This research was funded on behalf of The Hospital Research Foundation.

The procedures performed in this manuscript comply with the guidelines of the Canadian Council on Animal Care and the guide for the care and use of laboratory animals. The institutional animal care committee of the University of Alberta approved the protocols. Female juvenile Yorkshire pigs between 35-50 kg were used exclusively. Proper biosafety training was required by all individuals involved in ESLP procedures. A schematic overview of the entire NPV-ESLP experiment is represented in Figure 1</str...

<ol>
	<li>Chambers, D. 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=The+international+thoracic+organ+transplant+registry+of+the+international+society+for+heart+and+lung+transplantation:+Thirty-fifth+adult+lung+and+heart-lung+transplant+report-2018;+focus+theme:+Multiorgan+transplantation.">The international thoracic organ transplant registry of the international society for heart and lung transplantation: Thirty-fifth adult lung and heart-lung transplant report-2018; focus theme: Multiorgan transplantation.</a> The Journal of Heart and Lung Transplantation. 37 (10), 1169-1183 (2018).</li><li>Valapour, M., 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=OPTN/SRTR+2017+annual+data+report:+Lung.">OPTN/SRTR 2017 annual data report: Lung.</a> American Journal of Transplantation. 19, 404-484 (2019).</li><li>Chambers, D. 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=The+registry+of+the+international+society+for+heart+and+lung+transplantation:+Thirty-fourth+adult+lung+and+heart-lung+transplantation+report-2017;+focus+theme:+Allograft+ischemic+time.">The registry of the international society for heart and lung transplantation: Thirty-fourth adult lung and heart-lung transplantation report-2017; focus theme: Allograft ischemic time.</a> The Journal of Heart and Lung Transplantation. 36 (10), 1047-1059 (2017).</li><li>Klein, A. 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=Organ+donation+and+utilization+in+the+united+states,+1999-2008.">Organ donation and utilization in the united states, 1999-2008.</a> American Journal of Transplantation. 10 (4), 973-986 (2010).</li><li>Singh, 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=Sequence+of+refusals+for+donor+quality,+organ+utilization,+and+survival+after+lung+transplantation.">Sequence of refusals for donor quality, organ utilization, and survival after lung transplantation.</a> The Journal of Heart and Lung Transplantation. 38 (1), 35-42 (2019).</li><li>Bhorade, S. M., Vigneswaran, W., McCabe, M. A., Garrity, E. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liberalization+of+donor+criteria+may+expand+the+donor+pool+without+adverse+consequence+in+lung+transplantation.">Liberalization of donor criteria may expand the donor pool without adverse consequence in lung transplantation.</a> The Journal of Heart and Lung Transplantation. 19 (12), 1199-1204 (2000).</li><li>Snell, G. I., Griffiths, A., Levvey, B. J., Oto, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Availability+of+lungs+for+transplantation:+Exploring+the+real+potential+of+the+donor+pool.">Availability of lungs for transplantation: Exploring the real potential of the donor pool.</a> The Journal of Heart and Lung Transplantation. 27 (6), 662-667 (2008).</li><li>Cypel, M., 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=Normothermic+ex+vivo+lung+perfusion+in+clinical+lung+transplantation.">Normothermic ex vivo lung perfusion in clinical lung transplantation.</a> The New England Journal of Medicine. 364 (15), 1431-1440 (2011).</li><li>Wallinder, A., 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=Early+results+in+transplantation+of+initially+rejected+donor+lungs+after+ex+vivo+lung+perfusion:+A+case-control+study.">Early results in transplantation of initially rejected donor lungs after ex vivo lung perfusion: A case-control study.</a> European Journal of Cardio-Thoracic Surgery. 45 (1), 40-45 (2014).</li><li>Cypel, M., 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=Experience+with+the+first+50+ex+vivo+lung+perfusions+in+clinical+transplantation.">Experience with the first 50 ex vivo lung perfusions in clinical transplantation.</a> The Journal of Thoracic and Cardiovascular Surgery. 144 (1), 1200-1206 (2012).</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=Total+parenteral+nutrition+in+ex+vivo+lung+perfusion:+Addressing+metabolism+improves+both+inflammation+and+oxygenation.">Total parenteral nutrition in ex vivo lung perfusion: Addressing metabolism improves both inflammation and oxygenation.</a> American Journal of Transplantation. 19 (12), 3390-3397 (2019).</li><li>Andreasson, A. S. I., 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=Profiling+inflammation+and+tissue+injury+markers+in+perfusate+and+bronchoalveolar+lavage+fluid+during+human+ex+vivo+lung+perfusion.">Profiling inflammation and tissue injury markers in perfusate and bronchoalveolar lavage fluid during human ex vivo lung perfusion.</a> European Journal of Cardio-Thoracic Surgery. 51 (3), 577-586 (2017).</li><li>Sadaria, M. 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=Cytokine+expression+profile+in+human+lungs+undergoing+normothermic+ex-vivo+lung+perfusion.">Cytokine expression profile in human lungs undergoing normothermic ex-vivo lung perfusion.</a> The Annals of Thoracic Surgery. 92 (2), 478-484 (2011).</li><li>Ricard, J. D., Dreyfuss, D., Saumon, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ventilator-induced+lung+injury.">Ventilator-induced lung injury.</a> European Respiratory Journal. 42, 2-9 (2003).</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>Lai-Fook, S. J., Rodarte, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pleural+pressure+distribution+and+its+relationship+to+lung+volume+and+interstitial+pressure.">Pleural pressure distribution and its relationship to lung volume and interstitial pressure.</a> Journal of Applied Physiology. 70 (3), 967-978 (1991).</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=Clinical+transplantation+using+negative+pressure+ventilation+ex+situ+lung+perfusion+with+extended+criteria+donor+lungs.">Clinical transplantation using negative pressure ventilation ex situ lung perfusion with extended criteria donor lungs.</a> Nature Communications. 11 (1), 5765 (2020).</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+perfusion.">A low-cost perfusate alternative for ex vivo perfusion.</a> Transplantation Proceedings. 52 (10), 2941-2946 (2020).</li><li>Forgie, K. A., 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=Left+lung+orthotopic+transplantation+in+a+juvenile+porcine+model+for+ESLP.">Left lung orthotopic transplantation in a juvenile porcine model for ESLP.</a> The Journal of Visualized Experiments. , (2021).</li></ol>

