Large Animal Models for Simulating Physiology of Transfusion of Red Cell Concentrates-A Scoping Review of The Literature.

Background and Objectives: Transfusion of red cell concentrates is a key component of medical therapy. To investigate the complex transfusion-associated biochemical and physiological processes as well as potential risks for human recipients, animal models are of particular importance. This scoping review summarizes existing large animal transfusion models for their ability to model the physiology associated with the storage of erythrocyte concentrates. Materials and Methods: The electronic databases PubMed, EMBASE, and Web of Science were systematically searched for original studies providing information on the intravenous application of erythrocyte concentrates in porcine, ovine, and canine animal models. Results: A total of 36 studies were included in the analysis. The majority of porcine studies evaluated hemorrhagic shock conditions. Pig models showed high physiological similarities with regard to red cell physiology during early storage. Ovine and canine studies were found to model typical aspects of human red cell storage at 42 days. Only four studies provided data on 24 h in vivo survival of red cells. Conclusions: While ovine and canine models can mimic typical human erythrocyte storage for up to 42 days, porcine models stand out for reliably simulating double-hit pathologies such as hemorrhagic shock. Large animal models remain an important area of translational research since they have an impact on testing new pharmacological or biophysical interventions to attenuate storage-related adverse effects and allow, in a controlled environment, to study background and interventions in dynamic and severe disease conditions.

Loss of resistance: A randomised controlled trial assessing four low-fidelity epidural puncture simulators.

BACKGROUND: Detecting loss of resistance (LOR) can either be taught with dedicated simulators, with a cost ranging from &OV0556;1500 to 3000, or with the 'Greengrocer's Model', requiring simply a banana. OBJECTIVES: The purpose of this study was to compare three dedicated epidural puncture training simulators and a banana in their ability to simulate LOR. Our hypothesis was that there was a difference between the four simulators when comparing the detection of LOR. DESIGN: Single-blinded, randomised, controlled study. SETTING: Department of Anaesthesiology and Pain Therapy, Bern University Hospital, Switzerland. PARTICIPANTS: Fifty-five consultant anaesthesiologists. INTERVENTIONS: The participants were asked to insert an epidural catheter in four different epidural puncture training simulators: Lumbar Puncture Simulator II (Kyoto Kagaku, Kyoto, Japan), Lumbar Epidural Injection Trainer (Erler-Zimmer, Lauf, Germany), Normal Adult Lumbar Puncture/Epidural Tissue (Simulab Corp., Seattle, Washington, USA) and a banana. The simulators were placed in identical boxes to blind the participants. MAIN OUTCOME MEASURES: The primary outcome was the detection of LOR rated on a 100-mm visual analogue scale, in which 0 mm represented 'completely unrealistic' and 100 mm represented 'indistinguishable from a real patient'. RESULTS: The mean visual analogue scale scores for LOR in the four simulators were significantly different: 60 ±â€Š25 mm [95% confidence interval (CI), 55 to 65 mm], 50 ±â€Š29 mm (95% CI, 44 to 55 mm), 64 ±â€Š24 mm (95% CI, 58 to 69 mm) and 49 ±â€Š32 mm (95% CI, 44 to 54 mm); P less than 0.001, Friedman test. CONCLUSION: Two of the three dedicated epidural simulators were rated more realistic in detecting LOR than the banana, but some participants preferred the banana to the other three simulators. Given the relative cost of a banana compared with a dedicated simulator, we suggest that a banana be used to teach the technique of LOR for epidural puncture. TRIAL REGISTRATION: KEK Nr: Req-2015-z087.