Nosocomial infection and related risk factors in a general surgery service: a prospective study.

Objectives: The aim of this study was to quantify the frequency of nosocomial infection in the general surgery service of a tertiary-care hospital and to identify associated risk factors.

Methods: A prospective, longitudinal, descriptive and analytical study was made from January 1995 to December 1998 of a clinical cohort of 2794 patients who underwent a surgical procedure with a post-surgery stay of more than 48 h. The criteria for infection were those defined by the Center for Disease Control and Prevention (CDC) of the USA.

Results: The most frequent nosocomial infection was surgical infection (SI), with a global cumulative incidence (CI) of 7.7%, ranging from 3.4% for clean surgery to 23.7% for dirty surgery. The next most frequent were urinary tract infection (UTI) and bacteremia (1.5%) and nosocomial pneumonia (NP) (0.5%). The global CI of SI decreased from 11.7% in 1995 to 4% in 1998. An ASA classification higher than 2 multiplied the risk of SI by 1.76; with respect to UTI multiplied the risk by 2.13; the risk of NP by 5.93 and multiplied the risk of B by 4.72.

Conclusions: The most frequent nosocomial infection was surgical infection. An ASA higher than 2, the stay prior to surgery; the number of days with a urinary catheter, with a central venous catheter and with mechanical ventilation; as well as the improvement in the use of antimicrobial prophylaxis, were all factors that influenced the frequency of nosocomial infection.