Is There Too Much Foot Traffic In and Out of the OR?

    A study from John Hopkins suggests the answer is yes, and it could compromise the safety effects of positive pressure systems during joint replacement procedures.

    A study by researchers at Johns Hopkins analyzing foot traffic in and out of operating rooms (OR) suggests that for the sake of patient safety, OR teams may want to stay put more often.

    For the study, published online in the journal Orthopedics, investigators tracked the number and length of door openings during nearly 200 knee and hip replacement surgeries performed at Johns Hopkins Bayview Medical Center over a 3-month period.

    They found enough door openings in nearly one-third of the procedures to potentially defeat the safety effects of so-called positive pressure systems meant to keep contaminated air out of sterile ORs.

    Excessive OR traffic, the researchers said, is believed to be a common occurrence not unique to Johns Hopkins, and previous studies have documented frequent OR door openings during cardiac surgeries performed elsewhere.

    “Our findings add to a growing body of evidence of a relatively common practice that could be a potential safety concern, and raises questions about why doors get opened and how we can prevent or minimize the frequency and duration of behaviors that could compromise OR sterility,” said study senior author Stephen Belkoff, PhD, MD, an associate professor in the Johns Hopkins University School of Medicine’s Department of Orthopaedic Surgery and the director of the International Center for Orthopaedic Advancement.

    Because the research team monitored door openings without the knowledge of OR staff, it is not possible to determine why the doors were opened in the first place.

    “What we know for sure is that there was a whole lot more traffic in and out of the OR than seems necessary or easily explained,” Dr. Belkoff said.

    There was a single case of postoperative infection in the 191 surgeries monitored for excessive door openings, Dr. Belkoff noted, emphasizing that the cause of that infection was unknown.

    Infections following joint replacement surgery at Johns Hopkins Bayview Medical Center are rare, with rates of 0.33% for knee replacement surgery and 0.66% for hip replacement surgery. Those numbers are well below the national averages of 0.89% for knee replacement and 1.26% for hip replacement.

    “Yes, we have low infection rates, and yes, we take great many precautions, but we cannot be complacent, and we must remain vigilant about practices that pose risk — theoretical or otherwise,” said co-investigator Simon Mears, MD, PhD. “Excessive door opening is one such practice.”

    Door openings during surgery, the researchers said, could represent an easily modifiable risk factor.

    “Undoubtedly, a handful of door openings during surgery are necessary and unavoidable,” Dr. Belkoff said. “What we ought to figure out next is what’s causing the unnecessary and avoidable ones.”

    Part of the solution, the researchers said, could be simply planning better to ensure all necessary materials and equipment are pre-stocked before surgery starts so there’s no need to shuffle in and out of the room once the procedure begins.

    Between March and June 2011, the researchers used sensors inside and outside the ORs at at Johns Hopkins Bayview Medical Center where knee and hip replacement procedures were being performed to measure:

    • When a door opened
    • How long it stayed open
    • Pressure in the OR
    • Pressure in the surrounding corridors

    They also tracked how long each procedure took from “cut to close,” or the total time in which patients were actively operated on, excluding setup and cleanup time. Then they reviewed records to find out if patients had developed postoperative infections.

    Of the 100 knee replacements and 91 hip replacement performed during the study period, the OR doors were opened on average every 2.5 minutes. That’s a door-open time of 9.6 minutes per average case, which lasted about 90 minutes, or about 9% of the total cut-to-close time.

    In 77 of the 191 cases, doors were open long enough to compromise the ORs’ positive pressure systems, allowing air from surrounding corridors to flow inside.

    Beyond potential contamination from airflow, the researchers said excessive foot traffic could suggest distraction among OR staff or simply logistical or personnel management inefficiencies, underscoring the need to find out the reasons behind the frequent door opening.

    Because the infection rates for these procedures are so low, said Dr. Mears, researchers would need to study data from many more such surgeries to determine whether variations in foot traffic could affect patients’ postoperative infection rates.