Video-based, student tutor- versus faculty staff-led ultrasound course for medical students - a prospective randomized study

Background Ultrasound education is propagated already during medical school due to its diagnostic importance. Courses are usually supervised by experienced faculty staff (FS) with patient bedside examinations or students among each other but often overbooked due to limited FS availability. To overcome this barrier, use of teaching videos may be advantageous. Likewise, peer teaching concepts solely with trained student tutors have shown to be feasible and effective. The aim was to evaluate 1) objective learning outcomes of a combined video-based, student-tutor (ViST) as compared to a FS-led course without media support, 2) acceptance and subjective learning success of the videos. Methods Two ultrasound teaching videos for basic and advanced abdominal ultrasound (AU) and transthoracic echocardiography (TTE) were produced and six students trained as tutors. Fourth-year medical students (N = 96) were randomized to either the ViST- or FS course (6 students per tutor). Learning objectives were defined equally for both courses. Acquired practical basic and advanced ultrasound skills were tested in an objective structured clinical examination (OSCE) using modified validated scoring sheets with a maximum total score of 40 points. Acceptance and subjective learning success of both videos were evaluated by questionnaires based on Kirkpatrick's evaluation model with scale-rated closed and open questions. Results 79 of 96 medical students completed the OSCE and 77 could be finally analyzed. There was no significant difference in the mean total point score of 31.3 in the ViST (N = 42) and 32.7 in the FS course (N = 35, P = 0.31) or in any of the examined basic or advanced ultrasound skill subtasks. Of the 42 ViST participants, 29 completed the AU and 27 the TTE video questionnaire. Acceptance and subjective learning success of both videos was rated positively in 14-52% and 48-88% of the rated responses to each category, respectively. Attendance of either the student or faculty tutor was deemed necessary in addition to the videos. Conclusions A ViST versus FS teaching concept was able to effectively teach undergraduate students in AU and TTE, albeit acceptance of the teaching videos alone was limited. However, the ViST concept has the potential to increase course availability and FS resource allocation

Oxygenation effect of interventional lung assist in a lavage model of acute lung injury: a prospective experimental study

INTRODUCTION: The aim of the study was to test the hypothesis that a pumpless arteriovenous extracorporeal membrane oxygenator (interventional lung assist (ILA)) does not significantly improve oxygenation in a lavage model of acute lung injury. METHODS: The study was designed as a prospective experimental study. The experiments were performed on seven pigs (48–60 kg body weight). The pigs were anesthetized and mechanically ventilated. Both femoral arteries and one femoral vein were cannulated and connected with ILA. Acute lung injury was induced by repeated bronchoalveolar lavage until the arterial partial pressure of O(2 )was lower than 100 Torr for at least 30 minutes during ventilation with 100% O(2). RESULTS: ILA was applied with different blood flow rates through either one or both femoral arteries. Measurements were repeated at different degrees of pulmonary gas exchange impairment with the pulmonary venous admixture ranging from 35.0% to 70.6%. The mean (± standard deviation) blood flow through ILA was 15.5 (± 3.9)% and 21.7 (± 4.9)% of cardiac output with one and both arteries open, respectively. ILA significantly increased the arterial partial pressure of O(2 )from 64 (± 13) Torr to 71 (± 14) Torr and 74 (± 17) Torr with blood flow through one and both femoral arteries, respectively. O(2 )delivery through ILA increased with extracorporeal shunt flow (36 (± 14) ml O(2)/min versus 47 (± 17) ml O(2)/min) and reduced arterialization of the inlet blood. Pulmonary artery pressures were significantly reduced when ILA was in operation. CONCLUSION: Oxygenation is increased by ILA in severe lung injury. This effect is significant but small. The results indicate that the ILA use may not be justified if the improvement of oxygenation is the primary therapy goal

Assessment of tidal recruitment and overdistension by regional analysis of respiratory system compliance at different tidal volumes

In this pilot clinical study, we assessed the effects of positive end-expiratory pressure (PEEP) on tidal recruitment and overdistension in mechanically ventilated patients. Changes in EIT-derived regional respiratory system compliance (Crs) induced by variation of tidal volume (VT) were analysed in the chest cross-section and identified the simultaneous occurrence of tidal recruitment and overdistension in the examined patients

Rapid Emergence of Resistance to Linezolid during Linezolid Therapy of an Enterococcus faecium Infection

We report the emergence of linezolid resistance (MICs of 16 to 32 mg/liter) in clonally related vancomycin-susceptible and -resistant Enterococcus faecium isolates from an intensive care unit patient after 12 days of linezolid therapy. Only linezolid-susceptible isolates of the same clone were detected at 28 days after termination of linezolid therapy

Effect of PEEP and Tidal Volume on Ventilation Distribution and End-Expiratory Lung Volume: A Prospective Experimental Animal and Pilot Clinical Study

<div><p>Introduction</p><p>Lung-protective ventilation aims at using low tidal volumes (V_T) at optimum positive end-expiratory pressures (PEEP). Optimum PEEP should recruit atelectatic lung regions and avoid tidal recruitment and end-inspiratory overinflation. We examined the effect of V_T and PEEP on ventilation distribution, regional respiratory system compliance (C_RS), and end-expiratory lung volume (EELV) in an animal model of acute lung injury (ALI) and patients with ARDS by using electrical impedance tomography (EIT) with the aim to assess tidal recruitment and overinflation.</p><p>Methods</p><p>EIT examinations were performed in 10 anaesthetized pigs with normal lungs ventilated at 5 and 10 ml/kg body weight V_T and 5 cmH₂O PEEP. After ALI induction, 10 ml/kg V_T and 10 cmH₂O PEEP were applied. Afterwards, PEEP was set according to the pressure-volume curve. Animals were randomized to either low or high V_T ventilation changed after 30 minutes in a crossover design. Ventilation distribution, regional C_RS and changes in EELV were analyzed. The same measures were determined in five ARDS patients examined during low and high V_T ventilation (6 and 10 (8) ml/kg) at three PEEP levels.</p><p>Results</p><p>In healthy animals, high compared to low V_T increased C_RS and ventilation in dependent lung regions implying tidal recruitment. ALI reduced C_RS and EELV in all regions without changing ventilation distribution. Pressure-volume curve-derived PEEP of 21±4 cmH₂O (mean±SD) resulted in comparable increase in C_RS in dependent and decrease in non-dependent regions at both V_T. This implied that tidal recruitment was avoided but end-inspiratory overinflation was present irrespective of V_T. In patients, regional C_RS differences between low and high V_T revealed high degree of tidal recruitment and low overinflation at 3±1 cmH₂O PEEP. Tidal recruitment decreased at 10±1 cmH₂O and was further reduced at 15±2 cmH₂O PEEP.</p><p>Conclusions</p><p>Tidal recruitment and end-inspiratory overinflation can be assessed by EIT-based analysis of regional C_RS.</p></div

Regional lung opening and closing pressures in patients with acute lung injury

Purpose: In acute lung injury (ALI), the application of positive end-expiratory pressure (PEEP) is known to prevent the alveoli from cyclic c

Respiratory and hemodynamic data of the studied patients.

<p>Data are shown as mean values ± standard deviation. V_T: tidal volume, F_Io₂: fraction of inspired oxygen, PEEP: positive end-expiratory pressure, PIP, peak inspiratory pressure, C_RS: respiratory system compliance, P_aco₂: end-expiratory partial pressure of carbon dioxide, HR: heart rate.</p><p>*The measurement at LIP+7 and high V_T was not conducted in patient 1 due to excess of peak inspiratory pressure limit of 40 cm H₂O (see Methods for further details).</p