BACKGROUND: In lung transplantation (LT), the length of ischemia time is controversial as it was arbitrarily stablished. We ought to explore the impact of extended cold-ischemia time (CIT) on ischemia-reperfusion injury in an experimental model.
METHODS: Experimental, randomized pilot trial of parallel groups and final blind analysis using a swine model of LT. Donor animals (n=8) were submitted to organ procurement. Lungs were subjected to 6h (n=4) or 12h (n=4) aerobic hypothermic preservation. The left lung was transplanted and re-perfused for 4h. Lung biopsies were obtained at (i) the beginning of CIT, (ii) the end of CIT, (iii) 30min after reperfusion, and (iv) 4h after reperfusion. Lung-grafts were histologically assessed by microscopic lung injury score and wet-to-dry ratio. Inflammatory response was measured by determination of inflammatory cytokines. Caspase-3 activity was determined as apoptosis marker.
RESULTS: We observed no differences on lung injury score or wet-to-dry ratio any given time between lungs subjected to 6h-CIT or 12h-CIT. IL-1β and IL6 showed an upward trend during reperfusion in both groups. TNF-α was peaked within 30min of reperfusion. IFN-γ was hardly detected. Caspase-3 immunoexpression was graded semiquantitatively by the percentage of stained cells. Twenty percent of apoptotic cells were observed 30min after reperfusion.
CONCLUSIONS: We observed that 6 and 12h of CIT were equivalent in terms of microscopic lung injury, inflammatory profile and apoptosis in a LT swine model. The extent of lung injury measured by microscopic lung injury score, proinflammatory cytokines and caspase-3 determination was mild.

BACKGROUND: In lung transplantation (LT), the length of ischemia time is controversial as it was arbitrarily stablished. We ought to explore the impact of extended cold-ischemia time (CIT) on ischemia-reperfusion injury in an experimental model.
METHODS: Experimental, randomized pilot trial of parallel groups and final blind analysis using a swine model of LT. Donor animals (n=8) were submitted to organ procurement. Lungs were subjected to 6h (n=4) or 12h (n=4) aerobic hypothermic preservation. The left lung was transplanted and re-perfused for 4h. Lung biopsies were obtained at (i) the beginning of CIT, (ii) the end of CIT, (iii) 30min after reperfusion, and (iv) 4h after reperfusion. Lung-grafts were histologically assessed by microscopic lung injury score and wet-to-dry ratio. Inflammatory response was measured by determination of inflammatory cytokines. Caspase-3 activity was determined as apoptosis marker.
RESULTS: We observed no differences on lung injury score or wet-to-dry ratio any given time between lungs subjected to 6h-CIT or 12h-CIT. IL-1β and IL6 showed an upward trend during reperfusion in both groups. TNF-α was peaked within 30min of reperfusion. IFN-γ was hardly detected. Caspase-3 immunoexpression was graded semiquantitatively by the percentage of stained cells. Twenty percent of apoptotic cells were observed 30min after reperfusion.
CONCLUSIONS: We observed that 6 and 12h of CIT were equivalent in terms of microscopic lung injury, inflammatory profile and apoptosis in a LT swine model. The extent of lung injury measured by microscopic lung injury score, proinflammatory cytokines and caspase-3 determination was mild.

BACKGROUND: The latest Difficult Airway Society (DAS) guidelines recommend that all anaesthesiologists should to be trained in the performing of a surgical cricothyrotomy (CtQ). The aim of this study was to analyse the learning results of a CtQ workshop by assessing the success rate and time to perform CtQ on a porcine tracheal model.
METHODS: A workshop was designed in which each student completed a questionnaire with demographic data and theoretical knowledge about surgical approaches of airway. During the following hour, a review was presented theoretical aspects of CtQ. The model was shown and a CtQ was performed using a classical technique. Afterwards, in groups of 3-4 students with an instructor, each one of the students performed 6 CtQ. A record was made on whether the ventilation was correct, the time to perform CtQ, and the ease of performing the CtQ by the students and instructors. Finally, students completed a questionnaire on the theoretical aspects. Students and instructors performed a workshop debriefing. A statistical analysis was performed, considering a P-value <0.05 as statistically significant.
RESULTS: A total of 8 workshop sessions were held with a total of 91 students. At first attempt, 86% of students performed a CtQ with successful ventilation, and 92% at the sixth attempt (P<.0001). Time taken was 163 [107-211] seconds at first attempt, and 70 [55-85] seconds at the sixth (P<.0001). At the end of workshop, students had improved their theoretical knowledge (P<.0001) and perception of the ease of the technique.
CONCLUSIONS: Workshop performance improved theoretical knowledge and competence in surgical cricothyrotomy.

