Name: ex vivo porcine experimental model for studying and teaching lung mechanics
Uploaded: 2024-04-19T12:30:00
Description: Watch this Scientific Journal Video about Ex Vivo Porcine Experimental Model for Studying and Teaching Lung Mechanics at JoVE.com

We thank all colleagues and professionals who contributed to and supported the construction of this ex vivo porcine lung model protocol.
This study had no funding sources.

The protocol was approved by the Animal Research Ethics Committee of our Institution (protocol no. 1610/2021).
1. Anesthesia and animal preparation
<ol>
	<li>Initially, place the animal on a scale and check the weight to adjust the medications and sedation necessary for the procedure.</li>
	<li>Administer ketamine 5 mg/kg and midazolam 0.25 mg/kg intramuscularly.</li>
	<li>Puncture the marginal ear vein with a 20 G venous catheter and administer intravenous propofol (5 mg/kg...

<ol>
	<li>Roberto, C., Carvalho, R., Toufen Jr, C., Franca, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+Ventilation:+Principles,+graphic+analysis+and+ventilation+modalities.">Mechanical Ventilation: Principles, graphic analysis and ventilation modalities.</a> Jornal Brasileiro de Pneumologia. 33 (2), 54-55 (2007).</li><li>Barbas, C. S. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Brazilian+recommendations+for+mechanical+ventilation+2013.+Part+I.">Brazilian recommendations for mechanical ventilation 2013. Part I.</a> Revista Brasileira de Terapia Intensiva. 26 (2), 89-121 (2014).</li><li>Walter, J. M., Corbridge, T. C., Singer, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invasive+mechanical+ventilation.">Invasive mechanical ventilation.</a> Southern Medical Journal. 111 (12), 746-753 (2018).</li><li>Faustino, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concepts+and+monitoring+of+pulmonary+mechanics+in+patients+under+ventilatory+support+in+the+intensive+care+unit.">Concepts and monitoring of pulmonary mechanics in patients under ventilatory support in the intensive care unit.</a> Revista Brasileira de Terapia Intensiva. 19 (2), 161-169 (2007).</li><li>Holanda, M. A., Vasconcelos, R. S., Ferreira, J. C., Pinheiro, B. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patient-ventilator+asynchrony.">Patient-ventilator asynchrony.</a> Jornal Brasileiro de Pneumologia. 44 (2), 321-333 (2018).</li><li>Rezoagli, E., Laffey, J. G., Bellani, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+lung+injury+severity+and+ventilation+intensity+during+mechanical+ventilation.">Monitoring lung injury severity and ventilation intensity during mechanical ventilation.</a> Seminars in Respiratory and Critical Care Medicine. 43 (3), 346-368 (2022).</li><li>Tallo, F. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+self-perception+of+mechanical+ventilation+knowledge+among+Brazilian+final-year+medical+students,+residents,+and+emergency+physicians.">Evaluation of self-perception of mechanical ventilation knowledge among Brazilian final-year medical students, residents, and emergency physicians.</a> Clinics. 72 (2), 65-70 (2017).</li><li>Schroedl, C. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+simulation-based+mastery+learning+on+resident+skill+managing+mechanical+ventilators.">Impact of simulation-based mastery learning on resident skill managing mechanical ventilators.</a> American Thoracic Society Scholar. 2 (1), 34-48 (2021).</li><li>Wilcox, S. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Academic+emergency+medicine+physicians'+knowledge+of+mechanical+ventilation.">Academic emergency medicine physicians' knowledge of mechanical ventilation.</a> The Western Journal of Emergency Medicine. 17 (3), 271-279 (2016).</li><li>Cox, C. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effectiveness+of+medical+resident+education+in+mechanical+ventilation.">Effectiveness of medical resident education in mechanical ventilation.</a> American Journal of Respiratory and Critical Care Medicine. 167 (1), 32-38 (2003).</li><li>Keegan, R., Henderson, T., Brown, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+the+virtual+ventilator,+a+screen-based+computer+simulation,+to+teach+the+principles+of+mechanical+ventilation.">Use of the virtual ventilator, a screen-based computer simulation, to teach the principles of mechanical ventilation.</a> Journal of Veterinary Medical Education. 36 (4), 436-443 (2009).