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Donaldson AC, Meyer LCR, Fuller A, Buss PE. Comparison of the cardiovascular effects of immobilization with three different drug combinations in free-ranging African lions. CONSERVATION PHYSIOLOGY 2023; 11:coac077. [PMID: 36655170 PMCID: PMC9835075 DOI: 10.1093/conphys/coac077] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 11/11/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Thirty-six free-ranging lions (12 per group) were immobilized with tiletamine-zolazepam (Zoletil 0.6 mg/kg i.m.) plus medetomidine (0.036 mg/kg i.m.) (TZM), ketamine (3.0 mg/kg i.m.) plus medetomidine (0.036 mg/kg i.m.) (KM) or ketamine (1.2 mg/kg i.m.) plus butorphanol (0.24 mg/kg i.m.) plus medetomidine (0.036 mg/kg i.m.) (KBM). During immobilization cardiovascular variables were monitored at 5-minute intervals for a period of 30 minutes. Lions immobilized with all three drug combinations were severely hypertensive. Systolic arterial pressure was higher at initial sampling in lions immobilized with KM (237.3 ± 24.8 mmHg) than in those immobilized with TZM (221.0 ± 18.1 mmHg) or KBM (226.0 ± 20.6 mmHg) and decreased to 205.8 ± 19.4, 197.7 ± 23.7 and 196.3 ± 17.7 mmHg, respectively. Heart rates were within normal ranges for healthy, awake lions and decreased throughout the immobilization regardless of drug combination used. Lions immobilized with TZM had a higher occurrence (66%) of skipped heart beats than those immobilized with KBM (25%). The three drug combinations all caused negative cardiovascular effects, which were less when KBM was used, but adverse enough to warrant further investigations to determine if these effects can be reversed or prevented when these three combinations are used to immobilize free-living lions.
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Affiliation(s)
| | - Leith Carl Rodney Meyer
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Pretoria, Gauteng, South Africa, 0110
- Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Pretoria, South Africa, 0110
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, York Road, Parktown, Johannesburg, South Africa, 2193
| | - Andrea Fuller
- Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Pretoria, Gauteng, South Africa, 0110
- Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Pretoria, South Africa, 0110
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, York Road, Parktown, Johannesburg, South Africa, 2193
| | - Peter Erik Buss
- Centre for Veterinary Wildlife Research, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Pretoria, South Africa, 0110
- Veterinary Wildlife Services, South African National Parks, Kruger National Park, Skukuza, South Africa, 1350
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Soutpan Road, Onderstepoort, Gauteng, South Africa, 0110
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Cardiac troponin I in dogs anaesthetized with propofol and sevoflurane: the influence of medetomidine premedication and inspired oxygen fraction. Vet Anaesth Analg 2018; 45:745-753. [PMID: 30309716 DOI: 10.1016/j.vaa.2018.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate changes in serum cardiac troponin I (cTnI) concentrations in dogs in which medetomidine was used for sedation or for premedication prior to anaesthesia with propofol and sevoflurane. STUDY DESIGN Prospective clinical study. ANIMALS A total of 66 client-owned dogs. METHODS The dogs were sedated with medetomidine (0.04 mg kg-1) intravenously (IV) (group M; n = 20) and left to breath room air or anaesthetized with propofol (6.5 ± 0.76 mg kg-1 IV) and sevoflurane (4.5% vaporizer setting) in oxygen (group P + S; n = 20) or with medetomidine (0.04 mg kg-1 IV), propofol (1.92 ± 0.63 mg kg-1) and sevoflurane (3% vaporizer setting) in oxygen (group M + P + S; n = 26), respectively. After 35 minutes, medetomidine was antagonized with atipamezole (0.1 mg kg-1 intramuscularly). Blood samples for serum cTnI determination were taken before sedation or anaesthesia, 6 and 12 hours and 4 days thereafter. Serum cTnI concentrations were measured with the Architect STAT Troponin-I assay. RESULTS Before sedation or anaesthesia, cTnI concentrations were above the detection limit in 22 out of 66 (33%) of dogs. Compared to basal values, cTnI concentrations significantly increased at 6 and 12 hours in all groups and at day 4 in group M. There were no differences in cTnI concentration between groups at baseline, at 6 hours and at 4 days. At 12 hours, cTnI concentrations were significantly higher in groups M and P + S, respectively, compared to group M + P + S. CONCLUSIONS AND CLINICAL RELEVANCE Oxygenation during anaesthesia and reduction of propofol and sevoflurane dose due to the sparing effects of medetomidine might have played a role in alleviation of myocardial hypoxic injury as indicated by the less severe and short-lived increase of cTnI in the M + P + S group.
