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1.
J Zoo Wildl Med ; 52(3): 986-996, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34687514

RESUMO

Dependent on timing of assessment, anesthetic agents and specifically medetomidine negatively affect cardiac function in great apes. The aim of this study was to determine the influence of tiletamine-zolazepam (TZ) with and without medetomidine on cardiac structure and function in healthy chimpanzees (Pan troglodytes) during a period of relative blood pressure stability. Twenty-four chimpanzees living in an African wildlife sanctuary undergoing routine health assessments were stratified by age, sex, and body mass and randomized to be anesthetized using either TZ (6 mg/kg; n = 13; seven males and six females) or a combination of TZ (2 mg/kg) and medetomidine (TZM; 0.02 mg/kg; n = 11; five males and six females). During health checks, regular heart rate and blood pressure readings were taken and a standardized echocardiogram was performed 20-30 min after induction. Data were compared between the two anesthetic groups using independent-samples t or Mann-Whitney U tests. Although heart rate (mean ± SD; TZ: 76 ± 10 bpm; TZM: 65 ± 14 bpm, P = 0.027), cardiac output (TZ: 3.0 ± 0.7 L/min; TZM: 2.4 ± 0.7 L/min, P = 0.032), and mitral A-wave velocities (TZ: 0.51 ± 0.16 cm/s; TZM: 0.36 ± 0.10 cm/s, P = 0.013) were lower in the TZM group, there were no statistically significant differences in cardiac structure or the remaining functional variables between groups. Furthermore, there were no statistical differences in systolic (TZ 114.6 ± 14.9 mmHg; TZM: 123.0 ± 28.1 mmHg; P = 0.289) or diastolic blood pressure (TZ: 81.8 ± 22.3 mmHg, TZM: 83.8 ± 20.1 mmHg; P = 0.827) between the groups during the echocardiogram. This study has shown that during a period of relative blood pressure stability, during the first 20-30 min after induction there are few differences in measures of cardiac structure and function between protocols using TZ with or without medetomidine in healthy chimpanzees.


Assuntos
Anestesia , Anestésicos , Anestesia/veterinária , Anestésicos/farmacologia , Animais , Feminino , Frequência Cardíaca , Masculino , Medetomidina/farmacologia , Pan troglodytes
2.
J Zoo Wildl Med ; 52(3): 1018-1023, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34687519

RESUMO

This study is aimed at evaluating the efficacy of two protocols for the immobilization of mouflon (Ovis orientalis musimon). Six mouflon were immobilized twice using IM medetomidine 0.07 ± 0.01 mg/kg, ketamine 2.88 ± 0.48 mg/kg, and morphine 0.57 ± 0.09 mg/kg (MKM) or dexmedetomidine 0.04 ± 0.01 mg/kg, ketamine 3.01 ± 0.6 mg/kg, and morphine 0.60 ± 0.12 mg/kg (DKM). Anesthetic times were recorded from injection to initial drug effects, sternal recumbency, lateral recumbency, unresponsiveness to external stimuli, and recovery following atipamezole IM administration. Cardiopulmonary variables (HR in beats/min, RR in breaths/min, mean, systolic, and diastolic noninvasive blood pressure [MAP, SAP, DAP] in mm Hg, oxygen hemoglobin saturation [SpO2)], expired end tidal carbon dioxide [PECO2]), and rectal temperature in °C were monitored and recorded. No statistically significant differences were detected between protocols at any time point and no significant differences were detected in any measured variables at any time point between protocols. However, a significant decrease in the noninvasive blood pressure variables (SAP, MAP, and DAP) and in the RR were detected over time. Both chemical immobilization protocols provided at least 50 min of immobilization in mouflon, allowing minor procedures and tracheal intubation.


Assuntos
Dexmedetomidina , Ketamina , Anestésicos Dissociativos/farmacologia , Animais , Dexmedetomidina/farmacologia , Frequência Cardíaca , Hipnóticos e Sedativos/farmacologia , Imobilização/veterinária , Ketamina/farmacologia , Medetomidina/farmacologia , Morfina/farmacologia , Carneiro Doméstico
3.
Vet Anaesth Analg ; 48(5): 707-715, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34332900

RESUMO

OBJECTIVE: To compare ketamine-butorphanol-medetomidine (KBM) with butorphanol-midazolam-medetomidine (BMM) immobilization of serval. STUDY DESIGN: Blinded, randomized trial. ANIMALS: A total of 23 captures [KBM: five females, six males; 10.7 kg (mean); BMM: 10 females, two males; 9.6 kg]. METHODS: Serval were cage trapped and immobilized using the assigned drug combination delivered via a blow dart into gluteal muscles. Prior to darting, a stress score was assigned (0: calm; to 3: markedly stressed). Drug combinations were dosed based on estimated body weights: 8.0, 0.4 and 0.08 mg kg-1 for KBM and 0.4, 0.3 and 0.08 mg kg-1 for BMM, respectively. Time to first handling, duration of anaesthesia and recovery times were recorded. Physiological variables including blood glucose and body temperature were recorded at 5 minute intervals. Atipamezole (5 mg mg-1 medetomidine) and naltrexone (2 mg mg-1 butorphanol) were administered intramuscularly prior to recovery. Data, presented as mean values, were analysed using general linear mixed model and Spearman's correlation (stress score, glucose, temperature); significance was p < 0.05. RESULTS: Doses based on actual body weights were 8.7, 0.4 and 0.09 mg kg-1 for KBM and 0.5, 0.4 and 0.09 mg kg-1 for BMM, respectively. Time to first handling was 10.2 and 13.3 minutes for KBM and BMM, respectively (p = 0.033). Both combinations provided cardiovascular stability during anaesthesia that lasted a minimum of 35 minutes. Recovery was rapid and calm overall, but ataxia was noted in KBM. Stress score was strongly correlated to blood glucose (r2 = 0.788; p = 0.001) and temperature (r2 = 0.634; p = 0.015). CONCLUSIONS AND CLINICAL RELEVANCE: Both combinations produced similar effective immobilization that was cardiovascularly stable in serval. Overall, BMM is recommended because it is fully antagonizable. A calm, quiet environment before drug administration is essential to avoid capture-induced hyperglycaemia and hyperthermia.


