Indoor Air Quality: Mold, Patients

Transcription

1 Indoor Air Quality: Mold, Patients and Elevators? Matthew L. Berkheiser, DrPH, CIH, CSP Executive Director & Chief Safety Officer Environmental Health & Safety May 2012 Background Cost of hospital-acquired infections History on decision to investigate the elevator shaft Other Regulatory Requirements American Institute of Architects Created in Expanded in 2001 edition of The Guidelines for Design and Construction of Hospital and Healthcare Facilities. Created the Infection Control Risk Assessment (ICRA). Revised in 2003 and 2006 and 2010 An ICRA is multidisciplinary, organizational, documented process that considers the facility's patient population and program. Focuses on reduction of risk from infection Acts through phases of facility planning, design, construction, renovation, facility maintenance. Coordinates and weighs knowledge about infection, infectious agents, permitting the organization to anticipate potential impact. 1

2 Other Regulatory Requirements Joint Commission Adopted AIA guidelines 2002 Environment of Care (EC ) When planning for demolition, construction, or renovation, the hospital conducts a preconstruction risk assessment for air quality requirements, infection control, utility requirements, noise, vibration, and other hazards that affect care, treatment, and services. MD Anderson Cancer Center Because we are a cancer hospital, the majority of our population is immuno-compromised and therefore are susceptible to opportunistic infections that can be caused by exposure to mold spores. Very important that we contain mold spores to protect our patients from opportunistic infections. Valuable research that can be invalidated by contamination. Minimum Precautions Some type of containment: surface, double flap of poly on door, zip wall, containment cube, or full containment. 2

3 Minimum Precautions Room air supply should be covered and exhaust should be filtered or covered completely Trash must be double bagged and removed in a covered trash cart Terminal cleaning once work is complete Minimum Precautions Clearance: visual, surface sampling, air sampling. Personal protective equipment: safety glasses, gloves, tyvek, respirator. Do not leave containment wearing PPE!!! Mold Prevention 3

4 Mold needs 3 things to grow Spore Food Water Eliminate any one of the three and mold cannot grow Spores are ubiquitous-impossible to eliminate all of them Food sources exist everywhere-its impossible to eliminate all paper based products. So that leaves WATER! All that effort 4

5 Visualization of air leaving shaft While difficult to see in the pictures the air is leaving the shaft through the gap between the door and the floor and entering the hospital lobby and elevator car. The Theoretical Path Spores enter vents on roof Into elevator shaft Air travels through vent to top of shaft Air escapes from shaft into hospital around gaps b/t car and bldg Elevators travel up and down Vent terminates into shaft Elevator Vulnerability Assessment Air entering elevator shaft HVAC air enters On 8 th floor HEPA filtered??? In Houston Cladosporium 98% frequency on spore traps, penicillium/ aspergillusspores 91% and basidiospores 96% frequency?? Air/spores Enter through first floor?? = what are the frequencies and concentrations 5

6 Hypothesis There is a positive correlation between the number of Penicillium/Aspergillus-like spores, cladosporium, ascospores, basidiospores in spores/m 3 found in the hoistway vent of an elevator shaft and the levels of the same spores, sampled near simultaneously and near the outdoor intake of the elevator shaft. There is a positive correlation between the number of Penicillium/Aspergillus-like spores, cladosporium, ascospores, basidiospores in spores/m 3 found in the hoistway vent of an elevator shaft and the levels of the same spores, sampled near simultaneously in elevator lobbies of the study location. Hypothesis There is a positive correlation between the number of Penicillium/Aspergilluslike spores, cladosporium, ascospores, basidiospores in spores/m 3 found in the 5 th floor elevator lobby and the levels of the same spores, sampled in the 5 th floor surgery recovery area collected on the same day within the same time frame. Hypothesis Compare hoistway vent to outdoor environment for 0.3, 0.5, 1.0, 2.5, 5.0, 10.0 µm particle concentrations. Are the two areas similar or different? 6

7 Hypothesis There is a positive correlation between the concentration of particles at 0.3 um, 0.5 um, 1.0 um, 2.5 um, 5.0 um, 10.0 um sizes air found in the hoistway vent of an elevator shaft and the levels of the same collection of particles found in the elevator lobbies and other sampling locations. Specific Aims Aim 1: To determine if external Penicillium/Aspergillus-like spores are entering the healthcare facility via the elevator shaft and hoistway vents. Aim 2: To determine levels of Penicillium/Aspergillus-like spores outdoors, in the elevator shafts, and indoors in areas possibly affected by elevator shaft air. Aim 3: To determine if Aspergillus spores (niger, flavus, fumigatus, terreus, versicolor) identified indoors are the same as spores found outside the healthcare facility. Aim 4: To determine if there is a direct correlation between Aspergillus spores/m 3 of air, species occurrence and particle counts for the locations sampled. Aim 5: To obtain air velocity in the elevator shaft during controlled situations and calculate air flows to provide additional data that addresses the hypotheses. Sample/Measurement Methods Particle counts (0.3, 0.5, 1.0, 2.5, 5.0, 10.0 um) Temperature and relative humidity Polycarbonate filters Aspergillus (niger, flavus, fumigatus, terreus, versicolor) Spore Traps Penicillium/Aspergillus-like spores Basidiospores (>5.0 um and <5.0 um) Cladosporium (>5.0 um and <5.0 um) Ascospores (>5.0 um and <5.0 um) 7

