With medical institutions increasing the use of medical simulators for educational purposes it is detrimental that the knowledge gap regarding tissue mechanical properties be researched further in depth. The grasper device discussed throughout this paper aims to provide researchers a handheld device capable of testing soft organs and tissue in-vivo and ex-situ in a laboratory setting. The device consists of two load cells on the inner jaws of the grasper to measure compressive force and an encoder to monitor the graspers angular position which yields tissue position and strain. Accompanying the grasper is a GUI written in Rust which is capable of data file management, and providing a 10 second live feed of load cell and encoder readings. The grasper device is currently being employed in a study testing the tissue mechanical response of porcine tissue at states ranging from in-vivo to ex-situ post freeze. The results from this test, and subsequent tests using the grasper have the capability of providing much needed knowledge regarding tissue mechanical properties to improve medical simulators and medical education as a whole.

Background Healthcare simulators have been demonstrated to be a valuable resource for training several technical and nontechnical skills. A gap in the fidelity of tissues has been acknowledged as a barrier to application for current simulators; especially for interventional procedures. Inaccurate or unrealistic mechanical response of a simulated tissue to a given surgical tool motion may result in negative training transfer and/or prevents the “suspension of disbelief” necessary for a trainee to engage in the activity. Thus, where it is relevant to training outcomes, there should be an effort to create healthcare simulators with simulated tissue mechanical responses that match or represent those of biological tissues. Historically, this data is most often gathered from preserved (post mortem) tissue; however, there is a concern that the mechanical properties of preserved tissue, that lacks blood flow, may lack adequate accuracy to provide the necessary training efficacy of simulators. Methods and findings This work explores the effect of the “state” of the tissue testing status on liver and peritoneal tissue by using a customized handheld grasper to measure the mechanical responses of representative porcine (Sus domesticus) tissues in n = 5 animals across five test conditions: in vivo, post mortem (in-situ), ex vivo (immediately removed from fresh porcine cadaver), post-refrigeration, and post-freeze-thaw cycle spanning up to 72 hours after death. No statistically significant difference was observed in the mechanical responses due to grasping between in vivo and post-freeze conditions for porcine liver and peritoneum tissue samples (p = 0.05 for derived stiffness at grasping force values F = 5N and 6.5N). Furthermore, variance between in vivo and post-freeze conditions within each animal, was comparable to the variance of the in vivo condition between animals. Conclusions Results of this study further validate the use of preserved tissue in the design of medical simulators via observing tissue mechanical responses of post-freeze tissue comparable to in vivo tissue. Therefore, the use of thawed preserved tissue for the further study and emulation of mechanical perturbation of the liver and peritoneum can be considered. Further work in this area should investigate these trends further, particularly in regard to other tissues and the potential effects varying preservation methods may yield.

Healthcare simulators have been demonstrated to be a valuable resource for training several technical and nontechnical skills. A gap in the fidelity of tissues has been acknowledged as a barrier to application for current simulators; especially for interventional procedures. Inaccurate or unrealistic mechanical response of a simulated tissue to a given surgical tool motion may result in negative training transfer and/or prevents the “suspension of disbelief” necessary for a trainee to engage in the activity. Thus, where it is relevant to training outcomes, there should be an effort to create healthcare simulators with simulated tissue mechanical responses that match or represent those of biological tissues. Historically, this data is most often gathered from preserved (post mortem) tissue; however, there is a concern that the mechanical properties of preserved tissue, that lacks blood flow, may lack adequate accuracy to provide the necessary training efficacy of simulators. This work explores the effect of the “state” of the tissue testing status on liver and peritoneal tissue by using a customized handheld grasper to measure the mechanical responses of representative porcine (Sus domesticus) tissues in N=5 animals across five test conditions: in vivo, postmortem (in-situ), ex vivo (immediately removed from fresh porcine cadaver), post-refrigeration, and post-freeze-thaw cycle spanning up to 72 hours after death. No statistically significant difference was observed in the mechanical responses due to grasping between in vivo and post-freeze conditions for porcine liver and peritoneum tissue samples (p = 0.05 for derived stiffness at grasping force values F = 5N and 6.5N). Furthermore, variance between in vivo and post-thaw conditions within each animal, was comparable to the variance of the in vivo condition between animals. Thus, the use of thawed, preserved tissue for the further study and emulation of mechanical perturbation of the liver and peritoneum can be considered.

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Introduction The brevity of training for soldiers and combat medics to learn how to provide treatment on the battlefield may restrict optimal performance for treating chest and airway injuries, particularly when treating female soldiers. The present study tested treatment performance on patient simulators by battlefield medic trainees to determine whether there is a need for more extensive training on chest and airway procedures on female soldiers. Materials and Methods Battlefield medic trainees treated male and female patient simulators in counterbalanced order. The assessment considered the effects of patient gender and order on procedures performed, particularly critical chest and airway interventions such as needle chest decompression (NCD), and considered the appropriate order of treatment tasks. Four coders rated video footage of three simulated procedures, i.e., tourniquet, chest seal (front and back application), and NCD, using a binary coding system to determine completeness and order correctness according to the Massive hemorrhage, Airway, Respiration, Circulation, and Head injury/Hypothermia (MARCH) mnemonic. Results Results from analysis of variance showed that when presented with a female patient first, trainees performed significantly fewer total procedures on both the female and male simulators. More experienced trainees completed significantly more procedures compared to trainees with minimal experience. Results from the binary logistic regression showed that trainees with more experience and trainees presented with the male patient simulator first performed significantly more procedures in the correct order. Finally, an examination of the NCD procedure found that trainees presented with the female patient simulator first had more errors and that trainees with less experience were less likely to perform the procedure adequately. Conclusions The findings suggest that treating a female patient first may lead to undertreatment of both patients. Furthermore, the observed differences in treating sensitive areas of the body (e.g., near female breasts) suggest providing greater opportunities for trainees to practice often missed or incorrectly performed procedures. Treating a female patient remains a novel experience for many trainees, such that trainees are less likely to fully treat a female patient and are less likely to treat female soldiers for the most life-threatening injuries. In fact, the initial presentation of the female patient simulator appeared to affect experienced trainees, suggesting that removing the experience of novelty and stress requires more extensive exposure and alternative training. The study’s small sample size with a wide range of trainee experience may limit the findings, which may fail to capture some study effects. Finally, the study did not request trainees’ experience treating female soldiers, so future studies should examine the extent to which experience is predictive of performance. There is a need for more interactive approaches in patient simulations to provide opportunities for practice, especially those that require the treatment of sensitive areas.