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

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.

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.

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.

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.