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A simple ex vivo model has been developed using porcine large bowel. Various endoluminal procedures can be simulated and trained in this easy-to-use model. The main advantages are realistic human-bowel configuration and use of biological tissue simulating some of the bowel-wall properties. X-ray transparent materials were used for radiological-assisted procedures and the simple set-up allows multiple use.
An image-based approach has been developed to represent bleeding in a simulator for transurethral resection of prostate (TURP). While previous attempts have simulated bleeding over tissue surfaces or in blood vessels, our approach focused on the macroscopic visualization of bleeding in a fluid environment. TURP is an ideal procedure for simulation-based training because of the dynamic environment and the variety of flow patterns it presents. The first step in the development of the simulator was the generation of blood flow movies which consisted of capturing videos of bleeding vessels in vitro, processing them to separate the actual blood from the background anatomy and organizing the movies into a parametric database. During the running of the simulation, resection of prostate tissue systematically triggers bleeding events and the playback of a blood flow movie. The blood flow movie is texture mapped onto a virtual surface that is positioned oriented, morphed, composited and looped into the virtual scene.
Although the many advantages of laparoscopic surgery have made it an established technique, training in laparoscopic surgery posed problems not encountered in conventional surgical training. Virtual reality simulators open up new perspectives for training in laparoscopic surgery. Under realistic conditions in real time, trainees can tailor their sessions with the VR simulator to suit their needs and goals, and can repeat exercises as often as they wish. VR simulators reduce the number of experimental animals needed for training purposes and are suited to the pursuit of research in laparoscopic surgery.
BACKGROUND: Human error can be expected to play a significant role in adverse outcomes in perinatal acute care. In acute care of the adult, simulator based training is recommended and used to improve patient safety. AIMS: Our general goal is to develop model-driven foetal and neonatal educational simulators and curricula. The specific objectives of this paper are to introduce the reader to the perinatal acute care context and simulator design considerations, as well as to give initial results and describe ongoing developments. A brief description of adult simulators and simulation engines is followed by a more detailed description of a foetal distress simulator (FDS) and of models for a neonatal simulator developed at the University of Porto. Ongoing developments involve the modelling of foetal baroreflexes, the effect of uterine contractions, and an adapted method for estimating foetal heart rate variability parameters. RESULTS: We present FDS simulation results reflecting the changes in oxygen supply to the foetus and the foetal heart rate in response to a reduction in uterine blood flow. We also present a structural diagram of a model for the educational simulation of congenital heart disease and preliminary simulation results reflecting a patent ductus arteriosus. CONCLUSION: We expect that, after initial clinical and educational validation, the presented models and simulators will play a role in simulator-based educational programmes contributing to increased perinatal safety.
Isokinetic contraction is the muscular contraction that accompanies constant velocity limb movements around a joint. The velocity of movement is maintained constant by a special dynamometer. The resistance of the dynamometer is equal to the muscular forces applied throughout the range of movement. This method allows the measurement of the muscular forces in dynamic conditions and provides optimal loading of the muscles. However, during movements in the vertical plane, the torque registered by the dynamometer is the resultant torque produced by the muscular and gravitational forces. The error depends on the angular position and the torque potential of the tested muscle group. Several methods have been developed for the correction of gravitational errors in isokinetic data. The torque output also contains artefacts that are associated with the inertial forces during acceleration and deceleration periods before the development of the constant preset angular velocity. For an accurate assessment of muscle function, only constant velocity data should be analysed. The most frequently used isokinetic parameters are the maximum torque and the angular position where it was recorded, the torque output at different angular velocities of movement, the torque ratio of reciprocal muscle groups and the torque output during repeated contractions. The unique features of isokinetic dynamometry are optimal loading of the muscles in dynamic conditions and constant preselected velocity of movement. These features provide safety in the rehabilitation of patients with muscular and ligamentous injuries. Isokinetic dynamometry has also been used for the training of various muscle groups in order to improve the muscular performance in dynamic conditions. The movement velocity of different activities can be simulated during training in order to improve the training effect. Data acquisition and analysis have been improved by using computer systems interfaced to isokinetic dynamometers. Recently developed computer systems provide correction for gravitational and inertial errors, accurate computation of isokinetic parameters and real-time display of the torque output.
One of the applications developed within the EU-funded projects TESEMED and TESEMED-II is a program for the information and continuous training of community pharmacists, with the aim to empower them as advisors of the citizens about self-medication topics. Several programs are being developed on the basis of ad-hoc developed protocols about minor ailments (currently, cold and flu, haemorrhoids, constipation and cough). Each program includes three modules: a hypertextual version of the protocol, an interactive scheme of it, and an educational tool called Encounter Simulator, that trains the pharmacist about the protocol by means of simulated pharmacist-customer interactions. The testing of these applications with 84 community pharmacists offers positive results in terms of expectations, program characteristics and perceived usefulness.