</li><li>Spadaro, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simulation+training+for+residents+focused+on+mechanical+ventilation:+A+randomized+trial+using+mannequin-based+versus+computer-based+simulation.">Simulation training for residents focused on mechanical ventilation: A randomized trial using mannequin-based versus computer-based simulation.</a> Simulation in Healthcare. 12 (6), 349-355 (2017).</li><li>Chase, J. G., Yuta, T., Mulligan, K. J., Shaw, G. M., Horn, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+mechanical+lung+model+of+pulmonary+diseases+to+assist+with+teaching+and+training.">A novel mechanical lung model of pulmonary diseases to assist with teaching and training.</a> BMC Pulmonary Medicine. 6 (21), 1-11 (2006).</li><li>Kuebler, W. M., Mertens, M., Pries, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+two-component+simulation+model+to+teach+respiratory+mechanics.">A two-component simulation model to teach respiratory mechanics.</a> Advances in Physiology Education. 31 (2), 218-222 (2007).</li><li>Heili-Frades, S., Peces-Barba, G., Rodr&#237;guez-Nieto, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Design+of+a+lung+simulator+for+learning+lung+mechanics+in+mechanical+ventilation.">Design of a lung simulator for learning lung mechanics in mechanical ventilation.</a> Archivos de Bronconeumolog&#237;a. 43 (12), 674-679 (2007).</li><li>Ngo, C., Dahlmanns, S., Vollmer, T., Misgeld, B., Leonhardt, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+object-oriented+computational+model+to+study+cardiopulmonary+hemodynamic+interactions+in+humans.">An object-oriented computational model to study cardiopulmonary hemodynamic interactions in humans.</a> Computer Methods and Programs in Biomedicine. 159, 167-183 (2018).</li><li>Lazzari, C. D., Genuini, I., Pisanelli, D. M., D'Ambrosi, A., Fedele, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactive+simulator+for+e-Learning+environments:+a+teaching+software+for+health+care+professionals.">Interactive simulator for e-Learning environments: a teaching software for health care professionals.</a> Biomedical Engineering Online. 13 (172), 1-18 (2014).</li><li>Perinel, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+ex+vivo+human-porcine+respiratory+model+for+preclinical+studies.">Development of an ex vivo human-porcine respiratory model for preclinical studies.</a> Scientific Reports. 7, 1-6 (2017).</li><li>Aboelnazar, N. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+pressure+ventilation+decreases+inflammation+and+lung+edema+during+normothermic+ex-vivo+lung+perfusion.">Negative pressure ventilation decreases inflammation and lung edema during normothermic ex-vivo lung perfusion.</a> The Journal of Heart and Lung Transplantation. 37 (4), 520-530 (2018).</li><li>Sattari, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Introducing+a+custom-designed+volume-pressure+machine+for+novel+measurements+of+whole+lung+organ+viscoelasticity+and+direct+comparisons+between+positive-+and+negative-pressure+ventilation.">Introducing a custom-designed volume-pressure machine for novel measurements of whole lung organ viscoelasticity and direct comparisons between positive- and negative-pressure ventilation.</a> Frontiers in Bioengineering and Biotechnology. 8, 1-12 (2020).</li><li>Sattari, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Positive-+and+negative-pressure+ventilation+characterized+by+local+and+global+pulmonary+mechanics.">Positive- and negative-pressure ventilation characterized by local and global pulmonary mechanics.</a> American Journal of Respiratory and Critical Care Medicine. 207 (5), 577-586 (2023).</li><li>Montigaud, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+ex+vivo+preclinical+respiratory+model+of+idiopathic+pulmonary+fibrosis+for+aerosol+regional+studies.">Development of an ex vivo preclinical respiratory model of idiopathic pulmonary fibrosis for aerosol regional studies.</a> Scientific Reports. 9 (1), 17949 (2019).</li><li>Montigaud, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aerosol+delivery+during+invasive+mechanical+ventilation:+development+of+a+preclinical+ex+vivo+respiratory+model+for+aerosol+regional+deposition.">Aerosol delivery during invasive mechanical ventilation: development of a preclinical ex vivo respiratory model for aerosol regional deposition.</a> Scientific Reports. 9 (1), 17930 (2019).