[Nosocomial infection at an intensive care unit: multivariate analysis of risk factors]

Nosocomial infections, especially in the intensive care unit, are a very important problem due to their frequency and important consequences (morbility and mortality). On the other hand there are some risk factors and some preventive measures which are involved in the appearance of the nosocomial infections. The purpose of this work was to recognize these risk factors and to identify the preventive measures which are effective, and also to quantify the participation of each risk factors/preventive measures in the development of the nosocomial infections.

Follow-up of a cohort of patients admitted to the intensive care unit of the General Hospital of La Paz (Madrid, Spain) during a year and with a stay of at least 48 hours.

We have found a cummulative incidence of patients with nosocomial infection of 32.8%. More than 80% of the patients received antibiotic treatment during their stay in the intensive care unit. The stay of the patients no infected was 4 days while the stay of infected patients was 20 days. We have found a mortality of 29.5%, which was greater in the patients who were infected (42%). In the multivariate analysis we have developed an equation to predict the development of the nosocomial infection. The following variables were identified: six or more instrumentations (OR, 4.75; 95% CI, 2.75-8.19), more of ten days of hospitalization previous to the appearance of the first nosocomial infection (OR, 4.17; 95% CI, 2.60-6.70), administration of muscle relaxing drugs (OR, 2.25; 95% CI, 1.43-3.55), nasogastric tube (OR, 2.19; 95% CI, 1.25-3.84), and altered consciousness (OR, 2.19; 95% CI, 1.25-3.84). Therefore, those patients who present some of these characteristics should be monitored in a special way due to their high risk of development of a nosocomial infection.

Several factors play an important role in the development of a nosocomial infection in the intensive care unit; these are not only intrinsec (especially the altered consciousness) but also extrinsec (instrumentations and drugs), as well as the stay at the hospital previous to the appearance of the first nosocomial infection.