{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T09:01:43Z","timestamp":1789722103869,"version":"4.0.1"},"reference-count":39,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T00:00:00Z","timestamp":1783900800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>The immediate cardiorespiratory responses to etorphine immobilization and reversal with naltrexone in wildlife are underexplored.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>To evaluate the early cardiorespiratory changes after etorphine immobilization and reversal with naltrexone in sheep, as a model for wild ungulates.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Six sheep instrumented with electrical impedance tomography (EIT) belt, arterial and pulmonary arterial catheters were immobilized with intramuscular etorphine (0.05\u202fmg\u202fkg\n                      <jats:sup>\u22121<\/jats:sup>\n                      ) and reversed with intravenous naltrexone (1\u202fmg\u202fkg\n                      <jats:sup>\u22121<\/jats:sup>\n                      ) 26\u202fmin later. Mean pulmonary arterial pressure (MPAP) and EIT derived variables (minute tidal impedance variation-TIV\n                      <jats:sub>MIN<\/jats:sub>\n                      ; tidal impedance variation\u2013TIV; respiratory rate\u2013RR; end-expiratory lung impedance-EELI) were recorded continuously from 5\u202fmin before to 10\u202fmin after each drug. Arterial blood gasses were drawn at baseline and 5\u202fmin after each drug. Statistical analysis was performed in R to determine the timing of significant deviations from baseline, defined as the mean of the 5\u202fmin preceding drug administration, and compared with each minute thereafter. Post-administration values were expressed as ratios to baseline and analyzed using two-sided one-sample\n                      <jats:italic>t<\/jats:italic>\n                      -tests with False Discovery Rate (FDR) correction at 10% for multiple comparisons; FDR-adjusted\n                      <jats:italic>p<\/jats:italic>\n                      -values (\n                      <jats:italic>q<\/jats:italic>\n                      -values)\u202f&amp;lt;\u202f0.10 were considered significant.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      Three minutes after etorphine, MPAP increased (\n                      <jats:italic>q<\/jats:italic>\n                      \u202f=\u202f0.08, median 42%), accompanied by a decrease in TIV\n                      <jats:sub>MIN<\/jats:sub>\n                      (\n                      <jats:italic>q<\/jats:italic>\n                      \u202f=\u202f0.09, median 40.9%) due to decrease in TIV and RR. Arterial blood gasses confirmed hypoxemia (PaO\u2082 median [range]: 57.1 [26.9\u201393.6] mmHg) and hypercapnia (PaCO\u2082 49.45 [40\u201361.3] mmHg). Conversely, regional ventilation distribution and EELI remained unchanged. One minute after naltrexone, median RR (\n                      <jats:italic>q<\/jats:italic>\n                      \u202f=\u202f0.04) and TIV\n                      <jats:sub>MIN<\/jats:sub>\n                      (\n                      <jats:italic>q<\/jats:italic>\n                      \u202f=\u202f0.05) increased by 119.3 and 223.6% from baseline respectively, followed by increase in TIV from minute 4 (\n                      <jats:italic>q<\/jats:italic>\n                      \u202f=\u202f0.06, median 50.8%). Arterial blood gasses improved marginally (PaO\u2082 63.5 [48.6\u2013115.7] mmHg; PaCO\u2082 46 [41.5\u201352.4] mmHg) while MPAP did not return toward baseline.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Etorphine immobilization caused early pulmonary hypertension followed by progressive hypoventilation without ventilation redistribution. Naltrexone rapidly restored ventilation, whereas pulmonary vascular effects persisted.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fvets.2026.1850859","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T04:23:20Z","timestamp":1783916600000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Early cardiovascular and respiratory changes after etorphine immobilization and naltrexone reversal in sheep"],"prefix":"10.3389","volume":"13","author":[{"given":"Anna","family":"Binetti","sequence":"first","affiliation":[{"name":"Anaesthesiology and Intensive Care, Clinical Centre for Small Animals, Clinical Department for Small Animals and Horses, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hathaipat","family":"Rattanathanya","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Friederike","family":"Pohlin","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ulrike","family":"Auer","sequence":"additional","affiliation":[{"name":"Anaesthesiology and Intensive Care, Clinical Centre for Small Animals, Clinical Department for Small Animals and Horses, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J. Peter","family":"Schramel","sequence":"additional","affiliation":[{"name":"Anaesthesiology and Intensive Care, Clinical Centre for Small Animals, Clinical Department for Small Animals and Horses, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marlies","family":"Dolezal","sequence":"additional","affiliation":[{"name":"Platform for Bioinformatics and Biostatistics, Department of Biological Sciences and Pathobiology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Szilvia","family":"Kalogeropoulu","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cosima L.","family":"G\u00f6sele","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa","family":"Stahl","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lisa J.","family":"Ebenhofer","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christina","family":"Braun","sequence":"additional","affiliation":[{"name":"Anaesthesiology and Intensive Care, Clinical Centre for Small Animals, Clinical Department for Small Animals and Horses, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gabrielle","family":"Stalder","sequence":"additional","affiliation":[{"name":"Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martina","family":"Mosing","sequence":"additional","affiliation":[{"name":"Anaesthesiology and Intensive Care, Clinical Centre for Small Animals, Clinical Department for Small Animals and Horses, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"key":"ref1","first-page":"391","article-title":"Opioids in zoological 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