</li><li>Montigaud, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+ex+vivo+respiratory+pediatric+model+of+bronchopulmonary+dysplasia+for+aerosol+deposition+studies.">Development of an ex vivo respiratory pediatric model of bronchopulmonary dysplasia for aerosol deposition studies.</a> Scientific Reports. 9 (1), 5720 (2019).</li><li>Buchko, M. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+low-cost+perfusate+alternative+for+ex+vivo.+lung+perfusion.">A low-cost perfusate alternative for ex vivo. lung perfusion.</a> transplantation proceedings. 52 (10), 2941-2946 (2020).</li><li>Kondo, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+an+effective+method+utilizing+fibrin+glue+to+repair+pleural+defects+in+an+ex-vivo+pig+model.">Development of an effective method utilizing fibrin glue to repair pleural defects in an ex-vivo pig model.</a> Journal of Cardiothoracic Surgery. 15 (1), 110 (2020).</li><li>Gasek, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+alginate+and+gelatin-based+pleural+and+tracheal+sealants.">Development of alginate and gelatin-based pleural and tracheal sealants.</a> Acta Biomaterialia. 131, 222-235 (2021).</li><li>Li, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+individualized+positive+end-expiratory+pressure+combined+with+recruitment+maneuver+on+intraoperative+ventilation+during+abdominal+surgery:+a+systematic+review+and+network+meta-analysis+of+randomized+controlled+trials.">Effects of individualized positive end-expiratory pressure combined with recruitment maneuver on intraoperative ventilation during abdominal surgery: a systematic review and network meta-analysis of randomized controlled trials.</a> Journal of Anesthesia. 36 (2), 303-315 (2022).</li><li>Hu, M. C., Yang, Y. L., Chen, T. T., Lee, C. I., Tam, K. W. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recruitment+maneuvers+to+reduce+pulmonary+atelectasis+after+cardiac+surgery:+A+meta-analysis+of+randomized+trials.">Recruitment maneuvers to reduce pulmonary atelectasis after cardiac surgery: A meta-analysis of randomized trials.</a> The Journal of Thoracic and Cardiovascular Surgery. 164 (1), 171-181 (2020).</li><li>Hu, M. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recruitment+maneuvers+in+patients+undergoing+thoracic+surgery:+a+meta-analysis.">Recruitment maneuvers in patients undergoing thoracic surgery: a meta-analysis.</a> General Thoracic and Cardiovascular Surgery. 69 (12), 1553-1559 (2021).</li><li>Zeng, C., Lagier, D., Lee, J. W., Melo, M. F. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Perioperative+pulmonary+atelectasis:+Part+I.+Biology+and+mechanisms.">Perioperative pulmonary atelectasis: Part I. Biology and mechanisms.</a> Anesthesiology. 136 (1), 181-205 (2022).</li><li>Niman, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lung+recruitment+after+cardiac+arrest+during+procurement+of+atelectatic+donor+lungs+is+a+protective+measure+in+lung+transplantation.">Lung recruitment after cardiac arrest during procurement of atelectatic donor lungs is a protective measure in lung transplantation.</a> Journal of Thoracic Disease. 14 (8), 2802-2811 (2022).</li><li>Calvo, R. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+efficacy+of+two+alveolar+recruitment+maneuvers+in+improving+the+lung+mechanics+and+the+degree+of+atelectasis+in+anesthetized+healthy+sheep.">Comparison of the efficacy of two alveolar recruitment maneuvers in improving the lung mechanics and the degree of atelectasis in anesthetized healthy sheep.</a> Research in Veterinary Science. 150 (5), 164-169 (2022).</li><li>Pensier, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+lung+recruitment+maneuver+on+oxygenation,+physiological+parameters+and+mortality+in+acute+respiratory+distress+syndrome+patients:+a+systematic+review+and+meta-analysis.">Effect of lung recruitment maneuver on oxygenation, physiological parameters and mortality in acute respiratory distress syndrome patients: a systematic review and meta-analysis.</a> Intensive Care Medicine. 45 (12), 1691-1702 (2019).</li><li>Mariano, C. A., Sattari, S., Quiros, K. A. M., Nelson, T. M., Eskandari, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Examining+lung+mechanical+strains+as+influenced+by+breathing+volumes+and+rates+using+experimental+digital+image+correlation.">Examining lung mechanical strains as influenced by breathing volumes and rates using experimental digital image correlation.</a> Respiratory Research. 23 (1), 92 (2022).</li></ol>

