{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T21:16:42Z","timestamp":1792790202851,"version":"4.5.0"},"reference-count":43,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2025,11,16]],"date-time":"2025-11-16T00:00:00Z","timestamp":1763251200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Arden and Claudia Sims Colic Research Fund"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>Dexmedetomidine improves pulmonary function in dogs and humans, but evidence in horses is scarce. This study evaluated dexmedetomidine infusion on oxygenation and respiratory mechanics in anesthetized horses. Twenty horses undergoing elective surgery were included in a prospective, non-randomized, observational study. Horses received either lidocaine alone (1.3 mg\/kg over 15 min, then 3 mg\/kg\/hour; LIDO) or combined with dexmedetomidine (1.75 \u03bcg\/kg over 15 min, then 1.75 \u03bcg\/kg\/hour; DL). Respiratory mechanics, gas exchange, and cardiovascular variables were recorded at baseline, post-loading, and after 30, 60, and 90 min. Data were analyzed using mixed-effects linear models with horse as a random effect and time and treatment and their interaction as fixed effects (p \u2264 0.05). Peak inspiratory pressure increased over time with both treatments but was lower with DL at 90 min (\u22121.26 mmHg, p = 0.046). There was no evidence that arterial oxygen pressure or oxygenation ratio improved over time with DL (p &gt; 0.75). Shunt fraction did not significantly change over time or between treatments (Wald \u03c72 = 4.77, p = 0.85). Heart rate with DL decreased from baseline (p \u2264 0.001) but remained higher than LIDO overall (p = 0.001). Dexmedetomidine infusion showed no benefit on oxygenation or respiratory mechanics in anesthetized horses.<\/jats:p>","DOI":"10.3390\/vetsci12111089","type":"journal-article","created":{"date-parts":[[2025,11,17]],"date-time":"2025-11-17T10:24:58Z","timestamp":1763375098000},"page":"1089","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Effects of Lidocaine Alone Versus Lidocaine\u2013Dexmedetomidine Infusion on Pulmonary Gas Exchange and Respiratory Mechanics During Isoflurane Anesthesia in Horses"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-5052-7706","authenticated-orcid":false,"given":"Ludovica","family":"Chiavaccini","sequence":"first","affiliation":[{"name":"Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0003-3053-5567","authenticated-orcid":false,"given":"Raiane A.","family":"Moura","sequence":"additional","affiliation":[{"name":"Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-9132-0714","authenticated-orcid":false,"given":"Tatiana Moreira Batista P. R.","family":"Azevedo","sequence":"additional","affiliation":[{"name":"Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-9735-8633","authenticated-orcid":false,"given":"Chiara","family":"De Gennaro","sequence":"additional","affiliation":[{"name":"Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1664-6135","authenticated-orcid":false,"given":"Enzo","family":"Vettorato","sequence":"additional","affiliation":[{"name":"Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-5072-6893","authenticated-orcid":false,"given":"Marta","family":"Romano","sequence":"additional","affiliation":[{"name":"Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1796-9710","authenticated-orcid":false,"given":"Diego A.","family":"Portela","sequence":"additional","affiliation":[{"name":"Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,11,16]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1111\/vaa.12285","article-title":"Twenty years later: A single-centre, repeat retrospective analysis of equine perioperative mortality and investigation of recovery quality","volume":"43","author":"Dugdale","year":"2016","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Gozalo-Marcilla, M., Bettschart-Wolfensberger, R., Johnston, M., Taylor, P.M., and Redondo, J.I. (2021). Data Collection for the Fourth Multicentre Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4) Study: New Technology and Preliminary Results. Animals, 11.","DOI":"10.3390\/ani11092549"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.vaa.2023.10.032","article-title":"The influence of hypoxaemia, hypotension and hypercapnia (among other factors) on quality of recovery from general anaesthesia in horses","volume":"51","author":"Meier","year":"2024","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1055","DOI":"10.1111\/evj.13541","article-title":"Risk factors associated with hypoxaemia in horses undergoing general anaesthesia: A retrospective study","volume":"54","author":"Hovda","year":"2021","journal-title":"Equine Vet. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"369","DOI":"10.1111\/jvp.12855","article-title":"Pharmacokinetics and clinical effects of xylazine and dexmedetomidine in horses recovering from isoflurane anesthesia","volume":"43","author":"Guedes","year":"2020","journal-title":"J. Vet. Pharmacol. Ther."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1111\/vaa.12196","article-title":"Partial intravenous anaesthesia in the horse: A review of intravenous agents used to supplement equine inhalation anaesthesia. Part 2: Opioids and alpha-2 adrenoceptor agonists","volume":"42","author":"Gasthuys","year":"2015","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Ru\u00edz-L\u00f3pez, P., Cuypers, C., and Schauvliege, S. (2023). Xylazine Infusion during Equine Colic Anesthesia with Isoflurane and Lidocaine: A Retrospective Study. Animals, 13.","DOI":"10.3390\/ani13182902"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"624","DOI":"10.1016\/j.vaa.2022.07.004","article-title":"Effects of detomidine or romifidine during maintenance and recovery from isoflurane anaesthesia in horses","volume":"49","author":"Alonso","year":"2022","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1111\/jvp.12474","article-title":"Is there a place for dexmedetomidine in equine anaesthesia and analgesia? A systematic review (2005\u20132017)","volume":"41","author":"Gasthuys","year":"2018","journal-title":"J. Vet. Pharmacol. Ther."