Ultraviolet

Air disinfection in an inpatient pharmacy using a shielded ultraviolet C system

Original Post on: https://www.healthcarefacilitiestoday.com
By: By Maureen Spencer M.Ed, BSN, RN, CIC, FAPIC

Background: the risk of contaminated air

The bioburden of indoor air in healthcare settings has significant health implications for patients, staff, and visitors and is increasingly becoming the focus of environmental disinfection efforts. This bioburden is influenced by a number of factors including human shedding, internal ventilation and plumbing systems, and, outdoor air.1 There is a bounty of evidence documenting the presence of nosocomial organisms, beyond traditional respiratory pathogens, in hospital air.2-9 Numerous bacteria, fungi, and viruses can survive for extended periods of time in the relatively harsh airborne environment.

Furthermore, aerobiology research has demonstrated that there may be a discrepancy between measured air bioburdens and true air bioburdens as some vegetative bacteria can enter a non-replicative starvation state in air which renders them non-culturable by standard microbiological techniques despite the fact the organisms are still viable.10

The unique air quality requirements of the sterile compounding pharmacy

One area of the hospital in which air quality is particularly critical is the sterile compounding pharmacy. Medications that are to be administered through muscular injection, intravenous (IV) infusion, intrathecal (spine) or Intraocular (eye) injection must be sterile. During the compounding process, the air to which these medications are exposed has the potential to contaminate the preparations and, thus, strict guidelines, as outlined by United States Pharmacopeial (USP) Convention chapter 797, are in place to mitigate this risk.11  USP 797 requires measuring of volumetric viable airborne particles in and around sterile compounding areas every 6 months for maintenance of certification.11 This guideline has established thresholds for these measurements specific to each medication preparation area. In the direct compounding area, a threshold of 1 colony forming unit (CFU) per cubic meter (m3) bacteria or fungus requires a re-evaluation of cleaning protocols, operational procedures, and air-filtration metrics while in the adjoining anteroom, the threshold is higher at >10 CFU/m3.11

The Le Bonheur Children’s Hospital inpatient pharmacy success story

In an article published this year in the American Journal of Infection Control, Guimera et al describe their experience with employing a novel air disinfection technology utilizing UV germicidal irradiation (Vidashield, South Bend, IN) to reduce the bacterial and fungal bioburden within the inpatient pharmacy, including the sterile compounding areas, at Le Bonheur Children’s Hospital in Memphis, TN.12 The technology is an enclosed air disinfection device incorporated into a standard 2’ x 4’ ceiling light fixture panel. These systems utilize fans to actively draw air at a rate of 50 ft 3 per minute (cfm) through filters that remove larger particles such as dust and then pull the air into a shielded UV chamber where it is irradiated. The emitted light, occurring at a wavelength of 253.7 nanometers (nm), is actually amplified by mirrored UV chambers that reflect and thereby intensify the light, a proven means of amplifying the irradiation.13  Safety baffles prevent the light from escaping, thus eliminating UV exposure risk to patients and healthcare providers alike. Once the air is irradiated, it is then pushed out of the chambers by fans at a 30 degree angle to promote circulation throughout the room and to prevent the continuous re-treatment of the same air.

The areas included in their study were a 600-square-foot (sq ft) anteroom next to the main pharmacy work area which is flanked on one end by a 264-sq-ft IV preparation room and an 88-sq-ft chemotherapy preparation room. The chemotherapy room has negative pressure relative to Continue Reading…

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