FREE SHIPPING over $40
OVER 9000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
Home / Equine Research Bank / Vet Sci / Effects of Lidocaine Alone Versus Lidocaine-Dexmedetomidine ...
Veterinary sciences2025; 12(11); 1089; doi: 10.3390/vetsci12111089

Effects of Lidocaine Alone Versus Lidocaine-Dexmedetomidine Infusion on Pulmonary Gas Exchange and Respiratory Mechanics During Isoflurane Anesthesia in Horses.

Abstract: 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 μg/kg over 15 min, then 1.75 μg/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 ( ≤ 0.05). Peak inspiratory pressure increased over time with both treatments but was lower with DL at 90 min (-1.26 mmHg, = 0.046). There was no evidence that arterial oxygen pressure or oxygenation ratio improved over time with DL ( > 0.75). Shunt fraction did not significantly change over time or between treatments (Wald χ = 4.77, = 0.85). Heart rate with DL decreased from baseline ( ≤ 0.001) but remained higher than LIDO overall ( = 0.001). Dexmedetomidine infusion showed no benefit on oxygenation or respiratory mechanics in anesthetized horses.
Get Full Text
Publication Date: 2025-11-16 PubMed ID: 41295727PubMed Central: PMC12656796DOI: 10.3390/vetsci12111089Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

Overview

  • This study investigates whether adding dexmedetomidine to lidocaine infusion improves lung function, oxygen exchange, and breathing mechanics in horses anesthetized with isoflurane compared to lidocaine alone.
  • The researchers found that dexmedetomidine did not provide significant benefits for oxygenation or respiratory mechanics during anesthesia in horses.

Background and Purpose

  • Dexmedetomidine is known to enhance pulmonary function in humans and dogs by potentially improving oxygen exchange and respiratory mechanics.
  • However, evidence of these effects in horses during anesthesia is limited or lacking.
  • The study aimed to explore the impact of dexmedetomidine infusion, combined with lidocaine, on pulmonary gas exchange and respiratory parameters in horses anesthetized with isoflurane.

Methodology

  • Subjects: Twenty horses undergoing elective surgeries participated in this prospective, non-randomized observational study.
  • Treatment Groups:
    • LIDO group: horses received lidocaine alone at 1.3 mg/kg loading dose over 15 minutes, followed by 3 mg/kg per hour infusion.
    • DL group: horses received lidocaine plus dexmedetomidine, with dexmedetomidine dosed at 1.75 μg/kg loading over 15 minutes, then 1.75 μg/kg per hour infusion.
  • Measurements:
    • Respiratory mechanics (including peak inspiratory pressure)
    • Pulmonary gas exchange (arterial oxygen pressure, oxygenation ratio, and shunt fraction)
    • Cardiovascular variables (heart rate)
  • Parameters were recorded at baseline (before drug administration), after loading dose, and at 30, 60, and 90 minutes during anesthesia.
  • Statistical Analysis: Mixed-effects linear models were used with horse as a random effect and time, treatment, and their interaction as fixed effects. Significance was set at p ≤ 0.05.

Results

  • Peak Inspiratory Pressure:
    • Both groups showed an increase over time.
    • The DL (lidocaine + dexmedetomidine) group had significantly lower peak inspiratory pressure at 90 minutes compared to LIDO group (-1.26 mmHg difference, p = 0.046).
  • Oxygenation (Arterial Oxygen Pressure and Oxygenation Ratio):
    • No evidence that dexmedetomidine improved oxygenation over time (p-values > 0.75).
  • Shunt Fraction:
    • Did not significantly change over time or differ between treatment groups (p = 0.85).
  • Heart Rate:
    • In the DL group, heart rate decreased significantly from baseline (p ≤ 0.001).
    • However, overall heart rate was higher in the DL group compared to LIDO (p = 0.001).

Conclusions

  • Adding dexmedetomidine to lidocaine infusion during isoflurane anesthesia in horses did not improve pulmonary oxygenation or respiratory mechanics.
  • The minor beneficial effect seen in lowering peak inspiratory pressure at 90 minutes is of uncertain clinical relevance.
  • Results suggest that dexmedetomidine infusion offers no significant advantage over lidocaine alone for respiratory support in anesthetized horses under these experimental conditions.