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1016\/j.vaa.2019.04.013","article-title":"Plasma concentrations at two dexmedetomidine constant rate infusions in isoflurane anaesthetized horses: A clinical study","volume":"46","author":"Bettembourg","year":"2019","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"38","DOI":"10.1111\/j.1467-2995.2011.00669.x","article-title":"Pharmacokinetics and pharmacodynamics of intravenous medetomidine in the horse","volume":"39","author":"Grimsrud","year":"2012","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1111\/jvp.12157","article-title":"The pharmacokinetics of dexmedetomidine administered as a constant rate infusion in horses","volume":"38","author":"Ranheim","year":"2015","journal-title":"J. Vet. Pharmacol. Ther."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Xiong, W., Zhou, R., Qu, Y., Yang, Y., Wang, Z., Song, N., Liang, R., and Qian, J. (2021). Dexmedetomidine preconditioning mitigates myocardial ischemia\/reperfusion injury via inhibition of mast cell degranulation. Biomed. Pharmacother., 141.","DOI":"10.1016\/j.biopha.2021.111853"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"569","DOI":"10.1111\/evj.13337","article-title":"Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses","volume":"53","author":"VanderBroek","year":"2021","journal-title":"Equine Vet. J."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"K\u00f6nig, K.S., Verhaar, N., Hopster, K., Pfarrer, C., Neudeck, S., Rohn, K., and K\u00e4stner, S.B.R. (2020). Ischaemic preconditioning and pharmacological preconditioning with dexmedetomidine in an equine model of small intestinal ischaemia-reperfusion. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0224720"},{"key":"ref_16","first-page":"14741","article-title":"Dexmedetomidine alleviates the spinal cord ischemia-reperfusion injury through blocking mast cell degranulation","volume":"8","author":"Ma","year":"2015","journal-title":"Int. J. Clin. Exp. Med."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1251","DOI":"10.1111\/evj.14099","article-title":"Dexmedetomidine preconditioning reduces ischaemia\u2013reperfusion injury in equine model of large colon volvulus","volume":"56","author":"Watkins","year":"2024","journal-title":"Equine Vet. J."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1547","DOI":"10.1007\/s12013-013-9659-8","article-title":"Effect of intravenous infusion of dexmedetomidine combined with inhalation of isoflurane on arterial oxygenation and intrapulmonary shunt during single-lung ventilation","volume":"67","author":"Xia","year":"2013","journal-title":"Cell Biochem. Biophys."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Hasanin, A., Taha, K., Abdelhamid, B., Abougabal, A., Elsayad, M., Refaie, A., Amin, S., Wahba, S., Omar, H., and Kamel, M.M. (2018). Evaluation of the effects of dexmedetomidine infusion on oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease. BMC Anesth., 18.","DOI":"10.1186\/s12871-018-0572-y"},{"key":"ref_20","first-page":"96","article-title":"Respiratory and hemodynamic effects of 2 protocols of low-dose infusion of dexmedetomidine in dogs under isoflurane anesthesia","volume":"84","author":"Skouropoulou","year":"2020","journal-title":"Can. J. Vet. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1111\/vaa.12099","article-title":"A novel flow partition device for spirometry during large animal anaesthesia","volume":"41","author":"Schramel","year":"2014","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Mosing, M., B\u00f6hm, S.H., Rasis, A., Hoosgood, G., Auer, U., Tusman, G., Bettschart-Wolfensberger, R., and Schramel, J.P. (2018). Physiologic factors influencing the arterial-to-end-tidal CO2 difference and the alveolar dead space fraction in spontaneously breathing anesthetised horses. Front. Vet. Sci., 5.","DOI":"10.3389\/fvets.2018.00058"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"446","DOI":"10.2460\/ajvr.72.4.446","article-title":"Effects of intravenous administration of lidocaine on the minimum alveolar concentration of sevoflurane in horses","volume":"72","author":"Rezende","year":"2011","journal-title":"Am. J. Vet. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2013","DOI":"10.2460\/ajvr.73.12.2013","article-title":"Use of the oxygen content-based index, Fshunt, as an indicator of pulmonary venous admixture at various inspired oxygen fractions in anesthetized sheep","volume":"73","author":"Araos","year":"2012","journal-title":"Am. J. Vet. Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"640","DOI":"10.1016\/j.vaa.2018.02.010","article-title":"Comparison of different methods to calculate venous admixture in anaesthetized horses","volume":"45","year":"2018","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1016\/j.tvjl.2015.04.002","article-title":"Accuracy of different oxygenation indices in estimating intrapulmonary shunting at increasing infusion rates of dobutamine in horses under general anaesthesia","volume":"204","author":"Briganti","year":"2015","journal-title":"Vet. J."