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Sinclair MD, McDonell WN, O'Grady M, Pettifer G. The cardiopulmonary effects of romifidine in dogs with and without prior or concurrent administration of glycopyrrolate. Vet Anaesth Analg 2016; 29:1-13. [PMID: 28404263 DOI: 10.1046/j.1467-2987.2001.00056.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2000] [Accepted: 12/06/2000] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the electrocardiographic and cardiopulmonary effects of romifidine with and without prior or concurrent administration of glycopyrrolate. STUDY DESIGN Randomized crossover experimental study. ANIMALS Six (three male, three female) cross-bred dogs weighing 23 ± 2.4 kg. METHODS Baseline cardiopulmonary measurements were obtained in conscious dogs and one of five treatments was administered. Glycopyrrolate (G) 0.01 mg kg-1, or saline (S) 0.5 mL, were administered IM as premedication (Gp or Sp), or G was administered concurrently (Gc) with romifidine (RO). Treatments were as follows T1, Sp + RO 40 μg kg-1; T2, Gp + RO (40 μg kg-1); T3, Sp + RO 120 μg kg-1; T4, Gp + RO (120 μg kg-1); T5, Sp + Gc + RO (120 μg kg-1). Romifidine or RO + Gc was administered subcutaneously 20 minutes after premedication (time 0), and further measurements were taken 10, 20, 30, 60 and 90 minutes after RO. The main treatment effect was evaluated using two-way anova for repeated measures, followed by one-way anova and a post-hoc least squares difference test with a modified Bonferroni correction (p < 0.02). A Student's t-test was used to compare the effect of romifidine at 20 and 60 minutes versus baseline values (p < 0.05). RESULTS Both low- and high-dose RO (T1, T3) significantly decreased heart rate (HR), respiratory rate (RR), cardiac index (CI) and stroke volume index, and increased arterial blood pressure (SAP), systemic vascular resistance (SVR), pulmonary arterial occlusion pressure (PAOP) and central venous pressure. High-dose RO produced greater increases in SVR and SAP measurements. Neither dose of RO produced an alteration in blood gas values or the alveolar to arterial oxygen gradient. Glycopyrrolate significantly increased HR and CI from 10 to 90 minutes between T1/T2 and T3/T4. Increases in SAP were dose related with significant differences between T1/T3 and T2/T4 at 90 and 10 minutes, respectively, and were highest in animals receiving Gp or Gc. High-dose RO groups (T3, T4) had higher values for SVR than low-dose RO groups (T1, T2), unrelated to G administration. There was an increase in PAOP in all treatments. The oxygen extraction ratio was increased with all treatments: larger increases were observed in T1, T3 and T4 compared with only minimal changes in T2. Concurrent G administration was associated with an increased frequency of high-grade second-degree atrioventricular heart block with variable conduction at 10 and 20 minutes. CONCLUSIONS Romifidine produced effects consistent with other selective α2-adrenoreceptor agonists. Glycopyrrolate offset the decrease in HR and partially offset the decrease in CI associated with RO administration. Glycopyrrolate premedication produced an initial tachycardia and added to the increase in SAP associated with RO. Concurrent G administration was associated with a higher frequency of dysrhythmias and is not recommended. Despite the decrease in RR, RO sedation did not alter blood gas values. CLINICAL RELEVANCE It appears likely that G administration prior to or concurrent with RO produces an increase in myocardial workload and oxygen demand suggesting that this combination should not be used in dogs with cardiomyopathy or heart failure. The improvement in oxygen extraction ratio with T2 suggests that G may be beneficial with lower doses of RO, nevertheless, the use of G and RO in cardiovascularly compromised patients is not advised.
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Affiliation(s)
- Melissa D Sinclair
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Ontario, Canada
| | - Wayne N McDonell
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Ontario, Canada
| | - Mike O'Grady
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Ontario, Canada
| | - Glenn Pettifer
- Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, USA
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Singh GD, Kinjavdekar P, Amarpal, Aithal HP, Pawde AM, Zama MMS, Singh J, Tiwary R. Clinicophysiological and haemodynamic effects of fentanyl with xylazine, medetomidine and dexmedetomidine in isoflurane-anaesthetised water buffaloes (Bubalus bubalis). J S Afr Vet Assoc 2013; 84:E1-E11. [PMID: 23718913 DOI: 10.4102/jsava.v84i1.67] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/24/2012] [Accepted: 11/21/2012] [Indexed: 11/01/2022] Open
Abstract
The present study was undertaken to investigate the sedative, analgesic and clinical effects of xylazine, medetomidine and dexmedetomidine with fentanyl as pre-anaesthetics in water buffaloes and to compare the dose-sparing effect of xylazine, medetomidine and dexmedetomidine on thiopental for induction and isoflurane for maintenance of anaesthesia in water buffaloes. Six male water buffaloes randomly received intravenous fentanyl (5.0 µg/kg body weight) and xylazine (0.05 mg/kg body weight), fentanyl (5.0 µg/kg body weight) and medetomidine (2.5 µg/kg body weight), fentanyl (5.0 µg/kg body weight) and dexmedetomidine (5.0 µg/kg body weight) at weekly intervals in groups I1, I2 and I3, respectively. After 15 min, the animals were restrained in right lateral recumbency and anaesthesia was induced by 5% thiopental sodium administered intravenously. The intubated animal was connected to the large animal anaesthesia machine and isoflurane in 100% oxygen (5 L/min) was insufflated for 60 min. The treatments were compared by clinicophysiological, haematobiochemical and haemodynamic parameters. Fentanyl-medetomidine and fentanyl-dexmedetomidine produced more cardiovascular depression during the pre-anaesthetic period but less depression of cardio-respiratory dynamics in the post induction and maintenance period. Quicker recovery was recorded in I2 and I3 groups. A lower dose of thiopental was required in group I3 (4.33 mg/kg ± 0.66 mg/kg) than in groups I2 (4.41 mg/kg ± 0.98 mg/kg) and I1 (4.83 mg/kg ± 0.79 mg/kg). The dose of isoflurane was less in group I3 (45.50 mL ± 5.45 mL) than in group I1 and I2 (48.66 mL ± 5.10 mL and 48.00 mL ± 6.38 mL). Better anaesthesia was recorded with fentanyl-dexmedetomidine-thiopental-isoflurane (group I3) than with fentanyl-medetomidine-thiopental-isoflurane (group I2) and fentanyl-xylazine-thiopental-isoflurane (group I1). Fentanyl-medetomidine and fentanyl-dexmedetomidine were better pre-anaesthetic agents in comparison to fentanyl-xylazine for thiopental and isoflurane anaesthesia. Fentanyl-dexmedetomidine-thiopental-isoflurane and fentanyl-medetomidine-thiopental-isoflurane produced effective surgical anaesthesia and were found to be safe, as cardio-pulmonary functions were well preserved during maintenance anaesthesia with no deleterious effect on vital organ functions in water buffaloes.
