Considerations for the use of porcine organ donation models in preclinical organ donor intervention research.

Use of animal models in preclinical transplant research is essential to the optimization of human allografts for clinical transplantation. Animal models of organ donation and preservation help to advance and improve technical elements of solid organ recovery and facilitate research of ischemia-reperfusion injury, organ preservation strategies, and future donor-based interventions. Important considerations include cost, public opinion regarding the conduct of animal research, translational value, and relevance of the animal model for clinical practice. We present an overview of two porcine models of organ donation: donation following brain death (DBD) and donation following circulatory death (DCD). The cardiovascular anatomy and physiology of pigs closely resembles those of humans, making this species the most appropriate for pre-clinical research. Pigs are also considered a potential source of organs for human heart and kidney xenotransplantation. It is imperative to minimize animal loss during procedures that are surgically complex. We present our experience with these models and describe in detail the use cases, procedural approach, challenges, alternatives, and limitations of each model.

Cardiac function unchanged following reanimation with normothermic regional perfusion in donation after circulatory death.

Objectives: To determine whether hearts reanimated with normothermic regional perfusion (NRP) have clinically detectable changes in function using echocardiography comparing the prearrest and post-NRP imaging. As heart transplantation from donation after circulatory death (DCD) continues to increase, preliminary results suggest outcomes comparable with donation after brain death. It is unknown whether the obligatory period of warm ischemia experienced during DCD withdrawal process causes immediate changes in cardiac allograft function following in situ reanimation. Methods: We retrospectively reviewed and compared predonation with postreanimation echocardiographic findings in all DCD donors at our institution from January to October 2021. All DCD donor organs were reanimated with in situ thoracoabdominal NRP after circulatory death. Echocardiographic assessment included (1) 2-dimensional and speckle-tracking measures of chamber size and function; (2) ejection fraction; (3) fractional area change; and (4) global longitudinal strain. Results: Altogether, 4 DCD heart donations were performed during the study period. Basic demographics and withdrawal ischemic time periods are reported. There were no changes in left ventricular ejection fraction and right ventricular fractional area change when comparing the predonation and the postreanimation echocardiogram. There was a minimal, nonstatistically significant decrease in left ventricular global longitudinal strain and right ventricular free-wall systolic strain in 3 of the 4 donors following reanimation. Conclusions: DCD cardiac allografts reanimated with NRP demonstrated no change in echocardiographic parameters used for a standard predonation donor heart evaluation. Findings suggest cardiac function of DCD allografts reanimated with thoracoabdominal NRP is not adversely impacted by limited period of warm ischemia following circulatory arrest.

Creation of a High-Fidelity, Low-Cost, Intraosseous Line Placement Task Trainer via 3D Printing.

The description of procedural task trainers includes their use as a training tool to hone technical skills through repetition and rehearsal of procedures in a safe environment before ultimately performing the procedure on a patient. Many procedural task trainers available to date suffer from several drawbacks, including unrealistic anatomy and the tendency to develop user-created 'landmarks' after the trainer tissue undergoes repeated manipulations, potentially leading to inappropriate psychomotor skill development. To ameliorate these drawbacks, a process was created to produce a high-fidelity procedural task trainer, created from anatomy obtained from computed tomography (CT) scans, that utilize ubiquitous three-dimensional (3D) printing technology and off-the-shelf commodity supplies. This method includes creating a 3D printed tissue mold capturing the tissue structure surrounding the skeletal element of interest to encase the bony skeletal structure suspended within the tissue, which is also 3D printed. A tissue medium mixture, which approximates tissue in both high-fidelity geometry and tissue density, is then poured into a mold and allowed to set. After a task trainer has been used to practice a procedure, such as intraosseous line placement, the tissue media, molds, and bones are reclaimable and may be reused to create a fresh task trainer, free of puncture sites and manipulation defects, for use in subsequent training sessions.

Infectious Aerosol Capture Mask as Environmental Control to Reduce Spread of Respiratory Viral Particles.

