Search Results (18)

Four entire male sugar gliders (Petaurus breviceps) belonging to the same colony were presented for elective orchiectomy. After clinical examination, dexmedetomidine (120 μg/kg) in combination with ketamine (5 mg/kg) were administered subcutaneously (SC). Once righting and pedal withdrawal reflexes were lost, ringer lactate solution, enrofloxacin and meloxicam were administered SC and a bilateral intratesticular block with lidocaine 0.25% was performed. Heart, respiratory rates and pulse oximetry values were recorded every minute. Onset of sedation, additional use of isoflurane, duration of anaesthesia, duration of surgery, time of recovery after atipamezole administration, quality of recovery and time of food intake were recorded. Postoperative assessment (posture, level of activity, vocalisation, response to manipulation, attention to the surgical wound) was performed hourly until discharge, five hours after surgery. Dexmedetomidine in combination with ketamine provided adequate short-lasting anaesthesia for castration in 3 out of 4 sugar gliders. One sugar glider needed additional isoflurane administration to perform orchiectomy. No perioperative additional analgesia was needed in any sugar glider. Full article

Jaguars play a crucial role in population control across multiple biomes. They are endangered and protected by in situ and ex situ conservation mechanisms to ensure their conservation. Cardiovascular diseases in wild mammals, including jaguars, often have unclear etiopathogenies, underscoring the need for research into novel hemodynamic parameters. This study evaluates the cardiovascular health of fifteen clinically healthy jaguars using conventional and Holter electrocardiography, non-invasive systemic blood pressure measurement, and echocardiography. Chemical restraint was achieved with medetomidine (0.08–0.1 mg/kg) and ketamine (5 mg/kg), with anesthesia reversed using atipamezole (0.25 mg/kg). The average heart rate was 72 ± 18 bpm, with sinus rhythm in ten animals and sinus arrhythmia in five. Six animals exhibited first and second-degree atrioventricular blocks, one had supraventricular complexes, and another had premature ventricular complexes. Non-invasive systolic blood pressure remained stable at 163 ± 29 mmHg during anesthesia. Echocardiographic examination revealed mitral, tricuspid, pulmonary, and aortic valve insufficiencies via color Doppler. The transmitral flow showed a normal E/A ratio and E` < A`, suggesting a pseudonormal ventricular filling pattern. No significant anesthetic complications were observed, affirming the protocol’s safety. This study provides valuable data, validating the anesthetic protocol and establishing reference cardiovascular values for jaguars, thus paving the way for future research in other veterinary species. Full article

Formosan serows are an endemic species in Taiwan. Alfaxalone, a γ-aminobutyric acid_A agonist, induces or maintains anesthesia in various veterinary species with reported potential adverse effects of respiratory depression and tachycardia. α2-Adrenoceptor agonists exert sedative and muscle relaxation effects, along with substantial cardiovascular adverse effects. Here, we aimed to evaluate the anesthetic effects of alfaxalone combined with xylazine or dexmedetomidine (AX vs. AD, respectively) in Formosan serows. In this randomized, masked study, AX was administered to four serows, and AD was administered to five serows intramuscularly via blow dart. The time and score of induction and recovery were recorded. Post-intubation, isoflurane was administered for maintenance anesthesia. Heart rate (HR), respiratory rate (RR), peripheral saturation of oxygenation (SpO₂), rectal temperature (RT), and end-tidal CO₂ (EtCO₂) were recorded every five to eight minutes. Atipamezole and tolazoline were administered to antagonize dexmedetomidine and xylazine post-procedure, respectively. Both combinations allowed smooth induction and recovery. The AD group exhibited significantly lower HR and SpO₂ and significantly higher RT and EtCO₂ than the AX group (both p < 0.01). The AD-treated serows exhibited notable muscle rigidity after induction and significant hypoventilation and hypoxemia during the procedure. Although alfaxalone combined with dexmedetomidine or xylazine can produce satisfactory induction and recovery in Formosa serows, notable hypoxemia and hypoventilation are induced by the alfaxalone–dexmedetomidine combination compared to the alfaxalone–xylazine combination. Full article