The described protocol is useful for producing an ex vivo porcine lung model under positive-pressure MV. It can be used for studying and teaching lung mechanics through visual feedback from the lungs during recruitment and analysis of the curves and values projected on the device screen. To achieve this result, pilot studies are needed to understand the behavior of the lungs outside the rib cage and to identify the need for adaptations.
We identified that the critical point was the fo...

Mechanical ventilation (MV) is widely used in intensive care units (ICUs) and surgical centers. Its monitoring is essential to help recognize asynchronies and prevent injuries for all patients, especially when the patient has serious lung injuries1,2,3,4,5,6. Monitoring respiratory mechanics can also contribute to the clinical understanding of the disease progression and therapeutic applications, such as the use of positive end-expiratory pressure (PEEP) or the alveolar recruitment maneuver (ARM). However, the use of these techniques requires a proficient understanding of curves and basic lung mechanics3,4.
Students, residents, and medical professionals feel insecure about MV management, from turning on the ventilator and initial adjustments to monitoring plateau and driving pressures, and this insecurity is associated with a lack of knowledge and adequate prior training7,8,9,10. We observed that professionals who participated in simulations and used a lung model reported greater confidence, understanding of the parameters, and understanding of the components of lung mechanics8,11,12.
Models for studying and training MV with test lungs, bellows, and pistons can simulate different pressures and volumes, as well as different lung mechanics conditions13,14,15. Computational and software models also contribute to the study of cardiopulmonary interaction by generating simulations that can be used to teach the principles of MV11 to health professionals16,17.
While computational models may present difficulties in representing pulmonary hysteresis16, models with test lung and bellows13,14,15can produce pressure-volume curves similar to the physiological curve and demonstrate pulmonary dynamics. As an advantage, the ex vivo porcine lung presents similar anatomy to humans18, also producing MV curves, pulmonary hysteresis, and providing visual feedback of the lungs inside the acrylic box during the lung mechanics analysis. Visual models are important and can help understand difficult-to-imagine components and concepts. Thus, ex vivo lung models represent a practical way of teaching.
Studies with ex vivo porcine lungs, such as those on MV with positive and negative pressure19,20,21, analysis of aerosol distribution22,23, pediatric simulations24, and lung perfusion25 can improve the knowledge on MV. Recent studies analyzing models in positive and negative pressure have shown that positive-pressure ventilation can lead to abrupt recruitment with greater local deformation, greater distension, hysteresis curve differences, and possible tissue lesions compared to negative pressure pressure19,20,21. Nevertheless, positive-pressure models are necessary because patients are under positive pressure during MV pressure19,20,21. The development of a lung model for preclinical studies opens possibilities for new research and applications, including MV teaching and training.
Here, we present an ex vivo porcine lung model for studying and training purposes. Our primary objective is to describe the steps for the generation of this ex vivo porcine lung model under positive-pressure MV. It can be used in the future to study and teach lung mechanics.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>0.9% Saline solution</td>
			<td></td>
			<td></td>
			<td>2500ml</td>
		</tr>
		<tr>
			<td>Anesthesia machine - Primus</td>
			<td>Drager</td>
			<td>REF 8603800-18</td>
			<td>Anesthesia work station used in the procedure</td>
		</tr>
		<tr>
			<td>Aspirator</td>
			<td></td>
			<td></td>
			<td>For blood aspiration from thorax</td>
		</tr>
		<tr>
			<td>Bedside Monitor - Life Scope</td>
			<td>Nihon Kohden</td>
			<td>BSM-7363</td>
			<td>Multiparameter monitor used during the procedure</td>
		</tr>
		<tr>
			<td>Bonney Tissue Forceps</td>
			<td></td>
			<td></td>
			<td>Any tissue forceps is suitable</td>
		</tr>
		<tr>
			<td>Disposable scalper, #23</td>
			<td></td>
			<td></td>
			<td>Any scalper is suitable</td>
		</tr>
		<tr>
			<td>Disposable syringe needles, 18G x 1 1/2&#34;, 23G x 1&#34;</td>
			<td>BD</td>
			<td>302814</td>
			<td>Widely available</td>
		</tr>
		<tr>
			<td>Disposable syringes, 10ml</td>
			<td></td>
			<td></td>
			<td>Widely available</td>
		</tr>
		<tr>
			<td>Electrosurgical unit - SS-501</td>
			<td>WEM</td>
			<td></td>
			<td>For cutting and coagulation during thorax incision</td>
		</tr>
		<tr>
			<td>Fentanyl</td>
			<td></td>
			<td></td>
			<td>10 mcg/kg bolus + 10 mcg/kg/hour continuous infusion</td>
		</tr>
		<tr>
			<td>Finochietto retractor</td>
			<td></td>
			<td></td>
			<td>Any finochietto retractor is suitable</td>
		</tr>
		<tr>
			<td>heparin</td>
			<td></td>
			<td></td>
			<td>3ml</td>
		</tr>
		<tr>
			<td>Infusion set</td>
			<td></td>
			<td></td>
			<td>Any infusion set is suitable</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td></td>
			<td></td>
			<td>1.5%</td>
		</tr>
		<tr>
			<td>Kelly Forceps Curved</td>
			<td></td>
			<td></td>
			<td>Any kelly forceps is suitable</td>
		</tr>
		<tr>
			<td>Ketamine</td>
			<td></td>
			<td></td>
			<td>5mg/kg</td>
		</tr>
		<tr>
			<td>Lactated Ringer solution</td>
			<td></td>
			<td></td>
			<td>500ml</td>
		</tr>
		<tr>
			<td>Mechanical ventilator - Servo I</td>
			<td>Maquet</td>
			<td>REF 6449701</td>
			<td>Mechanical ventilator used in the procedure</td>
		</tr>
		<tr>
			<td>Metzenbaum Scissor (Straight and curved)</td>
			<td></td>
			<td></td>
			<td>Any metzenbaum scissor is suitable</td>
		</tr>
		<tr>
			<td>Midazolam</td>
			<td></td>
			<td></td>
			<td>0.25mg/kg</td>
		</tr>
		<tr>
			<td>Orotracheal intubation cannula, #6.5</td>
			<td>Rusch</td>
			<td>112282</td>
			<td>Widely available</td>
		</tr>
		<tr>
			<td>Plexiglass</td>
			<td></td>
			<td></td>
			<td>Custom made plexiglass box: 30x45x60cm</td>
		</tr>
		<tr>
			<td>Polyester suture, 2-0</td>
			<td></td>
			<td></td>
			<td>Widely available</td>
		</tr>
		<tr>
			<td>Potassium choride</td>
			<td></td>
			<td></td>
			<td>10 ml, 19.1% potassium chloride.</td>
		</tr>
		<tr>
			<td>propofol</td>
			<td></td>
			<td></td>
			<td>5mg/kg</td>
		</tr>
		<tr>
			<td>Three way stopcock</td>
			<td></td>
			<td></td>
			<td>Widely available</td>
		</tr>
		<tr>
			<td>Venous catheter, G20 x 1&#34;</td>
			<td>BD</td>
			<td>38183314</td>
			<td>Widely available</td>
		</tr>
	</tbody>
</table>

