perception that being clean and germ-free is healthier. Though not universally true, this principle does apply to the field of healthcare, particularly so in preventing the spread of infections within hospitals.
Hospitals are places where dangerous germs can be found. These germs are brought in by sick patients, but can go on to colonise hospital wards, rooms, ICU’s, ventilators, operation theatres and instruments. To keep patients safe, hospitals therefore have strict cleaning and disinfection practices. When these systems are inadequate, infections sometimes spread to other patients; these are called nosocomial or hospital-acquired infections.
Earlier this year, news broke about how dirty endoscopes were used at an American air base clinic in Qatar, exposing as many as 135 patients to infection. Under ideal conditions, an invasive instrument used on a patient requires to be cleaned thoroughly and disinfected prior to using it on another patient. It turned out that the technician involved in this case failed to follow the recommended disinfection protocol.
This incident raises several important points. First, it exposes the vulnerability of any system to fail. The role of human error is highlighted. It also serves as an opportunity for all healthcare facilities to take a look at their own disinfection practices.
By taking a detailed behind-the-scenes look at endoscopy, this article explains how hospitals and clinics reprocess their instruments in a way that makes it safe for use in the next patient. Common pitfalls, and simple yet effective preventive strategies are also discussed.
What is reprocessing?
Not all medical equipment is disposable. Inexpensive items such as gloves, masks, syringes and needles are discarded after a single use; hence there is no chance of infection spreading from the first patient to the next.
However, more complex equipment such as endoscopes and surgical instruments cannot be discarded after a single use, as the cost of buying another one is huge. They often get used on several patients on the same day. For this, they get put through a series of steps which clean and disinfect the equipment, making it safe for use in the next patient. These steps collectively are called reprocessing.
Surgical equipment made of steel can be put through an autoclave, which is sterilisation by heat. However, instruments such as the endoscope are made of plastic and rubber with sensitive fibreoptic cables and linings that will get damaged by heat. Therefore, chemical methods of disinfection are preferred for these.
How is an endoscope reprocessed?
An endoscope is a long lighted rubber tube with a camera which is passed inside a patent’s gastrointestinal tract to diagnose and treat illnesses such as ulcer, bleeding, cancer and colitis. By the nature of its work, it is expected that the endoscope used on one patient will contain the bacteria and viruses from that person’s digestive tract. Getting rid of these involves several steps, which are described in brief below.
First, the scope is cleaned thoroughly using water containing an enzyme which removes all the debris, blood and secretions on the scope. Special brushes are used to clean the channels inside the body of the scope. This requires careful manual work by a trained technician.
It is important to note that this step does not kill bacteria or viruses; it merely removes the organic matter from the instrument. In other words, though the endoscope is ‘clean’, it is not yet ready for reuse.
The next step is disinfection, where the cleaned scope is immersed in a disinfectant solution, which kills off all the bacteria and viruses remaining on it. This step can also be carried out by an automatic washer.
The endoscope is then rinsed thoroughly so that all of the chemical disinfectant is washed away. It is then flushed with clean water, and later with 70% alcohol and forced air which removes all moisture.
The endoscope is now ready to be used again or for storage.
For storage, the endoscope is hung vertically with all of the channels left open so that there is free air circulation, preventing any further accumulation of moisture. A moist environment attracts bacteria, allowing them to multiply and grow colonies.
How hard is it to kill viruses?
While performing endoscopy on a series of patients, one of the biggest concerns is the spread of viruses. Diseases such as AIDS and hepatitis are caused by viruses—and an improperly reprocessed medical instrument can transmit these from one patient to another.
Although the term virus might sound scary, they are fortunately quite easy to kill. In fact, when a scope is immersed in disinfectant, the first germs to die are the viruses. In the first few minutes, HIV and hepatitis viruses are eliminated.
What about bacteria?
Bacteria are larger organisms than viruses. Most bacteria are harmless—billions of them live within our digestive tract without causing disease. It is now known that some of these are actually beneficial for our health.
It is the disease-causing bacteria that we are concerned about in this context. Such bacteria include Pseudomonas, Salmonella, Mycobacteria and Serratia.
Once the cleaned scope is kept immersed in the disinfectant solution for the stipulated period of time, these bacteria also get killed, although it takes longer for them to die than the viruses.
How safe are endoscopes in Kerala?
It has been proven beyond all doubt that if endoscopes are reprocessed according to protocol, they will be completely safe and germ-free. To a large extent, this depends on how diligent the endoscopy technicians are in sticking to protocols and staying updated with reprocessing techniques. Reports from all over the world have linked faulty cleaning and disinfection methods with the spread of serious infections.
