{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,24]],"date-time":"2026-10-24T15:36:10Z","timestamp":1792856170452,"version":"4.5.0"},"reference-count":31,"publisher":"American Veterinary Medical Association (AVMA)","license":[{"start":{"date-parts":[[2023,9,5]],"date-time":"2023-09-05T00:00:00Z","timestamp":1693872000000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2023,9,5]]},"abstract":"<jats:title>Abstract<\/jats:title>\n<jats:sec id=\"sc_a1\">\n<jats:title>OBJECTIVE<\/jats:title>\n<jats:p>To elucidate the cardiovascular effects of escalating doses of phenylephrine and norepinephrine in dogs receiving acepromazine and isoflurane.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sc_a2\">\n<jats:title>ANIMALS<\/jats:title>\n<jats:p>8 beagles aged 1 to 2 years (7.4 to 11.2 kg).<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sc_a3\">\n<jats:title>METHODS<\/jats:title>\n<jats:p>All dogs received acepromazine 0.01 mg\/kg, propofol 4 to 5 mg\/kg, and isoflurane and were mechanically ventilated. Mean arterial pressure (MAP) from a femoral artery catheter and continuous electrocardiogram were recorded. Cardiac output (CO) was measured with transpulmonary thermodilution. Systemic vascular resistance (SVR), global end-diastolic volume (GEDV), and global ejection fraction (GEF) were subsequently calculated. Phenylephrine and norepinephrine were infused in random order at 0.07, 0.3, 0.7, and 1.0 \u03bcg\/kg\/min. All variables were measured after 15 minutes of each infusion rate. The effects of dose, agent, and their interaction on the change of each variable were evaluated with mixed-effect models. A <jats:italic>P<\/jats:italic> &lt; .05 was used for significance.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sc_a4\">\n<jats:title>RESULTS<\/jats:title>\n<jats:p>Atrial premature complexes occurred in 3 dogs during norepinephrine infusion at doses of 0.3, 0.7, and 1 \u03bcg\/kg\/min; no dysrhythmias were seen with phenylephrine administration. MAP increased during dose escalation (<jats:italic>P<\/jats:italic> &lt; .0001) within each agent and did not differ between agents (<jats:italic>P<\/jats:italic> = .6). The decrease in HR was greater for phenylephrine (<jats:italic>P<\/jats:italic> &lt; .0001). Phenylephrine decreased CO and GEF and increased GEDV and SVR (all <jats:italic>P<\/jats:italic> &lt; .03). Norepinephrine decreased the SVR and increased CO, GEDV, and GEF (all <jats:italic>P<\/jats:italic> &lt; .03).<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sc_a5\">\n<jats:title>CLINICAL RELEVANCE<\/jats:title>\n<jats:p>Our results confirm that phenylephrine increases arterial pressures mainly through vasoconstriction in acepromazine-premedicated dogs while norepinephrine, historically considered a vasopressor, does so primarily through an increase in inotropism.<\/jats:p>\n<\/jats:sec>","DOI":"10.2460\/ajvr.23.06.0147","type":"journal-article","created":{"date-parts":[[2023,9,1]],"date-time":"2023-09-01T12:50:52Z","timestamp":1693572652000},"page":"1-7","source":"Crossref","is-referenced-by-count":6,"title":["Phenylephrine and norepinephrine increase blood pressure through opposing physiologic mechanisms in isoflurane-anesthetized dogs receiving acepromazine"],"prefix":"10.2460","author":[{"given":"Cheyenne J.","family":"Cannarozzo","sequence":"first","affiliation":[{"name":"Cornell University Hospital for Animals, College of Veterinary Medicine, Cornell University, Ithaca, NY"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joaquin","family":"Araos","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manuel","family":"Martin-Flores","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1272","reference":[{"key":"B1","series-title":"Ann Transl Med. 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