Risk factors for nosocomial intensive care infection: a long-term prospective analysis

Background: To identify risk factors for nosocomial infection in intensive care and to provide a basis for allocation of resources. Methods: Long‐term prospective incidence study of risk factors for nosocomial infection in the surgical‐medical intensive care unit of a university hospital. Results: A total of 2671 patients were admitted during four years, and 562 of 574 patients staying >48 h were observed during 4921 patient days (median length of stay 5 days, range 2–114). Of these, 196 (34%) patients had 364 nosocomial infections after median 8–10 days, an infection rate of 14/100 admissions. Infection prolonged length of stay 8–9 days and doubled the risk of death. The infections were 17% blood stream, 26% pneumonias, 34% wound, 10% urinary tract and 13% other infections. The incidence of bloodstream infection declined significantly during the study years, from 12% to 5%. In multiple regression analysis, the important variables for infection were central venous catheter, mechanical ventilation, pleural drainage and trauma with open fractures. High age, immunosuppression and infection on admission did not influence the risk of acquiring infection. Trauma patients constituted 24% of the study population. Trauma with open fractures increased the risk of infection more than twice (P=0.003), mainly due to wound infections. Conclusion: Trauma cases, with open fractures, were the patients most at risk of infection, despite low disease severity scores. Resources to prevent nosocomial infection should be allocated to these patients.