8 Sampling Locations Outside Hoistway 11 th Floor Elevator Lobby 5 th Floor Elevator Lobby 5 th Floor Surgery Recovery Area 5 th Floor Building Cross Connection 1 st Floor Elevator Lobby 5 th Floor Sampling Locations Shaft Duct Drill holes in duct to complete sampling to capture spores and particles 8

9 Sampling Equipment Laser Particle Counter 2.83 liters of air collected 3 measurements averaged Spore Traps 15 liters/minute 10 minutes Polymerase Chain Air sample on 37 mm polycarbonate filters 30 liters/minute for 34 minutes Study Duration First sample collected April 7 th, 2010 Final sampling event was September 2nd, 2010 A change of direction occurred in May27th, 2010 (pre/post) Aim 6. To evaluate whether any effect is observed due to the installation of a hoistway vent damper, installed serendipitously during this study. Damper Installed Installed a damper in the ductwork between the air shaft and the outdoor air Damper is designed to operate between 0.01 and 0.05 inches water gauge Stays closed unless pressure dictates opening 9

10 Final Data Collected 254 PCR Cassettes 363 Spore Traps for seven spore types 2178 Particle counts 363 Temperature and relative humidity Data was divided into pre and post conditions because of the damper installation Analysis of Data Fisher s Exact test to compare locations for positive sample frequency and determine differences between pre and post Spearman correlation to determine if spores and particles are correlated between two environments Wilcoxon Rank Sum to compare median values for differences pre and post Geometric Mean, Penicillium/Aspergilluslike spores Pre Post only 1 sample positive 270 spores/m Outside Hoistway 11th floor 5th floor 5th floor 5th floor first floor recovery cross connection 10

11 Fisher s Exact Test and Spearman Results Penicillium/Aspergillus like spores, Comparison of Positive Samples Pre and Post Conditions Fisher s Outside Hoistway Vent p value Penicillium/Aspergillus like spores Pre-Installation Post-Installation 11/21 (52%) 8/22 (36.4%) /30 (87%) 1/30 (3.3%) Spearman Pre Rho p Value Post Rho p Value LOCATION Outside th Floor Elevator lobby th Floor Elevator Lobby th Floor Recovery G5P5 Cross Connection st floor elevator lobby Comparison of Particle Count Means Hoistway vs. Outside 6.00E E+07 outside pre 4.00E+07 hoistway pre outside post 3.00E+07 hoistway post 2.00E E E um 0.5 um 1.0 um 2.5 um 5.0 um 10 um Comparison of Particle Count Means Pre and Post the 11 th floor 1.20E E E E+06 Pre mean Post mean 4.00E E E um 0.5 um 1.0 um 2.5 um 5.0 um 10 um 11

12 Geometric Mean Cladosporium (>5.0 um) pre post Outside Hoistway 11th floor 5th floor 5th floor recovery 5th floor cross connection first floor Geometric Mean Cladosporium (<5.0 um) Outside Hoistway 11th floor 5th floor 5th floor recovery 0 5th floor cross connection first floor pre post Additional Results Ascospores and basidiospores did not provide enough positive samples inside the building to be useful as a tracer during this study. Particle count correlations supported the hypothesis between outside and the hoistway and other floors to hoistway comparisons. Relative humidity inside the duct decreased from 49.3 to 37.8 following the damper installation. 12

13 Conclusions (continued) Hospital areas studied were clean in relation to the outside Aspergillus species levels, particle levels and other mold spores collected The use of Penicillium/Aspergillus-like and Cladosporium(>5.0 um) spores and particle counts were the most effective measures for evaluating the indoor quality compared to outside levels. A significant correlation existed between parameters for the environment outside and inside the hoistway. Conclusions (continued) Consider elevator shafts as potential spore sources. Evaluate and understand how the air flows through the shafts and into the buildings. The findings may prompt consideration of retrofits of similar dampers. Design criteria should be updated for future hospital buildings. The new criteria should include consideration for protecting the elevator shaft from exterior air utilizing a damper similar to the one in this study, or alternate solutions achieving the same results. Sharing this information with building code organizations in future comment sessions when updating elevator and building ventilation code sections may be helpful. No existing recommendations or building code requirements specifically address this issue. QUESTIONS / COMMENTS Matthew L. Berkheiser, DrPH, CIH, CSP Executive Director & Chief Safety Officer Environmental Health & Safety May 2012 mlberkhe@mdanderson.org 13