A deadly dust may be in the wind during renovations
Work with construction crews to reduce risks to patients
Infection control practitioners at hospitals undergoing construction or renovation should ensure adequate air quality precautions are in place and strictly enforced to prevent deadly outbreaks of aspergillosis, advise ICP’s who have investigated recent outbreaks.
Hospital construction and renovation projects pose particular risk to immunocompromised patients who may inhale airborne dust particles that can carry fungal spores that cause aspergillosis. The federal Centers for Disease Control and Prevention in Atlanta warns that construction increases the risk of aspergillosis, and the agency recommends using special airflow and air filtration systems to keep fungal spores down in bonemarrow transplant patient rooms. (CDC Guidelines included later in article)
But ICP’s who have dealt with outbreaks have gone even further by working directly with construction crews to set up barriers, to redirect or block air intake systems from construction sites, and to restrict the movements of workers between construction and patient care areas. (Construction specifications included later in article)
Lorie Lerner-DurJava, RN, MSN, CIC, director of infection control, employee health, and safety at Children’s Hospital Medical Centre of Akron (Ohio), says her facility has undergone many construction projects in the last five years. Some projects have involved extensive demolition and renovation of existing patient care areas. To prevent Aspergillus from entering the hospital environment, Lerner-DurJava says she worked to limit access of workers to patient areas and had workers install ceiling-to-floor partitions to contain dust and debris.
Deaths – despite aggressive control measures
Despite implementation of the control measures, a patient was diagnosed with aspergillosis in January 1994, she says. A retrospective review uncovered other cases of nosocomial aspergillosis that had occurred since June 1993. The patients
were from different areas of the hospital including the burn unit, the dialysis unit, and oncology. There were no common factors between them such as age, diagnosis or type of surgery. Three of the patients died.
“We counted all 5 as nosocomial, but one of the cases, we really don’t think was related to construction,” she says. “In 3 cases, we knew the direct route. The demolition activity occurred and within 3 days they were diagnosed and that air handler directly connects the patient area to the construction area”.
Investigating the air-handling system at the hospital, she found that air intake vents in each of the nursing units the patients were housed in had not been covered during demolition.
“We forgot about the air-handling systems,” Lerner-DurJava tells Hospital Infection Control. “We had done everything we thought we were supposed to do. We had blocked off the construction areas. But we ended up with the air-handling system taking Aspergillus from one area to another.
After the investigation, Lerner-DurJava says she had the construction crew place plastic sheets over the intake vents.
In that area where the outbreak occurred, we could not shut down that air-handler because it serviced too many areas,” she explains. “So we just told the construction people to cover the intake valves with a piece of plastic and put duct tape around it until the project was over.
Put guidelines in the contract
Because there are 49 intake valves for the whole hospital, she says shutting off a few of them temporarily didn’t affect the whole air-handling system. Lerner-DurJava made daily rounds when construction projects were under way to make sure guidelines for construction were followed. She even negotiated to get the guidelines incorporated into construction contracts.
“So when a contractor came in to do work, it was part of the contract that they would in fact follow these infection control guidelines,” she says. “I developed a relationship with those contractors, which helped tremendously.”
A common problem was not taping plastic partitions to seal them off correctly.
“I’ve closed projects down,” she says. “I’ve told them they can’t do any more work until they get the area cleared out or whatever is needed.”
Air-sampling testing done during construction indicated that any projects involving the removal of ceiling tiles were particularly likely to spread Aspergillus, she adds.
“The aspergillus lives up there on top of those ceiling tiles,” she explains. “It doesn’t cause problems until you disrupt them, but when you start moving them around in that air space between the false ceiling and the cement ceiling, that’s where the contaminated air will get picked up and recirculated. What we’ve said is that if any type of demolition is occurring that will create dust, such as knocking down walls or removing ceiling tiles, workers have to follow our guidelines.”
Another safeguard during demolition was to have workers put up new ceiling tile as soon as the old tiles were removed.
“We had all of that area partitioned off, and the air handler to that area was either shut off or we covered the air intake valve,” Lerner-DurJava says. “They would take the old ceiling down, do what they had to do, and put a new ceiling up right away.”
No further cases of nosocomial aspergillosis have been identified since early last year, she notes, adding that there have been no new construction projects at the hospital since that time.
Faced with a long-range construction schedule and wary of aspergillosis, an ICP at another hospital set up a quality improvement project as a preventive measure. Gena Turner, RN, MSN, CEN, CCRN, infection control coordinator at Oregon Health Sciences University in Portland, developed a multidisciplinary quality improvement (QI) group to help prevent construction-related aspergillosis.
“We were embarking on a 6 year, multiproject construction stretch,” she says. “What we attempted to do was look at our baseline (air quality) level for a year prior to construction and we found no aspergillus. So the whole focus of our ongoing QI project has been to monitor and maintain those levels and use those as a quantitative basis to know whether our dust control measures were working or not.”