Implications

  • Veterinarians and anesthesiologists should be aware that dexmedetomidine may not enhance pulmonary function during equine anesthesia despite success in other species.
  • Further research might be needed to explore different dosing, timing, or combinations with other drugs for improving pulmonary outcomes in horses.
  • The study contributes to evidence-based decisions about anesthesia protocols in large animal practice.

Cite This Article

APA
Chiavaccini L, Moura RA, Azevedo TMBPR, De Gennaro C, Vettorato E, Romano M, Portela DA. (2025). Effects of Lidocaine Alone Versus Lidocaine-Dexmedetomidine Infusion on Pulmonary Gas Exchange and Respiratory Mechanics During Isoflurane Anesthesia in Horses. Vet Sci, 12(11), 1089. https://doi.org/10.3390/vetsci12111089

Publication

Veterinary sciences
ISSN: 2306-7381
NlmUniqueID: 101680127
Country: Switzerland
Language: English
Volume: 12
Issue: 11
PII: 1089

Researcher Affiliations

Chiavaccini, Ludovica
  • Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA.
Moura, Raiane A
  • Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 SW 16th Ave, Gainesville, FL 32608, USA.
Azevedo, Tatiana Moreira Batista P R
  • Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA.
De Gennaro, Chiara
  • Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA.
Vettorato, Enzo
  • Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA.
Romano, Marta
  • Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA.
Portela, Diego A
  • Department of Comparative, Diagnostic & Population Medicine, College of Veterinary Medicine, University of Florida, 1945 SW 16th Ave Room V2-117, Gainesville, FL 32608, USA.

Conflict of Interest Statement

The authors declare no conflicts of interest.