A computer simulation of the circulatory system was used to kinetically model secretion, inhibition, and clearance of tissue plasminogen activator (t-PA) during three different processes that increase active t-PA levels: epinephrine infusion, exercise, and endurance training. Infusion of epinephrine stimulated an increase in t-PA secretion that was proportional to the plasma epinephrine concentration. In addition, epinephrine infusion increased hepatic blood flow and t-PA clearance, thus slowing the increase of plasma t-PA levels. During exercise, t-PA levels increased due both to increased t-PA secretion and to decreased clearance secondary to reduced hepatic blood flow. The increase in t-PA secretion during exercise was directly proportional to the epinephrine concentration in blood with the same ratio of t-PA secretion to epinephrine as found during epinephrine infusion, suggesting that increased plasma epinephrine during exercise was the primary stimulus for t-PA secretion. Lastly, the simulation predicted that 6 months of endurance training produced a decrease in resting plasminogen activator inhibitor type 1 (PAI-1) secretion, resulting in less t-PA inhibition and an overall increase in active t-PA after training. Accurate analysis of the regulation of active t-PA levels in blood required simultaneous modeling of t-PA and PAI-1 secretion, hepatic clearance, and inhibition of t-PA by PAI-1.
STUDY OBJECTIVES: To determine (1) reliability and validity estimates of three modalities used to assess open thoracotomy procedural competency and (2) the effect of computer practice on procedural performance as measured by the three assessment modalities. METHODS: An experimental, sequential assessment design with volunteer examinees completing all three assessment modalities (paper, computer, pig model) was implemented at the animal support facilities of a university medical school with an affiliated emergency medicine residency program. Level of physician training (student, resident, faculty) and type of computer practice (thoracotomy, cricothyrotomy) were independent variables. Procedural competency scores were determined for each modality; scores were defined in terms of performance time and performance accuracy for three thoracotomy procedures (opening the chest, pericardiotomy, and aortic cross-clamping). RESULTS: Thoracotomy performance on the pig reliably discriminated among examinees known to differ in level of training. However, computer simulation performance did not significantly differ among examinees with different levels of training. Computer simulation practice significantly improved later performance on the computer assessment (P < .05) but not on the pig assessment. The greatest predictor of procedural competency (time and accuracy) on the pig assessment was the ability to sequentially order procedural steps. CONCLUSION: This study establishes the pig model as superior to the paper and computer models as the criterion standard for open thoracotomy assessment. Psychometric properties support the pig model as the most reliable and valid model yet described for assessing thoracotomy procedural competency. Computer simulation practice using visual images (complex anatomy) and the sequential ordering of procedural steps through paper modeling show promise for teaching and assessment of prerequisite skills required to develop psychomotor procedural competency.
Memory training programs for cognitively impaired patients have often been criticized for their lack of relevance to everyday activities. We therefore report our experience with four patients suffering from probable Alzheimer's disease, who were trained with a new computer-based program recently developed by our research group. An everyday task of personal relevance to the patient is simulated and trained on a PC-touch-screen using personal photographs of the patient's surroundings and biography. According to the degree of cognitive impairment, training has three major aspects 1) social competence in patients with beginning deficiencies, 2) orientation in patients with moderate disease, and 3) emotional aspects in patients with advanced deficiencies. The patient's training performance improved substantially. While psychopathometric tests showed no significant effects with regard to general cognitive performance, levels of motivation were high and there was a positive acceptance of the training and signs of emotional activation.
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Memory training programs for cognitively impaired patients have often been criticized for their lack of relevance to everyday activities. We therefore report our experience with two patients suffering from probable Alzheimer's disease who were trained with a new computer-based program recently developed by our research group. An everyday task of personal relevance to the patient was simulated and trained on a PC touch screen using personal photographs of the patient's surroundings and biography. The patient's training performance (time, mistakes, number of advices) improved substantially. While psychopathometric tests showed no significant effects with regard to general cognitive performance, levels of motivation were high and there was a positive acceptance of the training, signs of emotional activation and of a transfer of the trained skills into real situations.
The UofL Center for the Deterrence of Biowarfare and Bioterrorism's (CDBB's) training involving standardized patients, who can make convincingly accurate representations of clinical signs and symptoms, and patient simulators has proven to be an effective means of enhancing bioterrorism preparedness. In addition to providing ready access to formative measures of preparedness, both of these teaching and learning tools also offer the option of summative evaluation of skills and knowledge acquired during training sessions. The use of moulage allows for very realistic representations of cutaneous anthrax and smallpox as well as other conditions such as recluse spider bites and chickenpox with which these biothreat infections can be confused. Exercises and drills expose deficiencies and permit essential reinforcement of skills developed in training. Unannounced exercises are especially useful in assessing public health preparedness.
The successful decoding of kinematic variables from spike trains of motor cortical neurons is essential for cortical neural prosthesis. Spike trains from each single unit must be extracted from extracellular neural signals and, thus, spike detection and sorting procedure is indispensable but the detection and sorting may involve considerable error. Thus, a decoding algorithm should be robust with respect to spike train errors. Here, we show that spike train decoding algorithms employing nonlinear mapping, especially a support vector machine (SVM), may be more advantageous contrary to previous results which showed that an optimal linear filter is sufficient. The advantage became more conspicuous in the case of erroneous spike trains. Using the SVM, satisfactory training of the decoder could be achieved much more easily, compared to the case of using a multilayer perceptron, which has been employed in previous studies. Tests were performed on simulated spike trains from primary motor cortical neurons with a realistic distribution of preferred direction. The results suggest the possibility that a neuroprosthetic device with a low-quality spike sorting preprocessor can be achieved by adopting a spike train decoder that is robust to spike sorting errors.
