RESUMO
The authors detail the characteristics for the sterility of drained serums placed in a mobile emergency service unit and they determine how much time they can maintain optimum conditions for the use of these serums by means of a controlled, random, triple blind clinical test in which the units studied were serums prepared by an infusion system and a three-way valve. Data were gathered during a 12 month study period. The authors designed six operating groups based on their exposure time and where they were kept. These samples totaled 672 units. The authors carried out 12 microbiological cultural analyses for each unit; these analyses were tested for bacteria and fungi, both aerobic and anaerobic. The authors contrasted their hypothesis with a multivariable logistic regression model used as the variable for sterility A value of p < 0.05 was considered to be significant. Results were obtained on 669 serums, 98.82% of samples. Colonization was found in 1.7% of the 8028 cultures analyzed; in only 2 cases was there a register greater than 10 UFC/ml. This colonization corresponded to 103 serums which were then classified as non-sterile. For sterility the logistic regression model did not show any significant association with the various operating groups, which were controlled by means of two possible variable methods. The authors did not find evidence that recently drained serums were different, from the point of view of sterility, than the serums exposed during 24, 48 or 72 hours but, as well as for the groups, the incidences of these serums tripled the risk of colonization. The authors concluded they could use serums prepared previously and these serums sterility were guaranteed to the same degree as recently drained serums.