Hospital Design and Risk of Nosocomial Infections: A Prospective Controlled Trial

• Incidence of hospital-acquired infection with Clostridium difficile, and hospital-acquired infection or colonization with vancomycin-resistant Enterococcus (VRE), or methicillin-resistant Staphylococcus aureus (MRSA). [ Time Frame: in-hospital ]
  

• Incidence of the same infections in room-mates of study subjects. (i.e., event rates in non-study patients who have contact with infected study subjects). [ Time Frame: in-hospital ]
  

Recent studies have underscored the importance of optimizing design standards to maximize patient and health care worker safety, including the prevention of hospital acquired infections (HAI) in patients. Health care associated infections are a major contributor to adverse events in healthcare, estimated to occur in 3-20% of all acute care admissions in Canada. A review of the role of the physical environment and adverse events identified no prospective randomized controlled trials of physical plant design and its impact on hospital acquired infections. With the construction in 2004 of a unique $5-million, 36-bed medical teaching unit at Foothills Medical Centre (FMC) with a prototypical design with features to reduce HAI and an overarching mandate to test new concepts in health care delivery, the opportunity exists to rigorously study the impact of design, construction and engineering controls (DCECs) on specific hospital acquired infections and antibiotic resistant organism (ARO) colonization. In the first year of operation the incidence density of hospital acquired infections and/or colonization with marker organisms has declined by almost 70%. Given that there were no changes in the types of patients, medical, nursing or housekeeping staff, we hypothesized that the design of the new ward was the major factor which contributed to the improved outcomes. Given the pre-post study design we are uncertain as to which factor is most important in reducing HAI /colonization rates.

We therefore propose to conduct a prospective, controlled investigator blinded trial of the impact of DCECs on specific HAIs and ARO colonization. We propose to allocate general medical patients, with an allocation scheme that incorporates randomness, to one of 2 types of medical wards at the FMC, either "historic design" wards (ie control wards in the non-renovated portions of FMC or Unit 36 (the experimental new design ward). The medical wards are very similar with respect to the patient mix, acuity of care, medical staff, nursing staff and skill mix, educational levels, housekeeping and levels of knowledge about infection control practices but differ in design. Variables which may otherwise have confounded the outcome of hospital acquired infections/colonizations may be controlled allowing the effect of the differences in design, construction and engineering controls to be studied. The older design wards have predominantly 4-bed and some 2-bed rooms with shared bathrooms, less space and fewer handwashing sinks/patient. The study will require 9750 patient days of observation in the "historic design"wards and 19,500 patient days of observation in Unit 36 to ensure 80% statistical power to detect a 60% difference in the rates of incident cases of selected HAIs and ARO colonizations (the primary outcome measure) with an α level of 0.05 assuming that incident cases in each unit follow Poisson distribution based on well established historic trends on these units.

In addition we propose to add a nested mixed methods social science study within the construct of the prospective study to understand the fit between the health care workers and the physical environment. In recognition that the proposed intervention may be defined as a "complex intervention" with HAIs affected by many factors related to physical plant design, organizational factors, and health care worker practices, it was considered prudent to measure and describe worker and organizational factors on the medical inpatient care units included in the proposed intervention.

Our proposed study is being done with the collaboration and support of both the Operations and Planning & Capital Development portfolios of the Calgary Health Region. The Region is in the throes of a major expansion with over $1 billion of new capital health care developments and the addition of over 700 new beds by 2010. The finding of favorable outcomes on the medical ward with its special design, construction and engineered controls in a well designed prospective study of this nature would be the first of its kind and has the potential to change the fundamental design of new medical wards in the Calgary Health Region and in other jurisdictions within Canada.