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Affiliation(s)
- Gyan D Singh
- Division of Surgery, Indian Veterinary Research Institute, Izatnagar-243122, Bareilly, India
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Silva A, Antunes L. Electroencephalogram-based anaesthetic depth monitoring in laboratory animals. Lab Anim 2012; 46:85-94. [PMID: 22517991 DOI: 10.1258/la.2012.011135] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Objective measurements of physiological parameters controlled by the autonomic nervous system such as blood pressure, heart rate and respiration are easily obtained nowadays during anaesthesia by the use of monitors: oscillometers, pulseoximeters, electrocardiograms and capnographs are available for laboratory animals. However, the effect-site of hypnotic drugs that cause general anaesthesia is the central nervous system (the brain). In the present, the adjustment of hypnotic drugs in veterinary anaesthesia is performed according to subjective evaluation of clinical signs which are not direct reflexes of anaesthetic effects on the brain, making depth of anaesthesia (DoA) assessment a complicated task. The difficulties in assessing the real anaesthetic state of a laboratory animal may not only result in welfare-threatening situations, such as awareness and pain sensation during surgery, but also in a lack of standardization of experimental conditions, as it is not easy to keep all animals from an experiment in the same DoA without a measure of anaesthetic effect. A direct measure of this dose-effect relationship, although highly necessary, is still missing in the veterinary market. Meanwhile, research has been intense in this subject and methods based on the brain electrical activity (electroencephalogram) have been explored in laboratory animal species. The objective of this review is to explain the achievements made in this topic and clarify how far we are from an objective measure of DoA for animals.
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Affiliation(s)
- Aura Silva
- REQUIMTE, Faculdade de Farmácia da Universidade do Porto, Rua de Jorge Viterbo Ferreira No. 228, 4050-313 Porto, Portugal.
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6
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Abnormal motor activity during anaesthesia in a dog: a case report. Acta Vet Scand 2010; 52:64. [PMID: 21118580 PMCID: PMC3003231 DOI: 10.1186/1751-0147-52-64] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 12/01/2010] [Indexed: 11/10/2022] Open
Abstract
Seizures or convulsions that occur during anaesthesia in veterinary patients are infrequently reported in the literature. Consequently, the incidence of such events is unknown. Several drugs commonly used in clinical veterinary anaesthesia have been shown to induce epileptiform activity in both human clinical patients and experimental candidates. The present case report describes convulsions in a four-year old male Bernese mountain dog during maintenance of anaesthesia with isoflurane after premedication with acepromazine and methadone followed by co-induction with propofol and ketamine. The dog had no history of previous convulsions. The use of several sedative and anaesthetic drugs makes it difficult to find one single causative pharmaceutical.
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Martinez Taboada F, Murison PJ. Induction of anaesthesia with alfaxalone or propofol before isoflurane maintenance in cats. Vet Rec 2010; 167:85-9. [DOI: 10.1136/vr.b4872] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- F. Martinez Taboada
- Department of Clinical Veterinary Science; University of Bristol; Langford House Langford North Somerset BS40 5DU
| | - P. J. Murison
- Department of Clinical Veterinary Science; University of Bristol; Langford House Langford North Somerset BS40 5DU
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Hofmeister EH, Weinstein WL, Burger D, Brainard BM, Accola PJ, Moore PA. Effects of graded doses of propofol for anesthesia induction on cardiovascular parameters and intraocular pressures in normal dogs. Vet Anaesth Analg 2009; 36:442-8. [DOI: 10.1111/j.1467-2995.2009.00482.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Gómez-Villamandos RJ, Palacios C, Benítez A, Granados MM, Domínguez JM, Estepa JC, Ruiz I, Aguilera E, Santisteban JM. Effect of medetomidine infusion on the anaesthetic requirements of desflurane in dogs. Res Vet Sci 2008; 84:68-73. [PMID: 17408710 DOI: 10.1016/j.rvsc.2007.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 02/08/2007] [Accepted: 02/12/2007] [Indexed: 11/30/2022]
Abstract
The objective of this paper was to evaluate the effect of constant rate infusion of medetomidine on the anaesthetic requirements of desflurane in dogs. For this, six healthy dogs were studied. Measurements for baseline were taken in the awake, unsedated dogs, then each dog received intravenously (i.v.) three anaesthetic protocols: M (no medetomidine infusion), M0.5 (infusion of medetomidine at 0.5 microg/kg/h, i.v.) or M1 (infusion of medetomidine at 1 microg/kg/h, i.v.). All dogs were sedated with medetomidine (2 microg/kg, i.v.) and measurements repeated in 10 min. Induction of anaesthesia was delivered with propofol (3 mg/kg, i.v.) and maintained with desflurane for 90 min to achieve a defined surgical plane of anaesthesia in all cases. After tracheal intubation infusion of medetomidine was initiated and maintained until the end of anaesthesia. Cardiovascular, respiratory, arterial pH (pHa) and arterial blood gas tensions (PaO(2), PaCO(2)) variables were measured during the procedure. End tidal desflurane concentration (EtDES) was recorded throughout anaesthesia. Time to extubation, time to sternal recumbency and time to standing were also noted. Heart rate and respiratory rate were significantly decreased during sedation in all protocols compared to baseline values. Mean heart rate, mean arterial pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate, tidal volume, arterial oxygen saturation, end-tidal CO(2), pHa, PaO(2), and PaCO(2) during anaesthesia were similar for all protocols. EtDES for M (8.6 +/- 0.8%) was statistically higher than for M0.5 (7.6 +/- 0.5%) and M1 (7.3 +/- 0.7%) protocols. Infusion of medetomidine reduces desflurane concentration required to maintain anaesthesia in dogs.
