Roger Wahba

3D Immersive Patient Simulators and Their Impact on Learning Success: A Thematic Review

Background Immersive patient simulators (IPSs) combine the simulation of virtual patients with a three-dimensional (3D) environment and, thus, allow an illusionary immersion into a synthetic world, similar to computer games. Playful learning in a 3D environment is motivating and allows repetitive training and internalization of medical workflows (ie, procedural knowledge) without compromising real patients. The impact of this innovative educational concept on learning success requires review of feasibility and validity. Objective It was the aim of this paper to conduct a survey of all immersive patient simulators currently available. In addition, we address the question of whether the use of these simulators has an impact on knowledge gain by summarizing the existing validation studies. Methods A systematic literature search via PubMed was performed using predefined inclusion criteria (ie, virtual worlds, focus on education of medical students, validation testing) to identify all available simulators. Validation testing was defined as the primary end point. Results There are currently 13 immersive patient simulators available. Of these, 9 are Web-based simulators and represent feasibility studies. None of these simulators are used routinely for student education. The workstation-based simulators are commercially driven and show a higher quality in terms of graphical quality and/or data content. Out of the studies, 1 showed a positive correlation between simulated content and real content (ie, content validity). There was a positive correlation between the outcome of simulator training and alternative training methods (ie, concordance validity), and a positive coherence between measured outcome and future professional attitude and performance (ie, predictive validity). Conclusions IPSs can promote learning and consolidation of procedural knowledge. The use of immersive patient simulators is still marginal, and technical and educational approaches are heterogeneous. Academic-driven IPSs could possibly enhance the content quality, improve the validity level, and make this educational concept accessible to all medical students.

Results of kidney transplantation after rescue allocation

In 2009, Eurotransplant (ET) offered 4026 kidneys from deceased donors. Only 3587 were transplanted resulting in a discard rate of 11% [1]. During the standard allocation, 16% of all renal grafts were refused because of medical reasons. In the case of nonacceptance, ET offers these organs to other centers. If such a renal allograft is also refused for medical reasons by the five further centers consecutively according to the regular allocation system, the process of rescue allocation (RA) is initiated, i.e. the renal allograft is offered as noncompetitive center allocation in the region of explantation (first line-RA) and thus define the allograft to orginate from a donor with extended donor criteria (ECD) [1]. If the organ is declined by all the regional centers, a competitive center allocation in the greater area of explantation starts (second line-RA) until the organ is accepted. Thus, the number of transplanted allografts could be increased. In this manner, 7.5% of the RA-kidneys are discarded ultimately [1,2]. The reasons for the refusal of RA-kidneys are not clear. Attributable factors could include the medical history of the donor, or a ‘‘cascade effect,’’ meaning that the refusal itself is an extra factor for the following refusals [3,4]. There are only sparse published data on the outcome of rescue-allocated kidneys. We evaluated our center experience with kidneys allocated by RA. The records of all patients who received a RA kidney (first or second line) from January 2000 until December 2009 were analysed retrospectively. The main outcome parameters were the graft function according to 1-month and 12-month serum-creatinine and estimated glomerular filtration rate (eGFR), the graft survival and the patient survival. The estimated GFR was calculated according to MDRD-equation[5]. Secondary outcomes were a delayed graft function, acute rejection and the existence of long-time survivors. Data concerning the main outcome parameters were complete. From January 2000 until December 2009, 16 patients received a rescue-allocated kidney. In the same period, 330 regularly allocated kidneys from deceased donors were transplanted (ratio 4.8%). The kidneys originated from 13 donors. In three cases, we accepted both organs from the same donor. All donors were heart-beating (i.e. brain-dead on artificial life-support and artificial life-support about to be withdrawn as per advanced directives or per the power of attorney’s instructions). The demographic and medical data characterizing the donors are presented in Table 1. The 16 organs included in our study were refused 108 times by other centers. The mean number of refusal for a single kidney before acceptance was 6.8 ± 2.8 times (median 8.0). The reasons for refusal in 90.7% (n = 98) of the cases were because of medical reasons, in 5.6% (n = 6) of the cases because of logistical reasons and in the remaining 3.7% (n = 4) because the designated recipients were not transplantable. The 1-month patient survival rate was 100%. In three cases, the kidneys had a macroscopic damage that was not described in the ET-donor report. One graft was lost on the first day after transplantation because of a total venous thrombosis. Three out of the 16 recipients (18.8%) demonstrated delayed graft function. In four out of the 16 allografts, an episode of acute rejection was diagnosed during the postoperative period, which could

Laparoscopic deroofing of nonparasitic liver cysts with or without greater omentum flap.

