You are draped in a sterile sheet, lying on a gurney, shivering in the cold air and looking up at the anesthetist’s face; you feel a little woozy (yeah what was in that shot he gave you?) as he asks you to slowly count backward from one hundred. As you begin counting, someone holding up gloved hands and dressed in blue scrubs, leans toward you and says, “it will be just fine; don’t worry about a thing.” Only a pair of friendly eyes is visible between the covered head and blue mask, but you recognize your surgeon; as you respond with a final slurred number, you slowly drift off into the calm, inky-blackness of medicated unconsciousness. Little do you suspect that the very man who is reassuring you of your safety may actually be the culprit in contaminating your open wound with bacteria! Yet, what hidden fault in this procedure could possibly circumvent both the training of the medical team and the sterile techniques employed during surgery?
It’s a wonderful age in which to live; modern medicine is on the cutting edge of new treatments and techniques! (Get it – cutting edge?) Yet the technology which is being developed is not without potential problems. In operating rooms, an optical-fiber system is used to coordinate the surgeon’s use of instruments with a projected image on the viewing screen of a video monitor. The screen is kept positively charged, attracting the electrons being emitted from the back of the monitor, which then displays an image. However, “the positive charge of the screen also attracts negatively-charged airborne particles which naturally float around in the operating room, such as lint, dust, and skin cells.”1
Compounding the problem, electrically neutral particles can also become polarized as they near the screen, causing an induced charge in which one side of the particle is negative and the other side is positive; the nearer negative charge of the particle is pulled towards the screen, thus contaminating the screen’s surface. “If a surgeon should point closely towards the screen, there is a possibility that the positively charged screen will pull electrons from inside his fingers to the fingertips (through the glove); then the negatively charged fingertips cause particles from either the air or the screen to collect on the gloves at the tips.”2 In other words, as the surgeon shouts, “Eureka!” and points to or touches the video monitor to show his medical team the problem he has found, his glove has developed an induced charge which attracts nasty bacteria, which in turn, is transmitted to you as the procedure continues.
Would using an LCD monitor instead of a video monitor make a difference concerning bacterial contamination? Is there a way to eliminate the hidden electrical charges which are prevalent in operating rooms? The LEDs or light emitting diodes of a flat screen monitor are just “tiny light bulbs that fit easily into an electrical circuit, without a filament and which don’t get hot. They are illuminated solely by the movement of electrons in a semiconductor material.”3 To have fewer electrons, the electrical behavior of a ‘doped’ semiconductor (one in which different materials have been added) may be manipulated by such external stimuli as heat, light and electric or magnetic fields; fewer electrons mean it is less likely to attract airborne particles. However, there may be a problem viewing the display on the LCD screen if the viewer is looking at the screen from a position other than frontal; the members of the surgical team not standing directly in front of the monitor may see a blurred image.
Other vectors of contamination in the operating room are the plastic aprons worn by surgical staff as well as the packages of different supplies such as sterile gloves or needles. The plastic apron “pulled from its sterile package and put on against the usual ‘scrubs’ clothing can become charged by contact.” 4 The same process also occurs when packages of sealed instruments or tubing are opened, thus allowing the build-up of bacteria on those surfaces having a static charge. Subsequently, bacteria can be transferred to the patient through further contact. Therefore, simply changing video monitors with LCD screens will not fully solve the problem of electrically induced bacterial contamination; the question concerning prevention remains.
One of the possible solutions currently under study is the laminar air flow system (LAF) in which High-Efficiency Particulate Air (HEPA) filters are used; these reduce the formation of airborne bacterial colonies. Another possible solution is the treatment of “latex drains, silicon drains and plastic coverings with antistatic solution or by applying a conducting coating on plastic film that prevents the build-up of static charge.” 5
Presently, there are no certain answers to the problem of electrically induced bacterial transfer during surgery; a patient’s best option for a successful operation is having an informed, conscientious surgical team using best practice, sterile techniques, as well as the appropriate use of prophylactic antibiotics.
1.) Walker, J. (2007). The flying circus of physics. New Jersey: John Wiley & Sons, Inc.
2.) Walker, J. (2007). The flying circus of physics. New Jersey: John Wiley & Sons, Inc.
3.) Harris, T. (2009). How light emitting diodes work. Retrieved October 19, 2009. Web site: http://electronics.howstuffworks.com/led.htm/printable
4.) Walker, J. (2009). The flying circus of physics. Chap 5 (electricity & magnetism) archived stories. Retrieved October 9, 2009. Web site: http://www.flyingcircusofphysics.com/NewsDetail.aspx?NewsID=41
5.) Allen, J.E., Henshaw, D.L., Wynne, H., Ross, F., Oakhill, A. (2003). Static electric charge may contribute to infections in bone marrow transplant wards. Journal of Hospital Infection, 54(1), 80-81. doi: 10.1016/SO195-6701(02)00401-2
1.) Allen, J.E., Henshaw, D.L., Ross, F., Oakhill, A. (2003). Static electric charge may contribute to infections in bone marrow transplant wards. Journal of Hospital Infection, 54(1), 80-81. doi: 10.1016/SO195-6701(02)00401-2
A short technical article, but not difficult to understand.
2.) Becker, R., Kristjanson, A., Waller, J. (1996). Static electricity as a mechanism of bacterial transfer during endoscopic surgery. Surgical Endoscopy, 10, 397-399. Retrieved October 19, 2009, from http://resources.metapress.com/pdf-preview.axd?code=v6p65g841077h14m&size=largest
This abstract gives a good basic overview of the study performed and it includes some specific details and results.
3.) Evans, R. (2006). Laminar air flow in the operating room; how effective is it in reducing infection? American Academy of Orthopaedic Surgeons Bulletin. Retrieved October 19, 2009, from http://www2.aaos.org/aaos/archives/bulletin/jun06/fline7.asp
This article is short, but easily read and understood; specific to the subject of airflow and contamination.
4.) Harris, T. (2009). How light emitting diodes work. Retrieved October 19, 2009, from http://electronics.howstuffworks.com/led.htm/printable
One has to enjoy this website! With pictures, links and good explanations, trying to understand becomes fun!
5.) Meschke, S., Smith, B.D., Yost, M., Miksch, P., Gefter, S., Halpin, H.A. (2009). The effect of surface charge, negative and bipolar ionization on the deposition of airborne bacteria. Journal of Applied Microbiology, 106 (4), 1133-1139. doi: 10.1111j.1365-2672.2008.04078.x
This article is certainly the standard research article, but it is well done. It has good general information usable to the casual reader and more technical information for professionals.
6.) Walker, J. (2007). The flying circus of physics. New Jersey: John Wiley & Sons, Inc.
This book is great fun to read; the information presented is well organised and easily understood with illustrations which help clarify ideas.
1. Journal of Hospital Infection
3. American Academy of Orthopaedic Surgeons Bulletin
5. Journal of Applied Microbiology
6. Flying Circus Of Physics, updates, 5.31
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