Anaesthesia is sometimes required for the effective restraint of laboratory pigs for sample collection. Yet, anaesthesia can initiate a range of physiological disruptions that can increase variability in study data and lead to poorer animal welfare. Judicious use of anaesthesia can mitigate experimental, human safety, and animal welfare concerns, but it does not eliminate the potential for adverse effects. The use of reversal agents can shorten recovery time and reduce the physiological impacts of anaesthesia but can also cause additional side effects. We, therefore, trialled the use of low-dose atipamezole (0.12 mg/kg) for the antagonism of xylazine in laboratory pigs anaesthetised using a combination of xylazine and zolazepam/tiletamine. We measured time to recovery, selected clinical variables, recovery characteristics, and behaviours to investigate if a low dose of antagonist decreased recovery time and reduced the physiological impacts of anaesthesia whilst avoiding adverse negative side effects. We categorised side effects and behaviours as having either a low or high negative welfare impact based on the potential risk of injury and whether behaviours were displayed before or after return to consciousness. Collectively, our results indicated that while the use of low-dose atipamezole decreased recovery time and improved thermoregulation in most pigs, it introduced and exacerbated adverse side effects and behaviours that can lead to poorer welfare outcomes for laboratory pigs. Full article

Anesthesia protocols in laboratory-held rhesus macaques (Macaca mulatta) are well described, but fewer reports exist in zoo, safari park or field environments. This study recorded and compared the level of sedation, heart rate (HR), respiratory rate (RR), and induction and recovery times of ketamine–medetomidine (KM), ketamine–dexmedetomidine (KD) and ketamine–xylazine (KX) protocols in ninety-five safari-park-managed rhesus macaques. In total, 31 animals received the KM protocol, which included 25 mg ketamine (6.08 ± 1.54 mg/kg) and 0.15 mg medetomidine (0.04 ± 0.01 mg/kg); 33 animals received the KD protocol, which included 25 mg ketamine (6.19 ± 2.42 mg/kg) and 0.08 mg dexmedetomidine (0.02 ± 0.01 mg/kg); and 31 animals received the KX protocol, which included 50 mg ketamine (12.64 ± 3.79 mg/kg) and 1.2 mg xylazine (0.30 ± 0.09 mg/kg). Anesthesia was reversed with atipamezole. The mean bodyweight of the study population was lower than expected, so actual doses were higher than intended; no adverse effects were reported. Induction and recovery times were longer for KX than KD or KM (p < 0.05) but did not differ significantly between KD and KM (p > 0.05). HR and RR did not differ between protocols (p > 0.05). Sedation score was negatively correlated with bodyweight, and mean sedation score was lower for KX than KM or KD. KD and KM provided more rapid and reliable sedation than KX at the doses described; however, alterations in the KX dose may improve reliability. Full article

Formosan serows are endemic to the mountainous regions of Taiwan. This crossover study aimed to assess and compare the anesthetic induction and recovery using either dexmedetomidine–tiletamine–zolazepam (DZ) or dexmedetomidine–ketamine (DK) by intramuscular injection from a blow-dart in a zoo environment. Ten anesthetic procedures were performed with five adult Formosan serows. Each participant was anesthetized with both combinations at least once with a minimal 12-month washout. The average dosages were 22.6 ± 8.3 µg/kg and 35.8 ± 2.5 µg/kg for dexmedetomidine and 185.6 ± 123.6 and 357.8 ± 25.2 µg/kg for atipamezole for the DZ and DK groups, respectively. The doses of tiletamine–zolazepam and ketamine were 2.1 ± 0.25 mg/kg and 3.6 ± 0.3 mg/kg, respectively, in the DZ and DK groups. All participants were induced within 10 min (median: 8 min for both groups), except one serow in the DK group with an induction time of 22 min. Serows in the DZ group had a lower respiratory rate (p = 0.016) and lower rectal temperature (p = 0.008) than those in the DK group. The quality of recovery was poor for DZ because of paddling, prolonged recovery, and ataxia after antagonism of dexmedetomidine with atipamezole. The induction of anesthesia with dexmedetomidine–tiletamine–zolazepam was uneventful and rapid. However, recovery from this combination was not smooth. Full article

