Infusing oleic acid continuously into the pulmonary artery of an anesthetized adult pig induces acute respiratory failure, enabling controlled experimentation during acute respiratory decompensation.
This protocol outlines an acute respiratory distress model utilizing centrally administered oleic acid infusion in Yorkshire pigs. Prior to experimentation, each pig underwent general anesthesia, endotracheal intubation, and mechanical ventilation, and was equipped with bilateral jugular vein central vascular access catheters. Oleic acid was administered through a dedicated pulmonary artery catheter at a rate of 0.2 mL/kg/h. The infusion lasted for 60-120 min, inducing respiratory distress. Throughout the experiment, various parameters including heart rate, respiratory rate, arterial blood pressure, central venous pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, end-tidal carbon dioxide, peak airway pressures, and plateau pressures were monitored. Around the 60 min mark, decreases in partial arterial oxygen pressure (PaO2) and fraction of oxygen-saturated hemoglobin (SpO2) were observed. Periodic hemodynamic instability, accompanied by acute increases in pulmonary artery pressures, occurred during the infusion. Post-infusion, histological analysis of the lung parenchyma revealed changes indicative of parenchymal damage and acute disease processes, confirming the effectiveness of the model in simulating acute respiratory decompensation.
The utilization of porcine models in translational research holds significant importance in advancing our understanding of human medicine1. Porcine models, due to their physiological and anatomical similarities to humans, provide a valuable platform for studying complex diseases and therapeutic interventions1. In the context of acute respiratory failure, porcine models offer a unique opportunity to investigate the pathophysiological mechanisms, evaluate treatment strategies, and assess potential interventions1,2,3. The ability to replicate key aspects of human respiratory physiology and responses to various stimuli in porcine models allows for a comprehensive evaluation of therapeutic modalities before progressing to human trials1,2,3. This research paradigm enables researchers to bridge the gap between preclinical investigations and clinical application, facilitating the development of novel therapies and improving patient outcomes1. Therefore, the establishment of an efficient, effective, and reproducible acute respiratory failure porcine model serves as a crucial tool in advancing the knowledge of respiratory diseases and guiding the development of effective interventions in human medicine1.
Respiratory distress, a critical medical condition, has witnessed limited advancements in its diagnosis and management over the past three decades4. The currently employed evaluation and triage metrics, which include subjective symptoms, physical examination findings, SpO2, and respiratory rate, often exhibit limitations in detecting acute pulmonary conditions at an early stage5,6,7. This inadequacy not only hampers efficient triage and resource allocation but also fails to provide effective, quantitative monitoring of disease progression and treatment response in patients with chronic pulmonary diseases. The emerging landscape of chronic respiratory conditions, such as long COVID, along with the burden of acute respiratory insufficiencies on hospital resources, underscores the urgent need to expand translational research and foster innovation in respiratory disease management.
The direct infusion of oleic acid into a pig's bloodstream has been recognized as a robust method to induce acute respiratory distress8. Oleic acid, a monounsaturated fatty acid, has demonstrated the ability to trigger significant pulmonary injury and compromise respiratory function when introduced into the pulmonary circulation8. Upon infusion, oleic acid provokes vasoconstriction, resulting in increased pulmonary arterial pressure and resistance, leading to impaired gas exchange and oxygenation9. Furthermore, oleic acid promotes the activation of inflammatory pathways, including the release of pro-inflammatory mediators and recruitment of immune cells, which contribute to the development of lung injury and respiratory distress10. All of this results in severe hypoxemia, increases in pulmonary arterial pressures, and the accumulation of extravascular lung water11. Histological evaluation of the lung parenchyma has demonstrated injury that is indistinguishable from human acute respiratory distress9.
This article details a method involving the direct administration of oleic acid into the pulmonary artery to induce acute respiratory distress, avoiding untreatable, severe hemodynamic compromise. The described method is anticipated to be a valuable tool for future researchers exploring the underlying pathophysiological mechanisms of acute respiratory failure and assessing potential therapeutic interventions and innovations.
The key element in this protocol is to closely monitor the hemodynamic condition of the pig during the administration of oleic acid to induce respiratory distress15. It is of the utmost importance for researchers to take the necessary time to appropriately position the hemodynamic monitoring devices. One specific drawback of this model is the potential hemodynamic instability that may arise as a result of inflammation and injury to the respiratory vasculature8,<s…
The authors have nothing to disclose.
