natural ventilation and exposure to sunlight. Because the most germi-
cidal wavelengths of light fall in the UV spectrum (240nm to 260nm),
healthcare facilities have been slow to adopt technologies using light in
the visible spectrum. More recent research has shown, however, that
systems generating narrow-spectrum light near the 405nm wavelength
(which falls within the visible spectrum of 400nm to 700nm) inactivate a
number of bacteria, including many common HAI-associated organisms.
This inactivation appears to be species-dependent, though, with a gener-
al trend towards greater Gram-positive species susceptibility than Gram-
negative species. Additionally, viruses are thought to have little suscepti-
bility due to the mechanism of microbial inactivation.
Several studies over the past decade have shown effective reduc-
tions in environmental surface contamination in a number of health-
care settings, including one study that demonstrated use in the OR
was associated with a concomitant reduction in periprosthetic joint
SSIs — one of the costliest and devastating surgical site infections. To
date, there have been no studies on air disinfection.
These ceiling-mounted systems contain a combination of violet and
white light-emitting diodes (LED) to provide the necessary illumina-
tion. They are automated, and some are equipped with an occupancy
sensor that lets the light switch to a higher and more germicidal dose
of high-intensity narrow spectrum— or HINS — light when the room is
unoccupied. Their ability to be used in an occupied space is a notable
advantage over UV-C light.
OSM
7 6 • O U T PA T I E N T S U R G E R Y M A G A Z I N E • A P R I L 2 0 1 9
Dr. Boehm Johnson (hboehm705@gmail.com) is a physician, research consult-
ant and medical writer whose primary focus is the field of infection prevention
and control.