There are several critical surgical steps along with troubleshooting needed to ensure a successful ESLP run. Juvenile porcine lungs are extremely delicate compared to adult human lungs, so the procuring surgeon must be cautious when handling porcine lungs. It is critical to attempt a &#34;no-touch&#34; technique to avoid causing trauma and atelectasis when dissecting out the lungs. &#34;No-touch&#34; means using the bare minimum amount of manual manipulation of the lungs during procurement. Recruitment maneuvers while on...

Lung transplantation (LTx) remains the standard of care for end-stage lung disease1; however, LTx has significant limitations including inadequate donor organ utilization2 and a waitlist mortality of 40%3, which is higher than any other solid organ transplant4,5. Donor organ utilization rates are low (20-30%) due to organ quality concerns. Excessive geographic transportation distance compounded by stringent donor organ acceptance criteria exacerbates these quality concerns. LTx also trails other solid organ transplants in terms of long-term graft and patient outcomes2. Primary graft dysfunction (PGD), most often caused by ischemic reperfusion injury (IRI), represents the leading cause of 30-day mortality and morbidity post-LTx and increases the risk for chronic graft dysfunction6,7. Efforts to decrease IRI and extend safe transport times are paramount to improve patient outcomes.
Ex situ lung perfusion (ESLP) is an innovative technology that has shown promise in attenuating these limitations. ESLP facilitates the preservation, assessment, and reconditioning of donor lungs before transplantation. It has exhibited satisfactory short- and long-term outcomes following transplantation of extended criteria donor (ECD) lungs, contributing to an increase in the number of suitable donor lungs for LTx, with organ utilization rates increasing by 20% in some centres8,9,10. Compared to the current clinical standard for LTx, cold static preservation (CSP), ESLP offers several advantages: organ preservation time is not limited to 6 h, evaluation of organ function is possible before implantation, and due to continuous organ perfusion, modifications can be made to the perfusate that optimizes organ function11.
The vast majority of current ESLP devices designed for human use utilize positive pressure ventilation (PPV); however, recent literature has indicated that this ventilation strategy is inferior to negative pressure ventilation (NPV) ESLP, with PPV inducing more significant ventilator-induced lung injury12,13,14,15. In both human and porcine lungs, NPV-ESLP exhibits superior organ function when compared to positive pressure ex situ lung perfusion (PPV-ESLP) across various physiological domains, including pro-inflammatory cytokine production, pulmonary edema, and bullae formation15. The homogenous distribution of intrathoracic pressure across the entire lung surface in NPV-ESLP has been suggested as a significant factor underlying this advantage15,16. In addition to its pre-clinical benefits, the clinical safety and feasibility of NPV-ESLP have been demonstrated in a recent clinical trial17. Utilizing a novel NPV-ESLP device, twelve extended criteria donor human lungs were successfully preserved, evaluated, and subsequently transplanted with 100% 30-day and 1-year survival.
The objective of the present manuscript is to demonstrate a working protocol of our lab&#39;s NPV-ESLP device using juvenile porcine lungs under normothermic conditions for 12 h of duration. The surgical retrieval is covered in detail, and our custom software platform&#39;s initiation, management, and termination are also described. The strategy for tissue collection and the management of the samples is also explained.