OBJECTIVE: Microvascular obstruction exerts deleterious effects after myocardial infarction. To elucidate the role of ischemia-reperfusion injury on the occurrence and dynamics of microvascular obstruction, we performed a preliminary methodological study to accurately define this process in an in vivo model.
METHODS: Myocardial infarction was induced in swine by means of 90-min of occlusion of the mid left anterior descending coronary artery using angioplasty balloons. Intracoronary infusion of thioflavin-S was applied and compared with traditional intra-aortic or intraventricular instillation. The left anterior descending coronary artery perfused area and microvascular obstruction were quantified in groups with no reperfusion (thioflavin-S administered through the lumen of an inflated over-the-wire balloon) and with 1-min, 1-week, and 1-month reperfusion (thioflavin-S administered from the intracoronary catheter after balloon deflation).
RESULTS: In comparison with intra-aortic and intraventricular administration, intracoronary infusion of thioflavin-S permitted a much clearer assessment of the left anterior descending coronary artery perfused area and of microvascular obstruction. Ischemia-reperfusion injury exerted a decisive role on the occurrence and dynamics of microvascular obstruction. The no-reperfusion group displayed completely preserved perfusion. With the same duration of coronary occlusion, microvascular obstruction was already detected in the 1-min reperfusion group (14%±7%), peaked in the 1-week reperfusion group (21%±7%), and significantly decreased in the 1-month reperfusion group (4%±3%; P<.001).
CONCLUSIONS: We present proof-of-concept evidence on the crucial role of ischemia-reperfusion injury on the occurrence and dynamics of microvascular obstruction. The described porcine model using intracoronary injection of thioflavin-S permits accurate characterization of microvascular obstruction after myocardial infarction.

BACKGROUND: The effectiveness of endoscopic submucosal dissection (ESD) is similar to that of surgery in the treatment of early lesions. The technique requires a high level of technical skill. Training on biologic models and the mastering of accessories facilitate ESD.
OBJECTIVE: The aim was to evaluate the usefulness of the Endolifter in facilitating tissue exposure during ESD in an in vivo porcine model performed at the experimental surgery laboratory of the School of Medicine at the Universidad de São Paulo in Brazil.
METHODS: A study with an experimental design employing an in vivo porcine model was conducted on 5 Yorkshire pigs weighing 20-25kg. ESDs were performed using the Endolifter. Mucosal layer dissection was carried out with a dual knife and IT knife and all the endoscopic procedures were performed by a single expert endoscopist.
RESULTS: A total of 25 ESDs were performed, with a technical success rate of 100%. The mean dissection time was 12.34min (range: 10.40-14.50 min) and the mean lesion size was 2.7cm (range: 2.3-3.2cm). There were no episodes of bleeding or perforations during the procedures.
CONCLUSIONS: The Endolifter enables rapid and effective ESDs to be carried out. It is an applicable and easy-to-use device that can be manipulated by a single operator.

BACKGROUND: Peroral endoscopic myotomy has recently been developed and performed on patients with good results.
OBJECTIVE: To evaluate the technical feasibility of peroral endoscopic full-thickness and partial thickness myotomy in a porcine model.
METHODS: Eighteen criollo pigs were randomly assigned to 2 groups: group A (partial-thickness myotomy) and group B (full-thickness myotomy). The mucosal defect proximal to the myotomy site was left open. On the seventh postoperative day the pig was euthanized and follow-up surgical exploration was performed. The duration of each procedure, postoperative progression of the animal, complications, and anatomopathologic findings were registered.
RESULTS: The procedure was viable in all the pigs. The mean surgery duration was 81±35.3min (group A 51.11±11.12, group B 111±22.61; P<.05). The main complication during myotomy was subcutaneous emphysema (16%). The histopathologic study of the group A surgical specimens reported complete circular myotomy in all cases, and complete circular and longitudinal myotomy was reported in 100% of the group B sample.
CONCLUSIONS: The endoscopic myotomy technique is feasible. Endoscopic partial-thickness myotomy was associated with shorter surgery duration and better results during the intraoperative period and the 7-day follow-up.