References

This article includes 43 references
  1. Dugdale AH, Obhrai J, Cripps PJ. Twenty years later: A single-centre, repeat retrospective analysis of equine perioperative mortality and investigation of recovery quality.. Vet. Anaesth. Analg. 2016;43:171–178.
    doi: 10.1111/vaa.12285pubmed: 26081190google scholar: lookup
  2. Gozalo-Marcilla M, Bettschart-Wolfensberger R, Johnston M, Taylor PM, Redondo JI. Data Collection for the Fourth Multicentre Confidential Enquiry into Perioperative Equine Fatalities (CEPEF4) Study: New Technology and Preliminary Results.. Animals 2021;11:2549.
    doi: 10.3390/ani11092549pmc: PMC8472153pubmed: 34573515google scholar: lookup
  3. Meier M, Kazmir-Lysak K, Kälin I, Torgerson PR, Ringer SK. The influence of hypoxaemia, hypotension and hypercapnia (among other factors) on quality of recovery from general anaesthesia in horses.. Vet. Anaesth. Analg. 2024;51:135–143.
    doi: 10.1016/j.vaa.2023.10.032pubmed: 38331674google scholar: lookup
  4. Hovda T, Love L, Chiavaccini L. Risk factors associated with hypoxaemia in horses undergoing general anaesthesia: A retrospective study.. Equine Vet. J. 2021;54:1055–1063.
    doi: 10.1111/evj.13541pubmed: 34796547google scholar: lookup
  5. Guedes A, Knych H, Tucker L, Almeida DC, Baldo CF, Wendt-Hornickle E, Allweiler S. Pharmacokinetics and clinical effects of xylazine and dexmedetomidine in horses recovering from isoflurane anesthesia.. J. Vet. Pharmacol. Ther. 2020;43:369–376.
    doi: 10.1111/jvp.12855pubmed: 32166760google scholar: lookup
  6. Gozalo-Marcilla M, Gasthuys F, Schauvliege S. 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.. Vet. Anaesth. Analg. 2015;42:1–16.
    doi: 10.1111/vaa.12196pubmed: 24984895google scholar: lookup
  7. Ruíz-López P, Cuypers C, Schauvliege S. Xylazine Infusion during Equine Colic Anesthesia with Isoflurane and Lidocaine: A Retrospective Study.. Animals 2023;13:2902.
    doi: 10.3390/ani13182902pmc: PMC10525755pubmed: 37760302google scholar: lookup
  8. Alonso B, Carregaro A, Cuypers C, Michielsen A, Gasthuys F, Schauvliege S. Effects of detomidine or romifidine during maintenance and recovery from isoflurane anaesthesia in horses.. Vet. Anaesth. Analg. 2022;49:624–633.
    doi: 10.1016/j.vaa.2022.07.004pubmed: 36175293google scholar: lookup
  9. Gozalo-Marcilla M, Gasthuys F, Luna SPL, Schauvliege S. Is there a place for dexmedetomidine in equine anaesthesia and analgesia? A systematic review (2005–2017). J. Vet. Pharmacol. Ther. 2018;41:205–217.
    doi: 10.1111/jvp.12474pubmed: 29226340google scholar: lookup
  10. Bettembourg V, Dulgheriu D, Haga HA. Plasma concentrations at two dexmedetomidine constant rate infusions in isoflurane anaesthetized horses: A clinical study.. Vet. Anaesth. Analg. 2019;46:627–635.
    doi: 10.1016/j.vaa.2019.04.013pubmed: 31395482google scholar: lookup
  11. Grimsrud KN, Mama KR, Steffey EP, Stanley SD. Pharmacokinetics and pharmacodynamics of intravenous medetomidine in the horse.. Vet. Anaesth. Analg. 2012;39:38–48.
    doi: 10.1111/j.1467-2995.2011.00669.xpubmed: 22103480google scholar: lookup
  12. Ranheim B, Risberg AI, Spadavecchia C, Landsem R, Haga HA. The pharmacokinetics of dexmedetomidine administered as a constant rate infusion in horses.. J. Vet. Pharmacol. Ther. 2015;38:93–96.
    doi: 10.1111/jvp.12157pubmed: 25229603google scholar: lookup
  13. Xiong W, Zhou R, Qu Y, Yang Y, Wang Z, Song N, Liang R, Qian J. Dexmedetomidine preconditioning mitigates myocardial ischemia/reperfusion injury via inhibition of mast cell degranulation.. Biomed. Pharmacother. 2021;141:111853.
    doi: 10.1016/j.biopha.2021.111853pubmed: 34237593google scholar: lookup
  14. VanderBroek AR, Engiles JB, Kästner SBR, Kopp V, Verhaar N, Hopster K. Protective effects of dexmedetomidine on small intestinal ischaemia-reperfusion injury in horses.. Equine Vet. J. 2021;53:569–578.
    doi: 10.1111/evj.13337pubmed: 32862437google scholar: lookup
