Issue: August 2007
August 01, 2007
2 min read

Laminar air flow and ultraviolet light can combat operating room contamination

Additionally, reduced operative time and fewer people in the OR, can cut the risk of infection.

Issue: August 2007
You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

Reducing operating room contamination and effectively avoiding infection during total joint arthroplasty depends on many factors, including environmental control of laminar air flow or ultraviolet light, according to Merrill A. Ritter, MD.

What is more, allowing fewer people in the operating room (OR), eliminating “shedders” and reducing operating time can also lower the chances of contamination, he said.

"Infections are decreased with less environmental contamination, prophylactic antibiotics and a good host," Ritter said at the 8th Annual Current Concepts in Joint Replacement Spring 2007 Meeting. After all, studies have shown a direct correlation between sepsis and environmental contamination.

Merrill A. Ritter, MD
Merrill A. Ritter

Results with ultraviolet light

“All you really need to know is at the wound site we can reduce the amount of bacteria over 90% with the use of laminar air flow,” Ritter said. “Ultraviolet light can do this as well, but it does not reduce them. It kills the bacteria. And it’s very inexpensive to use.”

With ultraviolet light, Ritter has found he can statistically reduce infections, most notably knee infections.

In an experiment on the efficacy of laminar air flow, Ritter and his colleagues evaluated 40 ORs, including two conventional ORs for open heart surgery, and two laminar air flow ORs for bilateral total hip arthroplasty.

In one of the conventional ORs and one laminar air flow OR, a nurse moved a hemostat from a back table into a thioglycollate jar every 15 minutes; and in the other two ORs, one conventional and one with laminar flow, the nurse used sterile pick-ups to move the hemostats.

Looking at 12 sample cases, in the conventional OR in which a scrub nurse used her hands to move the hemostat, 6.4 were contaminated; as opposed to the OR that used laminar air flow and sterile pick-ups, in which 0.5 became contaminated, according to Ritter.

Methods to reduce bacteria

It is understood that people are the primary source of bacteria in the OR – and men carry more bacteria than women.

“About 30% of people carry Staphylococcus aureus, and 13% of men … exude more than 10,000 bacteria per minute,” Ritter said.

Wearing hooded exhausts has been shown to reduce the bacteria shed in an OR, Ritter said, “but for it to work, all people must wear this. That means the scrub people, the circulators, anesthesiologists and visitors.”

Ritter said that wearing head covers, masks, conventional gowns, shoe covers and body exhausts ultimately have no effect in keeping the environment uncontaminated.

Plastic iodophor impregnated adhesive drapes are effective when applied after a 30 second wound prep with alcohol, Ritter said. “When we did this, we had a 0.5% infection rate,” he said. With these drapes, the bacteria do not penetrate, migrate or multiply.

The surgical scrub actually only needs 30 seconds of an antibiotic foam. With this, he has been able to maintain an infection rate of 0.47%, he said.

0.5% infection rate over 2 years
Ritter and his colleagues had only a 0.5% infection rate (two infections) when using these drapes over a 2-year period.

Plastic adhesive drapes help prevent bacteria
Ritter suggested using a plastic adhesive drape over wounds because they prevent bacteria from penetrating, migrating or multiplying.

Images: Ritter MA

For more information:
  • Merrill A. Ritter, MD, can be reached at The Center for Hip and Knee Surgery, St. Francis Hospital, 1199 Hadley Road, Mooresville, IN 46158; 317-831-2273; e-mail: He receives research support from Biomet Inc.
  • Ritter MA. Preventing infection: An OR algorithm. #85. Presented at the 8th Annual Current Concepts in Joint Replacement Spring 2007 Meeting. May 20-23, 2007. Las Vegas.