[The bacteriological diagnosis of catheter-related sepsis. The advantages of quantitative blood cultures]

If sepsis due to a catheter is suspected in a patient receiving parenteral nutrition, the doctor responsible for the patient usually withdraws the catheter and sends the point to the bacteriological laboratory for examination. This operation is usually accompanied by the extraction of several blood samples for haemoculture. With this attitude, it has been observed that most of the catheters withdrawn are sterile or if they are contaminated, they are not the cause of the sepsis. This leads to a series of unnecessary expenses and risks. This problem has prompted us to design a clinical study for the prospective investigation of the efficiency of quantitative haemocultures in the diagnosis of sepsis due to the catheter. During an 8-month period, all the patients who received parenteral nutrition in our centre were followed up by members of the nutritional support unit and participated in the study. In the face of the clinical suspicion of sepsis due to the catheter, blood was obtained for haemoculture, both through the catheter and from the peripheral veins. However, the catheters were not withdrawn until after the results of the cultures, between 16 and 24 hours following the extraction. A count of colonies in blood proceeding from the catheter which was five times or more greater than the count in the peripheral blood was interpreted as sepsis due to the catheter and the catheter was withdrawn. Differences between both counts (central and peripheral) which were less were interpreted as sepsis with a different origin to the catheter and in this case, the catheter was not withdrawn. A total of 26 catheters were evaluated using this method.(ABSTRACT TRUNCATED AT 250 WORDS)