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			<td>0 ETHIBOND Green 1 x 36&#34; Endo Loop 0</td>
			<td>ETHICON</td>
			<td>D8573</td>
			<td></td>
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			<td>2-0 SILK Black 12&#34; x 18&#34; Strands</td>
			<td>ETHICON</td>
			<td>SA77G</td>
			<td></td>
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			<td>ABL 800 FLEX Blood Gas Analyzer</td>
			<td>Radiometer</td>
			<td>989-963</td>
			<td></td>
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			<td>Adult-Pediatric Electrostatic Filter HME - Small</td>
			<td>Covidien</td>
			<td>352/5877</td>
			<td></td>
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			<td>Arterial Filter</td>
			<td>SORIN GROUP</td>
			<td>01706/03</td>
			<td></td>
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		<tr>
			<td>Backhaus Towel Clamp</td>
			<td>Pilling</td>
			<td>454300</td>
			<td></td>
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			<td>Biomedicus Pump</td>
			<td>Maquet</td>
			<td>BPX-80</td>
			<td></td>
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		<tr>
			<td>Cable Ties &#8211; White 12&#8221;</td>
			<td>HUASU International</td>
			<td>HS4830001</td>
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			<td>Calcium Chloride</td>
			<td>Fisher Scientific</td>
			<td>C69-500G</td>
			<td></td>
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			<td>Cooley Sternal Retractor</td>
			<td>Pilling</td>
			<td>341162</td>
			<td></td>
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		<tr>
			<td>CUSHING Gutschdressing Forceps</td>
			<td>Pilling</td>
			<td>466200</td>
			<td></td>
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		<tr>
			<td>D-glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G5767-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Deep Deaver Retractor</td>
			<td>Pilling</td>
			<td>481826</td>
			<td></td>
		</tr>
		<tr>
			<td>Debakey Straight Vascular Tissue Forceps</td>
			<td>Pilling</td>
			<td>351808</td>
			<td></td>
		</tr>
		<tr>
			<td>Debakey-Metzenbaum Dissecting</td>
			<td>Pilling</td>
			<td>342202</td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td>Pilling</td>
			<td>342202</td>
			<td></td>
		</tr>
		<tr>
			<td>Endotracheal Tube 9.0mm CUFD</td>
			<td>Mallinckrodt</td>
			<td>9590E</td>
			<td>Cuff removed for ESLP apparatus</td>
		</tr>
		<tr>
			<td>Flow Transducer</td>
			<td>BIO-PROBE</td>
			<td>TX 40</td>
			<td></td>
		</tr>
		<tr>
			<td>Human Albumin Serum</td>
			<td>Grifols Therapeutics</td>
			<td>2223708</td>
			<td></td>
		</tr>
		<tr>
			<td>Infusion Pump</td>
			<td>Baxter</td>
			<td>AS50</td>
			<td></td>
		</tr>
		<tr>
			<td>Inspire 7 M Hollow Fiber Membrane Oxygenator</td>
			<td>SORIN GROUP</td>
			<td>K190690</td>
			<td></td>
		</tr>
		<tr>
			<td>Intercept Tubing 1/4&#34; x 1/16&#34; x 8&#39;</td>
			<td>Medtronic</td>
			<td>3108</td>
			<td></td>
		</tr>
		<tr>
			<td>Intercept Tubing 3/8&#34; x 3/32&#34; x 6&#39;</td>
			<td>Medtronic</td>
			<td>3506</td>
			<td></td>
		</tr>
		<tr>
			<td>Intercept Tubing Connector 3/8&#34; x 1/2&#34;</td>
			<td>Medtronic</td>
			<td>6013</td>
			<td></td>
		</tr>
		<tr>
			<td>MAYO Dissecting Scissors</td>
			<td>Pilling</td>
			<td>460420</td>
			<td></td>
		</tr>
		<tr>
			<td>Medical Carbon Dioxide Tank</td>
			<td>Praxair</td>
			<td>5823115</td>
			<td></td>
		</tr>
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			<td>Medical Nitrogen Tank</td>
			<td>Praxair</td>
			<td>NI M-K</td>
			<td></td>
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		<tr>
			<td>Medical Oxygen Tank</td>
			<td>Praxair</td>
			<td>2014408</td>
			<td></td>
		</tr>
		<tr>
			<td>Organ Chamber</td>
			<td>Tevosol</td>
			<td></td>
			<td></td>
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		<tr>
			<td>PlasmaLyte A</td>
			<td>Baxter</td>
			<td>TB2544</td>
			<td></td>
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		<tr>
			<td>Poole Suction Tube</td>
			<td>Pilling</td>
			<td>162212</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium Phosphate</td>
			<td>Fischer Scientific</td>
			<td>P285-500G</td>
			<td></td>
		</tr>
		<tr>
			<td>Scale</td>
			<td>TANITA</td>
			<td>KD4063611</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicon Support Membrane</td>
			<td>Tevosol</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Bicarbonate</td>
			<td>Sigma-Aldrich</td>
			<td>792519-1KG</td>
			<td></td>
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		<tr>
			<td>Sodium Chloride 0.9%</td>
			<td>Baxter</td>
			<td>JB1324</td>
			<td></td>
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			<td>Sorin XTRA Cell Saver</td>
			<td>SORIN GROUP</td>
			<td>75221</td>
			<td></td>
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			<td>Sternal Saw</td>
			<td>Stryker</td>
			<td>6207</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical Electrocautery Device</td>
			<td>Kls Martin</td>
			<td>ME411</td>
			<td></td>
		</tr>
		<tr>
			<td>Temperature Sensor probe</td>
			<td>Omniacell Tertia Srl</td>
			<td>1777288F</td>
			<td></td>
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			<td>THAM Buffer</td>
			<td>Thermo Fisher Scientific</td>
			<td>15504020</td>
			<td>made from UltraPureTM Tris</td>
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		<tr>
			<td>TruWave Pressure Transducer</td>
			<td>Edwards</td>
			<td>VSYPX272</td>
			<td></td>
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			<td>Two-Lumen Central Venous Catheter 7fr</td>
			<td>Arrowg+ard</td>
			<td>CS-12702-E</td>
			<td></td>
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		<tr>
			<td>Vorse Tubing Clamp</td>
			<td>Pilling</td>
			<td>351377</td>
			<td></td>
		</tr>
		<tr>
			<td>Willauer-Deaver Retractor</td>
			<td>Pilling</td>
			<td>341720</td>
			<td></td>
		</tr>
		<tr>
			<td>Yankauer Suction Tube</td>
			<td>Pilling</td>
			<td>162300</td>
			<td></td>
		</tr>
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</table>

