In-depth report: expedient methods for surge airborne isolation within healthcare settings during response to a natural or manmade epidemic.
Mead KR; Feng A; Hammond D; Shulman S
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, EPHB 301-05f, 2012 Apr; :1-184
History: Airborne Disease Transmission Theory: Throughout recorded history, mankind has used concepts of "isolation" as a means to protect the larger population from exposure to those with a potentially infectious disease. Biblical references in the books of Numbers and Leviticus delineate instructions to both cover the mouth and send from the encampment any individuals thought to have leprosy or other infectious health "issues" [McMillen and Stern 2000]. The instruction to "cover the mouth" appears to guard against some form of droplet spread. The Centers for Disease Control and Prevention (CDC) still is not certain how leprosy is transmitted, though droplet spread is the most likely means [CDC 2003a]. This concept of separating potentially infectious persons from the general population has remained a predominant protection mechanism throughout much of the world's history [CDC 2003b], even when knowledge of the mechanisms responsible for the spread of disease or infection is lacking. Conclusion: The U.S. healthcare system lacks sufficient engineered AII surge capacity to meet the demands of a widespread airborne infectious epidemic. Some healthcare facilities, including two included as part of this research effort, lack the engineered AII room capacity to handle even a single airborne infectious patient. Government programs have begun spending billions of dollars to improve this engineered capacity, but at a government-predicted average of $500 million to upgrade a single major city, the time and resources required to sufficiently protect the entire U.S. healthcare system in both rural and urban environments is beyond the scope of any government program. Alternative solutions are needed to meet surge airborne isolation requirements. Some proposed "solutions" have included resorting to a heavy dependence on respiratory protection and the establishment of large "hot zones" of potentially infectious aerosol. The expedient airborne isolation research discussed within this document has identified isolation configurations that rely upon inexpensive, off-the-shelf materials and HEPA filtration systems that are commonly found within healthcare facilities. Most provide better real-time source protection from infectious aerosol than that expected to result from an N95 respirator. In several cases, the protection is several times better. These findings are not intended to replace the respiratory protection guidance provided to healthcare workers; however; the additional reduction in contaminant concentrations will lessen the dependence upon the N95 as the last line of airborne defense. Healthcare workers need and deserve assurances that their safety will not be sacrificed in the name of emergency response. U.S. citizens share that need if they expect healthcare workers to report to work and to stay sufficiently healthy to provide treatment. While millions of dollars will continue to be spent seeking cures and immunizations for airborne and other infectious diseases, the objectives of this modest project and its identified interventions may be summed up in the words of Thomas Fuller (1608-1661), British clergyman and author: "He who cures a disease may be the skillfullest, but he that prevents it is the safest physician."
Infectious-diseases; Health-care-facilities; Infection-control; Ventilation-systems; Airborne-particles; Aerosols; Aerosol-particles; Engineering-controls; Environmental-contamination; Filtraction; Environmental-engineering; Work-environment; Employee-exposure; Employee-health; Environmental-technology; Personal-protective-equipment; Respiratory-protective-equipment; Disease-control; Disease-prevention; Air-contamination; Emergency-response; Safety-measures;
Author Keywords: Expedient Airborne Infection Isolation; Surge; Airborne Isolation; Healthcare; Engineering Controls; Ventilation
Field Studies; Control Technology
NTIS Accession No.
Healthcare and Social Assistance
National Institute for Occupational Safety and Health