Prevention of central venous catheter-associated bloodstream infections: A questionnaire evaluating the knowledge of the selected 11 evidence-based guidelines by Polish nurses. 
This study evaluated the questionnaire testing nurses' knowledge about the maintenance of a central venous catheter (CVC) and assessed it with regard to age, work experience, type of ward, frequency of trainings, and postgraduate education.  There were 1,180 questionnaires (N = 784; 66.4% of the total sample) distributed in several regions of Poland for a period of 7 months.  The difficulty level for each question ranged from 0.22-0.88.