Causes of hospital-acquired septicaemia--a case control study

Hospital-acquired septicaemia is common and an important cause of morbidity and expense. Few studies have explored its cause by comparing features of people who do and do not develop septicaemia—the aim of this study. All blood cultures were monitored over one year in a 400-bed tertiary care hospital where special care is taken with intravenous cannulae to prevent septicaemia. Cases had at least one positive blood culture taken at least 48 h after admission. The nearest two patients in the same ward were controls, and information was abstracted on all three from the hospital records by a research nurse. There were 84 cases during the 12 months (3.8 per 1000 admissions) and 167 controls. Univariate odds ratios (95% CD were 5.57 (2.06–15.95) with the presence of a central venous line, 3.40 (1.16–16.40) with total parenteral nutrition, 2.41 (1.30–4.32) with blood transfusion, 2.10 (1.16–4.56) with immuno- suppressive disease, 2.06 (1.02–4.44) with the presence of a urinary catheter and 0.32 (0.17–0.69) with recent surgery. Conditional logistic regression identified a central venous line and blood transfusion to be independent risk factors for septicaemia, odds ratios (and 95% CD being 5.14 (1.74–15.23) and 2.74 (1.28–5.88), respectively, while recent surgery and antibiotic prophylaxis were independently ‘protective’ at 0.31 (0.12–0.79) and 0.38 (0.16–0.90), respectively. Thus, in a hospital where great care has been taken to avoid septicaemia, especially by attention to intravenous cannulae, there were only two independent risk factors for the development of hospital-acquired septicaemia—a central venous line and blood transfusion. Further work seems indicated as to why blood transfusion may increase the risk of septicaemia.