Assuntos
Butorfanol , Hipnóticos e Sedativos , Ketamina , Medetomidina , Midazolam , Animais , Animais Selvagens , Butorfanol/farmacologia , Feminino , Hipnóticos e Sedativos/farmacologia , Imobilização/veterinária , Ketamina/farmacologia , Masculino , Medetomidina/farmacologia , Midazolam/farmacologia
4.
J Avian Med Surg ; 35(2): 167-179, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34256547

RESUMO

The effects of an injectable anesthesia with 0.05 mg/kg medetomidine, 5 mg/kg ketamine, and 0.5 mg/kg butorphanol administered together intramuscularly were evaluated in 22 captive Humboldt penguins (Spheniscus humboldti, 10 male and 12 female), with a mean age of 8.5 ± 8.23 years. The birds fasted for18-24 hours prior to the procedure. Induction was followed by 4 distinct progressive responses of the birds to the anesthetic effect, including onset of initial effects at 2.0 ± 1.7 minutes (x̄ ± SD), sternal recumbency with the head still elevated at 2.2 ± 1.6 minutes, lowering and placing the beak tip to the ground at 3.6 ± 3.4 minutes, and lateral positioning of the neck and head at 4.2 ± 3.4 minutes. A general state of sedation, muscle relaxation, and analgesia were noted 10.0 ± 2.8 minutes postinjection. However, according to an established scoring system for the assessment of anesthetic depth in avian patients, a surgical plane of anesthesia was not achieved. Muscle relaxation determined by the same scoring system lasted for 31.4 ± 17.1 minutes. The penguins' mean respiratory rate did not demonstrate significant change and spontaneous ventilation was present throughout the procedure. Relative peripheral arterial oxygen saturation decreased significantly from 92.83 ± 5.77% at 10 minutes to 90.91 ± 5.77% at 40 minutes following induction. The birds' heart rate also decreased significantly from 112.55 ± 23.97 beats/min at 10 minutes to 101.65 ± 25.42 beats/min at 40 minutes. The measured cloacal temperatures were maintained within normal range despite ambient temperatures of up to 28.3°C (82.9°F). Reversal of medetomidine with 0.25 mg/kg atipamezole was conducted after 45.1 ± 7.3 minutes. Recovery was smooth but of variable duration with patients being able or willing to stand steadily in an upright position after 50.1 ± 34.6 minutes. One penguin died during recovery from a ruptured left ventricle and consecutive pericardial tamponade, but no predisposing factors were identified. The anesthetic protocol proved to be effective for noninvasive and minor painful procedures (eg, diagnostic imaging, blood collection). Disadvantages to the administration of the combined anesthetic agents in the penguins included a short period of muscle relaxation and smooth but potentially prolonged recovery. The safety of the anesthetic protocol described for Humboldt penguins in this report has to be evaluated critically against the the death of 1 penguin during recovery.


Assuntos
Anestesia , Ketamina , Spheniscidae , Anestesia/veterinária , Animais , Butorfanol/farmacologia , Feminino , Frequência Cardíaca , Hipnóticos e Sedativos/farmacologia , Ketamina/farmacologia , Masculino , Medetomidina/farmacologia
5.
J Neurosci ; 41(33): 7048-7064, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34244361

RESUMO

The mouse auditory cortex is comprised of several auditory fields spanning the dorsoventral axis of the temporal lobe. The ventral most auditory field is the temporal association cortex (TeA), which remains largely unstudied. Using Neuropixels probes, we simultaneously recorded from primary auditory cortex (AUDp), secondary auditory cortex (AUDv), and TeA, characterizing neuronal responses to pure tones and frequency modulated (FM) sweeps in awake head-restrained female mice. As compared with AUDp and AUDv, single-unit (SU) responses to pure tones in TeA were sparser, delayed, and prolonged. Responses to FMs were also sparser. Population analysis showed that the sparser responses in TeA render it less sensitive to pure tones, yet more sensitive to FMs. When characterizing responses to pure tones under anesthesia, the distinct signature of TeA was changed considerably as compared with that in awake mice, implying that responses in TeA are strongly modulated by non-feedforward connections. Together, these findings provide a basic electrophysiological description of TeA as an integral part of sound processing along the cortical hierarchy.SIGNIFICANCE STATEMENT This is the first comprehensive characterization of the auditory responses in the awake mouse auditory temporal association cortex (TeA). The study provides the foundations for further investigation of TeA and its involvement in auditory learning, plasticity, auditory driven behaviors etc. The study was conducted using state of the art data collection tools, allowing for simultaneous recording from multiple cortical regions and numerous neurons.


