[Current status of teaching in lung ultrasound : Query of knowledge, utilization, need, and preferred teaching method]. / Zum Stand der Ausbildung im Lungenultraschall : Abfrage von Kenntnissen, Verwendung, Bedarf und bevorzugter Unterrichtsform.

BACKGROUND: Lung ultrasound (LUS) is a point-of-care technique which can quickly identify or rule out pathological findings. To date, it is unclear if knowledge about the use of LUS is readily available. OBJECTIVES: We aimed to identify how much knowledge about the use of LUS is present, if there is a need for teaching in LUS, as well as the preferred teaching method in LUS. MATERIALS AND METHODS: A total of 54 participants from two university departments of anesthesiology were randomized into the groups Online, Classroom, and Control. The Online group was taught by videos, the Classroom group by a traditional lecture with hands-on training, and the Control group was not taught at all. We conducted a pre- and posttest as well as a retention test 4 weeks after the end of the study by means of a survey (comparison with Mann-Whitney U test or t­test, respectively, with p < 0.05 considered to be significant). RESULTS: LUS is used "rarely" or "never", and mainly if there is a suspicion for pleural effusion (41.3%). There is a need for LUS (Online: 21.7%; Classroom: 60.9%; Control: 62.5%, p < 0.05). Hybrid teaching consisting of classroom-based and online-based teaching is preferred by the users (Online: 52.2%; Classroom: 56.5%; Control: 62.5%). At the end of the study, 32.6% of the participants of the intervention groups had used LUS in the diagnosis of a pneumothorax. Of the participants, 93.5% planned to use LUS more often in the future. CONCLUSIONS: LUS is rarely used. There is a considerable need for teaching of LUS. Internet-based teaching and traditional lectures are considered equal. Both teaching methods improve the knowledge about LUS and lead to increased use of LUS in daily practice. The participants prefer hybrid teaching incorporating both teaching methods.

Simulation training for rare medications in the intensive care unit-a study with bivalirudin.

The purpose of this study was to assess whether simulation training can improve the clinician's ability to predict the effect of bivalirudin infusion. Six clinicians with experience using bivalirudin and six without experience (Groups Exp and NoExp) entered predictions for partial thromboplastin time while viewing a running display of clinical data obtained retrospectively from intensive care unit patients who had received bivalirudin infusion after cardiac surgery. All clinicians entered guesses for the same sequence of 30 patients. Average guessing-errors were analysed using analysis of variance and linear regression. All physicians evaluated 30 patients (813 partial thromboplastin time guesses overall) in less than two hours. Average errors in Groups Exp and NoExp decreased from 9.4 and 11.7 seconds in the first tercile, to 8.2 and 8.4 seconds in the last tercile of patients, respectively. The guessing-errors of Group NoExp were significantly higher than Group Exp in the first and second terciles, with no significant difference in the third tercile. Linear regression indicated a significantly steeper learning curve in Group NoExp than Exp. Brief simulation training using retrospective patient data improved the ability of inexperienced clinicians to predict the effect of bivalirudin as compared to experienced clinicians.

State-dependent block of human cardiac hNav1.5 sodium channels by propafenone.

State-dependent blockade of human cardiac hNav1.5 sodium channels by propafenone was studied using whole-cell patch clamp techniques. Both a direct investigation using cells with inactivation-deficient sodium channels and an algorithmic approach used on cells with wild-type channels revealed a rapid binding of propafenone to the open state. This occurs approximately 4000 and 700 times faster than the binding to the resting and inactivated state, respectively. An established mathematical "gating" model was modified to represent the experimental data.

Lumbar repetitive magnetic stimulation reduces spastic tone increase of the lower limbs.

STUDY DESIGN: Comparison of spinal lesion subjects and normal subjects. OBJECTIVE: To investigate the effects of a paravertebral repetitive magnetic stimulation on spastic tone increase of the lower limbs. SETTING: Munich, Germany. METHODS: We compared the effects in 15 patients with different spinal lesions and in 16 healthy subjects. The spastic tone increase was evaluated clinically with the Ashworth scale and apparatively with the pendulum test, both at fixed times before and after stimulation. Unilateral stimulation was applied to the lumbar nerve roots L3 and L4 of the clinically more spastic leg. RESULTS: The spastic tone decreased significantly in the interval between 4 and 24 h after stimulation. This effect was slightly more pronounced in the contralateral extremity. Furthermore, the stimulation motor threshold of the patients was significantly raised. CONCLUSION: Repetitive magnetic unilateral stimulation has a positive effect on spastic tone increase due to spinal lesions, causing a decrease that lasts for about 1 day not only on the ipsilateral but also on the contralateral side.

[Epicardial echocardiography intraoperative diagnostic utility to assess valve function]. / Epikardiale EchokardiographieIntraoperative Beurteilung der Klappenfunktion.