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1080\/00401706.1979.10489820","article-title":"The Use of the Rank Transform in Regression","volume":"21","author":"Iman","year":"1979","journal-title":"Technometrics"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"247","DOI":"10.1037\/1082-989X.12.3.247","article-title":"Combining propensity score matching and group-based trajectory analysis in an observational study","volume":"12","author":"Haviland","year":"2007","journal-title":"Psychol. Methods"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1111\/evj.12258","article-title":"Oxygenation, oxygen delivery and anaesthesia in the horse","volume":"47","author":"Hubbell","year":"2015","journal-title":"Equine Vet. J."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1707","DOI":"10.4103\/0366-6999.209891","article-title":"Can Dexmedetomidine Improve Arterial Oxygenation and Intrapulmonary Shunt during One-lung Ventilation in Adults Undergoing Thoracic Surgery? A Meta-analysis of Randomized, Placebo-controlled Trials","volume":"130","author":"Huang","year":"2017","journal-title":"Chin. Med. J."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1097\/EJA.0000000000000405","article-title":"Effects of dexmedetomidine on oxygenation and lung mechanics in patients with moderate chronic obstructive pulmonary disease undergoing lung cancer surgery: A randomised double-blinded trial","volume":"33","author":"Lee","year":"2016","journal-title":"Eur. J. Anaesthesiol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"624","DOI":"10.1136\/vr.159.19.624","article-title":"Cardiopulmonary effects of dexmedetomidine in goats and sheep anaesthetised with sevoflurane","volume":"159","author":"Kutter","year":"2006","journal-title":"Vet. Rec."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"359","DOI":"10.1097\/00000542-200402000-00026","article-title":"Effects of the alpha2-adrenoceptor agonist dexmedetomidine on bronchoconstriction in dogs","volume":"100","author":"Groeben","year":"2004","journal-title":"Anesthesiology"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"568","DOI":"10.1111\/j.1439-0442.1994.tb00124.x","article-title":"Increased airway pressure in response to xylazine is inhibited by both atipamezole and atropine in sheep","volume":"41","author":"Papazoglou","year":"1994","journal-title":"Zentralbl Vet. A"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1111\/j.1365-2885.1995.tb00581.x","article-title":"The effect of xylazine on the isolated sheep trachea","volume":"18","author":"Papazoglou","year":"1995","journal-title":"J. Vet. Pharmacol. Ther."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"930","DOI":"10.1016\/j.vaa.2021.05.005","article-title":"Effect of different inspired fractions of oxygen on F-shunt and arterial partial pressure of oxygen in isoflurane-anaesthetized and mechanically ventilated Shetland ponies","volume":"48","year":"2021","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Hubbell, J.A., Aarnes, T.K., Bednarski, R.M., Lerche, P., and Muir, W.W. (2011). Effect of 50% and maximal inspired oxygen concentrations on respiratory variables in isoflurane-anesthetized horses. BMC Vet. Res., 7.","DOI":"10.1186\/1746-6148-7-23"},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Tucker, L., Almeida, D., Wendt-Hornickle, E., Baldo, C.F., Allweiler, S., and Guedes, A.G.P. (2022). Effect of 15\u00b0 Reverse Trendelenburg Position on Arterial Oxygen Tension during Isoflurane Anesthesia in Horses. Animals, 12.","DOI":"10.3390\/ani12030353"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1111\/j.2042-3306.1989.tb02167.x","article-title":"Ventilation-perfusion relationships in the anaesthetised horse","volume":"21","author":"Nyman","year":"1989","journal-title":"Equine Vet. J."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"307","DOI":"10.2460\/ajvr.1998.59.03.307","article-title":"Influence of tidal volume and positive end-expiratory pressure on inspiratory gas distribution and gas exchange during mechanical ventilation in horses positioned in lateral recumbency","volume":"59","author":"Moens","year":"1998","journal-title":"Am. J. Vet. Res."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"169","DOI":"10.1111\/j.1467-2995.2011.00606.x","article-title":"Intermittent positive pressure ventilation with constant positive end-expiratory pressure and alveolar recruitment manoeuvre during inhalation anaesthesia in horses undergoing surgery for colic, and its influence on the early recovery period","volume":"38","author":"Hopster","year":"2011","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"110","DOI":"10.1111\/j.2042-3306.1995.tb03045.x","article-title":"Distribution of inspired gas to each lung in the anaesthetised horse and influence of body shape","volume":"27","author":"Moens","year":"1995","journal-title":"Equine Vet. J."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1016\/j.vaa.2023.03.002","article-title":"Effect of end-inspiratory pause on airway and physiological dead space in anesthetized horses","volume":"50","author":"Portela","year":"2023","journal-title":"Vet. Anaesth. Analg."}],"container-title":["Veterinary Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2306-7381\/12\/11\/1089\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,11,17]],"date-time":"2025-11-17T11:04:20Z","timestamp":1763377460000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2306-7381\/12\/11\/1089"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,11,16]]},"references-count":43,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2025,11]]}},"alternative-id":["vetsci12111089"],"URL":"https:\/\/doi.org\/10.3390\/vetsci12111089","relation":{},"ISSN":["2306-7381"],"issn-type":[{"value":"2306-7381","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,11,16]]}}}