Successful use of a competency step exam in a perfusion education program.

The perfusion education program at The Ohio State University uses a step exam to rank students and identify incompetent students in regard to the program learning objectives. The step exam determines student progress from the didactic to the clinical phase. Each student must pass the competency step exam to gain entry to the clinical rotations. The development, use, and results of the step exam are reported. The design and knowledge matrix establish the content validity of the exam. Single test question discrimination and difficulty statistics identify valid exam items. Examples of the exam's predictive ability are presented. The step exam is a 200-question exam using multiple choice items. The exam is modeled after several health-related national certification exam processes. The exam has content validity based on the published, written objectives for the education program. Each item on the exam has a history of use and meets criteria for difficulty, discrimination, and distraction. The use of a high-stake competency exam in clinical science and medical education programs is controversial and technically challenging. A step exam to have high-stake consequences must be reliable, meet requirements for content validity, and hopefully exhibit predictive validity.

Inflammatory mediator removal by zero-balance ultrafiltration during cardiopulmonary bypass.

The abnormal conditions to which blood is subjected during cardiopulmonary bypass (CPB) trigger an activation of the inflammatory response in all patients to varying degrees. Both complement activation and the release of cytokines characterize this response. Most inflammatory mediators have a molecular weight that is below the membrane pore size of commonly used ultrafilters, which should allow them to be freely filtered. However, some mediators have been shown to fail to cross through the membrane even though they are small enough to cross. The purpose of the present study was to determine whether certain inflammatory mediators could be removed by ultrafiltration when performed during the rewarming phase of CPB. Thirty adult patients undergoing a single, open-heart procedure were randomized to either control (no ultrafiltration) or to the zero-balance ultrafiltration (ZBUF) group. ZBUF was performed by removing 3 l/m2 blood using a 65-kDa ultrafilter with 1.3-m2 surface area. A volume of a balanced salt crystalloid solution (Plasmalyte) equal to the filtered blood volume was given to replace the fluid removed. Patient data was taken before CPB (T1), immediately following CPB (T2), and 12 h following the procedure (T3). The average volume of filtrate removed during ZBUF was 6405 ml, which was analyzed for the presence of interleukin (IL)-1, IL-6, tumor necrosis factor-alpha (TNF-alpha), C3a, and C5a. The average concentrations of the mediators measured in the effluent were: IL-1, 0.17 pg/ml; IL-6, 0.64 pg/ml; TNF-alpha, 1.25 ng/ml; C3a, 782.6 ng/ml; C5a, 25.6 ng/ml. In every case except for IL-1, the amounts of mediators removed were significantly greater than zero. This study demonstrates that ultrafiltration is a strategy that can be used during CPB in the adult to remove significant amounts of inflammatory mediators.