The authors would like to thank Dr. José A. Diaz, Jamie Adcock, Mary Susan Fultz and the S.R. Light Laboratory at Vanderbilt University Medical Center for their assistance and support. This work was supported by a grant from the National Heart, Lung, and Blood Institute of the National Institutes of Health (BA; R01HL148244). The content is the sole responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
1% Isoflurane | Primal, Boston, MA, USA | 26675-46-7 | https://www.sigmaaldrich.com/US/en/product/aldrich/792632?gclid=Cj0KCQjw9fqnBhDSARIsAHl cQYS_W-q6tS2s6LQw2Qn7Roa3T GIpTLPf52351vrhgp44foEcRozPqt YaAtvfEALw_wcB |
Arterial Catheter | Merit Medical, South Jordan, UT, USA | MAK401 | MAK Mini Access Kit 4F |
Blood Pressure Amp | AD Instruments, Colorado Springs, CO, USA | FE117 | https://www.adinstruments.com/products/bp-blood-pressure-amp |
Central Venous Catheter | Arrow International, Cleveland, OH, USA | AK-09800 | 8.5 Fr. x 4" (10 cm) Arrow-Flex |
Disposable Pressure Transducers | AD Instruments, Colorado Springs, CO, USA | MLT0670 | https://www.adinstruments.com/products/disposable-bp-transducers |
Edwards Lifesciences Triple Stage Venous Cannulas | Edwards Life Sciences, Irvine, CA | TF293702 | https://www.graylinemedical.com/products/edwards-lifesciences-triple-stage-venous-cannulas-venous-dual-stage-cannula-tf293702?variant=31851942576185&gad=1& gclid=Cj0KCQiAr8eqBhD3ARIsAIe -buNdmkzavUBaIx-1be7boWn2kW hbUR6QCjaobB08uuK9qJW66JvY TM4aAufGEALw_wcB |
Kelly Scissors | MPM Medical Supply, Freehold, NJ 07728 | 104-5516 | https://www.mpmmedicalsupply.com/products/kelly-scissors |
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Ketamine Hydrochloride 100 mg/mL, Injectable Solution, 10 mL | Patterson Veterinary, Loveland, CO 80538 | 07-894-8462 | https://www.pattersonvet.com/ProductItem/078948462?omni=ketamine |
LabChart 8 software | AD Instruments, Colorado Springs, CO, USA | N/A | https://www.adinstruments.com/products/labchart |
Lahey Retractor | BOSS Instruments LTD, Gordonsville, VA 22942 | 18-1210 | https://bossinstruments.com/product/7-3-4-lahey-thyroid-retractor-6mmx28mm/ |
Oleic Acid | Sigma-Aldrich, Merck, Darmstadt, Germany | O1008 | https://www.sigmaaldrich.com/US/en/product/sial/o1008?gclid=CjwKCAjwzJmlBhBBEiwAEJy Lu2047wRpXqF_Z2BegUyhgZJ _WygsWfErhgrGCIyMp8PxwNH sTZ8qARoCl1QQAvD_BwE&gcl src=aw.ds |
Peripheral IV Catheter Angiocath 18-24 G 1.16 inch | McKesson, Irving, TX, USA | 329830 | https://mms.mckesson.com/product/329830/Becton-Dickinson-381144 |
Piezoelectrode | MuRata Manuractoring Co, Ltd., Nagaokakyo, Kyoto, Japan | 7BB-12-9 | https://www.murata.com/en-us/products/productdetail?partno=7BB-12-9 |
PlasmaLyte | Baxter International, Deerfield, IL, USA | 2B2544X | https://www.ciamedical.com/baxter-2b2544x-each-solution-plasma-lyte-a-inj-ph-7-4-1000ml |
Pulmonary Artery Catheter | Edwards Life Sciences, Irvine, CA | 131F7 | Swan Ganz 7F x 110cm |
Standard Endotracheal Tubes | Teleflex, Morrisville, NC 27560 | 5-10313 | https://www.teleflex.com/usa/en/product-areas/anesthesia/airway-management/endotracheal-tubes/standard-tubes/index.html |
SurgiVet Clearview Foley Catheter, 8 Fr, 55 cm Silicone | Penn Veterinary Supply, Inc, West Rendering, PN 13971 | SVCFC1030 | https://www.pennvet.com/customer/portal/catalog/home?urile=wcm:path%3APennVet+Catalog/Super+Sku+Catalog/SS0672/Surgivet+Clearview+Silicone+Foley+Catheters |
Telazol (Tiletamine HCl and Zolazepam HCl), Injectable Solution, 5 mL | Patterson Veterinary, Loveland, CO 80538 | 07-801-4969 | https://www.pattersonvet.com/ProductItem/078014969?omni=telazol |
Welch Allyn E-MacIntosh Standard Laryngoscope Blade | MFIMedical, San Diego, CA 92131 | WLA-69242 | https://mfimedical.com/products/welch-allyn-e-macintosh-standard-laryngoscope-blade?variant=12965771870285¤cy =USD&utm_medium=product_sync &utm_source=google&utm_content =sag_organic&utm_campaign=sag _organic&gclid=Cj0KCQiAr8eqBhD 3ARIsAIe-buMhpgM96qRXkCUKA 6Mhmdat0p93JbecCGTaLStexhV pkUVa9VkWUzgaAr-iEALw_wcB |
Xylazine HCl 100 mg/mL, Injectable Solution, 50 mL | Patterson Veterinary, Loveland, CO 80538 | 07-894-5244 | https://www.pattersonvet.com/ProductItem/078945244 |
Yorkshire Pigs | Oak Hill Genetics, Ewing, IL, USA | 138274 | Female/Male Swine- Yorkshire/Landrace 81-100lbs |
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