Background Laparoscopic deroofing is the standard therapy for simple nonparasitic liver cysts. The operation is performed with or without a greater omentum flap sutured into the former cyst cavity. The aim of this study was to determine whether a greater omentum flap has influence on the recurrence rate of nonparasitic liver cysts during the long-term follow-up. Methods From September 1999 to November 2009, 23 patients underwent laparoscopic deroofing for single or multiple nonparasitic symptomatic liver cysts. A greater omentum flap to fill the former cyst cavity was used in 8 patients, whereas in 15 patients operation was carried out without such an omentum flap. The patients were identified retrospectively and subject to a follow-up examination. The 2 groups of patients were compared according to the recurrence of the liver cysts. Results The median follow-up time was 59±40 months. There was an overall recurrence rate of 4.3% (1 of 23), with 1 cyst recurrence in the greater omentum flap group (1 of 8). The Fisher exact test showed no difference in the recurrence rate between the 2 groups (P=0.35). Conclusion The overall recurrence rate is low. A greater omentum flap to prevent a local cyst recurrence after laparoscopic deroofing is dispensable and is a potential source of additional complications.

Web-Based Immersive Virtual Patient Simulators: Positive Effect on Clinical Reasoning in Medical Education

Background Clinical reasoning is based on the declarative and procedural knowledge of workflows in clinical medicine. Educational approaches such as problem-based learning or mannequin simulators support learning of procedural knowledge. Immersive patient simulators (IPSs) go one step further as they allow an illusionary immersion into a synthetic world. Students can freely navigate an avatar through a three-dimensional environment, interact with the virtual surroundings, and treat virtual patients. By playful learning with IPS, medical workflows can be repetitively trained and internalized. As there are only a few university-driven IPS with a profound amount of medical knowledge available, we developed a university-based IPS framework. Our simulator is free to use and combines a high degree of immersion with in-depth medical content. By adding disease-specific content modules, the simulator framework can be expanded depending on the curricular demands. However, these new educational tools compete with the traditional teaching Objective It was our aim to develop an educational content module that teaches clinical and therapeutic workflows in surgical oncology. Furthermore, we wanted to examine how the use of this module affects student performance. Methods The new module was based on the declarative and procedural learning targets of the official German medical examination regulations. The module was added to our custom-made IPS named ALICE (Artificial Learning Interface for Clinical Education). ALICE was evaluated on 62 third-year students. Results Students showed a high degree of motivation when using the simulator as most of them had fun using it. ALICE showed positive impact on clinical reasoning as there was a significant improvement in determining the correct therapy after using the simulator. ALICE positively impacted the rise in declarative knowledge as there was improvement in answering multiple-choice questions before and after simulator use. Conclusions ALICE has a positive effect on knowledge gain and raises students’ motivation. It is a suitable tool for supporting clinical education in the blended learning context.

ABO-incompatible kidney transplantation using regenerative selective immunoglobulin adsorption

Background: ABO‐incompatible (ABOi) kidney transplantation is an established procedure relying on the removal of donor‐specific isoagglutinine antibodies as part of the recipient preconditioning. At present, current protocols using immunoadsorption apply a single‐use selective carbohydrate isoagglutinine adsorber. A regenerative and selective immunoglobulin immunoadsorption could be an alternative but has not been reported for ABOi transplantation. Methods: Eight patients were treated with the commonly used isoagglutinine carbohydrate epitope adsorber and seven with a regenerative polyclonal sheep anti‐immunoglobulin adsorber as part of the preconditioning for ABOi kidney transplantation. An IgG‐isoagglutinine titer of less or equal 1:4 qualified for transplantation. Treatment safety, efficiency, length of desensitization, number of postoperative immunoadsorptions, and allograft outcome were retrospectively compared. Results: With the use of the immunoglobulin adsorber the median initial isoagglutinine IgG titers of 1:64 (range 1:32–1:256) were lowered to the target of 1:4 preoperatively with a mean of 6.2 immunoadsorptions (range 5–11). Mean IgG/IgM titer step reduction per IA was 1.98/1.21 for (range 0–4/0–4) and mean titer step rebound 1.31/0.82 (range 0–4/0–3), respectively. The number of immunoadsorptions and length of desensitization was not different from the use of the specific isoagglutinine adsorbers. After transplantation, no rejection occurred and only one postoperative immunoadsorption was necessary. No adverse events in relation to immunoadsorption were observed. Graft function was comparable to the isoagglutinine adsorber group. Conclusion: These data suggest that ABOi kidney transplantation can be performed safely and effectively with a selective regenerative immunoglobulin immunoadsorber. J. Clin. Apheresis, 2012.