Turner says the same construction companies that work for the hospital also have worked for computer-chip manufacturers in the area, following special precautions to prevent environmental contamination with fungal spores. She approached the construction supervisors to request that they follow similar precautions at the hospital. At first, the construction supervisors said the precautions were too expensive for them to implement, but Turner insisted, and they agreed to comply.
For example, she required that workers wear jumpsuits when working in the active construction areas and change clothes in a
designated vestibule before entering the hospital. Or workers could wear their regular clothes, but then had to change into a jumpsuit and booties in a vestibule when entering the hospital.
Air testing indicated that negative air flow had to be used in construction areas at all times; otherwise, when any door was opened from the construction site into the hospital, Aspergillus would enter the hospital.
“Every worker has to go through an education session, even the subcontractors,” Turner says. We’ve actually even fires several workers who have continued to break the rules. (Summary of rules included later)
In addition, she tests air in areas that she anticipates could be problematic. Turner obtains 10 samples a week, 2 of which are control samples from outside and inside air.
“That makes a dent with my administrators,” she explains. “When they say Aspergillus samples are nothing to worry about because they’re from outside air, I can tell them there was no Aspergillus outside and that the contamination did happen indoors from construction.”
Every week, representatives from nursing, safety, housekeeping, infection control, facilities management, housekeeping and physical plant make rounds at construction sites, she says, noting that it helps facilitate communication when problems occur.
“A contractor may call the physical plant and say he’s having a problem with airflow in an elevator shaft, and he may ask that the physical plant staff change the elevator shaft to positive air pressure.” she explains. “But that’s the wrong thing to do, because there are all kinds of cracks around elevator openings.”
Outbreak among surgery patients
At University Hospital in Hershey, PA, Mary Ann Bordner, MS, CIC, infection control specialist, says there were 3 patients who developed invasive Aspergillus fumigatus infections in March of 1992. All had undergone cardiothoracic surgery, and all died. When investigating the outbreak, Bordner found that the surgeries had taken place in 2 adjoining OR rooms that shared the same air-handling system. While the source of contamination was being investigated, all elective heart surgeries were canceled.
Two construction projects were going on near the operating rooms. Bordner says she cultured the air and environment in the OR, the construction area, and the air ducts supplying the rooms in question, and then had those air ducts cleaned. The same weekend the ducts were cleaned, another case of aspergillosis was identified that had been done in another OR with a different air-handling system.
“So that put an entirely different picture on the problem,” she says.
In addition, soon afterward, nonsterile latex gloves that had been used in the OR were found to have black moldy-looking growth on them. The cultures of the mold on the gloves grew A. fumigatus, the same type of Aspergillus infecting the patients.
Restriction endonuclease analysis (REA) testing on the Aspergillus strains from the gloves and the air and environment in the OR and the construction areas indicated there were heavy loads of Aspergillus in the construction areas, but very light loads in the OR air. But none of the strains from the gloves or from the construction site or the OR matched the strains from the infected patients. In addition, Bordner found out that the contaminated lots of gloves had not entered the hospital until after the patients had acquired their infections.
Although she rules out the gloves and the air-handling system as sources of contamination, Bordner instituted additional control measures related to the construction. She found that there was a door exit in the construction area that was adjacent to a back entrance to the OR. Those doors were in close proximity, Bordner notes. She also found that OR personnel were entering the back entrance of the OR in street clothes.
“Because of traffic patterns, it was probable that the construction was causing the problem,” Bordner says.
Aspergillus may have entered the OR via health care workers who carried it on their shoes after going through the construction areas, she suggests. Or, when the back entrance to the OR was open, the other door that led to the construction area may have been open as well, and a gust of wind could have blown the spores into the OR. Heavy demolition had been taking place prior to the patient’s infections, which exacerbated the problem, Bordner adds.
To reduce air contamination, the entrances to the construction areas were moved so traffic flow was kept totally separate form the OR. The back entrance to the OR was locked so workers couldn’t come in and out in street clothes. New doors had to be built for the construction areas so there was no way to enter the OR from the construction area.
“We looked at the traffic flow, and we stopped allowing any crossover between construction workers and OR people,” Bronder says.
Now she says that when any new construction project is planned, she works closely with the construction supervisors ahead of time to make sure that the site is designed to keep the area separated from the rest of the hospital.
Air is apparent, but water also can be a source
Keep in mind that not all aspergillus contamination is in the air. Water can act as a reservoir for the fungus, as well. During a construction project last year at the University of Minnesota Hospital in Minneapolis, a building contractor accidentally punched a hole in the roof and flooded a patient ward, says Andrew Streifel, MPH, hospital environmentalist.
“It stayed wet for about a week,” he says. “It takes from 5 – 7 days for a good Aspergillus colony to set up. We found a lot of wet spots throughout the building afterward. Behind those wet spots there was mold growth, and in some places, there was pure Aspergillus fumigatus.”
Streifel says that because of the Aspergillus contamination, the ward involved was abandoned, and the contractor’s insurance company had to pay for cleanup and renovation of the area, which took weeks, Cleanup included decontaminating the area with copper-8-quinolinolate, a chemical agent that kills Aspergillus on environmental surfaces.
