Song Yi Park

The effects of pulsatile versus non-pulsatile extracorporeal circulation on the pattern of coronary artery blood flow during cardiac arrest.

Background In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile versus non-pulsatile circulation to coronary artery flow and myocardial preservation in a cardiac arrest condition. Methods A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing 25–35 kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extracorporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the systemic arterial and coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of < 0.05. Results The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p < 0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p < 0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p < 0.05) except at 80min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the systemic and coronary sinus blood (p=NS). Conclusion In the cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.

Verbal communication of students with high patient–physician interaction scores in a clinical performance examination assessed by standardized patients

Purpose Standardized patients (SPs) tend to rate medical students’ communication skills subjectively and comprehensively, in contrast to such objective skill set defined in the clinical performance examination (CPX). Meanwhile, medical school instructors have a different approach in their evaluation of students’ communication skills. We aim to analyze medical students’ verbal communication skills using objective methods, and to determine the contributing factors of a patient–physician interaction (PPI) score. Methods Students with high- and low-ranking scores for PPI in CPX were selected. The Roter interaction analysis system was used to compare verbal communication behaviors of the students and SPs. Patient-centeredness scores (PCSs), physician’s verbal dominance, and number of utterances were compared between the two groups. Results PCSs and physician’s verbal dominance had no difference between the groups. The number of utterances during the limited time of 5 minutes of CPX was higher for the high-ranking students. They tended to employ more paraphrase/check for understanding, and closed questions for psychosocial state and open questions for medical condition. The SPs interviewed by high-ranking students gave more medical information and requested for more services. Conclusion In the case of the routine checkup, smooth conversations with more frequent utterances were detected in the high-ranking students. More medical information exchange and requests for services by SPs were higher for the high-ranking students. Medical communication instructors should keep in mind that our results could be indicators of a high PPI score.