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Patients as Bio-indicators of the Hospital B uilding. Stephanie Taylor, MD , M Arch. What is a bio-indicator?. “Any biological species whose population , or status can be used to monitor the health of an environment or ecosystem.”. Today’s Presentation. A problem and an opportunity.
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Patients as Bio-indicators of the Hospital Building Stephanie Taylor, MD, M Arch
What is a bio-indicator? “Any biological species whose population, or status can be used to monitor the health of an environment or ecosystem.”
Today’s Presentation A problem and an opportunity • The indoor environment is under suspicion • New tools give us new insight New understanding • The microbiome of humans and buildings • The patient as a building bio-indicator The influence of air • Human physiology • Microbes Optimal indoor air • Barriers and benefits to change • Your next steps
We shape our buildings, then they kill us Is this true?
Let’s design a study • How can we study the impact of the built environment on the most important metric? • What is the most important metric in hospitals? • energy consumption (or lack of) • hospital profits • clinician happiness • other?
New patient infections can guide building management too many patients are harmed by new infections, “healthcare-associated infections” (HAIs)
To better understand transmission, a 13 month study on indoor air quality, bacteria spread & patient HAIs was performed Monitorindoor conditions in 10 patient rooms and 2 nurse stations Mapbacterial communities in these spaces Track patient HAIs Colonization and Succession of Hospital-Associated Microbiota. In Press, Sept 2016 Simon Lax, et.al. U.Chicago, IL 60637
Patient room information collected every 30 minutes for 1 year Staff & visitor hand cleaning Room air changes Traffic in & out of room RH, absolute humidity Temperature Lux Outdoor air fractions Room pressurization CO2 level 8 million data points!!
Indoor air RH was found to be the most significant factor associated with patient HAIs Avg RH for all patient rooms
RH in patient rooms Avg daily RH
Conclusion This new data challenges the desire to minimize humidity in occupied spaces! patient infections as RH
The invisible world video goes here
New tools give us new understanding Microscope 1509 Telescope 1608 “Gene-o-scope” 2000”
Our microbes interact with the indoor environment We send our microbes to buildings Buildings send their microbes to us
Every bodily function requires water the average person is 75% H2O 100% 80% • Food digestion to produce energy and build tissues • Transport of dissolved O2 and CO2 (breathing) • Keeping our structure and epithelial layers intact • Training our immune system to decrease allergies and infections 60%
Our surface area is vast Epithelium exposed to air includes: • skin • nose, throat, sinuses • 2,400 kilometers of bronchial tubes • 500 million “air sacs” in our lungs
The universe strives for equilibrium Dry, thirsty air steals moisture from wherever it can – a law of physics
Dehydration causes “Dry building syndrome” • Sitting in room air with 20% RH, the average person becomes clinically dehydrated in 8 hours, before thirst begins • Dehydration harms: Defenses against infections & allergies Brain function & performance Skin integrity, wound healing
Dry air dehydrates our brain 30% RH 50% RH
Dry Building Syndrome affects our brain • 1% decrease of our body weight from water losses diminishes our: • ability to think • short-term memory • concentration • reaction times • visual-motor tracking
Dry air is harmful to our skin • Skin is essential for: • wound healing • immune system training • protection from injury • protection from infections • preserving internal water
Dry air harms our skin well hydrated dehydrated
Dry air impairs vision take off six hours later landing
Dry air damages our corneas normal cornea dry cornea after 30 days at 20% RH
Children and seniors are especially vulnerable to the ill-health effects of low RH • Delicate fluid balance • Higher transdermal water loss • no self-control over fluid input • no control on clothing • Sense of thirst is reduced and thus unreliable in preventing dehydration • Bedridden or unconscious persons have no autonomy • Seniors often limit drinking in order to reduce toilet visits Children Seniors
Conversely, pathogens love dry air! Evasion from surface cleaning through re-suspension Greater transmission through the air Prolonged survival in droplet nuclei and spores
Dry air is great in biological warfare • “Moisture content may, indeed, • be the most important environmental factor • influencing the survival of airborne microbes.” • Dr. Dimmick, Naval Biological Laboratory, Univ. CA, Berkeley, doing research on anthrax spores
Pathogens travel far in dry air Droplet diameter in microns (um) Float time 0.5 41 hours 1 3 10 1.5 hours 100 6 seconds 10m+ Distance travelled: 1m
Infectivity of many viruses is greater in dry air High HumidityLeads to Loss of Infectious Virus from SimulatedCoughs. U. Illinois, 2013 J Noti, et al.
Dry air promotes pathogen transmission in tiny droplets Pathogens circulate through the ventilation system Ventilation duct Infectious droplets are expelled into the hospital environment and dry rapidly Recirculate in turbulent flow Infectious droplets spread disease to in-patients (HAIs) Re-contaminate hands and surfaces
But, with healthy RH of 40%–60%, infectious droplets settle out of the airborne environment • Disinfection benefits of proper air hydration: • Bedrails and other frequently touched surfaces are more effectively cleaned • Hand hygiene is maintained • Settled infectious droplets are not re-suspended
Dry weather reliably predicts meningitis outbreaks • Bacteria spread through the air when the outdoor humidity is low • “Once the humidity exceeds 40%, the epidemic ends”
Sterling diagram, 1985, with optimal RH level for health of 40%–60% 45% actual humidity in winter season ideal humidity for winter season
The great indoor air RH debate! Protect the occupants Protect the building • Occupants need RH between 40% and 60% for optimal health • Decreased infections • Fewer allergies • Improved hydration • Improved wound healing • Increased work performance • Buildings don’t care about humidity • Facility managers often incorrectly think: • The drier the air the better • Easier to dry the air than fix the envelope construction RH: 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
250 bed hospital’s excess costs due to preventable patient infections *2015 volume of a selected 250-bed hospital, APIC calculated costs
Decrease building energy use with proper humidification • Although counterintuitive, reducing room ACH in hospitals decreases the spread of infectious droplet nuclei • Hospitals can save up to 70% HVAC fan and reheat energy costs by reducing ACH by 10% • Hospital indoor air change rates (ACH) are kept high because of a mistaken perception that high ACH will yield better IAQ • Air turbulence plus low RH in clinical spaces contributes to the spread of airborne pathogens as infectious droplet nuclei are propelled further away from an infected human host, exposing other room occupants to infections
Conclusions: 40 (percent RH) is the new 20! • New data reinforces the importance of indoor air hydration in patient outcomes • Dry indoor air harms people • Collaboration between engineers, building managers and clinicians is key to improving public health