Dexmedetomidine is an a₂-agonist commonly used in veterinary practice. Occasionally, the administered dose of dexmedetomidine may result in insufficient sedation, and an additional dose or drug may be required. The sedative effects of seven different drugs administered at subsequent time points after an initial, insufficient dose of dexmedetomidine were evaluated. Seven adult cats participated in this crossover, blind, randomised study. The groups consisted of two consecutive doses of dexmedetomidine (15 + 10 μg/kg) (DD) or a dose of dexmedetomidine (15 μg/kg) followed by either NS 0.9% (DC-control group), tramadol 2 mg/kg (DT), butorphanol 0.2 mg/kg (DBT), buprenorphine 20 μg/kg (DBP), ketamine 2 mg/kg (DK), or midazolam 0.1 mg/kg (DM). Sedation was evaluated using the Grint sedation scale. In all groups, atipamezole was administered at the end of the evaluation, and recovery was assessed using the Lozano and Sams recovery scales. The DC and DM groups exhibited minimal sedative effects. The maximum sedative effect was observed in the DD and DK groups, while sedation in the DD and DK groups was significantly higher compared to the DC group. Recovery in all groups was uneventful, except in the DM group, where it was prolonged and difficult, although no statistically significant difference was detected. Therefore, insufficient sedation with dexmedetomidine can be enhanced by a subsequent dose of dexmedetomidine, ketamine, or butorphanol, whereas the addition of midazolam reduces sedation and prolongs recovery. Full article

This study aimed to assess the impact of dexmedetomidine constant rate infusion (CRI) on key parameters in dogs. Six dogs received a 60 µg/kg/h dexmedetomidine infusion over 10 min, followed by three 15 min decremental CRIs (3, 2, and 1 µg/kg/h). A subsequent reversal phase employed 600 µg/kg/h atipamezole over 5 min. Continuous electroencephalogram (EEG) assessment, and cardiorespiratory and analgesia monitoring (every 3 min) were conducted, including analgesia evaluation through responses to electric stimulation. Dexmedetomidine induced profound sedation, evidenced by lateral recumbency and immobility. Patient State Index (PSI) decreased from awake (90.4 ± 4.3) to Phase 1 (50.9 ± 30.7), maintaining sedation (29.0 ± 18.1 to 33.1 ± 19.1 in Phases 2–4). Bradycardia (37.8 ± 3.5 bpm, lowest at Phase 3) and hypertension (133.7 ± 17.0 mmHg, highest at Phase 1) were observed, with minimal analgesia. Atipamezole promptly reversed sedation, restoring cognitive function (tail wagging behavior), and normalizing cardiovascular parameters. During atipamezole CRI, the EEG exhibited a transition from delta waves to alpha and low beta waves. This transition was observed alongside gradual increases in PSI and electromyographic activities. Additionally, spindle activities disappeared during this process. This study’s results suggest potential clinical utility for EEG-guided dexmedetomidine sedation with reversal using atipamezole, warranting further investigation. Full article

Sex identification through coelioscopy is a minimally invasive surgical technique used to determine the sex of chelonians by directly visualizing their internal reproductive organs. An adequate anaesthesiologic plan is essential to guarantee patient immobilization and proper analgesia during the entire surgical procedure. In this study, we evaluated the effects of a combination of dexmedetomidine (0.05 mg/kg), midazolam (1 mg/kg), ketamine (8 mg/kg), and morphine (1 mg/kg) (DMKM) randomly delivered intramuscularly (IM) or subcutaneously (SC) in twenty-one Aldabra giant tortoise (Aldabrachelys gigantea) into the right antebrachium for celioscopic sex identification. Heart rate (HR), respiratory rate (RR), and body temperature (BT) were measured, along with the skeletal muscle tone of the thoracic and pelvic limbs, neck retraction reflex, palpebral reflex, and jaw tone every 15 min. The anaesthesiologic plan was considered to be adequate at the loss of the thoracic and pelvic limb retraction reflexes. After a 45 min interval, if the anaesthetic plan was deemed insufficient for the celioscopic procedure, a 5 mg/kg dose of propofol was administered intravenously into the subcarapacial venous plexus. At the end of the procedure, atipamezole (0.5 mg/kg) and flumazenil (0.05 mg/kg) were administered intramuscularly into the left antebrachium as reversal agents. Both HR and RR decreased from baseline to both 15 and 30 min. Due to the persistence of thoracic and pelvic limb retraction reflexes 45 min after DMKM administration, 6/11 (55%) cases in the SC group required the additional administration of propofol, in contrast to only 1/10 (10%) cases in the IM group (p = 0.05). The recovery times were comparable between the successfully induced animals in the IM and SC groups. In this study, the intramuscular administration of a DMKM combination quickly produced chemical restraint, suitable for celioscopic sex determination. Full article

