Four Fronts In The War Against Evil Bugs

Scott Weese imparts wisdom regarding the prevention of surgical infections.

Surgical asepsis should constantly be on the mind of anyone with an interest in surgery. We asked Scott Weese, DVM, Dipl. ACVIM, to share some pearls of wisdom on how to prevent surgical infections. Our colleague at the University of Guelph vet school is an internist turned infectious disease specialist (see box).

We talked about the four facets of surgical asepsis: how to take care of surgical instruments, how to keep your OR sterile, how to scrub patients and how to scrub your hands.

Instrument sterility

“There is often a lack of quality control with instrument sterility. If you use chemical indicator strips, the first question is: do you look at them before using your instruments? The second question is, are you aware that autoclave tape (on the outside) and chemical indicator strips (on the inside) are not 100% reliable?”

Arguably, the best sterility indicators are biological. They are reasonably affordable (maybe around $5 each) and contain bacteria. If the bacteria have been killed by your sterilization cycle, then you can rest assured that your instruments are truly sterile.  Biological indicators probably don’t need to be used daily. “In general practice, they could be used every other week. In a general practice with a high surgical load or in a specialty practice, they could be used once a week to test your autoclave”

On another front, cold sterilization is often misused. “It takes 8 to 24 hours to sterilize instruments in cold sterile. If you use an instrument and put it back into the solution, then it takes another 8 to 24 hours for all instruments to be sterile again. In any case, using instruments from cold sterile to perform a procedure inside a body cavity is widely considered inappropriate.”

The good news is that we don’t believe in spontaneous generation anymore in 2010, so once instruments are sterile, they stay that way for an extended period of time. Specific time frames are readily available in surgery textbooks. “One important tip is to handle instruments with care, especially when they are wrapped in those flimsy paper and plastic pouches.” Technicians should inspect pouches and look for perforations before opening them.

Surgery suite guidelines

“Ideally, operation rooms (ORs) should be dedicated to surgery, with controlled airflow and controlled access.” They should not be used to take radiographs, clip patients or perform prophylactic dental procedures.

“The more tasks are performed in an OR, and the more people and patients are going in and out of an OR, the higher the risk of infection.”

Therefore, what is stored inside an OR should be carefully planned. “If you only use suture packs in your treatment room, it doesn’t make sense to store them in the OR. Likewise, it is not logical to keep your boxes with suture material outside the OR.”

Many of our clinics have small ORs that were rarely meant to serve that purpose. “Yet infection control should be part of any OR design, and beyond, of clinic design. Fortunately, newly built clinics tend to take infection prevention into consideration during the brainstorming phase of construction.”

Who is Scott Weese?

Scott Weese is an associate professor in the Department of Pathobiology at the University of Guelph vet school (Canada).  In addition, he is a public health and zoonotic disease microbiologist for the University's Centre for Public Health and Zoonoses.

He is also the chief of infection control at the Ontario Veterinary College Teaching Hospital. Scott Weese is the author of an excellent and highly entertaining blog at where he writes on topics as varied as service dogs, vaccination, pet food recalls, pigeon poop and infections of all kinds (plague in the US anyone?).

Patient asepsis

”Instead of trying to clip every single tiny hair, we should focus on having the patient’s skin as clean as possible and as the lesion-free as possible.” For example, stifles, hocks and digits are notoriously difficult to clip. Yet cuts and burns are perfect sites for bacterial contamination.

“Scrubbing the patient’s skin for 5 minutes should not be taken too literally. We are not trying to scrub a deck. There should be no change in the skin color or surface. What is most important is contact time. So scrubbing for 5 minutes includes time to allow soap to just sit there.”

“We do not really have a good idea of the ideal “prep” technique. The most important factor is probably to choose one logical method, and perform it well. The different steps have different goals.

1. The standard antiseptic soap scrub helps remove debris and gross contamination.
2. The antiseptic soap does some killing itself (with adequate contact time). At the same time, it renders the site more amenable to later antisepsis steps.
3. Alcohol kills vegetative bacteria.
4. Using an antiseptic solution as a final step should kill any bacteria that have survived the initial steps since the skin has been made more amenable to disinfection.”

Rinsing soap with sterile saline or water seems counterproductive. “It would remove the antiseptic soap, which is contraindicated since it would reduce overall contact time. Additionally, saline might just contribute to soaking the patient, and cause contamination of surgical drapes. By the way, soaking the patient may lead to hypothermia, which increases the risk of infection.”

“Using surgical gloves while scrubbing the patient is rarely done, but it makes perfect sense. Gloves protect the patient and yourself. They protect the patient because scrubbing a patient with bare hands makes no sense. If we are trying to remove bacteria from the patient’s skin, then let’s not add some from our own skin.”

Surgical gloves cost less than a regular postage stamp! If you really can’t afford surgical gloves, then exam gloves are probably an acceptable substitute.

“Wearing gloves also protects our skin from harsh chemicals. Having broken skin affects its natural barrier, which makes our skin more likely to harbor bacteria.”

Staff asepsis

“There is so much variation is the way people scrub their hands, that we have decided to perform a study with cameras at the University of Guelph vet school. We are in the process of filming people while they scrub to analyze what is actually done in daily practice, as opposed to what should be done.”

“Staff members involved in the surgery (practitioner, assistant) should wear a surgical gown, a cap, a mask and surgical gloves. To my knowledge, there is no study on the best way to glove up, but it seems logical that the “closed” way is a safer technique that the “open” way. It certainly doesn’t take more time, so why not glove up the closed way?” All other staff members present in the OR should wear a cap and a mask.

The bad news is that bacteria tend to be more and more resistant. Think of MRSA (Methicillin-Resistant Staphylococcus Aureus). The good news is that it is much easier (and cheaper) to present infection, including with MRSA, with proper aseptic technique and common sense, than to treat it with antibiotics.

Dr. Phil Zeltzman is a mobile, board-certified surgeon near Allentown, PA. His website is


Post a Comment