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Affiliation(s)
- R J Gómez-Villamandos
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, University of Córdoba, Campus Universitario de Rabanales, 14014 Córdoba, Spain.
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10
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Redondo JI, Rubio M, Soler G, Serra I, Soler C, Gómez-Villamandos RJ. Normal Values and Incidence of Cardiorespiratory Complications in Dogs During General Anaesthesia. A Review of 1281 Cases. ACTA ACUST UNITED AC 2007; 54:470-7. [DOI: 10.1111/j.1439-0442.2007.00987.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Redondo García JI. Clinical evaluation of a new formulation of propofol in a medium-chain and long-chain triglycerides emulsion in dogs. J Vet Pharmacol Ther 2007; 30:288-94. [PMID: 17610401 DOI: 10.1111/j.1365-2885.2007.00859.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Propofol formulated in a mixed medium-chain and long-chain triglycerides emulsion has been recently introduced for clinical use as an alternative to the conventional long-chain triglycerides formulation. This prospective multicentric study evaluated the clinical effectiveness and the complications associated with the use of this new formulation of propofol in dogs. Forty-six Spanish veterinary clinics participated in this study. A total of 541 anaesthesias (118 ASA I, 290 ASA II, 101 ASA III and 32 ASA IV) performed for various diagnostic and therapeutic purposes were evaluated. The anaesthetic protocol was not controlled, with the exception that propofol had to be used at least for induction of anaesthesia. The induction dose of propofol and the incidence of anaesthetic complications throughout the procedure were recorded. A chi-square test compared the incidence of complications according to the maintenance agent used (propofol vs. inhalatory anaesthesia), anaesthetic risk (ASA classification) and the reason for the anaesthesia. The patients premedicated with alpha2 agonists needed lower doses (mean +/- SD, 2.9 +/- 1.3 mg/kg i.v.) than the animals premedicated with phenothiazines (3.9 +/- 1.4 mg/kg i.v.) or benzodiazepines (4.0 +/- 1.4 mg/kg i.v.). The most frequent complications were difficult endotracheal intubation (1.3%), postinduction apnoea (11.3%), cyanosis (0.6%), bradypnoea (2.6%), tachypnoea (2.8%), bradycardia (2%), tachycardia (2.6%), hypotension (0.2%), shock (0.2%), vomiting (4.6%), epileptiform seizures (2.8%), premature awakening (7.4%) and delayed recovery (0.9%). There were no cases of pain on injection or aspiration pneumonia. Three dogs died (0.55%), one during induction and two during recovery from anaesthesia. This study demonstrates that the new formulation of propofol is an useful and effective drug to induce general anaesthesia in dogs.
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Affiliation(s)
- J I Redondo García
- Dpto. Medicina y Cirugía Animal, Universidad CEU Cardenal Herrera, Moncada, Valencia, Spain.
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12
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Gómez-Villamandos RJ, Domínguez JM, Redondo JI, Martín EM, Granados MM, Ruiz I, Santisteban JM. Comparison of Romifidine and Medetomidine Pre-medication in Propofol?Isoflurane Anaesthetised Dogs. ACTA ACUST UNITED AC 2006; 53:471-5. [PMID: 17054484 DOI: 10.1111/j.1439-0442.2006.00859.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The objective of this paper was to evaluate romifidine as a pre-medicant in dogs prior to propofol-isoflurane anaesthesia, and to compare it with medetomidine. For this, eight healthy dogs were anaesthetised. Each dog received three pre-anaesthetic protocols: R40 (romifidine, 40 microg/kg, IV), R80 (romifidine, 80 microg/kg, IV) or MED (medetomidine, 10 microg/kg, IV). Induction of anaesthesia was delivered with propofol and maintained with isoflurane. The following variables were studied before sedative administration and 10 min after sedative administration: heart rate (HR), mean arterial pressure (MAP), systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) and respiratory rate (RR). During maintenance, the following variables were recorded at 5-min intervals: HR, MAP, SAD, DAP, arterial oxygen saturation (SpO(2)), end-tidal CO(2)(EtCO(2)), end-tidal concentration of isoflurane (EtISO) required for maintenance of anaesthesia and tidal volume (TV). Time to extubation, time to sternal recumbency and time to standing were also registered. HR and RR experimented a significantly decreased during sedation in all protocols respect to baseline values. Mean HR, MAP, SAP, DAP, SpO(2), EtCO(2), and TV during anaesthesia were similar for the three protocols. End tidal of isoflurane concentration was statistically similar for all protocols. Recovery time for R40 was significantly shorter than in R80 and MED. The studied combination of romifidine, propofol and isoflurane appears to be an effective drug combination for inducing and maintaining general anaesthesia in healthy dogs.
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Affiliation(s)
- R J Gómez-Villamandos
- Department of Animal Medicine and Surgery, University of Córdoba, Campus Universitario de Rabanales, Cordoba, Spain.
