Too-frequent trips in and out of the hospital operating rooms could put surgical patients at a slightly elevated risk of infection.
For a new study, researchers secretly tracked how often and how long OR doors opened during nearly 200 knee and hip arthroplasty surgeries over three months.
In a third of those procedures, performed at Johns Hopkins Bayview Medical Center in Baltimore, doors were open long enough to potentially defeat positive air pressure systems designed to keep germ-laden air out of sterile ORs.
The findings suggest that OR teams may need to look for ways to cut back on entrances and exits during procedures.
“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,” says senior author Stephen Belkoff, associate professor of orthopaedic surgery at Johns Hopkins University and director of the International Center for Orthopaedic Advancement.
Higher pressure environments
Most operating rooms in US hospitals are kept at an atmospheric pressure slightly higher than surrounding corridors. The design allows air to flow out of the OR when doors open, preventing air potentially contaminated with infection-causing germs from flowing in. Positive pressure systems can become overwhelmed, however, when doors open too many times in quick succession or stay open too long.
Excessive OR traffic is believed to be a common occurrence at hospitals; 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,” Belkoff says, “and raise questions about why doors get opened and how we can prevent or minimize the frequency and duration of behaviors that could compromise OR sterility.”
Because researchers monitored door openings with sensors, without the knowledge of surgical teams, it’s impossible to know why OR staff were going in and out so often.
There was only one postoperative infection in the 191 surgeries monitored, Belkoff notes, and the cause of that infection is unknown. Infections are rare for arthroplasties, both at Johns Hopkins and in general.
“Yes, we have low infection rates, and, yes, we take a great many precautions, but we cannot be complacent, and we must remain vigilant about practices that pose risk—theoretical or otherwise,” says co-investigator Simon Mears. “Excessive door opening is one such practice.”
A handful of door openings during surgery are likely necessary and unavoidable, Belkoff says. “What we ought to figure out next is what’s causing the unnecessary and avoidable ones.” Part of the solution could be simply ensuring that all needed supplies and equipment are in the OR before surgery starts.
From ‘cut to close’
For the study, published in the journal Orthopedics, researchers studied knee and hip arthroplasty procedures performed from March to June 2011. These common procedures replace, remodel, or realign knee and hip joints.
Researchers used sensors inside and outside ORs to track when a door opened and how long it stayed open. They measured air pressure in the ORs and surrounding corridors. They also noted how long each surgery took from “cut to close” (in other words, excluding setup and cleanup time). They checked for postoperative infections.
In 100 knee and 91 hip arthroplasties, OR doors opened on average every 2.5 minutes. Doors were open 9.6 minutes during an average case, about 9 percent of the total cut-to-close time, Belkoff says. In 77 cases, doors were open long enough to compromise OR positive pressure, allowing air from surrounding corridors to flow inside.
Beyond potential contamination, excessive foot traffic could suggest distraction among OR staff or simply logistical or personnel management inefficiency.
Because postoperative infections are so rare, says Mears, researchers would need to study many more surgeries to determine if variations in foot traffic could reduce them.
Source: Johns Hopkins University