Assuntos
Córtex Auditivo/fisiologia , Discriminação Psicológica/fisiologia , Neurônios/fisiologia , Discriminação da Altura Tonal/fisiologia , Estimulação Acústica , Potenciais de Ação , Anestesia , Animais , Conjuntos de Dados como Assunto , Eletrodos Implantados , Feminino , Ketamina , Medetomidina , Camundongos , Camundongos Endogâmicos C57BL , Vigília
6.
Schweiz Arch Tierheilkd ; 163(6): 431-436, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34097637

RESUMO

INTRODUCTION: A mixed breed dog was anesthetized for diagnostic myelography to investigate acute onset neck pain. Instead of contrast medium, 444 µg/kg medetomidine were inadvertently injected into the cerebromedullaris cisterna owing to a human error. Severe bradycardia, undetectable peripheral pulse, respiratory arrest and loss of pupillary, palpebral and corneal reflexes were observed immediately after injection. Profound hypothermia developed and esophageal temperature, measured 20 minutes after medetomidine injection, was 33 °C. Atipamezole at 1 mg/kg im was administered, followed by a second dose of 0,5 mg/kg iv 20 minutes thereafter. In the meantime, cardiorespiratory parameters and body temperature were monitored, and supportive care that included manually assisted pulmonary ventilation, active warming, and administration of 5 µg/kg/min dopamine was initiated. The dog's clinical condition improved within one hour from the beginning of supportive care, at which time ocular reflexes and swallowing returned, spontaneous ventilation was deemed as adequate and the trachea could be extubated. The dog was discharged in good clinical conditions five days later. Human error and distraction led to a potentially life-threatening complication in the dog of this report and could have possibly been prevented with the use of checklists and with a clearer definition of roles and responsibilities of the personnel involved prior to commencing the clinical procedure. Profound cardiovascular, respiratory, and thermoregulatory depression caused by intracisternal injection of medetomidine responded to parenteral administration of its antagonist and supportive care.


Assuntos
Imidazóis/administração & dosagem , Medetomidina/administração & dosagem , Medetomidina/efeitos adversos , Erros Médicos/veterinária , Mielografia/veterinária , Antagonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Animais , Cães , Hipnóticos e Sedativos/administração & dosagem , Resultado do Tratamento
7.
J Zoo Wildl Med ; 52(2): 445-452, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34130386

RESUMO

Great ape anesthesia is reported to carry a significant risk. Therefore, techniques aiming to reduce stress and increase welfare, such as hand injection of anesthesia induction agents, have received considerable attention in zoo, laboratory, and captive wildlife environments. However, there is little evidence to support the superiority of such techniques. To investigate this issue, anesthesia records of healthy zoo-housed chimpanzees (Pan troglodytes) between 2012 and 2017 in which the animal was either darted or hand injected were analyzed (n = 50). Sex, age, induction, muscle relaxation, and overall anesthesia quality as well as recovery ratings, heart rate, systolic, mean and diastolic blood pressure, respiratory rate, end-tidal CO2, oxygen saturation (SpO2), and body temperature were analyzed. Chimpanzees that were darted showed statistically significantly higher heart rate, SpO2, and body temperature than those that were hand injected. It was found that darted chimpanzees were also significantly more likely to have poorer perianesthetic muscle relaxation and overall anesthesia rating scores. This study provides further evidence that the use of hand injection can reduce factors associated with stress and improve the quality of chimpanzee anesthesia.


Assuntos
Injeções Intramusculares/veterinária , Medetomidina/farmacologia , Pan troglodytes , Tiletamina/farmacologia , Zolazepam/farmacologia , Anestésicos Dissociativos/administração & dosagem , Anestésicos Dissociativos/farmacologia , Animais , Ansiolíticos/administração & dosagem , Ansiolíticos/farmacologia , Combinação de Medicamentos , Feminino , Hipnóticos e Sedativos/administração & dosagem , Hipnóticos e Sedativos/farmacologia , Injeções Intramusculares/métodos , Masculino , Medetomidina/administração & dosagem , Midazolam/farmacologia , Tiletamina/administração & dosagem , Zolazepam/administração & dosagem
8.
J Zoo Wildl Med ; 52(2): 715-720, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34130416

RESUMO

Fifty-three free-ranging moose (Alces americanus) cows were darted from a helicopter with 3-4 ml of a premix combination of butorphanol (27.3 mg/ml), azaperone (9.1 mg/ml), and medetomidine (10.9 mg/ml; BAM), equivalent to estimated dosages of: butorphanol 0.26 ± 0.08 (mean ± SD) mg/kg, azaperone 0.09 ± 0.03 mg/kg, and medetomidine 0.11 ± 0.03 mg/kg. After a mean chase time (from sighting to darting) of 6.1 ± 5.5 min, the mean induction time (from darting to recumbency) was 8.3 ± 2.6 min. This combination provided a safe and reliable sedation for minor procedures that lasted 30-60 min. Heart rate (50.4 ± 7.0 beats/min), respiratory rate (21.3 ± 11.1 breaths/minute), ETCO2 via nasal canula (43.2 ± 7.0 mmHg), and rectal temperature (38.5°C ± 0.7°C) mostly remained at expected values for wild cervid and bovid species anesthetized with this drug combination. SpO2 (90.0% ± 3.7%) was suggestive of moderate hypoxemia despite intranasal oxygen supplementation (1 L per 100 kg/min). The recovery time to standing was 6.7 ± 3.8 min after reversal with IM naltrexone (3 mg/mg butorphanol) and atipamezole (5 mg/mg medetomidine). Despite a larger volume to inject, this protocol offers an alternative to highly potent opioids, and should be considered for practical or staff safety reasons. On the basis of the results of this study, the use of 4 ml of BAM is considered a safe and effective protocol for immobilization of cow moose under comparable settings.