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13
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Gómez-Villamandos RJ, Palacios C, Benítez A, Granados MM, Domínguez JM, López I, Ruiz I, Aguilera E, Santisteban JM. Dexmedetomidine or medetomidine premedication before propofol-desflurane anaesthesia in dogs. J Vet Pharmacol Ther 2006; 29:157-63. [PMID: 16669859 DOI: 10.1111/j.1365-2885.2006.00732.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The objective of this study was to evaluate dexmedetomidine as a premedicant in dogs prior to propofol-desflurane anaesthesia, and to compare it with medetomidine. Six healthy dogs were anaesthetized. Each dog received intravenously (i.v.) five preanaesthetic protocols: D1 (dexmedetomidine, 1 microg/kg, i.v.), D2 (dexmedetomidine, 2 microg/kg, i.v.), M1 (medetomidine, 1 microg/kg, i.v.), M2 (medetomidine, 2 microg/kg, i.v.), or M4 (medetomidine, 4 microg/kg, i.v.). Anaesthesia was induced with propofol (2.3-3.3 mg/kg) and maintained with desflurane. The following variables were studied: heart rate (HR), mean arterial pressure, systolic arterial pressure, diastolic arterial pressure, respiratory rate (RR), arterial oxygen saturation, end-tidal CO2, end-tidal concentration of desflurane (EtDES) required for maintenance of anaesthesia and tidal volume. Arterial blood pH (pHa) and arterial blood gas tensions (PaO2, PaCO2) were measured during anaesthesia. Time to extubation, time to sternal recumbency and time to standing were also recorded. HR and RR decreased significantly during sedation in all protocols. Cardiorespiratory variables during anaesthesia were statistically similar for all protocols. EtDES was significantly different between D1 (8.1%) and D2 (7.5%), and between all doses of medetomidine. Desflurane requirements were similar for D1 and M2, and for D2 and M4 protocols. No statistical differences were observed in recovery times. The combination of dexmedetomidine, propofol and desflurane appears to be effective for induction and maintenance of general anaesthesia in healthy dogs.
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Affiliation(s)
- R J Gómez-Villamandos
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, University of Córdoba, Campus Universitario de Rabanales, Córdoba, Spain.
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14
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Ko JCH, Payton ME, White AG, Galloway DS, Inoue T. Effects of intravenous diazepam or microdose medetomidine on propofol-induced sedation in dogs. J Am Anim Hosp Assoc 2006; 42:18-27. [PMID: 16397191 DOI: 10.5326/0420018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This crossover study tested the hypothesis that both diazepam and microdose medetomidine would comparably reduce the amount of propofol required to induce sedation. Four different medications, namely high-dose diazepam (0.4 mg/kg intravenously [IV]), low-dose diazepam (0.2 mg/kg IV), medetomidine (1 mug/kg IV), and placebo (0.5 mL physiological saline IV) were followed by propofol (8 mg/kg IV) titrated to a point where intubation could be performed. The effects of medetomidine were comparable to the effects of high-dose diazepam and significantly better than the effects of low-dose diazepam or placebo. Dogs in all treatment groups had transient hypoxemia, and induction and recovery qualities were similar.
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Affiliation(s)
- Jeff C H Ko
- Department of Veterinary Clinical Sciences, College of Arts and Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA
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Prassinos NN, Galatos AD, Raptopoulos D. A comparison of propofol, thiopental or ketamine as induction agents in goats. Vet Anaesth Analg 2005; 32:289-96. [PMID: 16135210 DOI: 10.1111/j.1467-2995.2005.00204.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To compare propofol, thiopental and ketamine as induction agents before halothane anaesthesia in goats. STUDY DESIGN Prospective, randomized cross-over study. Animals Seven healthy adult female goats with mean (+/-SD; range) body mass of 38.9 +/- 3.29 kg; 35-45 kg. METHODS The seven animals were used on 21 occasions. Each received all three anaesthetics in a randomized cross-over design, with an interval of at least 2 weeks before re-use. Anaesthesia was induced with intravenous (IV) propofol (3 mg kg(-1)), thiopental (8 mg kg(-1), IV) or ketamine (10 mg kg(-1), IV). Following tracheal intubation, anaesthesia was maintained with halothane for 30 minutes. Indirect blood pressure, heart rate, respiratory rate and arterial blood gases were monitored. The quality of induction and recovery, recovery times and incidence of side-effects were recorded. RESULTS Induction of anaesthesia was smooth and uneventful, and tracheal intubation was easily performed in all but two goats receiving ketamine. Changes in cardiopulmonary variables and acid-base status were similar with all three induction agents and were within clinically acceptable limits. Mean recovery times (time to recovery of swallowing reflex and to standing) were significantly shorter, and side-effects, e.g. apnoea, regurgitation, hypersalivation and tympany, were less common in goats receiving propofol, compared with the other treatments. CONCLUSIONS AND CLINICAL RELEVANCE Propofol 3 mg kg(-1) IV is superior to thiopental and ketamine as an induction agent before halothane anaesthesia in goats. It provides uneventful recovery which is more rapid than thiopental or ketamine, so reduces anaesthetic risk.
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Affiliation(s)
- Nikitas N Prassinos
- Clinic of Surgery, Faculty of Veterinary Medicine, University of Thessaly, Greece.
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Gómez-Villamandos RJ, Redondo JI, Martín EM, Domínguez JM, Granados MM, Estepa JC, Ruiz I, Aguilera E, Santisteban JM. Romifidine or medetomidine premedication before propofol-sevoflurane anaesthesia in dogs. J Vet Pharmacol Ther 2005; 28:489-93. [PMID: 16207314 DOI: 10.1111/j.1365-2885.2005.00688.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- R J Gómez-Villamandos
- Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, University of Córdoba, Campus Universitario de Rabanales, Córdoba, Spain.