  15. König KS, Verhaar N, Hopster K, Pfarrer C, Neudeck S, Rohn K, Kästner SBR. Ischaemic preconditioning and pharmacological preconditioning with dexmedetomidine in an equine model of small intestinal ischaemia-reperfusion.. PLoS ONE 2020;15:e0224720.
    doi: 10.1371/journal.pone.0224720pmc: PMC7190151pubmed: 32348301google scholar: lookup
  16. Ma J, Zhang X.L, Wang C.Y, Lin Z, Tao J.R, Liu H.C. Dexmedetomidine alleviates the spinal cord ischemia-reperfusion injury through blocking mast cell degranulation.. Int. J. Clin. Exp. Med. 2015;8:14741–14749.
    pmc: PMC4658845pubmed: 26628956
  17. Watkins A, Engiles J, Long A, Brandly J, Hopster K. Dexmedetomidine preconditioning reduces ischaemia–reperfusion injury in equine model of large colon volvulus.. Equine Vet. J. 2024;56:1251–1258.
    doi: 10.1111/evj.14099pubmed: 38749762google scholar: lookup
  18. Xia R, Yin H, Xia Z.Y, Mao Q.J, Chen G.D, Xu W. Effect of intravenous infusion of dexmedetomidine combined with inhalation of isoflurane on arterial oxygenation and intrapulmonary shunt during single-lung ventilation.. Cell Biochem. Biophys. 2013;67:1547–1550.
    doi: 10.1007/s12013-013-9659-8pubmed: 23733668google scholar: lookup
  19. Hasanin A, Taha K, Abdelhamid B, Abougabal A, Elsayad M, Refaie A, Amin S, Wahba S, Omar H, Kamel M.M. Evaluation of the effects of dexmedetomidine infusion on oxygenation and lung mechanics in morbidly obese patients with restrictive lung disease.. BMC Anesth. 2018;18:104.
    doi: 10.1186/s12871-018-0572-ypmc: PMC6090793pubmed: 30103679google scholar: lookup
  20. Di Bella C, Skouropoulou D, Stabile M, Muresan C, Grasso S, Lacitignola L, Valentini L, Crovace A, Staffieri F. Respiratory and hemodynamic effects of 2 protocols of low-dose infusion of dexmedetomidine in dogs under isoflurane anesthesia.. Can. J. Vet. Res. 2020;84:96–107.
    pmc: PMC7088514pubmed: 32255904
  21. Schramel J.P, Wimmer K, Ambrisko T.D, Moens Y.P. A novel flow partition device for spirometry during large animal anaesthesia.. Vet. Anaesth. Analg. 2014;41:191–195.
    doi: 10.1111/vaa.12099pubmed: 24224723google scholar: lookup
  22. Mosing M, Böhm S.H, Rasis A, Hoosgood G, Auer U, Tusman G, Bettschart-Wolfensberger R, Schramel J.P. Physiologic factors influencing the arterial-to-end-tidal CO2 difference and the alveolar dead space fraction in spontaneously breathing anesthetised horses.. Front. Vet. Sci. 2018;5:58.
    doi: 10.3389/fvets.2018.00058pmc: PMC5882784pubmed: 29644221google scholar: lookup
  23. Rezende M.L, Wagner A.E, Mama K.R, Ferreira T.H, Steffey E.P. Effects of intravenous administration of lidocaine on the minimum alveolar concentration of sevoflurane in horses.. Am. J. Vet. Res. 2011;72:446–451.
    doi: 10.2460/ajvr.72.4.446pubmed: 21453144google scholar: lookup
  24. Araos J.D, Larenza M.P, Boston R.C, De Monte V, De Marzo C, Grasso S, Haskins S.C, Crovace A, Staffieri F. Use of the oxygen content-based index, Fshunt, as an indicator of pulmonary venous admixture at various inspired oxygen fractions in anesthetized sheep.. Am. J. Vet. Res. 2012;73:2013–2020.
    doi: 10.2460/ajvr.73.12.2013pubmed: 23176433google scholar: lookup
  25. van Loon J.P, de Grauw J.C, van Oostrom H. Comparison of different methods to calculate venous admixture in anaesthetized horses.. Vet. Anaesth. Analg. 2018;45:640–647.
    doi: 10.1016/j.vaa.2018.02.010pubmed: 30093318google scholar: lookup
  26. Briganti A, Portela D.A, Grasso S, Sgorbini M, Tayari H, Bassini J.R, Vitale V, Romano M.S, Crovace A, Breghi G. Accuracy of different oxygenation indices in estimating intrapulmonary shunting at increasing infusion rates of dobutamine in horses under general anaesthesia.. Vet. J. 2015;204:351–356.
    doi: 10.1016/j.tvjl.2015.04.002pubmed: 25920771google scholar: lookup
  27. Iman R.L, Conover W.J. The Use of the Rank Transform in Regression.. Technometrics 1979;21:499–509.
    doi: 10.1080/00401706.1979.10489820google scholar: lookup
  28. Haviland A, Nagin D.S, Rosenbaum P.R. Combining propensity score matching and group-based trajectory analysis in an observational study.. Psychol. Methods 2007;12:247–267.