When obvious wet places or molds are found, don’t jump on it like a bull in a china shop, because then you disrupt this incredible reservoir of fungal spores that then move around the building,” he warns.
Instead he advises decontaminating the area first with either bleach or copper-8-quinolinolate. Streifel says he prefers the latter.
“The reason I like it is it protects from future leaks and act as a preservative,” he notes. “We’ve actually incorporated it into our structural steel insulation for our building.”
If ICP’s notice any wet spots in the hospital environment – especially wet ceiling tiles – the source of the leak should be investigated promptly and spills should be wiped up right away, he says.
It’s very naive to think that buildings don’t leak.” Streifel says. “And once you put water together with anything made of cellulose – bingo – mold is everywhere.”
- Centers for Disease Control and Prevention’s Hospital
- The project site must be completely contained with construction barriers extending from the floor, beyond the false ceiling, to the underside of the floor above. That area should be vacuumed prior to beginning construction. All penetrations into the construction area must be sealed, windows closed, and air ducts capped.
- Construction barricade entrances must have gasketed doors with self-closing latching hardware and dampened walk-off mats both inside and outside of the construction area.
- Negative pressure must be maintained within the project site at all times by the use of negative air fan units fitted with high-efficiency particulate air (HEPA) filters. Alarms must be in use so that any loss of negative pressure to the construction site can be known immediately to those outside the site.
- Debris removal from the construction site must be completed by a predetermined route at times when patients are in their rooms with their doors closed. Debris should be transported in clean containers with tight-fitting covers.
- Construction activities required in patient-occupied areas outside of the barricade must be regulated by a ceiling access procedure that requires a mini-enclosure around the work area.
- Any dust tracked outside of the barrier must be removed immediately. Cleaning in patient occupied areas shall be by camp method or with HEPA-filtered vacuum cleaners.
- All air-handling ducts should be shut down or covered during all demolition activities.
- an intensive retrospective review of microbiologic, histopathologic, and postmortem records for other cases;
- alerting clinicians caring for high-risk patients to the possibility of infection;
- establishing a system for prospective surveillance for additional cases.
- high efficiency particulate air (HEPA) filtration that is 99.97% efficient in filtering 0.3 micron-sized particles from incoming air, either centrally or at point of use;
- positive air pressure in the room relative to the corridor;
- well-sealed rooms;
- high rates of room-air exchanges (a minimum of 15 exchanges per hour).
Infection Control Practices Advisory Committee. Guideline for Prevention of Nosocomial Pneumonia. Infect Control Hosp Epidemiol 1994; 15:587-627
Construction Specifications for Infection Control
Source: Children’s Hospital Medical Center of Akron (Ohio) as adapted from guidelines developed at the University of California-San Francisco Medical Center
One aspergillosis case should prompt inquiry Clinicians caring for high-risk patients beware
A single case of aspergillus pneumonia often is difficult to link to a specific environmental exposure, but without an active search, additional cases may go undetected, warns the federal Centers for Disease Control and Prevention in Atlanta.
The major extrinsic risk factor for opportunistic, invasive aspergillus infection is the presence of aspergilli in the hospital environment, especially from environmental disturbances during construction or renovation. Other less common causes of outbreaks in high-risk, immunosuppressed patients include bird droppings in air ducts and contaminated fireproofing material.
According to the CDC, an investigation for aspergillosis should include the following:
If additional cases are detected, it is likely that an environmental source for aspergillus can be identified, especially from contamination of air-handling systems during construction projects.
For patients with severe granulocytopenia – especially bone marrow transplant (BMT) patients – many large hospitals have installed protective environments and stepped up surveillance during construction projects. Routine maintenance of hospital air-infiltration and ventilation systems also prevents exposing high-risk patients to bursts of aspergillus spores.
According to the CDC, the protected environment for BMT patients usually includes the following:
The number of room-air changes necessary to prevent aspergillosis is unclear, but one study found that lower air-change rates of only 10 to 15 per hour kept cases of nosocomial aspergillosis at a low rate of 3.4%.
The most effective way to keep air clean in patients’ rooms is to use laminar airflow, which consists of a bank of HEPA filters along an entire wall of the room that pump air into the room at a uniform velocity. Such systems make the air virtually sterile. Laminar airflow systems, however, are expensive to install and maintain, and further studies are needed comparing their efficacy at preventing aspergillosis with more traditional air-filtration measures.
Using the chemical agent copper-8-quinolinolate on environmental surfaces contaminated with Aspergillus also has been used as a control measure, but whether it should be used routinely has not yet been established.
- Centers for Disease Control and Prevention’s Hospital Infection Control Practices Advisory Committee. Guideline for Prevention of Nosocomial Pneumonia. Infect Control Hosp Epidemiol 1994; 15;587-627
- Streifel AJ, Vesley D, Rhame FS, et al. Control of air-borne fungal spores in a university hospital. Environment International 1989; 12:441-444.
- Rhame FS. Nosocomial aspergillosis: how much protection for which patients? Infect Control Hosp Epidemiol 1989; 10:296-298