Assuntos
Azaperona/farmacologia , Butorfanol/farmacologia , Cervos , Medetomidina/farmacologia , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/farmacologia , Anestesia/veterinária , Animais , Animais Selvagens , Azaperona/administração & dosagem , Butorfanol/administração & dosagem , Feminino , Hipnóticos e Sedativos/administração & dosagem , Hipnóticos e Sedativos/farmacologia , Imobilização/veterinária , Medetomidina/administração & dosagem
9.
Eur J Neurosci ; 54(3): 4906-4919, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34137097

RESUMO

Medetomidine and isoflurane are commonly used for general anaesthesia in fMRI studies, but they alter cerebral blood flow (CBF) regulation and neurovascular coupling (NVC). In addition, medetomidine induces hypoinsulinemia and hyperglycaemia, which also alter CBF regulation and NVC. Furthermore, sudden changes in arterial pressure induced by noxious stimulation may affect NVC differently under medetomidine and isoflurane anaesthesia, considering their different effects on vascular functions. The first objective of this study was to compare NVC under medetomidine and isoflurane anaesthesia during noxious stimulation. The second objective was to examine whether fasting may improve NVC by reducing medetomidine-induced hyperglycaemia. In male Wister rats, noxious electrical stimulation was applied to the sciatic nerve in fasted or non-fasted animals. CBF and local field potentials (LFP) were recorded in the somatosensory cortex to assess NVC (CBF/LFP ratio). The CBF/LFP ratio was increased by medetomidine compared with isoflurane (p = 0.004), but this effect was abolished by fasting (p = 0.8). Accordingly, medetomidine produced a threefold increase in blood glucose (p < 0.001), but this effect was also abolished by fasting (p = 0.3). This indicates that isoflurane and medetomidine anaesthesia alter NVC differently, but the undesirable glucose dependent effects of medetomidine on NVC can be prevented by fasting.


Assuntos
Hiperglicemia , Isoflurano , Acoplamento Neurovascular , Animais , Jejum , Isoflurano/toxicidade , Masculino , Medetomidina , Ratos , Córtex Somatossensorial
10.
J S Afr Vet Assoc ; 92(0): e1-e5, 2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34082540

RESUMO

Anaesthesia in pinnipeds is considered a much higher risk than in most terrestrial mammals because of their frequent proximity to water and physiological and anatomical adaptations related to diving, which also influence their anaesthesia management. Anaesthetising and immobilising entangled seals does not allow for selection of animals that are at a safe distance from the water's edge. Medetomidine-midazolam-butorphanol (MMB) sedation was trialled on eight entangled Cape fur seals (CFS) (Arctocephalus pusillus pusillus) to determine if it was safe to use on animals that entered the water post-darting. The MMB was given at an estimated dose of 0.03 mg/kg, 0.2 mg/kg and 0.2 mg/kg, respectively, via remote darting. Sedation was reversed with intramuscular atipamezole (0.15 mg/kg) and naltrexone (0.4 mg/kg) to antagonise the effects of medetomidine and butorphanol, respectively. Moderate sedation was achieved in six animals. Six of the animals entered the water after being darted. There was a single mortality and a single animal that was too lightly sedated for capture. The preliminary results indicate that MMB produces suitable sedation for disentanglement of CFS. Additionally, MMB might be suitable for application to field-based biological research.


Assuntos
Butorfanol/farmacologia , Otárias , Medetomidina/farmacologia , Midazolam/farmacologia , Antagonistas de Receptores Adrenérgicos alfa 2/administração & dosagem , Antagonistas de Receptores Adrenérgicos alfa 2/farmacologia , Analgésicos Opioides/administração & dosagem , Analgésicos Opioides/farmacologia , Animais , Sedação Consciente , Combinação de Medicamentos , Hipnóticos e Sedativos/administração & dosagem , Hipnóticos e Sedativos/farmacologia , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Medetomidina/administração & dosagem , Midazolam/administração & dosagem , Naltrexona/administração & dosagem , Naltrexona/farmacologia , Antagonistas de Entorpecentes/administração & dosagem , Antagonistas de Entorpecentes/farmacologia
11.
BMC Vet Res ; 17(1): 201, 2021 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-34049559

