Study: Leave Social Distancing at the OR Door

The effectiveness of social distancing doesn’t apply to modern operating rooms (ORs). In fact, says a pre-print study in the American Journal of Infection Control, the further healthcare professionals are from the surgical site the more likely they are to being exposed to SARS-CoV-2 and other dangerous pathogens. Investigators note that “maintaining distances from released airborne particles has permeated colloquial considerations since the onset of the COVID-19 pandemic…. We recommend personnel awareness that in an OR it may be a counter-productive strategy to move away from the patient toward a wall (i.e., where air return grilles are located).”

Investigators note that during the coronavirus disease 2019 (COVID-19) pandemic, there have been discussions about the role of social distancing in ORs during tracheal intubation and/or extubation, and other aerosol generating procedures.

“When an anesthesiologist intubates or extubates the patient, or surgical smoke is produced, would others in the room be safer by moving away (e.g., complete their charting at a computer along a wall)?” the study asks.

The data were collected in January 2018 when 15 mock surgical procedures were conducted on steaks in 2 ORs that were built in 2017 and one that was constructed in 1992. “Modern OR airflow systems are so effective at protecting the surgical field and team from airborne particles emitted during surgery that concentrations of particles released at the OR table are greater at the OR walls than near the center of the room,” the study states.

One of the modern ORs had a single large diffuser system above the surgical site, while the other modern OR had a multiple diffuser array design. Air particle counting units were placed on the instrument table, and adjacent to the air return grille.

“Concentrations of air particles were greater at return grille than instrument table for the single large diffuser at 26 air exchanges per hour, and the multiple diffuser array at both 26 and 20 air exchanges per hour (all P ≤ .0044), including during electrocautery (all P ≤ .0072),” the study states. “The ratios of concentrations, return grille versus instrument table, were greater during electrocautery for 0.5 to 1.0-micron particles and 1.0 to 5.0-micron particles (both P < .0001).” In the older OR with its 4-way throw diffuser system, investigators found greater concentrations of larger particles at the return grille.

Those investigators—who included infection preventionist Jennifer A. Wagner, PhD, CIC, of the consulting company OnSite-LLC, and Franklin Dexter, MD, PhD, of the department of anesthesia at University of Iowa—say that their results prove the efficacy of modern OR airflow when it comes to keeping the surgical site as sterile as possible.

“Specifically, even though the ‘surgery’ on the uncooked steak was done at the OR table, the increases in particle concentrations was at the particle counter along the walls of the ORs.”

Healthcare workers not directly involved in operations or procedures performed on patients with COVID-19 won’t be better protected by moving six feet away from the surgical site.

“Our results for multiple particle sizes indicate strong chance that infectious aerosols, including viruses generated by patients, would pose as much a risk to healthcare workers at the periphery of the room than adjacent to the patient,” the study states.