On a good note, a recent survey of 35 gastroenterology centres in Kerala found that all of the technicians surveyed had undergone the required training, and over 97% were following appropriate reprocessing guidelines.
If reprocessing is effective, why do infections still occur?
As with any process, there is a proneness to failure in the system. The system can fail at multiple levels, due to assorted reasons.
For instance, if manual cleaning is not done immediately, bodily secretions and other organic matter can dry up on the surface of the scope. Once this happens, as in the case of a dirty dinner plate left in a dry sink for too long, it becomes extremely hard to clean afterwards. The more the organic residue left on the scope, the greater the number of bacteria that thrive inside it. The remedy for this is to ensure that the scope gets washed and cleaned immediately upon completing endoscopy.
The endoscope contains tiny channels and crevices which need to be cleaned thoroughly, using special brushes. Accessories often contain grooves that can harbour organic matter. Failure to clean these properly has caused outbreaks of serious infections such as Hepatitis C and Pseudomonas.
Not all scopes are equal: complex scopes such as those used for a procedure called ERCP are more difficult to clean, making it easier for bacteria to hide within. Such scopes have been associated with serious infections being spread from patient to patient. If the person assigned to cleaning the scope does not have specific training or skills in cleaning the ERCP scope, cleaning can be incomplete, increasing the risk of infection.
Once the instrument is immersed in the disinfectant solution, adequate exposure time is a must. In a busy endoscopy unit, if the reprocessing time is shortened to improve the availability of the endoscope, inadequate cleaning and disinfection can result.
What happens if a dirty scope is used on a patient?
When inadequately disinfected scopes are used on a number of patients, a few will contract infection. Not everyone who is exposed to a contaminated instrument gets infected, thanks to the body’s excellent defence mechanisms.
What about endoscopic accessories?
Accessories are instruments such as forceps, wires, needles and snares that get threaded through the channels of the scope. In an ideal world, all accessories should be disposable. However, accessories are expensive, and to use disposable equipment each time will escalate the cost of the procedure by several-fold. Therefore, it is a common practice worldwide to reprocess certain accessories such as endoscopic forceps, wires and snare. Those accessories that can withstand heat can be sent to the autoclave. Those made of plastic, which can suffer heat-related damage, are sent for ETO or ethylene dioxide gas sterilisation.
What is the difference between disinfection and sterilisation?
The difference between disinfection and sterilisation is that the latter involves complete eradication of all living organisms including bacterial spores, while disinfection gets rid of only bacteria and viruses. Commonly employed methods of sterilisation include autoclaving or the use of ethylene dioxide. Gluteraldehyde and orthophthaladehyde (OPA) are the most frequently used endoscope disinfectants in Kerala.
What is Spaulding’s classification?
In 1968, Earl H. Spaulding classified medical instruments into three, based on how easily they can spread infection from patient to patient.
Critical instruments are those that enter normally sterile spaces inside the body, and should therefore be completely germ-free before each use. Examples include endoscopy forceps and surgical instruments.
Semi-critical instruments are those that come into contact with mucous membranes: such as the endoscope, bronchoscope and vaginal speculum. As the mucous membrane is not easily breached and because there are already millions of bacteria normally present in the vicinity, there is no need for sterilisation of such devices. It is important however to get rid of bacteria and viruses that were present in the previous patient, though disinfection.
Non-critical instruments include the BP apparatus and stethoscope, which do not spread much infection in spite of being used on many patients. This is because our unbroken skin is an excellent barrier for germs. Such equipment need not be sterilised or disinfected after each use.
The logic of this classification is that the cleaning method and disinfection goals will depend on how critical the use of the instrument is. Acceptable level of disinfection varies, depending on the classification.
Thus, technically speaking, a clean endoscopy forceps doesn’t quite mean the same as a clean endoscope, which isn’t the same as a clean BP apparatus or even a clean door handle.
What is the best approach to prevent endoscope-related infections?
The universal principle of ‘prevention is better than cure’ applies here. Given that the reprocessing of scopes has to be carried out perfectly each time, the single most important factor here is the training and work ethic of the endoscopy technician.
Doctors performing endoscopy should make sure that cleaning standards are not compromised as a result of heavy patient volume or attrition of staff. Technicians should undergo periodic training on scope reprocessing, so that the chance of human error is minimised.
In summary, healthcare involves teamwork, and each team includes people of various job descriptions. Unfortunately, just as a strong chain would break if there was a weak link, bad outcomes can occur solely due to the fault of one bad team member. This could happen even when all others in the team are outstanding. In addition to hiring competent staff, investing in their training and mandating continuous self-monitoring are important steps in maintaining quality standards in healthcare.
(The author is a senior consultant gastroenterologist and deputy medical director, Sunrise group of hospitals)