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Workload and nosocomial infection in a medical intensive care unit

Applicant Pittet Didier
Number 68164
Funding scheme Project funding (Div. I-III)
Research institution Serv. Prévention et Contrôle de l’Infection Direction médicale HUG
Institution of higher education University of Geneva - GE
Main discipline Infectious Diseases
Start/End 01.01.2003 - 31.12.2008
Approved amount 798'000.00
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Keywords (10)


Lay Summary (English)

Lay summary
Healthcare-associated infections are the most common complications affecting hospitalized patients, making infection control a priority for patient safety. Determinants of hospital-acquired infections are numerous and only partially understood. It is only recently that the importance of the system as a whole and its components has been acknowledged and studied, although they are likely to become a pre-requisite for high quality of care. Healthcare workers are central to the system and the complex process of care delivery, but increased demands on their time conflict with somewhat inextensible resources. There is growing evidence to suggest that low staffing level might negatively impact on patient outcome, such as mortality, post-operative complications, or healthcare-associated infections.

We prospectively followed a cohort of critically-ill patients to assess the effect of staffing on the risk for nosocomial infection, and to estimate the proportion of infections attributable to low staffing level.

Of a cohort of 2470 patients, 415 developed at least one infection acquired while in critical care. Infected patients experienced higher mortality, stayed longer in critical care and in the hospital than non-infected patients. We found that increased staffing was associated with a 30% decrease in the infection rate (incidence relative rate, 0.69;95 percent confidence interval, 0.50 to 0.95), even after accounting for other risk factors. Furthermore, we estimated that 26.7% of all infections could be prevented providing that the nurse-to-patient ratio was maintained above 2.2, that is 183 of 686 infections observed over the study period.

The next step of the project is to have a closer look at the transmission of meticillin-resistant Staphylococcus aureus (MRSA) from one patient to another. Our surveillance system allows us to know for each patient who is admitted into the intensive care unit already colonized or infected with MRSA and who will acquire this microorganism during the ICU stay. This data will help to build a mathematical model that will be used to simulate the transmission of MRSA through the unit, and more importantly to assess the efficacy of several prevention methods. The following questions will be addressed: what happens in term of MRSA transmission if the level of nurse staffing is increased? If compliance with hand hygiene recommendation is improved? If patients are isolated until they are free of MRSA? If all patients are screened at admission?

This project will help understand the epidemiology of ICU-acquired infection, and inform policy makers as to what sort of interventions are efficacious to decrease the infection risk and consequently improve the patient’s safety.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
122324 Effectiveness of different strategies to improve hand hygiene and reduce healthcare-associated infections: a cluster randomised controlled trial 01.04.2009 Project funding (Div. I-III)