Ventilation management for patient care protection during construction in a bone marrow transplant unit

Protecting immune suppressed patients from construction generated airborne opportunisticinfectious agents is essential during their hospitalization. During modernization of thehospitals 32-bed bone marrow transplant unit (BMTU), an empty intensive care unit wasretrofitted to BMT ventilation criteria. Filtration, pressurization and room air exchangecriteria were required at 12/h. A condensate particle counter and a digitalpressure gauge were used to assess these criteria. A high volume slit impactor (700 l/min) wasused to evaluate airborne fungal samples before and during occupancy to assure fungal sporecontrol. The results show that the pre-retrofit particle counts in patient rooms had an averageof 900 p/cm3 with a range of 700-1200 p/cm3; the post-retrofit particle levels had an averageof 27 p/cm3 and a range from 1 to 285 p/cm3 before occupancy and an average of 74 p/cm3with a range of 1-3770 p/cm3 after occupancy. The BMTU was pressurized to about 2.5 Paafter ventilation adjustment. Nosocomial fungal infections caused by airborne fungi did notincrease during the time that patients occupied the retrofitted unit. This case studydemonstrates using ventilation performance criteria for establishing special ventilationrequirements.