normothermic negative pressure ventilation ex situ lung perfusion: evaluation of lung function and metabolism

Lung transplantation (LTx) remains the standard of care for end-stage lung disease. A shortage of suitable donor organs and concerns over donor organ quality exacerbated by excessive geographic transportation distance and stringent donor organ acceptance criteria pose limitations to current LTx efforts. Ex situ lung perfusion (ESLP) is an innovative technology that has shown promise in attenuating these limitations. The physiologic ventilation and perfusion of the lungs outside of the inflammatory milieu of the donor body affords ESLP several advantages over traditional cold static preservation (CSP). There is evidence that negative pressure ventilation (NPV) ESLP is superior to positive pressure ventilation (PPV) ESLP, with PPV inducing more significant ventilator-induced lung injury, pro-inflammatory cytokine production, pulmonary edema, and bullae formation. The NPV advantage is perhaps due to the homogenous distribution of intrathoracic pressure across the entire lung surface. The clinical safety and feasibility of a custom NPV-ESLP device have been demonstrated in a recent clinical trial involving extender criteria donor (ECD) human lungs. Herein, the use of this custom device is described in a juvenile porcine model of normothermic NPV-ESLP over a 12 h duration, paying particular attention to management techniques. Pre-surgical preparation, including ESLP software initialization, priming, and de-airing of the ESLP circuit, and the addition of anti-thrombotic, anti-microbial, and anti-inflammatory agents, is specified. The intraoperative techniques of central line insertion, lung biopsy, exsanguination, blood collection, cardiectomy, and pneumonectomy are described. Furthermore, particular focus is paid to anesthetic considerations, with anesthesia induction, maintenance, and dynamic modifications outlined. The protocol also specifies the custom device's initialization, maintenance, and termination of perfusion and ventilation. Dynamic organ management techniques, including alterations in ventilation and metabolic parameters to optimize organ function, are thoroughly described. Finally, the physiological and metabolic assessment of lung function is characterized and depicted in the representative results.