ex vivo porcine experimental model for studying and teaching lung mechanics

Mechanical ventilation is widely used and requires specific knowledge for understanding and management. Health professionals in this field may feel insecure and lack knowledge because of inadequate training and teaching methods. Therefore, the objective of this article is to outline the steps involved in generating an ex vivo porcine lung model to be used in the future, to study and teach lung mechanics. To generate the model, five porcine lungs were carefully removed from the thorax following the guidelines of the Animal Research Ethics Committee with adequate care and were connected to the mechanical ventilator through a tracheal cannula. These lungs were then subjected to the alveolar recruitment maneuver. Respiratory mechanics parameters were recorded, and video cameras were used to obtain videos of the lungs during this process. This process was repeated for five consecutive days. When not used, the lungs were kept refrigerated. The model showed different lung mechanics after the alveolar recruitment maneuver every day; not being influenced by the days, only by the maneuver. Therefore, we conclude that the ex vivo lung model can provide a better understanding of lung mechanics and its effects, and even of the alveolar recruitment maneuver through visual feedback during all stages of the process.

We used five female pigs weighing between 23.4-26.9 kg and followed the described protocol for cardiopulmonary extraction and lung mechanics analysis. Our intention is that the model is useful for the study of lung mechanics by analyzing peak pressure, plateau pressure, resistance, driving pressure, and dynamic compliance variables collected directly from the mechanical ventilator screen. The model flowchart is shown in Figure 1.
The lungs were analyzed for five c...

Watch this Scientific Journal Video about Ex Vivo Porcine Experimental Model for Studying and Teaching Lung Mechanics at JoVE.com

Ex Vivo Porcine Experimental Model for Studying and Teaching Lung Mechanics

We present an ex vivo pig lung model for the demonstration of pulmonary mechanics and alveolar recruitment maneuvers for teaching purposes. The lungs can be used for more than one day (up to five days) with minimal changes in pulmonary mechanics variables.

Ex Vivo Porcine Experimental Model for Studying and Teaching Lung Mechanics

Mechanical ventilation is widely used and requires specific knowledge for understanding and management. Health professionals in this field may feel ...

ex-vivo-porcine-experimental-model-for-studying-teaching-lung

Research

Without Section

JoVE Journal

Medicine

Steps for the Autologous Ex vivo Perfused Porcine Liver-kidney Experiment

The use of ex vivo perfused models can mimic the physiological conditions of the liver for short periods, but to maintain normal homeostasis for an extended perfusion period is challenging. We have added the kidney to our previous ex vivo perfused liver experiment model to reproduce a more accurate physiological state for prolonged experiments without using live animals. Five intact livers and kidneys were retrieved post-mortem from sacrificed pigs on different days and perfused for a minimum of 6 hr. Hourly arterial blood gases were obtained to analyze pH, lactate, glucose and renal parameters. The primary endpoint was to investigate the effect of adding one kidney to the model on the acid base balance, glucose, and electrolyte levels. The result of this liver-kidney experiment was compared to the results of five previous liver only perfusion models. In summary, with the addition of one kidney to the ex vivo liver circuit, hyperglycemia and metabolic acidosis were improved. In addition this model reproduces the physiological and metabolic responses of the liver sufficiently accurately to obviate the need for the use of live animals. The ex vivo liver-kidney perfusion model can be used as an alternative method in organ specific studies. It provides a disconnection from numerous systemic influences and allows specific and accurate adjustments of arterial and venous pressures and flow.

Steps for the Autologous Ex vivo Perfused Porcine Liver-kidney Experiment

Study of the animal organ physiology can be achieved by performing an experimental ex vivo perfusion system. The addition of a porcine kidney, as a homeostatic organ to our previously developed ex vivo liver perfusion model can be a principal step to achieve a better physiological environment.

The use of ex vivo perfused models can mimic the physiological conditions of the liver for short periods, but to maintain normal homeostasis for an ...

