Health Canada Issues Standard for Construction
Precautions in Hospitals

Health Canada has released a national standard for precautions to be taken during construction and maintenance work in hospitals and other health care settings. Contractors performing work in health care facilities must take care to apply these standards with diligence to minimize the very real risk of their work causing illness and death in susceptible patients.

Issued in July 2001, "Construction-related Nosocomial Infections in Patients in Health Care Facilities – Decreasing the Risk of Aspergillus, Legionella and Other Infections" is a guide for the planning of renovations and construction work. Its purpose is to lessen the risk of hospital-acquired (nosocomial infections).

Construction and renovation work causes settled dust containing fungal spores and bacteria in water supply systems to become airborne. Patients who are susceptible to infections may become infected by these microbial hazards, in some cases fatally so. The accompanying story chronicles some of the recent outbreaks of nosocomial infections in Montreal’s Victoria Hospital. In fact, all existing hospitals and health care facilities share this potential for illness due to construction work.

The Health Canada standard quotes a number of studies that powerfully demonstrate the need for these precautions. One study showed that the frequency of nosocomial Aspergillus infections tripled in a hospital during construction work (up to 10 cases per 1000 days at risk), compared to baseline conditions. However, following implementation of control measures, the frequency of nosocomial infection was reduced to the baseline level, demonstrating the effectiveness of the methods.

Fungal infections, particularly due to fungi of the Aspergillus family, are a major concern of the Health Canada standard.Several Aspergillus species can cause infections in susceptible patients. Aspergillus exposures may occur by a variety of pathways: through infiltration of outside unfiltered air, disturbance of dust in ceiling systems or other cavities, demolition of equipment, or from mould growth in the facility. The risk of Aspergillus infection is greatly increased when mould growth in building finishes or in ventilation units goes unchecked. For this reason, it is essential that managers of health care facilities proceed with utmost care when dealing with water damage or reports of potential health effects from mould contamination.

Legionella bacteria is the second risk factor addressed by the Health Canada standard. Legionella, typically present at low concentrations in lakes and rivers and treated water supplies, can become greatly amplified in water systems given the right conditions of warm water and nutrient matter. If these bacteria become airborne and are inhaled, a serious pneumonia can develop. Outbreaks of Legionnaire’s disease have been tracked to a variety of sources including cooling towers, faucet and shower aerators, spas, drinking fountains and water features. Another risk factor for development of Legionnaire’s disease in hospitals is the possible release of bacteria colonizing stagnant areas of water service caused by pressure surges during service interruptions.

Susceptible patients identified in the Health Canada standard include transplant patients, patients undergoing chemotherapy or prolonged use of antibiotics or steroids, dialysis patients, the very old and very young, patients with AIDS or other congenital immunodeficiencies, and other conditions.

Controlling the risk requires the collaborative effort of many involved in a construction project. For smaller scale projects, these would include at least the infection control practitioner at the facility, engineering services, the architects and engineers responsible for the project and of course the contractor and subcontractors. Larger scale renovations may require a specialist consultant to design the containment and ventilation controls and to supervise and test the ongoing isolation methods.

The Health Canada standard is based on a ranking of risk of a construction activity depending on the expected intensity of disturbance and the susceptibility of the surrounding patient population.

Four classes of controls are identified, as shown in Table 1, for the construction activities given in Table 2 and the risk groups given in Table 3.

Canada is not alone in having recently published standards for hospital construction precautions. The US Centres for Disease Control issued a similar document, "Draft Guideline for Environmental Infection Control in Healthcare Facilities, 2001".

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