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Sano T, Nishimura R, Mochizuki M, Sasaki N. Effects of midazolam-butorphanol, acepromazine-butorphanol and medetomidine on an induction dose of propofol and their compatibility in dogs. J Vet Med Sci 2004; 65:1141-3. [PMID: 14600358 DOI: 10.1292/jvms.65.1141] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effects of acepromazine-butorphanol (AB), midazolam-butorphanol (MB) and medetomidine (Med) on the induction dose of propofol and their compatibility with propofol were evaluated in client-owned dogs. All premedications induced good to excellent sedation and the induction dose of propofol was considerably reduced. Of the tested premedicants, Med induced the deepest sedation and the most potent dose-sparing effect. Induction of anesthesia was excellent to good in all dogs except for one dog premedicated with MB. Most dogs premedicated with AB or MB showed temporary apnea. Although other adverse effects such as bradycardia or hypotension may also occur, premedication with MB, AB or Med is a valuable technique for the induction of anesthesia with propofol in dogs in a clinical setting.
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Affiliation(s)
- Tadashi Sano
- The Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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18
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Mendes GM, Selmi AL, Barbudo-Selmi GR, Lins BT, Figueiredo JP. Clinical use of dexmedetomidine as premedicant in cats undergoing propofol-sevoflurane anaesthesia. J Feline Med Surg 2003; 5:265-70. [PMID: 12948501 DOI: 10.1016/s1098-612x(03)00053-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this report was to evaluate the cardiorespiratory effects and efficacy of dexmedetomidine as a premedicant agent in cats undergoing ovariohysterectomy anaesthetized with propofol-sevoflurane. Cats were randomly divided into two groups of eight animals each. Dexmedetomidine (0.01 mg/kg) or 0.9% saline was administered intravenously (D and S, respectively). After 5 min, propofol was administered intravenously and anaesthesia was maintained with sevoflurane. Heart and respiratory rates, arterial blood pressure, oxygen saturation, rectal temperature and the amount of propofol needed for induction were measured. Premedication with dexmedetomidine reduced the requirement of propofol (6.7+/-3.8 mg/kg), but induced bradycardia, compared with the administration of saline (15.1+/-5.1 mg/kg). Recovery quality was significantly better in D but no significant difference in time to return of swallowing reflex was observed between groups (D=2.5+/-0.5 min; S=3.2+/-1.8 min). In conclusion, dexmedetomidine is a safe and effective agent for premedication in cats undergoing propofol-sevoflurane anaesthesia with minimal adverse effects.
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Affiliation(s)
- G M Mendes
- Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Distrito Federal CEP 70910-970, Brasília, Brazil
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19
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Muir WW, Gadawski JE. Cardiovascular effects of a high dose of romifidine in propofol-anesthetized cats. Am J Vet Res 2002; 63:1241-6. [PMID: 12224853 DOI: 10.2460/ajvr.2002.63.1241] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the hemodynamic effects of IM administration of romifidine hydrochloride in propofol-anesthetized cats. ANIMALS 15 adult domestic shorthair cats. PROCEDURE Cats were randomly assigned to receive romifidine (0, 400, or 2,000 microg/kg, IM). Cats were anesthetized with propofol and mechanically ventilated with oxygen. The right jugular vein, left carotid artery, and right femoral artery and vein were surgically isolated and catheterized. Heart rate; duration of the PR, QRS, and QT intervals; mean pulmonary artery pressure; mean right atrial pressure; systolic, diastolic, and mean arterial pressures; left ventricular systolic pressure; left ventricular end-diastolic pressure; and cardiac output were monitored. Systemic vascular resistance, rate of change of left ventricular pressure, and rate pressure product were calculated. Arterial and venous blood samples were collected anaerobically for determination of pH and blood gas tensions (Po2 and Pco2). RESULTS Administration of romifidine at 400 and 2,000 microg/kg, IM, decreased heart rate, cardiac output, rate of change of left ventricular pressure, rate pressure product, and pH. Arterial and pulmonary artery pressures, left ventricular pressure, left ventricular end-diastolic pressure, and right atrial pressure increased and then gradually returned to baseline values. Arterial blood gas values did not change, whereas venous Pco2 increased and venous Po2 decreased. Significant differences between low and high dosages were rare, suggesting that the dosages investigated produced maximal hemodynamic effects. CONCLUSIONS AND CLINICAL RELEVANCE Romifidine produces cardiovascular effects that are similar to those of other alpha2-agonists. High dosages of romifidine should be used with caution in cats with cardiovascular compromise.
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Affiliation(s)
- William W Muir
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus 43210-1089, USA
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20
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Lamont LA, Bulmer BJ, Grimm KA, Tranquilli WJ, Sisson DD. Cardiopulmonary evaluation of the use of medetomidine hydrochloride in cats. Am J Vet Res 2001; 62:1745-9. [PMID: 11703018 DOI: 10.2460/ajvr.2001.62.1745] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the cardiovascular effects of the alpha2-adrenergic receptor agonist medetomidine hydrochloride in clinically normal cats. ANIMALS 7 clinically normal cats. PROCEDURE Cats were anesthetized with isoflurane, and thermodilution catheters were placed for measurement of central venous, pulmonary, and pulmonary capillary wedge pressures and for determination of cardiac output. The dorsal pedal artery was catheterized for measurement of arterial blood pressures and blood gas tensions. Baseline variables were recorded, and medetomidine (20 microg/kg of body weight, IM) was administered. Hemodynamic measurements were repeated 15 and 30 minutes after medetomidine administration. RESULTS Heart rate, cardiac index, stroke index, rate-pressure product, and right and left ventricular stroke work index significantly decreased from baseline after medetomidine administration, whereas systemic vascular resistance and central venous pressure increased. However, systolic, mean, and diastolic arterial pressures as well as arterial pH, and oxygen and carbon dioxide tensions were not significantly different from baseline values. CONCLUSIONS AND CLINICAL RELEVANCE When administered alone to clinically normal cats, medetomidine (20 microg/kg, IM) induced a significant decrease in cardiac output, stroke volume, and heart rate. Arterial blood pressures did not increase, which may reflect a predominant central alpha2-adrenergic effect over peripheral vascular effects.
