Efficacy of an information system addressed to nursing staff for diminishing contaminated blood cultures: a blind clinical trial

Introduction. Evaluate the efficacy of an information system addressed to nursing staff to lower the blood culture contamination rate. Methods. A blind clinical trial was conducted at Internal Medicine and Emergency Departments during 2011. After following a reeducation program in BC extraction, participants were randomly selected in a 1:1 ratio. Every participant of the experimental group was informed of each worker’s individual performance; whereas the control group was only informed of the global results. Results: A total of 977 blood extractions were performed in 12 months. Blood culture contamination rate was 7.5%. This rate was higher in the Emergency Department than in Internal Medicine (10% vs. 3.8%; p=0.001). Factors associated with the higher risk of contamination were, in the univariate analysis, the extraction through a recently implanted blood route and the time of professional experience, while those associated with a lower risk were the extraction in Internal Medicine and through a butterfly needle. On multivariate analysis, extraction through a recently placed access was an independent risk factor for an increased contamination rate (OR 2.29; 95%CI 1.18-4.44, p=0.014), while individual information about the blood culture results (OR 0.11; 95%CI 0.023-0.57; p=0.008), and more than 9 years of professional experience were associated with fewer contaminations (OR 0.30; 95%CI 0.12-0.77; p=0.012). In the intervention group the contamination rate diminished by a 26 %. Conclusions: Drawing blood cultures through a recently taken peripheral venous access increased their risk of contamination. The intervention informing the nurse staff of the contamination rate is effective to decrease it.