Procedure for Human Saphenous Veins Ex Vivo Perfusion and External Reinforcement

The mainstay of contemporary therapies for extensive occlusive arterial disease is venous bypass graft. However, its durability is threatened by intimal hyperplasia (IH) that eventually leads to vessel occlusion and graft failure. Mechanical forces, particularly low shear stress and high wall tension, are thought to initiate and to sustain these cellular and molecular changes, but their exact contribution remains to be unraveled. To selectively evaluate the role of pressure and shear stress on the biology of IH, an ex&#160;vivo perfusion system (EVPS) was created to perfuse segments of human saphenous veins under arterial regimen (high shear stress and high pressure). Further technical innovations allowed the simultaneous perfusion of two segments from the same vein, one reinforced with an external mesh. Veins were harvested using a no-touch technique and immediately transferred to the laboratory for assembly in the EVPS. One segment of the freshly isolated vein was not perfused (control, day 0). The two others segments were perfused for up to 7 days, one being completely sheltered with a 4 mm (diameter) external mesh. The pressure, flow velocity, and pulse rate were continuously monitored and adjusted to mimic the hemodynamic conditions prevailing in the femoral artery. Upon completion of the perfusion, veins were dismounted and used for histological and molecular analysis. Under ex&#160;vivo conditions, high pressure perfusion (arterial, mean = 100 mm Hg) is sufficient to generate IH and remodeling of human veins. These alterations are reduced in the presence of an external polyester mesh.

Procedure for Human Saphenous Veins Ex Vivo Perfusion and External Reinforcement

The mechanisms leading to the development of intimal hyperplasia (IH) and vein graft failure are still poorly understood. This study describes an ex&#160;vivo system to perfuse human veins under controlled flow and pressure. Furthermore the efficiency of external mesh reinforcement to limit the development of IH was evaluated.

The mainstay of contemporary therapies for extensive occlusive arterial disease is venous bypass graft. However, its durability is threatened by intimal ...

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. As this technology expands and improves, the ability to potentially evaluate and improve the quality of substandard lungs prior to transplant is a critical need. In order to more rigorously evaluate these approaches, a reproducible animal model needs to be established that would allow for testing of improved techniques and management of the donated lungs as well as to the lung-transplant recipient. In addition, an EVLP animal model of associated pathologies, e.g., ventilation induced lung injury (VILI), would provide a novel method to evaluate treatments for these pathologies. Here, we describe the development of a rat EVLP lung program and refinements to this method that allow for a reproducible model for future expansion. We also describe the application of this EVLP system to model VILI in rat lungs. The goal is to provide the research community with key information and &#8220;pearls of wisdom&#8221;/techniques that arose from trial and error and are critical to establishing an EVLP system that is robust and reproducible.

Method of Isolated Ex Vivo Lung Perfusion in a Rat Model: Lessons Learned from Developing a Rat EVLP Program

Ex-Vivo Lung Perfusion (EVLP) has allowed lung transplantation in humans to become more readily available by enabling the ability to assess organs and expand the donor pool. Here, we describe the development of a rat EVLP program and refinements that allow for a reproducible model for future expansion.

The number of acceptable donor lungs available for lung transplantation is severely limited due to poor quality. Ex-Vivo Lung Perfusion (EVLP) has allowed ...

An Ex vivo Model to Study Hormone Action in the Human Breast

The study of hormone action in the human breast has been hampered by lack of adequate model systems. Upon in vitro culture, primary mammary epithelial cells tend to lose hormone receptor expression. Widely used hormone receptor positive breast cancer cell lines are of limited relevance to the in vivo situation. Here, we describe an ex vivo model to study hormone action in the human breast. Fresh human breast tissue specimens from surgical discard material such as reduction mammoplasties or mammectomies are mechanically and enzymatically digested to obtain tissue fragments containing ducts and lobules and multiple stromal cell types. These tissue microstructures kept in basal medium without growth factors preserve their intercellular contacts, the tissue architecture, and remain hormone responsive for several days. They are readily processed for RNA and protein extraction, histological analysis or stored in freezing medium. Fluorescence activated cell sorting (FACS) can be used to enrich for specific cell populations. This protocol provides a straightforward, standard approach for translational studies with highly complex, varied human specimens.

An Ex vivo Model to Study Hormone Action in the Human Breast

We have developed a novel ex vivo model to study hormone action in the human breast. It is based on tissue microstructures isolated from surgical breast tissue specimens which preserve tissue architecture, intercellular interactions, and paracrine signaling.

The study of hormone action in the human breast has been hampered by lack of adequate model systems. Upon in vitro culture, primary mammary epithelial ...

Ex vivo Live Imaging of Lung Metastasis and Their Microenvironment

Metastasis is a major cause for cancer-related morbidity and mortality. Metastasis is a multistep process and due to its complexity, the exact cellular and molecular processes that govern metastatic dissemination and growth are still elusive. Live imaging allows visualization of the dynamic and spatial interactions of cells and their microenvironment. Solid tumors commonly metastasize to the lungs. However, the anatomical location of the lungs poses a challenge to intravital imaging. This protocol provides a relatively simple and quick method for ex vivo live imaging of the dynamic interactions between tumor cells and their surrounding stroma within lung metastasis. Using this method, the motility of cancer cells as well as interactions between cancer cells and stromal cells in their microenvironment can be visualized in real time for several hours. By using transgenic fluorescent reporter mice, a fluorescent cell line, injectable fluorescently labeled molecules and/or antibodies, multiple components of the lung microenvironment can be visualized, such as blood vessels and immune cells. To image the different cell types, a spinning disk confocal microscope that allows long-term continuous imaging with rapid, four-color image acquisition has been used. Time-lapse movies compiled from images collected over multiple positions and focal planes show interactions between live metastatic and immune cells for at least 4 hr. This technique can be further used to test chemotherapy or targeted therapy. Moreover, this method could be adapted for the study of other lung-related pathologies that may affect the lung microenvironment.