RESUMO

BACKGROUND: The bispectral index (BIS) is an anaesthesia monitoring technique able to assess the level of central nervous system depression in humans and various animal species. In birds, it has been validated in chickens undergoing isoflurane anaesthesia. The aim of this study was to evaluate in an avian species the influence of isoflurane and sevoflurane on BIS, each at different minimum anaesthetic concentrations (MAC) multiples, alone or combined with butorphanol or medetomidine. Ten chickens (5 males and 5 females) underwent general anaesthesia with isoflurane or sevoflurane alone, and combined with either intramuscular administration of butorphanol (1 mg/kg) or medetomidine (0.1 mg/kg), in a prospective and cross-over study (i.e., 6 treatments per animal). BIS measurements were compared to heart rate (HR), non-invasive blood pressure (NIBP) and to a visual analogue scale (VAS) of anaesthesia depth. RESULTS: HR was significantly increased, and both NIBP and VAS were significantly reduced, with higher gas concentrations. NIBP (but not HR or VAS) was additionally affected by the type of gas, being lower at higher concentrations of sevoflurane. Butorphanol had no additional effect, but medetomidine led to differences in HR, NIBP, and in particular a reduction in VAS. With respect to deeper level of hypnosis at higher concentrations and the absence of difference between gases, BIS measurements correlated with all other measures (except with HR, where no significant relationship was found) The difference in BIS before (BISpre) and after stimulation (BISpost) did not remain constant, but increased with increasing MAC multiples, indicating that the BISpost is not suppressed proportionately to the suppression of the BISpre values due to gas concentration. Furthermore, neither butorphanol nor medetomidine affected the BIS. CONCLUSIONS: The difference of degree of central nervous system depression monitored by BIS compared with neuromuscular reflexes monitored by VAS, indicate that BIS records a level of anaesthetic depth different from the one deducted from VAS monitoring alone. BIS provided complementary information such as that medetomidine suppressed spinal reflexes without deepening the hypnotic state. As a consequence, it is concluded that BIS improves the assessment of the level of hypnosis in chickens, improving anaesthesia monitoring and anaesthesia quality in this species.


Assuntos
Butorfanol/farmacologia , Galinhas , Monitores de Consciência/veterinária , Isoflurano/farmacologia , Medetomidina/farmacologia , Sevoflurano/farmacologia , Anestésicos Combinados/farmacologia , Animais , Estudos Cross-Over , Feminino , Frequência Cardíaca/efeitos dos fármacos , Masculino , Estudos Prospectivos
12.
J Wildl Dis ; 57(3): 495-502, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34015804

RESUMO

The nutria (Myocastor coypus), a rodent native to South America, has been introduced and has established feral populations at numerous locations in North America, Europe, and Asia. As such, the nutria is subject to research and management programs, including investigation of surgical fertility-control techniques. We evaluated the efficacy of a mixture of ketamine and medetomidine, with additional use of isoflurane and reversal with atipamezole, to provide safe, reliable anesthesia for surgical procedures under field conditions. We anesthetized 40 free-ranging nutrias between December 2018 and March 2019, in Turin, Italy, to perform surgical reproduction control techniques. We administered a ketamine and medetomidine mixture (6 mg/kg and 140 µg/kg, respectively) after trapping the animals and weighing them in the cage traps. After induction, we reweighed the rodents and performed a brief clinical examination. The times of loss of palpebral and pedal reflexes were noted. After induction of anesthesia, heart rate, respiratory rate, and percentage of oxygen saturation were monitored and recorded. Isoflurane was delivered through a face mask to 27 nutrias (70%) to maintain an adequate depth of anesthesia. Upon completion of surgery and other procedures, atipamezole was administered to the animals at doses 2.5 higher than those of medetomidine (actual dose: 366±31 µg/kg). Induction times were short (3±2 min), with the animals completely immobilized. The heart rate and respiratory rate both decreased. After administration of atipamezole, recoveries were smooth and complete. There were two deaths after higher doses of atipamezole and longer surgeries. Carprofen (4 mg/kg) was administered subcutaneously for its analgesic effects. The animals were released at the end of all the procedures. Overall, the medetomidine and ketamine mixture, with supplemental isoflurane in most instances, provided a reliable anesthesia in free-ranging nutrias, adequate for performing surgical procedures under field conditions.


Assuntos
Anestesia , Isoflurano , Ketamina , Anestesia/veterinária , Anestésicos Dissociativos/farmacologia , Animais , Frequência Cardíaca , Hipnóticos e Sedativos/farmacologia , Isoflurano/farmacologia , Ketamina/farmacologia , Medetomidina/farmacologia , Reprodução
13.
Vet Anaesth Analg ; 48(4): 537-540, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34023229

RESUMO

OBJECTIVE: To quantify induction time, reliability, physiological effects, recovery quality and dart volume of a novel formulation of alfaxalone (40 mg mL-1) used in combination with medetomidine and azaperone for the capture and handling of wild bighorn sheep. STUDY DESIGN: Prospective clinical study. ANIMALS: A total of 23 wild bighorn sheep (Ovis canadensis) in Sheep River Provincial Park, AB, Canada. METHODS: Free-ranging bighorn sheep were immobilized using medetomidine, azaperone and alfaxalone delivered with a remote delivery system. Arterial blood was collected for measurement of blood gases, physiologic variables (temperature, heart and respiratory rates) were recorded and induction and recovery length and quality were scored. RESULTS: Data from 20 animals were included. Administered dose rates were alfaxalone (0.99 ± 0.20 mg kg-1; 40 mg mL-1), azaperone (0.2 ± 0.04 mg kg-1; 10 mg mL-1) and medetomidine (0.16 ± 0.03 mg kg-1; 30 mg mL-1). The mean drug volume injected was 1.51 mL. The median (range) induction time was 7.7 (5.8-9.7) minutes, and recovery was qualitatively smooth. CONCLUSIONS AND CLINICAL RELEVANCE: An increased concentration formulation of alfaxalone was administered in combination with medetomidine and azaperone, and resulted in appropriate anesthesia for the capture and handling of bighorn sheep. The dart volume was small, with potential for reducing capture-related morbidity.