    doi: 10.1037/1082-989X.12.3.247pubmed: 17784793google scholar: lookup
  29. Hubbell J.A, Muir W.W. Oxygenation, oxygen delivery and anaesthesia in the horse.. Equine Vet. J. 2015;47:25–35.
    doi: 10.1111/evj.12258pubmed: 24612155google scholar: lookup
  30. Huang S.Q, Zhang J, Zhang X.X, Liu L, Yu Y, Kang X.H, Wu X.M, Zhu S.M. 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.. Chin. Med. J. 2017;130:1707–1714.
    doi: 10.4103/0366-6999.209891pmc: PMC5520559pubmed: 28685722google scholar: lookup
  31. Lee SH, Kim N, Lee CY, Ban MG, Oh YJ. 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. Eur. J. Anaesthesiol. 2016;33:275–282.
    doi: 10.1097/EJA.0000000000000405pmc: PMC4780481pubmed: 26716866google scholar: lookup
  32. Kutter AP, Kästner SB, Bettschart-Wolfensberger R, Huhtinen M. Cardiopulmonary effects of dexmedetomidine in goats and sheep anaesthetised with sevoflurane. Vet. Rec. 2006;159:624–629.
    doi: 10.1136/vr.159.19.624pubmed: 17088297google scholar: lookup
  33. Groeben H, Mitzner W, Brown RH. Effects of the alpha2-adrenoceptor agonist dexmedetomidine on bronchoconstriction in dogs. Anesthesiology 2004;100:359–363.
    doi: 10.1097/00000542-200402000-00026pubmed: 14739811google scholar: lookup
  34. Papazoglou L, Raptopoulos D, Kokolis N. Increased airway pressure in response to xylazine is inhibited by both atipamezole and atropine in sheep. Zentralbl Vet. A. 1994;41:568–572.
    doi: 10.1111/j.1439-0442.1994.tb00124.xpubmed: 8831272google scholar: lookup
  35. Papazoglou L, Raptopoulos D, Kounenis G. The effect of xylazine on the isolated sheep trachea. J. Vet. Pharmacol. Ther. 1995;18:216–219.
    doi: 10.1111/j.1365-2885.1995.tb00581.xpubmed: 7674458google scholar: lookup
  36. Calero Rodriguez A, de Grauw JC, van Loon J. Effect of different inspired fractions of oxygen on F-shunt and arterial partial pressure of oxygen in isoflurane-anaesthetized and mechanically ventilated Shetland ponies. Vet. Anaesth. Analg. 2021;48:930–934.
    doi: 10.1016/j.vaa.2021.05.005pubmed: 34544618google scholar: lookup
  37. Hubbell JA, Aarnes TK, Bednarski RM, Lerche P, Muir WW. Effect of 50% and maximal inspired oxygen concentrations on respiratory variables in isoflurane-anesthetized horses. BMC Vet. Res. 2011;7:23.
    doi: 10.1186/1746-6148-7-23pmc: PMC3133541pubmed: 21639886google scholar: lookup
  38. Tucker L, Almeida D, Wendt-Hornickle E, Baldo CF, Allweiler S, Guedes AGP. Effect of 15° Reverse Trendelenburg Position on Arterial Oxygen Tension during Isoflurane Anesthesia in Horses. Animals 2022;12:353.
    doi: 10.3390/ani12030353pmc: PMC8833611pubmed: 35158676google scholar: lookup
  39. Nyman G, Hedenstierna G. Ventilation-perfusion relationships in the anaesthetised horse. Equine Vet. J. 1989;21:274–281.
    doi: 10.1111/j.2042-3306.1989.tb02167.xpubmed: 2670542google scholar: lookup
  40. Moens Y, Lagerweij E, Gootjes P, Poortman J. 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. Am. J. Vet. Res. 1998;59:307–312.
    doi: 10.2460/ajvr.1998.59.03.307pubmed: 9522950google scholar: lookup
  41. Hopster K, Kästner SB, Rohn K, Ohnesorge B. 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. Vet. Anaesth. Analg. 2011;38:169–177.
    doi: 10.1111/j.1467-2995.2011.00606.xpubmed: 21492381google scholar: lookup
  42. Moens Y, Lagerweij E, Gootjes P, Poortman J. Distribution of inspired gas to each lung in the anaesthetised horse and influence of body shape. Equine Vet. J. 1995;27:110–116.
    doi: 10.1111/j.2042-3306.1995.tb03045.xpubmed: 7607142google scholar: lookup
  43. Portela DA, Di Franco C, Chiavaccini L, Araos J, Romano M, Otero PE, Biedrzycki AH, Schramel JP. Effect of end-inspiratory pause on airway and physiological dead space in anesthetized horses. Vet. Anaesth. Analg. 2023;50:363–371.
    doi: 10.1016/j.vaa.2023.03.002pubmed: 37055259google scholar: lookup

Citations

This article has been cited 0 times.
Subscribe to our newsletter
Join 99,030 horse owners like you who receive our email updates on horse health and nutrition.