Epicardial echocardiography has been available since the early 1970s as an intraoperative diagnostic modality to assess ventricular and valvular function. With this technique, an ultrasonic transducer is placed directly on the epicardial surface of the heart, following sternotomy and pericardiotomy. Under the guidance of the cardiac anesthesiologist, the surgeon places the transducer so that the desired views of cardiac structures and great vessels can be obtained. The anesthesiologist performs the acquisition, analysis and interpretation of the echocardiographic images. Despite the feasibility of epicardial echocardiography, transesophageal echocardiography (TEE) has emerged over the last two decades as the main form of intraoperative echocardiography. Although TEE allows continuous monitoring of cardiac and valvular function without interruption of the surgical procedure, placement of a TEE probe may be difficult or contraindicated in some patients. In such cases, epicardial echocardiography may be the optimal ultrasonographic imaging modality to assess ventricular and valvular function during cardiac surgery. We describe the use of epicardial echocardiography for intraoperative assessment of valvular function in two patients where TEE was either contraindicated or probe placement could not be performed safely. The first patient underwent surgical repair of the mitral valve for severe mitral regurgitation. After weaning the patient from cardiopulmonary bypass (CPB), epicardial echocardiography was used to confirm successful reconstruction of the valve and to exclude residual mitral regurgitation. The second patient was scheduled for coronary artery bypass grafting (CABG). Prior to the initiation of CPB, the presence of moderate aortic stenosis was confirmed using Doppler echocardiography via an epicardial approach.

Analysis of passive elastic joint moments in paraplegics.

In the functional electrical stimulation of the lower extremity of paraplegics to achieve standing and walking, a mathematical model describing the passive elastic joint moments is essential in order to implement model-based control algorithms. In a previous investigation of ten normal persons we had found significant coupling of passive, elastic joint moments between neighboring joints due to muscle groups that span both joints (biarticular muscles). Thus, we now investigated the biarticular coupling in six paraplegic patients. A comparison to the averaged results of the ten normal persons showed that while the biarticular joint moment coupling due to the gastrocnemius muscle was well preserved in all patients, the coupling due to the rectus femoris was greatly reduced and the coupling due to the hamstring muscle group was negligible. We offer pathophysiologically based explanations for these characteristic differences including the speculation that the predominantly extensor-type spasticity in our patients exercises mainly the anti-gravity muscles such as the gastrocnemius and the rectus femoris, while permitting greater atrophy of the hamstring muscle group. A previously presented double-exponential equation that predicts the joint moments under consideration of the neighboring joint angles could be fitted well to the experimental data.

Pulse oximetry: an improved in vitro model that reduces blood flow-related artifacts.

Artifacts may occur in many in vitro models of pulse oximetry due to the optical effects of synchronously oriented and/or deformed erythrocytes. Although these artifacts are most likely negligible in living superficial tissues, they are demonstrated to have considerable influence on the calibration curve obtainable from the in vitro simulation of pulse oximetry in such models, especially at low oxygen saturations. Therefore, we have developed a modified in vitro model which reduces the effect of these artifacts. This is achieved by excluding data obtained during pressure transients and by raising the blood flow velocity. As a result, the model more closely approximates in vivo pulse oximetry, particularly under clinically important conditions of low blood oxygen saturation levels.

Identification of passive elastic joint moments in the lower extremities.

Musculotendon actuators produce active and passive moments at the joints they span. Due to the existence of bi-articular muscles, the passive elastic joint moments are influenced by the angular positions of adjacent joints. To obtain quantitative information about this passive elastic coupling between lower limb joints, we examined the passive elastic joint properties of the hip, knee, and ankle joint of ten healthy subjects. Passive elastic joint moments were found to considerably depend on the adjacent joint angles. We present a simple mathematical model that describes these properties on the basis of a double-exponential expression. The model can be implemented in biomechanical models of the lower extremities, which are generally used for the simulation of multi-joint movements such as standing-up, walking, running, or jumping.

Fetal pulse oximetry: influence of tissue blood content and hemoglobin concentration in a new in-vitro model.

OBJECTIVE: To assess the influence of the blood content of the tissue and the hemoglobin content of the blood upon pulse oximetry at oxygen saturation ranges that commonly occur in the fetus during birth. METHOD: A new in-vitro model, which differs conceptually from models used by other authors, was developed to simulate the tissue. Our sensor measured absorption changes in red (640 nm) and infrared (880 nm) light as the blood concentration in the optical chamber changed in analogy to arterial pulsations. RESULTS: Blood content of the tissue and hemoglobin content of the blood both affect the pulse oximetric measurement adversely, especially at low oxygen saturations. Our simulations indicate, for example, that at a true oxygen saturation (SaO2) of 30%, a blood content change from 10 to 6 vol% would cause an underestimation of SaO2 by more than 16% points. CONCLUSION: Pulse oximetry at low saturations should take the blood content of the tissue and hemoglobin content of the blood into account in order to provide more accurate results.