Computed Tomography Volumetry in Preoperative Living Kidney Donor Assessment for Prediction of Split Renal Function.

Background Transplant centers commonly evaluate split renal function (SRF) with Tc-99m-mercapto-acetyltriglycin (MAG3) scintigraphy in living kidney donation. Alternatively, the kidney volume can be measured based on predonation CT scans. The aim of this study was to identify the most accurate CT volumetry technique for SRF and the prediction of postdonation kidney function (PDKF). Methods Three CT volumetry techniques (modified ellipsoid volume [MELV], smart region of interest [ROI] volume, renal cortex volume [RCV]) were performed in 101 living kidney donors. Preoperation CT volumetric SRF was determined and compared with MAG3-SRF, postoperation donor kidney function, and graft function. Results The correlation between donors predonation total kidney volume and predonation kidney function was the highest for RCV (0.58 with creatine clearance, 0.54 with estimated glomerular filtration rate-Cockcroft-Gault). The predonation volume of the preserved kidney was (ROI, MELV, RCV) 148.0 ± 29.1 cm3, 151.2 ± 35.4 and 93.9 ± 25.2 (P < 0.005 MELV vs RCV and ROI vs RCV). Bland-Altman analysis showed agreement between CT volumetry SRF and MAG3-SRF (bias, 95% limits of agreement: ROI vs MAG3 0.4%, −7.7% to 8.6%; MELV vs MAG3 0.4%, −8.9% to 9.7%; RCV vs MAG3 0.8%, −9.1% to 10.7%). The correlation between predonation CT volumetric SRF of the preserved kidney and PDKF at day 3 was r = 0.85 to 0.88, between MAG3-SRF and PDKF (r = 0.84). The difference of predonation SRF between preserved and donated kidney was the lowest for ROI and RCV (median, 3% and 4%; 95th percentile, 9% and 13%). Conclusions Overall renal cortex volumetry seems to be the most accurate technique for the evaluation of predonation SRF and allows a reliable prediction of donors PDKF.

Radiomorphology of the Habib Sealer-Induced Resection Plane during Long-Time Followup: A Longitudinal Single Center Experience after 64 Radiofrequency-Assisted Liver Resections

Background. Radiofrequency (RF-) assisted liver resection devices like the Habib sealer induce a necrotic resection plane from which a small margin of necrotic liver tissue remains in situ. The aim of the present paper was to report our long-time experience with the new resection method and the morphological characteristics of the remaining necrotic resection plane. Methods. 64 RF-assisted liver resections were performed using the Habib sealer. Followup was assessed at defined time points. Results. The postoperative mortality was 3,6% and morbidity was 18%. The followup revealed that the necrotic zone was detectable in all analyzed CT and MRI images as a hypodense structure without any contrast enhancement at all time points, irrespectively of the time interval between resection and examination. Conclusion. Liver resection utilizing radiofrequency-induced resection plane coagulation is a safe alternative to the established resection techniques. The residual zone of coagulation necrosis remains basically unchanged during a followup of three years. This has to be kept in mind when evaluating the follow up imaging of these patients.

Prognosis after "high urgent" kidney transplantation might be determined by control of preexisting septic condition.

