[Microbiological contamination of intraoperatively collected erythrocyte concentrate in mechanical autotransfusion in tumor surgery].

Intraoperative autotransfusion is an effective method of the autologous haemotherapy. Gamma irradiation of the salvaged erythrocyte concentrates leads to inactivation of malignant cells and allows retransfusion in oncologic surgery. The risk of microbiological contamination of the autologous blood product has not been systematically studied in this field of surgery. During the evaluation of intraoperative autotransfusion in oncologic surgery at the University Hospital of Leipzig, the salvaged blood of 46 patients who underwent tumour surgery (urology, gynaecology and neurosurgery) was processed to a washed erythrocyte concentrate with a Cell Saver 5 or a Haemolite 2 (Haemonetics). Specimens for microbiological studies were taken from the area of surgery, the reservoir bottle of the autotransfusion system and the salvaged erythrocyte concentrates. The investigation with plate cultures and the identification of microorganisms were performed according to standard procedures of microbiological diagnosis. The ethics committee of the University Hospital of Leipzig approved the study protocol. We found a microbiological contamination in 10 of 46 salvaged erythrocyte concentrates (22%), above all the growth of saprophytes (Streptococcus, Staphylococcus and Neisseria species). We also identified bacteria which have their habitats in the intestinal tract (E. coli and Enterococcus). The highest rate of microbial contaminated erythrocyte concentrates was found in urologic oncosurgery (37%). In neurosurgery (laminectomy and craniotomy including tumour extirpation), there was no bacterial growth in the salvaged erythrocyte concentrate. Intraoperative autotransfusion should be avoided during surgery touching the urinary tract, e.g. prostatectomy and cystectomy. In neurosurgery, it seems to be safe as far as microbiological contamination is concerned. To assess the real risk of microbiological contamination of the salvaged erythrocytes, more investigations are necessary to determine not only the extent and nature of contamination but also the clinical effects.