Infection Control Today - 10/2003: Instrument Reuse

Instrument Reuse: An Update on vCJD

BY JOHN ROARK

First identified in the 1920s, Creutzfeldt-Jakob disease (CJD) is a fatal degenerative disease of the central nervous system that is believed to be caused by a prion, an infectious particle smaller than a virus. The CJD prion can lay dormant for decades before any of its symptoms manifest themselves.

CJD has been transmitted as a result of medical treatments such as human pituitary derived growth hormone injections, dura mater and corneal tissue transplants, and brain surgery involving contaminated instruments. It is known at this point that the highest concentrations of the infectious agent are found in the brain, the spinal cord and the eye.

In March 1996, a new variant of CJD (vCJD, or Mad Cow) was identified in the United Kingdom. A casual link between vCJD and bovine spongiform encephalopathy (BSE) in cattle has been hypothesized, and there is now overwhelming epidemiological, neuropathological and experimental evidence that the agents causing BSE and vCJD are the same. The most plausible route of exposure is via BSE-contaminated food.

Up until this point, a carrier can only be identified by either a surgical brain biopsy or an autopsy after death.

The remarkable resistance of prions to standard methods of sterilization questions the safety of reusing metallic surgical instruments. Current guidelines for sterilization and decontamination can render instruments damaged and unusable. Yet the feasibility of using disposable instruments is an issue that is still in question, in part because the availability of disposable instruments in the U.S. is still limited.

It is already current practice to dispose of instruments used on any patient showing symptoms of vCJD. However, this cannot be done where symptoms of the disease have yet to appear, as there is no diagnostic test available. It is known that the abnormal prion protein believed to be associated with vCJD can be present in the body before a patient shows any sign of the disease. Conventional autoclaving processes do not completely inactivate the ineffective agent. There is risk, therefore, that surgical instruments could transmit vCJD to other patients when re-used.1

Lets look at the equipment cost for a straightforward open crani, says Becki Harter, CST, RCST, CRCST, FEL, president and CEO of Sterilization by Design. If you had to throw away everything due to contamination, you would be spending $1.5 million. One drill is $56,000; one hook may cost you $1,000. Even though you may only use five instruments designed distinctly for this procedure, and trust me, you use more than that, youre still going to throw it all away because its all contaminated. And youre not including the frame that the head is placed on well over $30,000. Lets do the math: $5,000 for disposable instruments vs. $1.5 million. Thats pretty easy. Youre throwing away a lot of money.

There are things out there that we can use chemicals that kill vCJD, says Harter. But the problem is that they kill the instruments as well. Cheri Ackert-Burr, RN, MSN, CNOR, CRCSP, perioperative clinical education coordinator for the Association of periOperative Registered Nurses (AORN) agrees. One of the recommendations is to soak any surgical instruments that have come in contact with a suspected CJD procedure in Clorox for five hours or so. Yes, thats a good recommendation, but the instruments are no good at the end of that time. You might as well throw them out to begin with.

The World Health Organization (WHO) recommends for economic reasons, that instruments used on patients suspected of carrying vCJD can be quarantined until final lab results are available. If the diagnosis of vCJD is excluded, the instruments may be sterilized per routine procedures and returned to circulation.2

Richard Johnson, MD, distinguished service professor of neurology, microbiology and neuroscience at Johns Hopkins School of Medicine, observes, There clearly is a concern, primarily about neurosurgical instruments. I know in neurosurgery, for instance, when they do cases here, they use as much disposable as possible, and they high-pressure prolonged-autoclave the rest, by specification. An issue that comes up all the time is what to do with things like endoscopes. The only evidence of iatrogenic, or inner-hospital transmission, has been with either injection of brain tissue (i.e., growth hormone) or the contamination of instruments in neurosurgical procedures. Theres no evidence that having had a dental extraction or an appendectomy or anything like that increases the risk at all. I think that people go along with when possible use disposable, if its a known case of vCJD. But what happens if you do a big abdominal surgery on somebody, and then reprocess the instruments exactly the way you always do. Then a month later somebody says, That patient you did last month now has CJD. With those look-back cases, and everything thats been studied, theres really been no evidence of transmission.