Assuntos
Hipnóticos e Sedativos , Pregnanodionas , Animais , Imobilização/veterinária , Medetomidina , Estudos Prospectivos , Reprodutibilidade dos Testes
14.
PLoS Biol ; 19(4): e3001146, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33793545

RESUMO

General anesthesia is characterized by reversible loss of consciousness accompanied by transient amnesia. Yet, long-term memory impairment is an undesirable side effect. How different types of general anesthetics (GAs) affect the hippocampus, a brain region central to memory formation and consolidation, is poorly understood. Using extracellular recordings, chronic 2-photon imaging, and behavioral analysis, we monitor the effects of isoflurane (Iso), medetomidine/midazolam/fentanyl (MMF), and ketamine/xylazine (Keta/Xyl) on network activity and structural spine dynamics in the hippocampal CA1 area of adult mice. GAs robustly reduced spiking activity, decorrelated cellular ensembles, albeit with distinct activity signatures, and altered spine dynamics. CA1 network activity under all 3 anesthetics was different to natural sleep. Iso anesthesia most closely resembled unperturbed activity during wakefulness and sleep, and network alterations recovered more readily than with Keta/Xyl and MMF. Correspondingly, memory consolidation was impaired after exposure to Keta/Xyl and MMF, but not Iso. Thus, different anesthetics distinctly alter hippocampal network dynamics, synaptic connectivity, and memory consolidation, with implications for GA strategy appraisal in animal research and clinical settings.


Assuntos
Anestésicos/efeitos adversos , Hipocampo/efeitos dos fármacos , Consolidação da Memória/efeitos dos fármacos , Coluna Vertebral/efeitos dos fármacos , Anestesia/efeitos adversos , Anestésicos/farmacologia , Animais , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Feminino , Fentanila/efeitos adversos , Fentanila/farmacologia , Hipocampo/citologia , Hipocampo/fisiologia , Isoflurano/efeitos adversos , Isoflurano/farmacologia , Ketamina/efeitos adversos , Ketamina/farmacologia , Masculino , Medetomidina/efeitos adversos , Medetomidina/farmacologia , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Midazolam/efeitos adversos , Midazolam/farmacologia , Rede Nervosa/efeitos dos fármacos , Rede Nervosa/fisiologia , Coluna Vertebral/fisiologia , Xilazina/efeitos adversos , Xilazina/farmacologia
15.
J Zoo Wildl Med ; 52(1): 287-294, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33827187

RESUMO

This study investigated the use of a fixed-dose combination of 30 mg/ml butorphanol, 12 mg/ml azaperone, and 12 mg/ml medetomidine for the standing sedation of captive African elephants (Loxodonta africana). In total, seven females (mean age 19.6 yr; range 6-31 yr) and six males (mean age 33.5 yr; range 9-35 yr) were sedated. The estimated dose was 0.0005 ± 0.0001 ml/kg and 0.006 ± 0.001 ml/cm shoulder height, which resulted in a dose of 0.016 ± 0.002 mg/kg or 0.19 ± 0.04 mg/cm shoulder height butorphanol, 0.006 ± 0.0008 mg/ kg or 0.076 ± 0.015 mg/cm shoulder height azaperone, and 0.006 ± 0.0008 mg/kg or 0.076 ± 0.015 mg/cm medetomidine. First signs of sedation were observed within 3-10 min (mean 6 ± 2 min) after darting, and monitoring of the animals started on average at 24 ± 9 min after darting. No bradycardia was observed in any of the elephants (mean heart rate 40.0 ± 6.55 beats/min), although all the animals were mildly hypotensive (mean blood pressure 118.5/86 [94.5]). Rectal temperatures fell within acceptable ranges, and respiratory parameters were stable in all the animals throughout sedation and fell within the standard ranges reported for conscious, standing elephants. Only one elephant had clinically significant hypoxemia characterized by a partial pressure of oxygen (PaO2) < 60 mm Hg. This elephant was also hypercapnic (PaCO2 > 50 mm Hg), although pH and peripheral capillary oxygen saturation fell within acceptable ranges. None of the elephants reacted to moderately painful stimuli while sedated. The combination was reversed with intramuscular injections of naltrexone (1 mg for every 1 mg butorphanol) and atipamezole (5 mg for every 1 mg medetomidine). Recovery was smooth and calm in all the animals. Time from injection of the reversals until the first signs of recovery was 4.6 ± 2.01 min (range 1-8 min).


Assuntos
Azaperona/administração & dosagem , Butorfanol/administração & dosagem , Fármacos do Sistema Nervoso Central/administração & dosagem , Sedação Consciente/veterinária , Elefantes/fisiologia , Medetomidina/administração & dosagem , Analgésicos Opioides/administração & dosagem , Animais , Combinação de Medicamentos , Feminino , Hipnóticos e Sedativos/administração & dosagem , Masculino , Naltrexona/administração & dosagem , Antagonistas de Entorpecentes/administração & dosagem
16.
Vet Anaesth Analg ; 48(3): 372-379, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33820746

