Aerosols flowed from one bed to another in shared hospital rooms

Closing the curtains between beds in shared hospital rooms could reduce spread of viral particles, a simulation study found.

The study used a device that emitted condensed moisture to identify airflow patterns in double-occupancy patient rooms with beds three meters apart and to assess the effectiveness of privacy curtains and portable air cleaners in reducing transfer of particles. Air flowed from inlet vents in the center of the room to an outlet vent near the door, resulting in air currents flowing toward the bed adjacent to the outlet vent. In the simulation, fluorescent microspheres (212 to 250 µm in diameter), 5% sodium chloride aerosol, and aerosolized bacteriophage MS2 (a single-stranded RNA virus) were released from the inner bed. Results were published by Clinical Infectious Diseases on April 27.

The study found that closing the curtains between the beds reduced the transfer of each of the particles. The portable air cleaner also reduced aerosol transfer to the bed by the outlet, but it did not offer a benefit over closing the curtains alone, and in some situations, it resulted in an increase in aerosol exposure for the other bed. The air cleaner was more effective when positioned between the inner bed and wall rather than between beds, the authors observed.

They concluded that airflow patterns in double rooms pose risk for transmission of SARS-CoV-2. “Keeping the curtains closed between beds may reduce but not eliminate the risk for transmission. Future studies are needed to determine if current ventilation systems could be modified to produce airflow patterns that minimize movement of air from patient-to-patient,” the study authors concluded.

Limitations of the study include that it was conducted in one hospital with a single configuration of ventilation ducts, beds, and curtains and that only one air cleaner was tested. Results could vary with different setups, the study authors noted.