Negative pressure isolation of COVID-19 patients is critical to limiting the nosocomial transmission of SARS-CoV-2; however, airborne isolation rooms are limited. Alternatives to traditional isolation procedures are needed. The evaluation of an Infectious Aerosol Capture Mask (IACM) that is designed to augment the respiratory isolation of COVID-19 patients is described. Efficacy in capturing exhaled breath aerosols was evaluated using laboratory experimentation, computational fluid dynamics (CFD) and measurements of exhaled breath from COVID-19 patients and their surroundings. Laboratory aerosol experiments indicated that the mask captured at least 99% of particles. Simulations of breathing and speaking showed that all particles between 0.1 and 20 µm were captured either on the surface of the mask or in the filter. During coughing, no more than 13% of the smallest particles escaped the mask, while the remaining particles collected on the surfaces or filter. The total exhaled virus concentrations of COVID-positive patients showed a range from undetectable to 1.1 × 106 RNA copies/h of SARS-CoV-2, and no SARS-CoV-2 aerosol was detected in the samples collected that were adjacent to the patient when the mask was being worn. These data indicate that the IACM is useful for containing the exhaled aerosol of infected individuals and can be used to quantify the viral aerosol production rates during respiratory activities.

Comparison of 3D printed anatomical model qualities in acetabular fracture representation.

Background: Acetabular fractures account for 10% of pelvis injuries, which are especially difficult to treat in developing countries with less access to resources. 3D printing has previously been shown to be a beneficial method of surgical planning, however the steep initial costs associated with purchasing a 3D printer may prevent some facilities form utilizing this technique. The purpose of this study was to develop 3D printed models for acetabular surgery using methodologies of varying cost to determine differences in model accuracy and overall quality. Methods: Five acetabular fracture models were developed from de-identified CT data using (I) proprietary and open-source segmentation software and (II) fused deposition modeling (FDM) and stereolithography (SLA) 3D printing methods. The distance between the posterior inferior iliac spine (PIIS) and the ischial spine as well as a unique fracture fragment for each model was compared between the different printing methodologies. The models were then given to 5 physicians and assessed on their overall accuracy compared to traditional 2D images. Results: Printing methodology did not affect the distance from PIIS to ischial spine (P=0.263). However, fracture fragment representation differed across 3D printed models, with the most accurate model produced by the high-end resin-based printer (P=0.007). The survey analysis showed that the low-cost printing methods produced models that were not as accurate in their representation of the fractured region (P=0.008). Conclusions: The differences between models developed using traditional methods and low-cost methods have slight differences but may still provide useful information when developing a surgical plan.

Thoracoabdominal Normothermic Perfusion in Donation After Circulatory Death.

Donation after circulatory death is emerging as an alternative pathway to donation after brain death to expand the cardiac organ donor pool. We describe the surgical technique and circuit configuration for in-situ organ reperfusion with thoracoabdominal normothermic regional perfusion using portable venoarterial extracorporeal membrane oxygenation.

2020 Clinical Update in Liver Transplantation.

The gold standard treatment of end-stage liver disease continues to be liver transplantation (LT). The challenges of LT require skilled anesthesiologists to anticipate physiologic changes associated with end-stage liver disease and surgical considerations that affect multiple organ systems. While on the waiting list, patients may be placed on new anticoagulation medications that can confound already complex coagulopathy in LT patients. Pain management often is an afterthought for such a complex procedure, but appropriate medications can help control pain while limiting opioid medications. Surgical stress and medications for immunosuppression can affect perioperative glucose management in ways that have implications for patient and graft survival. The coronavirus disease 2019 pandemic in 2020 provided a new challenge for anesthesiologists. The uncertainty of the novel respiratory virus challenged providers beyond just LT patients.

Successful lung transplantation with graft recovered after thoracoabdominal normothermic perfusion from donor after circulatory death.

Lung transplantation with lungs procured from donors after circulatory death (DCD) has been established as an alternative technique to traditional donation after brain death (DBD) with comparable outcomes. Recently, in situ thoracoabdominal normothermic regional perfusion (TA-NRP) has emerged as a novel technique employed in the procurement of cardiac allografts after circulatory death. TA-NRP, in contrast to ex situ machine perfusion, has the advantage of allowing in situ assessment of donor organs prior to final acceptance. However, there are some concerns that this technique may adversely impact the quality of lung allografts. Here, we present a case of a successful bilateral sequential lung transplantation in a patient with postinflammatory pulmonary fibrosis due to acute respiratory distress syndrome (ARDS), with lungs procured after normothermic in situ lung perfusion. Apart from the lungs, heart, liver, and kidneys were also successfully transplanted from this donor.