RESUMO

OBJECTIVE: To compare cardiovascular and ventilatory effects, immobilization quality and effects on tissue perfusion of a medetomidine-ketamine-midazolam combination with or without vatinoxan (MK-467), a peripherally acting α2-adrenoceptor antagonist. STUDY DESIGN: Randomized, blinded, crossover study. ANIMALS: A group of nine healthy Patagonian maras (Dolichotis patagonum). METHODS: Maras were immobilized twice with: 1) medetomidine hydrochloride (0.1 mg kg-1) + ketamine (5 mg kg-1) + midazolam (0.1 mg kg-1) (MKM) + saline or 2) MKM + vatinoxan hydrochloride (0.8 mg kg-1), administered intramuscularly. Drugs were mixed in the same syringe. At 20, 30 and 40 minutes after injection, invasive blood pressure, heart rate, respiration rate, end-tidal CO2, haemoglobin oxygen saturation, and muscle oxygenation were measured, arteriovenous oxygen content difference was calculated. Muscle tone, jaw tone, spontaneous blinking and palpebral reflex were evaluated. Times to initial effect, recumbency, initial arousal and control of the head were recorded. Paired t test, Wilcoxon matched-pairs signed rank test and analysis of variance were used to compare protocols; (p < 0.05). RESULTS: Vatinoxan significantly reduced systolic (p = 0.0002), mean (MAP; p < 0.0001) and diastolic (p < 0.0001) arterial blood pressures between 20 and 40 minutes. MAPs at 30 minutes (mean ± standard deviation) with MKM and MKM + vatinoxan were 105 ± 12 and 71 ± 14 mmHg, respectively. Without vatinoxan, four animals were hypertensive (MAP > 120 mmHg), whereas with vatinoxan, four animals were hypotensive (MAP < 60 mmHg). Muscle and jaw tone were significantly more frequently present with MKM (both p = 0.039). Other measurements did not significantly differ between protocols. CONCLUSIONS AND CLINICAL RELEVANCE: In Patagonian maras, vatinoxan attenuated the increase in blood pressure induced by medetomidine. Muscle and jaw tone were more frequently present with MKM, indicating that quality of immobilization with vatinoxan was more profound.


Assuntos
Ketamina , Medetomidina , Animais , Estudos Cross-Over , Frequência Cardíaca/efeitos dos fármacos , Hipnóticos e Sedativos/farmacologia , Imobilização/veterinária , Ketamina/farmacologia , Medetomidina/farmacologia , Midazolam/farmacologia , Quinolizinas
17.
Vet Anaesth Analg ; 48(3): 380-387, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33827780

RESUMO

OBJECTIVE: To assess the efficacy of butorphanol-azaperone-medetomidine (BAM) and butorphanol-midazolam-medetomidine (BMM) protocols for immobilization of wild common palm civets (Paradoxurus musangus) with subsequent antagonization with atipamezole. STUDY DESIGN: Prospective, randomized, blinded clinical trial. ANIMALS: A total of 40 adult wild common palm civets, 24 female and 16 male, weighing 1.5-3.4 kg. METHODS: The civets were randomly assigned for anesthesia with butorphanol, azaperone and medetomidine (0.6, 0.6 and 0.2 mg kg-1, respectively; group BAM) or with butorphanol, midazolam and medetomidine (0.3, 0.4 and 0.1 mg kg-1, respectively; group BMM) intramuscularly (IM) in a squeeze cage. When adequately relaxed, the trachea was intubated for oxygen administration. Physiological variables were recorded every 5 minutes after intubation. Following morphometric measurements, sampling, microchipping and parasite treatment, medetomidine was reversed with atipamezole at 1.0 or 0.5 mg kg-1 IM to groups BAM and BMM, respectively. Physiological variables and times to reach the different stages of anesthesia were compared between groups. RESULTS: Onset time of sedation and recumbency was similar in both groups; time to achieve complete relaxation and tracheal intubation was longer in group BAM. Supplementation with isoflurane was required to enable intubation in five civets in group BAM and one civet in group BMM. All civets in group BAM required topical lidocaine to facilitate intubation. End-tidal carbon dioxide partial pressure was lower in group BAM, but heart rate, respiratory rate, rectal temperature, peripheral hemoglobin oxygen saturation and mean arterial blood pressure were not different. All civets in both groups recovered well following administration of atipamezole. CONCLUSIONS AND CLINICAL RELEVANCE: Both BAM and BMM combinations were effective for immobilizing wild common palm civets. The BMM combination had the advantage of producing complete relaxation that allowed intubation more rapidly.


Assuntos
Azaperona , Combinação de Medicamentos , Medetomidina , Viverridae , Animais , Azaperona/farmacologia , Butorfanol/farmacologia , Feminino , Frequência Cardíaca/efeitos dos fármacos , Hipnóticos e Sedativos/farmacologia , Imobilização/veterinária , Masculino , Medetomidina/farmacologia , Midazolam/farmacologia , Estudos Prospectivos
18.
Lab Anim ; 55(5): 443-452, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33645310

RESUMO

Alpha2 receptor agonists (alpha2-agonists) are useful sedative and analgesic agents in sheep, but have adverse pulmonary effects, which are reportedly similar between different alpha2-agonists. This randomized crossover study compared pulmonary function after intravenous administration of an alpha2-agonist, either xylazine or an equipotent dose of medetomidine in 34 female sheep anaesthetized twice. Pulmonary function was assessed using spirometry, volumetric capnography, arterial blood gas analysis 1 min prior to, and 5 and 10 min after administration of the allocated alpha 2 agonist drug. Pulmonary structural changes were subsequently assessed using computed tomography (CT). Tachypnoea or hypoxaemia prompted reversal with atipamezole and exclusion of data. Data were analysed for a fixed effect of drug using a mixed effect linear model with significance set at p < 0.05. Ten sheep administered xylazine required atipamezole while none of sheep receiving medetomidine did. Xylazine produced significantly higher respiratory frequency, airway pressures, airway resistance and arterial carbon dioxide (CO2), and lower dynamic compliance, tidal volume, CO2 elimination and end tidal CO2 tension and arterial oxygen tension than medetomidine. This was associated with a significantly lower % of aerated tissue and higher % poorly and non-aerated tissue in CT images of sheep receiving xylazine versus medetomidine. In conclusion, xylazine administration produced marked decreases in pulmonary function, in ventilated isoflurane anaesthetized sheep, when compared to an equipotent dose of medetomidine when administered as an intravenous bolus supporting the use of medetomidine when alpha2-agonists are required.


