Basic echocardiography for undergraduate students: a comparison of different peer-teaching approaches.

BACKGROUND: The aim of this study was to assess the impact of different teaching interventions in a peer-teaching environment on basic echocardiography skills and to examine the influence of gender on learning outcomes. METHODS: We randomly assigned 79 s year medical students (55 women, 24 men) to one of four groups: peer teaching (PT), peer teaching using Peyton's four-step approach (PPT), team based learning (TBL) and video-based learning (VBL). All groups received theoretical and practical hands-on training according to the different approaches. Using a pre-post-design we assessed differences in theoretical knowledge [multiple choice (MC) exam], practical skills (Objective Structured Practical Examination, OSPE) and evaluation results with respect to gender. RESULTS: There was a significant gain in theoretical knowledge for all students. There were no relevant differences between the four groups regarding the MC exam and OSPE results. The majority of students achieved good or very good results. Acceptance of the peer-teaching concept was moderate and all students preferred medical experts to peer tutors even though the overall rating of the instructors was fairly good. Students in the Video group would have preferred a different training method. There was no significant effect of gender on evaluation results. CONCLUSIONS: Using different peer-teaching concepts proved to be effective in teaching basic echocardiography. Gender does not seem to have an impact on effectiveness of the instructional approach. Qualitative analysis revealed limited acceptance of peer teaching and especially of video-based instruction.

A computational model of a human single sinoatrial node cell.

For the investigation of the spontaneous rhythmical activity response in the application of cardiac neuromodulation, we formulated a human sinoatrial node (SAN) cell model. With the aim of decreasing elevated heart rate (HR), we want to establish a hardware-in-the-loop system including this model for the analysis of optimal stimulation patterns of the neurostimulation system. Base model structures are adopted from rabbit SAN cell models available in literature and conveyed with Hodgkin-Huxley-type model equations describing the complex time and voltage dependent activation and deactivation processes of individual ion channels. The resulting model consists of 15 currents which are currently known to be responsible for the generation of the membrane action potential (AP). The model reproduces AP frequencies equivalent to those measured in isolated human SAN cells with a resulting HR of 71.8 bpm. Model validation via simulation of the inhibitory effect of ivabradine showed accordance with experimental results obtained in human studies. Furthermore, we could validate the model in regard to its HR effects upon parasympathetic stimulation with results obtained in a human trial study.

A novel application for assessing diaphragmatic function by ultrasonic deformation analysis in noninvasively ventilated healthy young adults.

PURPOSE: Noninvasive pressure support ventilation is intended to relieve the load on respiratory muscles and to prevent exhaustion. This includes continuous positive airway pressure (CPAP) as well as pressure support ventilation (PSV). Speckle tracking echocardiography (STE) allows quantification of tissue deformation by tracing characteristic grayscale patterns, independent of the acquisition angle. The aim of the present study was to assess the applicability of using STE as a way to investigate diaphragm movement using deformation analysis as a parameter for respiratory workload. MATERIALS AND METHODS: Healthy male subjects (n = 13, 27 ±â€Š7 years) were treated while in a seated supine position with the following respirator settings: regular breathing, 5 mbar CPAP, CPAP + 5 / + 10 / + 15 mbar PSV. A 2 - 4 MhZ M5S phased array sector transducer was used on a Vivid E 9 (GE, Horton, Norway) to visualize the diaphragm. The inspiratory peak transverse strain was measured as a parameter of maximal inspiratory muscle workload and compared to the M-mode-based fractional thickening (FT). RESULTS: Both the FT and the transverse strain increased significantly under CPAP and PSV. The transverse strain correlated well with the FT (r = 0.753; p < 0.001). CONCLUSION: The results measured by STE were comparable to the M-mode-based measurements. The capturing of a larger diaphragmatic sample area and movement tracking possibly lead to higher precision compared to one-dimensional M-mode. The use of STE in patients might provide a reproducible, bedside method to analyze the respiratory workload. Due to the larger sampling area, it might prove superior to mere M-mode acquisition.

Influence of aortic dimensions on the hemodynamic performance of small aortic valve prostheses: impact on patient/prosthesis mismatch.