A non-invasive method of drug delivery, intranasal atomization, has shown positive results in human medicine and in some animal species. The objective of this study was to evaluate the effects of intranasal atomization, compared to intramuscular administration, of a mix of anesthetic drugs in pet rabbits. In total, 104 mixed-breed pet rabbits, undergoing various types of surgery, received a combination of ketamine, medetomidine, and butorphanol (20, 0.4, and 0.2 mg/kg) by intranasal atomization using a Mucosal Atomization Device (Group MAD) or intramuscular administration (Group IM). When required, isoflurane was dispensed through a face mask. At the end of the procedures, atipamezole was administered using the same routes in the respective Groups. There were no differences in time to loss of righting reflex between the groups, while differences were found for the need for isoflurane (higher in Group MAD) and recovery time, occurring earlier in Group MAD. The results suggest that intranasal atomization of a combination of ketamine, medetomidine, and butorphanol produces a lighter depth of anesthesia in pet rabbits, compared to intramuscular administration. Intranasal atomization can be performed to administer sedative and anesthetic drugs, avoiding the algic stimulus related to the intramuscular inoculation of drugs. Full article

This study aimed at describing the change in echocardiographic variables after high-dose medetomidine and the reversal with atipamezole in six cats undergoing sedation for semen collection. Further cardiac Troponin I (cTnI) concentration and the effect of repeated sedation were assessed. Echocardiography was performed before and 20 min after sedation with 0.1 mg/kg medetomidine intramuscularly (IM) for urethral catheterisation. Prior to epididymectomy, S-ketamine was administered intravenously. Twenty minutes after reversal with 0.5 mg/kg atipamezole IM, the third echocardiography was performed. Sedation with medetomidine and reversal with atipamezole was repeated on day 7, 14, 21 and 28. Heart rate (HR) and rhythm were monitored throughout all sedations. On day 0 and 28 cTnI concentrations were measured before and after the procedure. After normality testing, the values were compared over time. The administration of medetomidine led to a marked reduction in HR, cardiac output and ventricular systolic function and a significant increase in left ventricular dimensions. Rhythm abnormalities, such as ventricular premature complexes and idioventricular rhythm, could be observed. The administration of atipamezole completely reversed sedation and the changes in haemodynamic variables. No significant increase in cTnI concentrations could be detected, although two out of six cats showed values above the reference range. Full article

This study aimed to evaluate the effects of sedation and anesthesia on Feline Grimace Scale^© (FGS) scores. Twelve healthy cats were included in a prospective, blinded and randomized, cross-over study with a 14 day wash-out. Saline or dexmedetomidine-butorphanol (Dex-But) was administered intramuscularly before an anesthetic induction with propofol and maintenance with isoflurane. Saline or atipamezole (Dex-But) was administered at the end of the general anesthesia. Video-filming/image capturing was performed before and up to 24 h post-anesthesia. A total of 125 images were evaluated by four raters blinded to the treatment groups using the FGS (ear position/orbital tightening/muzzle tension/whiskers change/head position; action units (AU); scores 0–2 for each AU). The effects of the sedation/anesthesia were analyzed (p < 0.05). The total FGS and each AU scores were significantly higher with Dex-But than with saline 20 min post-sedation. In the saline group, the total FGS, orbital tightening, and whiskers and head position scores were significantly higher than baseline at 0.5 h post-anesthesia. In the Dex-But group, the total FGS and each AU scores were significantly higher after sedation, whereas the orbital tightening scores were significantly higher at 0.5 h post-anesthesia when compared with the baseline. None of the other comparisons between or within the groups was significantly different. The sedation with dexmedetomidine-butorphanol and anesthesia with propofol-isoflurane changed the FGS scores on a short-term basis; consequently, they may bias acute pain assessment. Full article