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Affiliation(s)
- L A Lamont
- Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana 61801, USA
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21
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Bettschart-Wolfensberger R, Bowen MI, Freeman SL, Feller R, Bettschart RW, Nolan A, Clarke KW. Cardiopulmonary effects of prolonged anesthesia via propofol-medetomidine infusion in ponies. Am J Vet Res 2001; 62:1428-35. [PMID: 11560273 DOI: 10.2460/ajvr.2001.62.1428] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine cardiopulmonary effects of total IV anesthesia with propofol and medetomidine in ponies and effect of atipamezole on recovery. ANIMALS 10 ponies. PROCEDURE After sedation was induced by IV administration of medetomidine (7 microg/kg of body weight), anesthesia was induced by IV administration of propofol 12 mg/kg) and maintained for 4 hours with infusions of medetomidine (3.5 microg/kg per hour) and propofol 10.07 to 0.11 mg/kg per minute). Spontaneous respiration was supplemented with oxygen. Cardiopulmonary measurements and blood concentrations of propofol were determined during anesthesia. Five ponies received atipamezole (60 microg/kg) during recovery. RESULTS During anesthesia, mean cardiac index and heart rate increased significantly until 150 minutes, then decreased until cessation of anesthesia. Mean arterial pressure and systemic vascular resistance index increased significantly between 150 minutes and 4 hours. In 4 ponies, PaO2 decreased to < 60 mm Hg. Mean blood propofol concentrations from 20 minutes after induction onwards ranged from 2.3 to 3.5 microg/ml. Recoveries were without complications and were complete within 28 minutes with atipamezole administration and 39 minutes without atipamezole administration. CONCLUSIONS AND CLINICAL RELEVANCE During total IV anesthesia of long duration with medetomidine-propofol, cardiovascular function is comparable to or better than under inhalation anesthesia. This technique may prove suitable in equids in which prompt recovery is essential; however, in some animals severe hypoxia may develop and oxygen supplementation may be necessary.
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Kuusela E, Raekallio M, Väisänen M, Mykkänen K, Ropponen H, Vainio O. Comparison of medetomidine and dexmedetomidine as premedicants in dogs undergoing propofol-isoflurane anesthesia. Am J Vet Res 2001; 62:1073-80. [PMID: 11453483 DOI: 10.2460/ajvr.2001.62.1073] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare 3 dose levels of medetomidine and dexmedetomidine for use as premedicants in dogs undergoing propofol-isoflurane anesthesia. ANIMALS 6 healthy Beagles. PROCEDURE Dogs received medetomidine or dexmedetomidine intravenously at the following dose levels: 0.4 microg of medetomidine or 0.2 microg of dexmedetomidine/kg of body weight (M0.4/D0.2), 4.0 microg of medetomidine or 2.0 microg of dexmedetomidine/kg (M4/D2), and 40 microg of medetomidine or 20 microg of dexmedetomidine/kg (M40/D20). Sedation and analgesia were scored before induction. Anesthesia was induced with propofol and maintained with isoflurane. End-tidal isoflurane concentration, heart rate, and arterial blood pressures and gases were measured. RESULTS Degrees of sedation and analgesia were significantly affected by dose level but not drug. Combined mean end-tidal isoflurane concentration for all dose levels was higher in dogs that received medetomidine, compared with dexmedetomidine. Recovery time was significantly prolonged in dogs treated at the M40/D20 dose level, compared with the other dose levels. After induction, blood pressure decreased below reference range and heart rate increased in dogs treated at the M0.4/D0.2 dose level, whereas blood pressure was preserved in dogs treated at the M40/D20 dose level. However, dogs in these latter groups developed profound bradycardia and mild metabolic acidosis during anesthesia. Treatment at the M4/D2 dose level resulted in more stable cardiovascular effects, compared with the other dose levels. In addition, PaCO2 was similar among dose levels. CONCLUSIONS AND CLINICAL RELEVANCE Dexmedetomidine is at least as safe and effective as medetomidine for use as a premedicant in dogs undergoing propofol-isoflurane anesthesia.