2019 Clinical Update in Liver Transplantation.

Liver transplantation continues be the standard for treatment of end-stage liver disease, and even with recent advances in organ preservation, the anesthetic management continues to require understanding of multiple organ systems beyond the liver. Multiple factors contribute to hemodynamic changes after reperfusion of the liver graft that anesthesiologists should be aware of before unclamping. Concomitant renal dysfunction in end-stage liver disease is not uncommon, and preparation for continuous renal replacement therapy may need to be considered in certain cases. Cardiac evaluation of liver transplantation patients with an emphasis on arrhythmias, including atrial fibrillation, can help prevent both intraoperative and postoperative complications detrimental to the patient and graft. Finally, combined liver and thoracic organ transplantations may be indicated for certain disease processes that affect multiple organs. These cases require an understanding of the surgical technique and acknowledgment that some goals of the procedures may be in direct opposition to each other.

3D printing of face shields to meet the immediate need for PPE in an anesthesiology department during the COVID-19 pandemic.

BACKGROUND: Anesthesia providers are at risk for contracting COVID-19 due to close patient contact, especially during shortages of personal protective equipment. We present an easy to follow and detailed protocol for producing 3D printed face shields and an effective decontamination protocol, allowing their reuse. METHODS: The University of Nebraska Medical Center (UNMC) produced face shields using a combination of 3D printing and assembly with commonly available products, and produced a simple decontamination protocol to allow their reuse. To evaluate the effectiveness of the decontamination protocol, we inoculated bacterial suspensions of E. coli and S. aureus on to the face shield components, performed the decontamination procedure, and finally swabbed and enumerated organisms onto plates that were incubated for 12-24 hours. Decontamination effectiveness was evaluated using the average log10 reduction in colony counts. RESULTS: Approximately 112 face shields were constructed and made available for use in 72 hours. These methods were successfully implemented for in-house production at UNMC and at Tripler Army Medical Center (Honolulu, Hawaii). Overall, the decontamination protocol was highly effective against both E. coli and S. aureus, achieving a ≥4 log10 (99.99%) reduction in colony counts for every replicate from each component of the face shield unit. DISCUSSION: Face shields not only act as a barrier against the soiling of N95 face masks, they also serve as more effective eye protection from respiratory droplets over standard eye shields. Implementation of decontamination protocols successfully allowed face shield and N95 mask reuse, offering a higher level of protection for anesthesiology providers at the onset of the COVID-19 pandemic. CONCLUSIONS: In a time of urgent need, our protocol enabled the rapid production of face shields by individuals with little to no 3D printing experience, and provided a simple and effective decontamination protocol allowing reuse of the face shields.

Assessment of Resident Performance During the Cardiac Anesthesia Rotation: Application of the House Officer Clinical Assessment in Cardiac Anesthesiology.

OBJECTIVE: The assessment of clinical skills was created that evaluates House Officer performance within 13 clinical domains during the Cardiac Anesthesiology rotation to provide an assessment and evaluation process for residents while performing a cardiac anesthetic. DESIGN: A retrospective evaluation of performance assessments over a 33-month period. SETTING: University hospital-based Accreditation Council for Graduate Medical Education accredited Residency Training program. PARTICIPANTS: Anesthesiology house officers within the Department Residency Program. INTERVENTIONS: This House Officer Clinical Assessment was created and implemented as residents rotated through the cardiac anesthesia service. Scores in 13 domain-specific components from this assessment were collected after the attending-resident debrief. MEASUREMENTS AND MAIN RESULTS: Most scores were found to be sufficient to suggest competency, and the evaluation allowed for a more detailed approach to assessment and feedback. The most common aspects of the case in which the residents showed reduced performance and proficiency were the transition off cardiopulmonary bypass and the performance of the transesophageal echocardiogram. Overall, the resident survey showed a positive response to the assessment and the feedback provided during the post-examination debrief. CONCLUSION: The House Officer Clinical Assessment in Cardiac Anesthesiology allows for a more objective assessment of performance for specific portions of the case and allows for improved feedback on performance. Aspects of the evaluation tool and where residents correlate with the Anesthesiology Milestones for residency are discussed, as well as the ability to determine sufficient proficiency with knowledge and skills over the use of subjective rank to determine competency.