But Johnson points out, With Mad Cow disease, the infectious protein, or the protein associated with infectivity has been demonstrated in fairly large quantity in the tonsil, in the ileum, and also in the spleen and lymph nodes. In that case you could say there might be a greater chance for contamination of either blood products or surgical instruments with the disease. In theory, that is true. In practice there is no evidence that there has been blood transfusion submission bearing CJD. But could it happen? Yes. Is it more likely to happen than sporadic cases? Without a doubt, so there is that concern. To that end, the British have tried to implement a system of performing all tonsillectomies with all disposable materials.

And theyve had some trouble with that theyve had some surgical complications. The whole question is, is it worth it? And the answer is probably no. At what point do you endanger the patient for a theoretical risk? Its not a real risk theres never been a shown transmission that way, but its a theoretical risk.

Reducing the Risk

One means of risk reduction is through thorough patient research prior to procedures where the presence of vCJD is suspected.

They have questionnaires for the patients prior to any procedure, says Harter. If youre going to invade the brain, going to do stereotactic procedures, youll ask questions. Does the patient have a family history? Are there any other disphasiac disorders that the person is dealing with? Is there potential this could be a vCJD case? In our hospital if there is potential that there is vCJD, the physician will do a stereotactic procedure first and test that material. If it comes back negative, they proceed. If it comes back positive, obviously we have to trash those instruments.

In the last year weve had maybe five suspect cases that turned out to be negative, continues Harter. None confirmed. But a great deal of that is because weve put protocols in place to prevent them. With questionnaires, with physicians doing a more thorough workup, especially with high-risk patients. If theres any type of mental disorder they try to define very clearly where thats coming from, and will do a biopsy.

There are a lot of challenges, observes Harter. However, by addressing it with biopsies first, and identifying it prior to any other further surgery, you really can minimize your cost and risk to your patients. Not only to the person who may have it, but the people who dont have it.

Ackert-Burr sees getting back to basics as a solution to the challenge of high-cost instruments and rigorous decontamination. In doing a brain biopsy for a definitive diagnosis, basically you can have a brace drill and bit and disposable tissue set that can be thrown away, she says. You know and plan ahead of time, and remove everything that could come in contact, and have just your basic fork and knife to do the procedure. But youve got to have a surgeon who is confident in their skills and doesnt need the kitchen sink to do their procedure. This is a highly contagious disease with a highly difficult decontamination procedure to control. Go with the simplest things you can use to get the job done, that will keep the patient from being under anesthesia for too long.

Some of your disposable instruments dont have the integrity that the others do, says Harter. We took the cheapest bottom-line instruments, and we created sets. Then, if we have to throw them away, were not throwing away millions.

Yesterdays News or Dangerous Threat?

How big of a concern is vCJD today? Richards has observed the evolution of CJD since the 1950s. There was really nothing back in those days about it, he says. Creutzfeld-Jacob disease, whats that? Nobody knew what it was, neurologists didnt know what it was, internists had no idea. When I was studying neuropathology at Harvard, the chief of pathology there had never heard of it. Thats how rare, how unknown it was.

Today you pick up The Baltimore Sun, and it refers to it as CJD, as though everybody knows what that is, in the popular press, he continues. Whats happened between then and now? People have come down with it at a rate of one per million per year then and now. All the hype its received and all the interest its gotten is because of these crazy things about the infectivity and the long incubation periods and the strange pathology and the strange nature of the agent. All of which are very interesting, but its not because weve had an epidemic of this disease. Its because of all the interesting things, and the Mad Cow disease epidemic in Britain, that has people interested. The rate of CJD is the same now as it was in 1960 when very few of us knew what it was.

While the rate hasnt changed, Richards points out that the awareness of vCJD and the worry level have changed considerably. Are doctors aware of it? Im amazed at how aware of it they are, considering its a very rare disease, he says. Theyre very sensitive to it. People raise the question, how many cases are there that get missed? I think very, very few. I think quite the contrary, there are more cases where the question is brought up where they dont have it. General internists and people like that will say, Could this be CJD? and its obviously not, its something else, but theyre very sensitive to making the diagnosis.

The biggest issue right now is just educating staff to current protocols recommended by the CDC, and following CDC, the Association for the Advancement of Medical Instrumentation (AAMI) and AORN, says Ackert-Burr. Those are the people who will have the most current information. This bug is not just going to jump off the table onto somebody. Education is the strongest thing that has to be in place. And it needs to be done through reputable organizations. Not just he said, she said. They need to follow the CDC and AORN guidelines. It is definitely about teamwork. Everybody needs to be at the same level for preparing, for caring for, and for cleanup. And it should go throughout the entire hospital, so that every level has that same information. The number one thing is education current, correct education.