ABSTRACT
This brief report examines the feasibility of using formalin-embalmed cadavers in training medical students to use ultrasound guidance to access the subclavian. This novel educational approach is discussed in the context of the ongoing integration of point-of-care ultrasound training into medical education. Additionally, this report explores how cadavers can provide practical, effective, and hands-on skills training opportunities for medical students to learn to perform common clinical procedures under ultrasound guidance. DESIGN: This report presents subjective and objective data evaluating the utility of teaching medical students to perform ultrasound-guided subclavian vein access on formalin-embalmed cadavers. SETTING: Rocky Vista University College of Osteopathic Medicine in Ivins, UT. SUBJECTS: Twenty-five first-year medical students at Rocky Vista University. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Pre and posttraining questionnaires were administered to assess each participant's self-confidence in using ultrasonography to access the subclavian vein of a cadaver. A statistically significant increase in participant self-confidence was observed across all questionnaire items from pre to posttraining. Objective evaluation consisted of a supervised skills test. Participants were evaluated on their ability to visualize the subclavian vein with ultrasound and achieve flashback of blood/embalming fluid into a syringe. During skills testing, the number of needle sticks and the time taken to achieve flashback were recorded for each participant. Twenty-three of the 25 participants were able to successfully complete the skills testing assessment. CONCLUSIONS: The formalin-embalmed cadaver can be a readily available and effective learning tool for medical education programs seeking to provide training opportunities in ultrasound-guided clinical procedures. The use of cadavers allows learners to train in a low stress and anatomically authentic environment without risk of patient discomfort.
ABSTRACT
Eosinophil recruitment to airway tissue is a key feature of asthma, and release of a wide variety of toxic mediators from eosinophils leads to the tissue damage that is a hallmark of asthma pathology. Factors that control the release of these toxic mediators are targets for potential therapeutic intervention. Protease-activated receptors (PARs) are a novel class of receptors that are activated by cleavage of the N terminus of the receptor by proteases such as thrombin or trypsin-like enzymes. To date, PAR1-4 have been identified, and there are several studies that have demonstrated the expression of PARs in airway tissue, particularly the respiratory epithelium. We have investigated whether eosinophils express PARs and if activation of these receptors will then trigger a functional response. Using a combination of reverse transcriptase-polymerase chain reaction, Western blotting, and flow cytometry analysis, we have demonstrated that eosinophils express PAR1 and PAR2. FACS analysis showed that PAR1 could be clearly detected on the surface of the cells, whereas PAR2 appeared to be primarily intracellular. Trypsin and the PAR2 agonist peptide were seen in trigger shape change, release of cysteinyl leukotrienes, and most obviously, generation of reactive oxygen species. In contrast, thrombin had no effect on eosinophil function. The PAR1 agonist peptide did have a minor effect on eosinophil function, but this was most likely down to its ability to activate PAR1 and PAR2. These results demonstrate that PAR2 is the major PAR receptor that is capable of modulating eosinophil function.