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Affiliation(s)
- E Kuusela
- Department of Clinical Veterinary Sciences, Faculty of Veterinary Medicine, University of Helsinki, Finland
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Bettschart-Wolfensberger R, Freeman SL, Jäggin-Schmucker N, Clarke KW. Infusion of a combination of propofol and medetomidine for long-term anesthesia in ponies. Am J Vet Res 2001; 62:500-7. [PMID: 11327455 DOI: 10.2460/ajvr.2001.62.500] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the minimal infusion rate of propofol in combination with medetomidine for long-term anesthesia in ponies and the effects of atipamezole on recovery. ANIMALS 12 ponies. PROCEDURE Ponies were sedated with medetomidine (7 microg/kg of body weight, IV). Ten minutes later, anesthesia was induced with propofol (2 mg/kg, IV). Anesthesia was maintained for 4 hours, using an infusion of medetomidine (3.5 microg/kg per hour, IV) and propofol at a rate sufficient to prevent ponies from moving after electrical stimulation. Arterial blood pressures and blood gas analysis, heart rates, and respiratory rates were monitored. For recovery, 6 ponies were given atipamezole (60 microg/kg, IV). Induction and recovery were scored. RESULTS Minimal propofol infusion rates ranged from 0.06 to 0.1 mg/kg per min. Mean arterial blood pressure was stable (range, 74 to 86 mm Hg), and heart rate (34 to 51 beats/min) had minimal variations. Variable breathing patterns were observed. Mean PaO2 (range, 116 to 146 mm Hg) and mean PaCO2 (range, 48 to 51 mm Hg) did not change significantly with time, but hypoxemia was evident in some ponies (minimal PaO2, 47 mm Hg). Recovery was fast and uneventful with and without atipamezole (completed in 20.2 and 20.9 minutes, respectively). CONCLUSIONS AND CLINICAL RELEVANCE Infusion of a combination of medetomidine and propofol was suitable for prolonged anesthesia in ponies. Recovery was rapid and uneventful. A combination of propofol and medetomidine may prove suitable for long-term anesthesia in horses. Monitoring of blood gases is essential because of potential hypoxemia.
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Abstract
The alpha 2 agonists can produce reliable dose-dependent sedation and analgesia in most species. Nevertheless, they can also produce significant physiological adverse side effects depending on dose, rate, route of administration, and the concurrent use of other CNS depressants. For this reason, it may be best to use a low dose of an alpha 2 agonist as a preanesthetic agent. The alpha 2 agonists are best suited for young, healthy, exercise-tolerant patients. The combining of low doses of alpha 2, opioid, and benzodiazepine agonists results in a synergistic CNS depressant response while minimizing the undesirable side effects of these three classes of drugs. Each group of drugs has specific antagonists available for their reversal, thus allowing veterinarians to reverse one or more of the agonists depending on the desired response. This may represent a significant advantage to the use of low-dose alpha 2 agonists in combination with opioids and benzodiazepines.
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Affiliation(s)
- R R Paddleford
- Department of Small Animal Clinical Science, University of Tennessee, College of Veterinary Medicine, Knoxville, USA.
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Hall L, Lagerweij E, Nolan A, Sear J. Disposition of propofol after medetomidine premedication in beagle dogs. ACTA ACUST UNITED AC 1997. [DOI: 10.1111/j.1467-2995.1997.tb00264.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Cullen LK, Reynoldson JA. Effects of tiletamine/zolazepam premedication on propofol anaesthesia in dogs. Vet Rec 1997; 140:363-6. [PMID: 9133720 DOI: 10.1136/vr.140.14.363] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The cardiovascular and pulmonary effects of tiletamine/zolazepam, propofol and tiletamine/zolazepam plus propofol were studied in five mongrel dogs. A cannula inserted into a raised carotid artery was used to measure mean arterial pressure (MAP) and heart rate continuously and to collect arterial blood for the determination of pH, PO2, PCO2, bicarbonate and base balance. Respiratory frequency and rectal temperature were also recorded. In the two propofol groups premedication had no significant effect on the time to rejection of an endotracheal tube and the return to sternal recumbency. The MAP and heart rate increased after tiletamine/zolazepam alone and after tiletamine/zolazepam plus propofol, although propofol alone reduced MAP and transiently increased heart rate. Respiratory frequency decreased transiently in both propofol groups in association with a significant increase in PaCO2 and decrease in PaO2. The most notable change was the hypoxaemia in the tiletamine/zolazepam plus propofol group in which the PaO2 was reduced. In all the dogs given tiletamine/zolazepam alone undesirable side effects were observed, effects which also occurred during the recovery of the dogs given tiletamine/zolazepam plus propofol.
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Affiliation(s)
- L K Cullen
- School of Veterinary Studies, Murdoch University, Australia
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Cullen LK. Medetomidine sedation in dogs and cats: a review of its pharmacology, antagonism and dose. THE BRITISH VETERINARY JOURNAL 1996; 152:519-35. [PMID: 8885463 DOI: 10.1016/s0007-1935(96)80005-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Medetomidine is a relatively new sedative analgesic in dogs and cats but some precautions are required when using it. It is a potent alpha 2-adrenoceptor agonist and stimulates receptors centrally to produce dose-dependent sedation and analgesia and receptors centrally and peripherally to cause marked bradycardia and decrease the cardiac output. While hypotension occurs frequently, higher doses of the sedative can raise the blood pressure due to an affect on peripheral receptors. Slowing of the respiratory rate is a frequent effect of medetomidine with some dogs showing signs of cyanosis. Other actions that follow medetomidine use are slowing of gastrointestinal motility, hypothermia, changes to endocrine function and, occasionally, vomiting and muscle twitching. The clinical use of medetomidine in dogs and cats is discussed. Recommended dose rates are presented along with precautions that should be taken when it is used alone for sedation, as an anaesthetic premedicant or in combination with ketamine, propofol or opioids. Hypoxaemia occurs frequently in dogs given medetomidine and propofol. The actions of medetomidine can be rapidly reversed with the specific alpha 2-adrenoceptor antagonist, atipamezole, which is an advantage because undesirable and sedative actions of medetomidine can be terminated.
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Affiliation(s)
- L K Cullen
- School of Veterinary Studies, Murdoch University, Australia
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28
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Hammond R, England G. The effect of medetomidine premedication upon propofol induction and infusion anaesthesia in the dog. ACTA ACUST UNITED AC 1994. [DOI: 10.1111/j.1467-2995.1994.tb00478.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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