INTRODUCTION Dialysis is the standard bridging method for patients with end-stage renal disease. In rare cases, dialysis is impossible and immediate kidney transplantation (KT) is the only option for survival. Most allocation organizations offer an immediate allocation procedure (high urgency [HU]), which focuses on immediate allocation at the cost of immunologic matching. The impossibility of dialysis is mainly caused by multiple systemic thromboses and blood stream infections. This situation creates an ethical dilemma: Accepting the HU-KT allocation potentially saves the patients life albeit with negatively effects on the expected patient and organ survivals. In times of organ shortage, more information is needed regarding this difficult decision; the published literature is limited to 4 papers. METHODS We performed a retrospective analysis of patients who were transplanted by HU allocation in our center between January 1989 and October 2010. RESULTS Of 1040 KT, 10 (0.96%) were performed in HU condition. Mean follow-up time was 37 months. The main reason for HU-KT was exhaustion of vascular access in combination with a bloodstream infection. All recipients showed severe preoperative comorbidities. Patient survival was 90% at 1, 80% at 3, and 60% at 5 years. There was 1 graft loss owing to chronic rejection. CONCLUSION When kidney transplantation is performed as an HU procedure, it is associated with a greater morbidity and mortality compared with elective cases. Bloodstream infections that existed before transplantation contributed considerably to mortality.

Can computed tomography volumetry of the renal cortex replace MAG3-scintigraphy in all patients for determining split renal function?

OBJECTIVES The current gold standard for determination of split renal function (SRF) is Tc-99m-mercapto-acetyltriglycin (MAG3) scintigraphy. Initial studies comparing MAG3-scintigraphy and CT-based renal cortex volumetry (RCV) for calculation of SRF have shown similar results in highly selected patient collectives with normal renal function (i.e. living kidney donors). This study aims to compare MAG3-scintigraphy and CT-RCV within a large unselected patient collective including patients with impaired renal function. MATERIALS AND METHODS For this assessment, 279 datasets (131 men, 148 women; mean age: 54.2 ± 12.9 years, range: 24-84 years) of patients who underwent MAG3-scintigraphy and contrast-enhanced abdominal CT within two weeks were retrospectively analyzed. Two independent readers assessed the CT-RCV in all CT datasets using a semi-automated volumetry tool. The MAG3-scintigraphy and CT-RCV methods were compared, stratified for the eGFR. Statistical analysis included descriptive statistics as well as inter- observer agreement. RESULTS The absolute mean difference between the percentage contribution of the left and the right kidneys in total MAG3-clearance was 8.6%. Independent of eGFR, an overall sufficient agreement between both methods was established in all patients. A relatively small, tolerable systemic error resulted in an underestimation (max. 2%) of the left renal contribution to overall RCV. CONCLUSION The results demonstrate that CT-RCV is a potential clinical replacement for MAG3-scintigraphy for calculation of SRF: CT-RCV demonstrates clinically tolerable differences with MAG3-scintigraphy, independent of patient eGFR. The relative complexity of the RCV method utilized is a potential limitation and may have contributed to the acceptable but only fair to moderate level of intra-reader reliability.

Rescue Allocation and Recipient Oriented Extended Allocation in kidney transplantation – Influence of the EUROTRANSPLANT allocation system on recipient selection and graft survival for initially non-accepted organs

Nonaccepted kidneys grafts enter the rescue allocation (RA) process to avoid discards. In December 2013, recipient oriented extended allocation (REAL) was introduced to improve transparency. The aim of this study was to evaluate the influence of REAL on recipients′ selection and graft function compared to the formerly existing RA as well as to identify factors that influence graft outcome. Therefore, a multicenter study of 10 transplant centers in the same region in Germany was performed. All transplantations after RA or REAL from December 1, 2012, until December 31, 2014, with a follow‐up time until December 31, 2015 were analyzed. 113 of 941 kidney transplantations were performed after RA or REAL (12%). With REAL, the number of refusals before transplantation had increased (12 ± 7.1 vs. 8.6 ± 8.6, P = 0.036), and cold ischemia time has decreased (13.6 ± 3.6 vs. 17.2 ± 4.8 h, P = 0.019). Recipients after REAL needed significantly more allocation points compared to RA to receive a kidney. One‐year graft survival was comparable. If kidneys from the same donor were transplanted to two recipients at one center, the greater the difference in recipient age, the greater the difference in serum creatinine after 12 months (‐0.019 mg/dl per year, P = 0.011) was, that is older recipients showed lower creatinine. REAL influences selection of the recipients compared to the former RA era for successful organ receipt. Graft function is comparable and seems to be influenced by recipient age.