At the beginning of lung perfusion and ventilation (preservation mode), the lungs will generally have a low pulmonary artery pressure (&#60; 10 mmHg) and low dynamic compliance (&#60; 10 mL/mmHg) as the perfusate warms to normothermia. Yorkshire pigs weighing 35-50 kg typically results in lungs weighing 350-500 g. During the first hour of NPV-ESLP, the measured expiratory tidal volumes (TVe) are 0-2 mL/kg, and the inspiratory tidal volumes (TVi) are 100-200 mL. TVe generally reaches 4-6 mL/kg within 3-6 h, and after that...

Watch this Scientific Journal Video about Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism at JoVE.com

Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism

This paper describes a porcine model of negative pressure ventilation ex situ lung perfusion, including procurement, attachment, and management on the custom-made platform. Focus is made on anesthetic and surgical techniques, as well as troubleshooting.

Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism

Lung transplantation (LTx) remains the standard of care for end-stage lung disease. A shortage of suitable donor organs and concerns over donor organ ...

Dr.Darren Freed created this ESLP device, and it uses patented negative pressure ventilation technology and software, which can't be seen anywhere else in the field of ESLP research. Our lab has previously shown that negative pressure ventilation causes less lung injury during ESLP compared to positive pressure ventilation. This is likely due to the more physiologic mechanism of negative pressure ventilation.This device and protocol are designed to extend the safe preservation time of donor lungs and to recondition marginal lungs to acceptable transplant standards. The device itself is very simple to operate. The greatest challenge is surgically removing the juvenile pig lungs without causing any injury.They're extremely fragile compared to adult human lungs. Begin by maintaining the expiratory tidal volume of 10 milliliters per kilogram by increasing the peak pressures for maximum alveolar recruitment. Perform a midline sternotomy.Use electrocautery to incise the skin and subcutaneous tissue. Bluntly dissect the soft tissue attachments from the posterior table of the inferior sternum. Use a sternal saw to divide the sternum.Insert a sternal retractor and open wide. After performing the cardiectomy, open and remove the mediastinal pleura bilaterally to expose the lungs. Then divide the pleural attachments from the diaphragm toward the left lower lung lobe, using a Deaver retractor to hold the diaphragm upwards.Now, divide the inferior pulmonary ligament on the left and continue up toward the hilum. Next, divide the inferior vena cava and pleural attachments from the diaphragm, and then retract the diaphragm upwards using the Deaver retractor. Divide the inferior pulmonary ligament on the right side and continue up towards the hilum.Then divide the innominate vein and arch vessels to expose the trachea. After bluntly dissecting the tissue surrounding the trachea, clamp the trachea using a tubing clamp at maximal inhalation, ensuring the expiratory tidal volume is 10 milliliters per kilogram. Transect the trachea and lift the clamp portion upwards to provide surgical traction.Then dissect the posterior trachea from the esophagus using blunt dissection with heavy Metzenbaum scissors and a free hand. Divide any remaining pleural attachments. Transect the aorta above and below the left bronchus and remove the lungs from the chest with a segment of descending aorta.After weighing the lungs with the clamp, quickly store them in a cooler full of ice. Begin by adding 500 milliliters of packed red blood cells to the perfusion circuit to reach a final volume of 1.5 liters of perfusate. Take photographs of the lungs for data records.For the lung biopsy, encircle a one cubic centimeter portion with zero silk suture and tie it. Then excise this tied portion, using scissors for tissue analysis as described in the text manuscript, and divide the biopsy segment. Next, to secure the 3/8 half-inch tubing adapter to the main pulmonary artery, grasp the opposite sides of the main pulmonary artery using forceps or snaps.Then, insert the adapter with the half-inch portion into the main pulmonary artery and hold it in place while simultaneously securing the adapter in position using zero silk or Ethibond ties. Now place the lungs in a supine position on the silicone support membrane and connect them to the ESLP device. Place a second tubing clamp on the trachea near the location of the tracheal bronchus.After removing the more distal clamp, intubate the trachea with the endotracheal tube and secure it in position using two zip ties. Then clamp the ventilation