Assuntos
Isoflurano , Medetomidina , Animais , Estudos Cross-Over , Feminino , Frequência Cardíaca , Hipnóticos e Sedativos , Injeções Intravenosas , Isoflurano/farmacologia , Medetomidina/farmacologia , Ovinos , Carneiro Doméstico , Xilazina/farmacologia
19.
Vet Med Sci ; 7(4): 1090-1095, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33751831

RESUMO

BACKGROUND: A great number of sedatives and anaesthetics have been used to perform surgeries or routine ophthalmologic examinations in animals and sometimes the combination of these medicines has more suitable effects than each one alone. OBJECTIVES: This paper aims to explore the main effects of Medetomidine + Acepromazine, Dexmedetomidine + Acepromazine on intraocular pressure, tear secretion and pupil diameter. METHODS: To accomplish the aforementioned aim, 32 adult dogs (aged one-to-three-years-old) were clinically examined. Dogs were divided into four groups consisting of group DA, Dexmedetomidine (5 µg/kg) + Acepromazine (0.05 mg/kg); Group D, Dexmedetomidine (5 µg/kg); Group M, Medetomidine (10 µg/kg); Group MA, Medetomidine (10 µg/kg) + Acepromazine (0.05 mg/kg). The ocular factors including tear production, pupil diameter and intraocular pressure of both right and left eyes were first measured and then recorded in each dog at time T0 (-15 min). Afterwards, the drugs were administered intramuscularly, based on which the ocular factors were re-measured at T1 (+5 min), T2 (+15 min) and T3 (+20 min). All four groups showed a reduction in intraocular pressure, which was significant in DA, D and M groups. RESULTS: Furthermore, there was a fluctuation in the amount of tear secretion in DA and D groups (increase and then decrease), as well as a significant reduction in M and MA groups. Decreasing in pupil diameter also occurred in all four groups, but the reduction was significant only in DA and MA groups. CONCLUSION: According to the results obtained, as the changes caused by the systemic administration of the above drug compounds did not exceed the physiological range, it can be concluded that these combinations could be utilized as suitable sedatives or pre-anaesthetic compounds in the eye surgeries.


Assuntos
Acepromazina/efeitos adversos , Dexmedetomidina/efeitos adversos , Hipnóticos e Sedativos/efeitos adversos , Pressão Intraocular/efeitos dos fármacos , Medetomidina/efeitos adversos , Pupila/efeitos dos fármacos , Lágrimas/efeitos dos fármacos , Animais , Cães , Combinação de Medicamentos , Pupila/fisiologia , Lágrimas/metabolismo
20.
Vet Anaesth Analg ; 48(3): 393-397, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33678574

RESUMO

OBJECTIVE: To evaluate the effects and utility of tiletamine-zolazepam-medetomidine (TZM) and ketamine-medetomidine (KM) for anesthesia of Amur leopard cats (Prionailurus bengalensis euptailurus). STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: A total of six female (3.70 ± 0.49 kg) and six male (5.03 ± 0.44 kg; mean ± standard deviation) Amur leopard cats aged 2-6 years. METHODS: Each animal was administered four protocols separated by ≥3 weeks. Each protocol included medetomidine (0.05 mg kg-1) combined with tiletamine-zolazepam (1 mg kg-1; protocol MTZLO); tiletamine-zolazepam (2 mg kg-1; protocol MTZHI); ketamine (2 mg kg-1; protocol MKLO); or ketamine (4 mg kg-1; MKHI) administered intramuscularly. At time 0 (onset of lateral recumbency) and 30 minutes, heart rate (HR), respiratory rate (fR), rectal temperature, noninvasive mean arterial pressure (MAP) and hemoglobin oxygen saturation (SpO2) were recorded. Times to onset of lateral recumbency, duration of anesthesia and time to standing were recorded. RESULTS: Overall, animals were anesthetized with all protocols within 10 minutes, anesthesia was maintained ≥57 minutes, and recovery (time from the first head lift to standing) was completed within 5 minutes. During anesthesia with all protocols, HR, fR, rectal temperature, SpO2 and MAP were 99-125 beats minute-1, 33-44 breaths minute-1, 37.6-39.4 °C, 90-95% and 152-177 mmHg, respectively. No adverse event was observed. CONCLUSIONS AND CLINICAL RELEVANCE: TZM and KM at various dosages resulted in rapid onset of anesthesia, duration of >57 minutes and rapid recovery without administration of an antagonist. Accordingly, all these combinations are useful for anesthetizing Amur leopard cats and for performing simple procedures. However, the low doses of the anesthetic agents are recommended because there was no difference in duration of anesthesia between the dose rates studied.


Assuntos
Anestésicos , Ketamina , Anestésicos/farmacologia , Anestésicos Combinados/farmacologia , Animais , Combinação de Medicamentos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Ketamina/farmacologia , Masculino , Medetomidina/farmacologia , Estudos Prospectivos , Tiletamina/farmacologia , Zolazepam/farmacologia
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