A PREVALENCE SURVEY OF NOSOCOMIAL INFECTI ONS IN INTENSIVE-CARE UNITS

In a large, multicenter survey in 1994, the prevalence of nosocomial i nfections in German hospitals was examined, predominant pathogens were identified, and possible risk factors evaluated. In this paper the re sults from the intensive care units (ICUs) are presented. Methods. Sev enty-two representative hospitals in Germany were selected by randomis ation and divided into four different groups according to their size ( <200 beds; 200-400 beds; 400-600 beds; >600 beds). During 10 months fo ur especially trained doctors documented the patients clinical and lab oratory data and possible endogenous and exogenous risk factors for no socomial infections. For better evaluation, they discussed the cases w ith the responsible senior officers and health care workers and visite d the patients. Diagnosis of nosocomial infection was based on CDC cri teria. Results. In 515 patients in 89 ICUs, 78 hospital-acquired infec tions were documented (15.3%). The most common were pneumonia (5.9%), bronchitis (2.7%), urinary tract infections (2.4%), and septicaemia (2 .2%). Possible exogenous risk factors included: peripheral venous cath eters (65.6%); catheterisation of the urinary tract (64.5%); central c atheters (60.4%); gastric (38.0%); wound and artificial drainage (28.6 %) and artificial ventilation (27.6%). The most frequent concomitant d iseases were cardiovascular (61.9%), diabetes (20.2%), malignancies (1 8.8%), pre-existing infections (15.3%), and chronic respiratory diseas e (14.0%). The prevalence of nosocomial infections was higher in hospi tals with more than 600 beds than in smaller ones (28.3% versus 12.9%, P<0.001). Predominant pathogens were Pseudomonas aeruginosa, enteroco cci, Staphylococcus aureus, Candida spp., Escherichia coli, and Klebsi ella spp.. Fifty per cent of the ICUs changed ventilation tubes and 66 .3% changed infusion sets daily; 34.8% of patients received drugs for the prevention of stress ulcers that neutralise or decrease production of gastric acid; only 7.6% received sucralfate. Routine microbiologic al surveillance of tracheal aspirates and urine was done by 25.9% and 24.6% of the ICUs, respectively. Discussion. Nosocomial infections are seen far more often in ICUs than on normal wards due to the immunosup pressed state of many ICU patients and the continuous use of invasive diagnostic and therapeutic procedures. Most of these infections are of endogenous origin. Other prevalence surveys have shown results compar able to ours. Daily changing of ventilation tubes is no longer necessa ry, but is still routine in many hospitals. Infusion sets were also ch anged more often than required. The use of selective decontamination o f the digestive tract for the prevention of pneumonia is still controv ersial; in our study it was practised in only 1.5% of the cases. The m ost commonly used drugs for the prevention of stress ulcers were H2-re ceptor blocking agents, although it has been shown that sucralfate is the better choice, as it can help prevent nosocomial pneumonia. Routin e microbiological surveillance of tracheal aspirates and urine was don e in 25.9% and 24.6% of the ICUs. No study so far has shown that routi ne cultures of tracheal secretions and urine have a preventive effect regarding infection.