This study investigated the sedative effects of dexmedetomidine in Asian elephants. We hypothesized that 2 µg/kg dexmedetomidine would provide sufficient standing sedation. A crossover design study was performed in three Asian elephants. Each elephant was assigned to 1 of 3 treatment groups—1 (D1), 1.5 (D1.5) or 2 (D2) µg/kg dexmedetomidine (intramuscular injection, IM) with a two-week ‘washout period’ between doses. Elephants were monitored for 120 min. At 120 min (Ta), atipamezole was administered IM. Sedation and responsiveness scores were evaluated. Physiological parameters (pulse rate, respiratory rate, and %SpO₂) and clinical observations were monitored during the study and for 3 days post drug administration. D2 provided the longest sedation (approximately 70 min), compared to D1 and D1.5. After Ta, each elephant’s sedative stage lessened within 10–15 min without complications. No significant abnormal clinical observations were noted throughout and during the 3-days post study period. These data suggest that a single 2 µg/kg IM dexmedetomidine injection provides sufficient standing sedation for approximately 70 min in Asian elephants. Full article

Alpha₂ receptor agonists are frequently used to provide sedation and analgesia in sheep. There are numerous reports of adverse pulmonary effects following intravenous (IV) injection; however, adverse effects following subarachnoid injection (SAI) are underreported. An adult Merino wether was one of eighteen animals anaesthetised during an experimental trial modelling intervertebral disc injury. The animal was premedicated with methadone 0.1 mg/kg and midazolam 0.3 mg/kg IV. Anaesthesia was induced using alfaxalone IV and it was maintained using isoflurane, delivered in 100% oxygen by controlled mechanical ventilation. An SAI of xylazine 0.05 mg/kg diluted to 1 mL with 0.9% saline was performed at the lumbosacral site prior to recovery. This resulted in rapid narcosis, oxygen dependency and ventilatory compromise. Treatment with frusemide 1 mg/kg IV and salbutamol 0.2 mg inhaled did not attenuate the adverse cardiopulmonary effects. A rapid improvement in all physiological variables was seen following high dose atipamezole 0.05 mg/kg IV. This case report adds to the current knowledge regarding the risk for potential side effects when using alpha₂ receptor agonists, such as xylazine, for the sedation or regional analgesia in sheep. Full article

It has been reported that α₂-adrenoceptor agonists such as medetomidine decrease tear flow in many species, including rats. Few studies have investigated the involvement of α₂-adrenoceptor in decreased tear flow; the issue has not been illustrated sufficiently. Therefore, we aimed to investigate the effect of different doses of atipamezole on the reversal of medetomidine-induced tear-flow decrease to reveal the specific involvement of α₂-adrenoceptor. Treatment with 400, 800, or 1600 µg/kg atipamezole (or saline as the control) was intramuscularly administered to rats 15 min following intramuscular administration of 200 µg/kg medetomidine. After medetomidine administration, tear flow was measured using a phenol red thread test (PRTT). PRTT values decreased significantly after 200 µg/kg medetomidine administration. The PRTT values after 800 (optimal dose to reverse) and 1600 µg/kg atipamezole administration reached baseline, but never exceeded it significantly. Treatment with 400 µg/kg atipamezole also reversed the decrease in PRTT value but the PRTT remained lower than baseline. The optimal dose and the higher dose of atipamezole fully reversed the medetomidine-induced decrease in tear flow to the baseline level in rats, while the lower dose of atipamezole partially recovered tear flow. Full article