Ex vivo Live Imaging of Lung Metastasis and Their Microenvironment

We describe a relatively simple method for ex vivo live imaging of the tumor cell-stroma interactions within lung metastasis, utilizing fluorescent reporters in mice. Using spinning-disk confocal microscopy, this technique enables visualization of live cells for at least 4 hr and could be adapted to study other inflammatory lung conditions.

Metastasis is a major cause for cancer-related morbidity and mortality. Metastasis is a multistep process and due to its complexity, the exact cellular ...

A Small Animal Model of Ex Vivo Normothermic Liver Perfusion

There is a significant shortage of liver allografts available for transplantation, and in response the donor criteria have been expanded. As a result, normothermic ex vivo liver perfusion (NEVLP) has been introduced as a method to evaluate and modify organ function. NEVLP has many advantages in comparison to hypothermic and subnormothermic perfusion including reduced preservation injury, restoration of normal organ function under physiologic conditions, assessment of organ performance, and as a platform for organ repair, remodeling, and modification. Both murine and porcine NEVLP models have been described. We demonstrate a rat model of NEVLP and use this model to show one of its important applications &#8212; the use of a therapeutic molecule added to liver perfusate. Catalase is an endogenous reactive oxygen species (ROS) scavenger and has been demonstrated to decrease ischemia-reperfusion in the eye, brain, and lung. Pegylation has been shown to target catalase to the endothelium. Here, we added pegylated-catalase (PEG-CAT) to the base perfusate and demonstrated its ability to mitigate liver preservation injury. An advantage of our rodent NEVLP model is that it is inexpensive in comparison to larger animal models. A limitation of this study is that it does not currently include post-perfusion liver transplantation. Therefore, prediction of the function of the organ post-transplantation cannot be made with certainty. However, the rat liver transplant model is well established and certainly could be used in conjunction with this model. In conclusion, we have demonstrated an inexpensive, simple, easily replicable NEVLP model using rats. Applications of this model can include testing novel perfusates and perfusate additives, testing software designed for organ evaluation, and experiments designed to repair organs.

A Small Animal Model of Ex Vivo Normothermic Liver Perfusion

There is a significant liver donor shortage, and criteria for liver donors have been expanded. Normothermic ex vivo liver perfusion (NEVLP) has been developed to evaluate and modify organ function. This study demonstrates a rat model of NEVLP and tests the ability of pegylated-catalase, to mitigate liver preservation injury.

There is a significant shortage of liver allografts available for transplantation, and in response the donor criteria have been expanded. As a result, ...

Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System

Since its invention in the late 19th century, the Langendorff ex vivo heart perfusion system continues to be a relevant tool for studying a broad spectrum of physiological, biochemical, morphological, and pharmacological parameters in centrally denervated hearts. Here, we describe a setup for the modulation of the intracardiac autonomic nervous system and the assessment of its influence on basic electrophysiology, arrhythmogenesis, and cyclic adenosine monophosphate (cAMP) dynamics. The intracardiac autonomic nervous system is modulated by the mechanical dissection of atrial fat pads-in which murine ganglia are located mainly&#8212;or by the usage of global as well as targeted pharmacological interventions. An octapolar electrophysiological catheter is introduced into the right atrium and the right ventricle, and epicardial-placed multi-electrode arrays (MEA) for high-resolution mapping are used to determine cardiac electrophysiology and arrhythmogenesis. F&#246;rster resonance energy transfer (FRET) imaging is performed for the real-time monitoring of cAMP levels in different cardiac regions. Neuromorphology is studied by means of antibody-based staining of whole hearts using neuronal markers to guide the identification and modulation of specific targets of the intracardiac autonomic nervous system in the performed studies. The ex vivo Langendorff setup allows for a high number of reproducible experiments in a short time. Nevertheless, the partly open nature of the setup (e.g., during MEA measurements) makes constant temperature control difficult and should be kept to a minimum. This described method makes it possible to analyze and modulate the intracardiac autonomic nervous system in decentralized hearts.

Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System

Here, we present a protocol for the modulation of the intracardiac autonomic nervous system and the assessment of its influence on basic electrophysiology, arrhythmogenesis, and cAMP dynamics using an ex vivo Langendorff setup.

Since its invention in the late 19th century, the Langendorff ex vivo heart perfusion system continues to be a relevant tool for studying a broad spectrum ...