BACKGROUND: Since Doppler echocardiography takes no account of pressure recovery, the true hemodynamic burden of aortic valve prostheses remains vague. The purpose of this study was to elucidate the methodological error of Doppler gradient estimation by means of a model demonstrating the different influence of aortic root diameters on net and Doppler gradients, respectively. This matters especially in small valves and the related patient/prosthesis mismatch calculation. METHODS: Two bileaflet small aortic valve prostheses (19 mm SJM Regent® and On-X® valve) were tested using a pulsatile circulatory mock loop simulator with two different aortic models: one with statistically normal diameters according to annular size, another one simulating an aortic aneurysm of 50 mm. Doppler and simultaneously recorded net gradients as well as systolic energy losses were obtained for different hemodynamic conditions. RESULTS: In all measurements a significant amount of pressure recovery was observed. In cases of aortic aneurysm systolic energy loss increased significantly for each cardiac output at each heart rate ( P < 0.0028), reflected by a significant ( P < 0.0001) increase in net gradients. The corresponding Doppler gradients were unchanged. This indicates significantly less pressure recovery ( P < 0.0001) in the aneurysmatic aorta. CONCLUSIONS: Geometry of the ascending aorta considerably alters aortic valve hemodynamic parameters. The hemodynamic function of small aortic valve prostheses, especially with corresponding normal outflow dimensions, is much better than expected from Doppler gradients. Thus, calculation of a patient/prosthesis mismatch can be misleading.

Quality of life and toxicity in breast cancer patients using adjuvant TAC (docetaxel, doxorubicin, cyclophosphamide), in comparison with FAC (doxorubicin, cyclophosphamide, 5-fluorouracil).

OBJECTIVES: The aim of this study was to compare two regimens of chemotherapy in patients with breast cancer, including FAC (doxorubicin, cyclophosphamide, and 5-fluorouracil) and TAC (docetaxel, doxorubicin and cyclophosphamide); and analyze the toxicity of these treatments and observe patient's health-related quality of life. METHODS: Health-related quality of life was assessed for up to 4 months (from the beginning to the end of chemotherapy cycles), using European organization and cancer treatment quality of life questionnaire (EORTC) QLQ-C30. A group of 100 patients, with node-positive breast cancer were studied in order to compare the toxicity of adjuvant therapy TAC with FAC and the subsequent effects on the patient's quality of life. RESULTS: After a 4-month follow-up of patients, our findings showed that despite having the same mean score of QOL at the start of adjuvant chemotherapy, the QOL in TAC arm was decreased more as a result of the higher range of toxicity in TAC regimen. CONCLUSION: In spite of increase in disease-free patients who received TAC regimen and increase their survival rate, there is significant toxicity and decrease in QOL in TAC protocol compare to FAC protocol. Using prophylactic granulocyte colony stimulating factor (G-CSF) along with increased education aimed at improving patient's knowledge and also the provision of a supportive group involving psychiatrics and patients that have successfully experienced the same treatment may be helpful.

Economic burden of inappropriate antibiotic use for prophylactic purpose in shiraz, iran.

BACKGROUND: Because economic data on the prophylactic usage of antibiotic in Iran are scant, we have conducted a cross-sectional study with provider perspective to measure costs and appropriate use of antibiotics in surgical wards of 6 training hospitals affiliated to Shiraz University of Medical Sciences (SUMS), Iran. METHODS: Over a six-month period 1,000 consecutive patients undergoing surgical operation were enrolled and information on prophylactic antibiotic administration was collected. The information included basic patient's demographic data, types of surgery, category of antibiotic, dosage, dosage intervals, route of administration, number of doses, initiation times and duration of administration. In order to determine the agreement between prescribed antibiotics and medical indication, the American Society of Health-System Pharmacists (ASHP) guidelines were applied. RESULTS: Nine hundred and ninety three out of 1,000 patients (99.3%) had received at least one antibiotic and 908 patients (91.4 %) received antibiotics because of a medical indication. Five out of 913 patients who had indications for antibiotic prophylaxis did not receive any antibiotic. Antibiotics were prescribed for 85 out of 87 (98%) procedures in which an antibiotic was not indicated. The average cost of antibiotic prescription per surgical procedure was 786,936 Iranian Rials (corresponding to 99.60 USD or €82.90). The most frequent prescribed antibiotic was cefazoline adding 53.3% of the total cost of antibiotics. In total, 36,516,190 Iranian Rials (corresponding to 4,622.95 USD or €3,845.20) were spent for cefazoline alone. CONCLUSION: The results of this study showed that all surgical patients received at least one antibiotic as prophylaxis for any infection in the surgical site. Our results indicate over- and misuse of antibiotics in Iran leading to a great amount of economic burden, since in 98% of all procedures, antibiotics were used inappropriately.