line using a tubing clamp before releasing the proximal clamp from the trachea. Connect the pulmonary artery adapter to the pulmonary artery line.Once the main pulmonary artery is de-aired, start the time for perfusion. On the settings page, click start heater and set the temperature to 38 degrees Celsius. Enter the pig's weight to calculate cardiac output flow.On the main page, set the continuous positive airway pressure to 20 centimeters of water and click start continuous positive airway pressure. When ventilation begins, unclamp the ventilation line. After zeroing the arterial pressure sensor, clamp the pulmonary artery line above the pressure sensor with the tubing clamp.Open the sensor, click zero pulmonary artery pressure and zero blood flow on the settings page and confirm the readings are zeroed on the main page. Close the pressure sensor stopcock to read the line pressure. Open the line to the pulmonary artery cannula.Select 10%cardiac output on the main page. Click return to PA Manual and unclamp the pulmonary line. Switch the perfusate solution in the top lid before securing it to the machine to prevent condensation formation during ESLP.Draw 10 milliliters of perfusate for centrifugal analysis and draw a time zero arterial blood gas. Place the sample on ice before centrifugation. Once the lungs have been perfused for 10 minutes, increase the flow to 20%of the cardiac output.When the perfusate temperature reaches 32 degrees Celsius, secure the chamber lid in place with clamps to create an airtight seal. Ensure that the lungs are optimally positioned and the air leaks are repaired. With the lid secure, clamp the ventilation tubing before turning off continuous positive airway pressure.On the settings page, select zero intrathoracic pressure, airway pressure, and airflow. Then confirm readings are zeroed on the main page. Click start CPAP before unclamping the ventilation tubing.Set the ventilation parameters mentioned in the text manuscript and click press to start vent to activate negative pressure ventilation. Attach the sideport ventilation tubing to the chamber. Over the next few breaths, maintain the ventilation parameters as mentioned in the text manuscript.After 10 minutes of perfusion, increase the flow to 20%and after 20 minutes of perfusion, increase the flow to 30%cardiac output. Add dextrose and insulin to the system. Evaluate lung function, using 50%cardiac output and a deoxygenating mixed sweep gas over a five minute duration, as per the manuscript instructions.At every odd hour during preservation mode, draw a 10 milliliters sample of perfusate for future analysis. Draw one milliliter of pre-deoxygenator arterial blood gas sample every hour and from pre and post deoxygenator ports following five minutes of evaluation mode. The trends in mean pulmonary artery pressure, dynamic compliance, and pulmonary vascular resistance over 12 hours of perfusion and ventilation can be affected by the specific ESLP experimental protocol employed.A typical trend for the ratio of partial pressure of arterial oxygen and fraction of inspired oxygen at the evaluation time points of five and 11 hours throughout negative pressure ventilation ex-situ lung perfusion is demonstrated here. Edema formation is another important index of inflammation associated with endothelial permeability, demonstrating a typical weight gain of 30%at the end of 12 hours of negative pressure ventilation ex-situ lung perfusion. The perfusate acts as a surrogate indicator of overall lung status.Therefore, blood gas analysis of the perfusate provides extensive information on the metabolic state of the lungs. During the evaluation model of ESLP, which occurs at three, five, seven, nine, and 11 hours during a 12 hour run, an upward trend in left arterial partial pressure of oxygen is observed. It's very important to be as gentle as possible when surgically removing the lungs and to also move quickly and efficiently.The establishment of this device, protocol, and lab has led to a successful clinical trial and several discoveries that prolong the preservation and reconditioning of donor lungs.

normothermic-negative-pressure-ventilation-ex-situ-lung-perfusion

Research

JoVE Journal

Medicine

1.9K visualizações.  University of Alberta. O Dr. Darren Freed criou este dispositivo ESLP, e ele usa tecnologia patenteada de ventilação por pressão negativa e software, que não pode ser visto em nenhum outro lugar no campo da pesquisa ESLP. Nosso laboratório já demonstrou que a ventilação com pressão negativa causa menos lesão pulmonar durante a PSLV em comparação com a ventilação com pressão positiva. Isso provavelmente se deve ao mecanismo mais fisiológico da ventilação com pressão negativa.Este dispositiv...