A variety of endoscopy simulators have been produced during the last several decades. Multiple factors have influenced the types of simulators that have been developed and the ongoing evolution of existing models. Realistic simulation is only one issue in providing simulation-based training in GI endoscopy. Details such as cost, technologic limitations, management and availability of training facilities, personnel, animal welfare and the procurement, handling, and disposal of animal parts are all major factors when considering the options available among existing endoscopy simulators. Table 1 summarizes the logistical factors for the different types of endoscopy simulator. These considerations clearly are of major importance in simulator design and development and in the conceptualization and organization of simulator-based curricula and courses.
BACKGROUND AND PURPOSE: An image-based approach has been developed to represent bleeding in a simulator for transurethral resection of the prostate (TURP). Whereas previous groups attempted to simulate bleeding mathematically over tissue surfaces or in blood vessels, our approach focused on macroscopic visualization of bleeding in a fluid environment. The TURP is an ideal procedure for simulator-based training because of its importance as a skill to acquire as well as its long learning curve. The most challenging step in creating a realistic TURP simulator is simulated bleeding. MATERIALS AND METHODS: We took an image-based approach in which we generated blood flow movies of bleeding vessels having different severity and position under variable fluid flow conditions and processed them to separate the blood flow from the background anatomy. We then organized the movies into a parametric database. During the running of the simulation, resection systematically triggers the playback of a blood flow movie (bleeding event). The movie is texture mapped onto a virtual surface that is positioned, oriented, morphed, composited, and looped into the virtual scene. RESULTS AND CONCLUSION: The technique produced an accurate depiction of bleeding vessels one would encounter during a TURP. The image changes readily according to the fluid flow state.
In endurance trained (TR) and untrained (UTR) rats heart rate (HR) and respiratory rate (RR) were recorded during perfusion of the circulatorily isolated hind leg of the rat with exercise simulating modified tyrode solutions (TR:n = 10, UTR:n = 10; compare part I). During the 20 min test period and the preceding and succeeding periods of control perfusions with an unmodified tyrode solution, [lactate], pH, [K+], [Na+], PO2 and PCO2 were measured in the outflow of the femoral vein. In 3 experimental series: (1) hypoxic tyrode solution enriched with lactic acid (15 mmol.l-1), (2) normoxic solution with lactic acid, (3) hypoxic solution without lactic acid, were applied. The outflow parameters were cross correlated with both HR and RR. The analysis revealed a significant temporal relationship between [lactate], pH, PO2, PCO2 and [K+] and both HR and RR. In the trained rats no temporal correlation between either of the outflow and reflex parameters could be determined. This result was not due to low [lactate], but was also found during perfusion with lactic acid. In all 3 test conditions [lactate] in untrained individuals was best correlated with both HR and RR. Although the correlation peaks of the respiratory response, but not of the HR response were definitely lower in normoxic lactic and perfusion than in the two other experimental conditions, both inter- and intraindividual correlation analyses revealed a high degree of interdependence between respiratory and cardiac responses.
In previous work it has been shown that a standard backpropagation neural network can be trained to reconstruct sections of single photon emission computed tomography (SPECT) images based on the planar image projections as inputs. In this study, it is demonstrated that an artificial neural network (ANN) trained on a series of simulated SPECT images or trained on a set of rudimentary geometric images can learn the planar data-to-tomographic image relationship for 64 x 64 tomograms. As a result, a properly trained ANN can produce accurate, novel image reconstructions but without the high computational cost inherent in some traditional reconstruction techniques. We also present a method of deriving activation functions for a backpropagation ANN that make it readily trainable for cardiac SPECT image reconstruction. The activation functions are derived from the estimated probability density functions (p.d.f.s) of the ANN training set data. The performance of the statistically tailored ANNs are compared with the performance of standard sigmoidal back-propagation ANNs, both in terms of their trainability and generalization ability. The results presented demonstrate that statistically tailored ANNs are significantly better than standard sigmoidal ANNs at reconstructing novel tomographic images based on a simulated SPECT image training set or a rudimentary geometric image training set. Neural network based image reconstruction has two potential advantages over conventional reconstruction methods. The first advantage is that ANNs can rapidly reconstruction tomograms. Secondly, the quality of the reconstructions produced are directly correlated to the quality of the images used to train the ANN.
Over the last few decades, there has been a rise in the number of minimally invasive techniques, such as arthroscopy, vascular radiology and our speciality, laparoscopy. Laparoscopy has resulted in a reduction in the damage caused during intervention, with the subsequent reduction in hospital stay, postoperative pain and infections. However, one disadvantage of these techniques is that they require a large investment in instruments and a long and costly training period. In the following chapter, we describe the laparoscopic training process of the medical residents from our Urology Service in the pelvitrainer and virtual simulator.