Ex Vivo Corneal Organ Culture Model for Wound Healing Studies

The cornea has been used extensively as a model system to study wound healing. The ability to generate and utilize primary mammalian cells in two dimensional (2D) and three dimensional (3D) culture has generated a wealth of information not only about corneal biology but also about wound healing, myofibroblast biology, and scarring in general. The goal of the protocol is an assay system for quantifying myofibroblast development, which characterizes scarring. We demonstrate a corneal organ culture ex vivo model using pig eyes. In this anterior keratectomy wound, corneas still in the globe are wounded with a circular blade called a trephine. A plug of approximately 1/3 of the anterior cornea is removed including the epithelium, the basement membrane, and the anterior part of the stroma. After wounding, corneas are cut from the globe, mounted on a collagen/agar base, and cultured for two weeks in supplemented-serum free medium with stabilized vitamin C to augment cell proliferation and extracellular matrix secretion by resident fibroblasts. Activation of myofibroblasts in the anterior stroma is evident in the healed cornea. This model can be used to assay wound closure, the development of myofibroblasts and fibrotic markers, and for toxicology studies. In addition, the effects of small molecule inhibitors as well as lipid-mediated siRNA transfection for gene knockdown can be tested in this system.

A protocol for an ex vivo corneal organ culture model useful for wound healing studies is described. This model system can be used to assess the effects of agents to promote regenerative healing or drug toxicity in an organized 3D multicellular environment.

The cornea has been used extensively as a model system to study wound healing. The ability to generate and utilize primary mammalian cells in two ...

An Ex Vivo Tissue Culture Model for Fibrovascular Complications in Proliferative Diabetic Retinopathy

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and one of the leading causes of blindness in working-age adults. No current animal models of diabetes and oxygen-induced retinopathy develop the full-range progressive changes manifested in human proliferative diabetic retinopathy (PDR). Therefore, understanding of the disease pathogenesis and pathophysiology has relied largely on the use of histological sections and vitreous samples in approaches that only provide steady-state information on the involved pathogenic factors. Increasing evidence indicates that dynamic cell-cell and cell-extracellular matrix (ECM) interactions in the context of three-dimensional (3D) microenvironments are essential for the mechanistic and functional studies towards the development of new treatment strategies. Therefore, we hypothesized that the pathological fibrovascular tissue surgically excised from eyes with PDR could be utilized to reliably unravel the cellular and molecular mechanisms of this devastating disease and to test the potential for novel clinical interventions. Towards this end, we developed a novel method for 3D ex vivo culture of surgically-excised patient-derived fibrovascular tissue (FT), which will serve as a relevant model of human PDR pathophysiology. The FTs are dissected into explants and embedded in fibrin matrix for ex vivo culture and 3D characterization. Whole-mount immunofluorescence of the native FTs and end-point cultures allows thorough investigation of tissue composition and multicellular processes, highlighting the importance of 3D tissue-level characterization for uncovering relevant features of PDR pathophysiology. This model will allow the simultaneous assessment of molecular mechanisms, cellular/tissue processes and treatment responses in the complex context of dynamic biochemical and physical interactions within the PDR tissue architecture and microenvironment. Since this model recapitulates PDR pathophysiology, it will also be amenable for testing or developing new treatments.

Here, we present a protocol to study the pathophysiology of proliferative diabetic retinopathy by using patient-derived, surgically-excised, fibrovascular tissues for three-dimensional native tissue characterization and ex vivo culture. This ex vivo culture model is also amenable for testing or developing new treatments.

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes and one of the leading causes of blindness in working-age adults. No ...

Manufacture of a Multi-Purpose Low-Cost Animal Bench-Model for Teaching Tracheostomy

Tracheostomy is one of the most frequent procedures, performed through various techniques in the intensive care unit and emergency situations. Despite this, there is a lack of training on this procedure that affects its outcome, which is also dependent on operator's dexterity. Here, we take the specific training and simulation into consideration. This article aims to describe every step of the manufacture of a new multi-purpose low-cost animal bench-model, with the support of video and images, and to obtain an opinion about the quality of this model by administering a questionnaire to professionals with experience in the procedures. 
Ten experts in the technique were enrolled. The model scored an average of 3.45/5 for its anatomical realism; 4.75/5 for its usefulness as a training tool for simulation courses and assessments. The time necessary to build the model was 15 minutes, and the cost amounted to 10&#8364;. The animal bench-model was considered a very useful simulator for tracheostomy training and assessments. Therefore, it could be used as a tool for medical courses and residencies.

This article illustrates every step of the manufacture of a new multi-purpose low-cost animal bench-model for subglottic airway access management. All the procedures are shown in the video. The model's realism and its suitability for training the given clinical maneuvers were assessed by independent senior otolaryngologists and anesthesiologists.

Tracheostomy is one of the most frequent procedures, performed through various techniques in the intensive care unit and emergency situations. Despite ...